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Volume 90-B, Issue SUPP_I March 2008

SK Gupta TDA Cosker KJJ Tayton

A study of 50 consecutive osteoporotic pelvic rami fractures has been carried out to investigate the full extent of injury following low energy falls.

50 consecutive elderly patients with fresh fractures of the pelvis were each investigated with an MRI scan of the pelvis in order to assess the competency of the pelvic ring. The 50 patients consisted of 45 female and 5 males with a mean age of 77.7 years. 44 patients had unilateral pubic rami fractures. The mechanism of injury in all cases was a simple fall in the home environment. On admission 96% of the patients complained of sacral pain and were tender in the sacral or posterior pelvic region. On MRI, 90% of patients had a sacral fracture associated with the pubic rami fractures and in all but 4 of these the posterior pelvic pain was directly related to the sacral fracture site. At 6 month follow-up, 82% still complained of posterior pelvic tenderness. Areas of tenderness corresponded to the sites of the fractures. Before the injury, 38 of the final 44 reviewed were reasonably independently mobile, whilst at review 39 were significantly disabled.

Conclusion: The study shows that the apparently benign traumatic pelvic rami fracture in the elderly has a high association with sacral fractures. After discharge from hospital, attention should be paid to treatment of the on-going anterior and posterior pelvic pain.


A Upadhayay L Maini P Jain S Kapoor

Twenty one cases of ipsilateral hip and femoral shaft fractures, between January 1998 and December 2001, managed by reconstruction nail were reviewed. All patients underwent simultaneous surgery for both fractures and operative treatment was executed as early as general condition of the patient permitted. Delay in treatment was generally because of associated injuries [head, chest or abdominal]. There were 20 males and 1female patients with an average age of 34.5 years. There was delayed diagnosis of neck fracture in 2 cases and these cases were not included in the study.

Our average follow-up is 30.9 months. There was one case of nonunion of a femoral neck fracture, one case of avascular necrosis and one neck fracture that united in varus. There were 4 nonunions and 6 cases of delayed union of femoral shaft fractures. Mean time for union of femoral neck fracture was 15 weeks and for shaft fracture was 22 weeks. In our results, shaft fracture determined the total union period. Though complications involving the femoral shaft fracture were greater than the femoral neck fractures, the shaft complications were more manageable compared to neck complications. This stresses the need to realize the significance and seriousness of both components of this complex injury, in evaluation, management and postoperative care.

Conclusion: Though technically demanding the reconstruction nail is an optimal alternative for management of concomitant fracture of femoral neck and shaft with low rates of complications and good results.


AA Syed M Agarwal PV Giannoudis SJE Matthews RM Smith

We prospectively studied 29 patients with distal femoral fractures stabilised using the less invasive stabilisation system [LISS]. Four patients were excluded from the final follow up [3 deaths and 1 case of quadriplegia]. The mean age of the remaining 25 patients [9 males] was 60.9 years and the mean follow up 18 months [12–24]. Eleven patients were tertiary referrals from other hospitals [7 cases were referred due to failure of primary fixation]. Overall, there were 12 cases of high-energy trauma [7 open fractures]. According to the AO classification there were 5 Type 33A, 2 Type 33B and 12 Type 33C fractures and 4 Type 32A, 1 Type 32B, 1 Type 32C fractures. Functional assessment was performed using the Modified HSS and the Schatzker and Lambert scores. The average time to union in 22 cases was 3.5 months [range, 2–5]. None of the acute cases required bone grafting with a 100% union rate. There were 3/7 cases of non-union in the salvage group still undergoing treatment. The overall results in the acute cases were good and in the salvage cases fair. While this is a small series of patients, our preliminary data indicate favourable results using the LISS in stabilizing acute distal femoral fractures. However, when the LISS is used as a revision tool despite the concept of preserving the bone biology, the results seem to be less satisfactory. The system appears to be user friendly and no technical difficulties were encountered.


R Raman SJE Matthews PV Giannoudis

We have reviewed the patients with vertical shear fractures of the Pelvis and report on our treatment protocol and long-term functional outcome.

Methods: Between January 1993 and January 2002, out of 581 pelvic ring injuries treated in our unit, we identified 31 vertical shear fractures in 29 (4.9%) patients (4 female). Data such as age, sex, aetiology, associated injuries, ISS, resuscitation and transfusion requirements were recorded. ICU/HDU stay, surgical stabilization, urological injuries, systemic complications, neurological injury and mortality were recorded and analysed. Functional outcome was assessed using the following generic tools: EuroQol EQ-5D, SF36v2, SMFA, Majeed score and VAS.

Results: The mean age was 43.5 (16–71). The median ISS was 22 (12–32). Motorcycle accidents were responsible for 27%. Associated injuries included the chest (12 patients), abdomen (8 patients) and extremities (14 patients). Urethral injury was present in 9 and ruptured viscus was identified in 3 patients. Neurologic deficit was present in 9 cases. Posterior ring was stabilized in 3 (0 – 13) days. 6 patients developed systemic complications – ARDS in 4 (12%) patients, sepsis in 2 (6%). The mean follow up was 39 (12–101) months. Functional outcome using the Majeed score revealed that one-third of the patients were fair. SF-36 (physical and mental scores) and EQ 5-score revealed that one-third of the patients were fair. SF-36 (physical and mental scores) and EQ 5-score revealed that one-third of the patients were fair. SF-36 (physical and mental scores) and EQ 5- D revealed a moderate functional outcome. The SMFA and the visual analogue score also revealed similar outcomes.

Conclusion: Prompt resuscitation and early temporarily stabilization of the pelvic ring is essential. Sound reconstruction of the pelvic ring is not always associated with good results, probably due to the extensive pelvic floor trauma seen in this series of patients. Younger individuals seem to have a relatively better outcome when compared to the older age group.


A Kumar NA Shah SA Kershaw AD Clayson

Delays in the surgical treatment of acetabular fractures often results in extensile or combined approaches being required. This study reports the outcome from a regional centre aiming to treat these fractures via a single surgical approach where possible.

Seventy-two patients (73 displaced acetabular fractures) with an average age of 39.5 years (range 15–76 years) were studied with an average follow up period of 45.5 months (range 24–96). All radiographs were reviewed together with a full clinical assessment of each patient including the Harris Hip Score.

Thirty-four fractures were simple and 39 were complex including 27 both column fractures. Eight were noted to have an associated injury to the femoral head. The average time from injury to surgery was 11.7 days (range 1–35 days) with 80 percent of cases being operated on within two weeks after injury.

In 67 fractures (92%), including 24 both column fractures, a single approach alone was used (Anterior Ilioin-guinal 26 cases; Posterior Kocher-Langenbeck 41 cases). Five fractures needed an extensile triradiate approach and only one case required a combined anterior and posterior approach. A congruent reduction (gap or step of 2mm or less) was achieved in 65 cases (89%). Functional outcome was good with an average Harris Hip Score of 85 (range 20–100). There were 2 cases of deep infection (2.7%) and 4 patients (5.5%) required later hip replacement. There were no cases of venous thrombosis. Twenty cases exhibited heterotopic ossification of varying degree but none of these were grade IV.

Conclusion: In most cases, internal fixation of a displaced acetabular fractures is possible via a single surgical approach. Morbidity and complications are much reduced but single approach surgery requires that patients are assessed and treated early and prompt referral to a specialist unit is recommended.


K Sehat R Baker R Price G Pattison W Harries TJS Chesser

We report the results of the use of the Long Gamma Nail in the treatment of complex proximal femoral fractures in our hospital.

All patients at one hospital treated with the Long Gamma Nail were reviewed. Information collected included the age, sex, type of injury, fracture classification, intra-operative complications, post-operative complications, and survival of the implant and patient.

One hundred nails were reviewed which were inserted in 97 patients. 70 patients were followed up for 1 month or more and their mean follow up was 8 months (range 3 months to 6 years). The mean age was 74 (range 16–98). Twenty were inserted into femurs with metastatic malignancy and four patients were victims of poly-trauma. The average length of the operation was 2 hours 22 minutes. Blood transfusion was required in 74% and on average was 2.5 units. There were 7 significant complications. Five patients underwent revision, 2 to Total Hip Arthroplasty after proximal screw migration and 2 patients required exchange nailing. There was one broken nail and two peri-prosthetic fractures at the tip of the nail.

Success was defined as achievement of stability of fracture until union or death; this was achieved in 15% of cases. The mortality was 7% at 30 days and 17% at one year. One death was directly related to the nail and the rest due to medical co-morbidities. Complication rate fell with increasing experience in the unit. The training of surgeons had no detrimental effect on outcome.

Complex proximal femoral fractures including pathological lesions, subtrochanteric fractures and pertrochanteric fractures with subtrochanteric extensions are difficult to treat, with all implants having high failure rates. The long gamma nail allows early weight bearing and seems effective in treating these difficult fractures. Furthermore the majority of these unstable fractures tend to occur in the very elderly with osteoporosis and other medical co-morbidity. Care should be taken to avoid malpositioning of the implant, as this was the major cause of failure and revision. The length of time surgery may take and the anticipated blood loss should not be underestimated especially when dealing with challenging fractures in frail and elderly patients or those with medical co-morbidity.


SP Trikha S Singh AJ Edge

We describe the clinical and radiological results of thirty eight consecutive total hip replacements, using the JRI Furlong Hydroxyapatite ceramic coated femoral component (JRI Instrumentation Ltd, London, UK) in patients under the age of 50 at the time of surgery. The mean age at the time of operation was 42 years (range 22 to 49 years). The average length of follow up was 10 years (range 63 to 170 months). All patients receiving a Furlong HAC THR were included regardless of their primary aetiology. These included patients on whom previous hip joint surgery had taken place.

The mean Harris hip score improved from 44 pre-operatively to 92 at the latest post-operative review. The mean WOMAC and Oxford scores at the latest review for this study were 29 and 16 respectively. Using the Charnley modification of the Merle d’Aubign_ and Postel hip score, at the latest follow up the mean scores were as follows: Pain 5.37, Function 5.47, and Range of Motion 5.71.

The mean pain visual analogue score was 1.1 and 94% of patients returned to outdoor activities or sports. There were no reports of thigh pain at any review. There was no loss to follow-up. There were no revisions of any femoral component. Radiological review of the femoral components revealed no continuous or progressive radiolucent lines around the stem. No osteolysis was noted. Using revision or impending revision as the end point at 12 years the cumulative survival for the stem was 100% (95% CI 89 to 100).

We present excellent clinical, radiological and survivrship results with the use of HAC components in young, active patients with varying primary pathology, after ten years use.


MM Mullins W Norbury JK Dowell M Heywood-Waddington

We present the results of 228 consecutive Charnley low friction arthroplasties, inserted in 193 patients between July 1972 and December 1976. All hips were inserted by the posterior approach without trochanteric osteotomy. All patients were enrolled into a prospective study and pre-and post-operative findings recorded. This series was reviewed in 1985 and once again in 2002.

The pre-and peri-operative findings are similar to contemporary series. Due to our stable population only two patients were lost to follow-up. Our survivorship results show a 10-year survival of 93%, 20-year survivorship of 84% deteriorating to a 30-year survival of 73%.

Of the 26 hips revised 6 were for recurrent dislocations and these were satisfactorily stabilised using acetabular augments. There were 8 revisions for fracture of the femoral component (all flatbacks), 8 revisions for aseptic loosening of the femoral component and 6 revisions for aseptic loosening of the acetabulum. There was one revision for deep infection and the remaining 3 were for periprosthetic fractures.

The survivors were scored clinically using the Merle d’Aubign-Postel score with a mean value of 12. None of the survivors were on the waiting list for revision arthroplasty or felt that it was indicated.

Overall our results are comparable to other studies and vindicate the choice of approach, which at the time was a source of some controversy


PC Birch A Wafai PW Howard

We reviewed 158 hip replacements performed using the Exeter® stem between 1992 and 1996. The operations were performed using third generation cementation and the majority using medium viscosity Simplex cement via a posterior approach. Per-operative complications [shaft fracture etc] were not seen.

Using stem revision as an endpoint, only one stem has been revised [0.6%] for aseptic loosening, and one for sepsis. Aseptic asymptomatic loosening was observed in a further 4 patients [2.5%]. Stem subsidence was seen in the majority [81%], but none greater than 3mm [mean 1.4mm]. Other complications were rare.

This medium term review confirms that the Exeter® stem is a prosthesis with excellent results. This is one of the first series published outside Exeter to confirm their reported results.


NJ Talbot A Rosewarne IT Sharpe PJ Schranz

To evaluate if adequate restoration of the medial cortical buttress reduces the high reported incidence of mechanical complications when using the AO unreamed femoral nail with spiral blade (UFN-SB) in the management of subtrochanteric femoral fractures. The clinical notes and radiographs of sixty-five patients treated with the UFN-SB between November 1996 and February 1999 were retrospectively reviewed. Twenty-eight of these fractures were subtrochanteric. Mean patient age was seventy-five and thirteen patients had metastatic disease. At the time of review the patients or their doctor were contacted by telephone to establish accurately the associated morbidity and mortality. Follow up information was obtained for every patient. Post-operative radiographs were assessed for accuracy of fracture reduction.

The medial cortical buttress was adequately restored in every case. This required open fracture reduction in eleven patients and cerclage wires augmented the reduction in eight of these cases. Open reduction did not significantly increase time to fracture union or transfusion requirement. Every surviving patient was fully weight bearing within three months. One patient required a second operation for spiral blade migration but there were no implant breakages or other mechanical complications after a mean follow-up of thirty-seven months.

Conclusion: Adequate restoration of the medial cortical buttress allows the UFN-SB to function as a load-sharing device and achieves reliable skeletal stability in these potentially unstable fractures that typically occur in osteoporotic or pathological bone.


R G Dias S A Jain PB Pynsent G J Benke

To determine the ten-year survivorship of the Original M E Muller Straight Stem Total Hip Replacement System with emphasis on the longevity of the femoral component in accordance with guidelines published by the National Institute of Clinical Excellence, 266 consecutive hip arthroplasties using the above prosthesis were performed by the senior author between 1983 and 1992. 24 patients were lost to follow-up. Of the remaining 242 patients 80 were male and 162 female. The mean age was 67.49 years. The diagnosis for the majority of patients was osteoarthritis of the hip joint. Pre-operative planning was carried out and the patients were scored using Charnley’s modification of the d’ Aubigne and Postel numerical grading system A mono-bloc stem with a 32-millimeter head used via the trans gluteal approach recommended by Muller. Following discharge serial follow-up consisted of both clinical and radiological evaluation. The data was prospectively stored on a Microsoft access database. The survival of the prosthesis using revision for aseptic loosening as an end-point was calculated by actuarial analysis.

135 patients attended their ten-year follow-up. 97% of patients had good to excellent pain relief and improvement in movement of the joint following surgery. 38% had good to excellent mobility with the remaining having restricted mobility due to associated co-morbid factors. Only in 3% of patients was mobility restricted as a result of the arthroplasty. 7 revisions were carried out for aseptic loosening, all as a result of failure of the acetabular component. The cumulative survival for this hip replacement system was 95.9% and that for the femoral component was 100% at 10 years.

The Muller Straight Stem femoral component is based on a press-fit concept and gives predictable long-term results when recommended surgical technique is followed. This series confirms the reliability of the stem design and satisfies the NICE guidelines.


N Ashwood G Bain N Wardle

Symptomatic isolated scaphotrapeziotrapezoid joint arthritis affects approximately 10% of the population. Involvement of the scaphotrapeziotrapezoid (STT) joint occurs in 15–30% of all degenerate wrists. Investigation of the technique of arthroscopic debridement of this joint was undertaken to assess the symptom relief achieved and record any resulting postoperative morbidity which limits the success of other techniques used for this condition.

Ten consecutive patients with persistent symptoms were assessed prospectively by a research nurse. Measurements of range of motion and grip strength were obtained before and after surgery. Visual analogue scores for pain and satisfaction levels were also recorded and any limitation to activities of daily living was noted. Assessment included clinical examination for local tenderness over the STT joint.

Good or excellent subjective results were achieved in nine patients at final review at an average of 36 (12–65) months after arthroscopic debridement. One patient graded the result as fair due to failure to achieve normal range of motion. All patients described significant reduction in visual analogue pain scores from an average of 86.5 to 14.1 points. The Green and O’Brien wrist scores improved from a mean of 63.2 to 91.2 during the same time frame. Eight of the patients were in employment and returned to work at 3 months post-surgery without the use of any external splints. The wrist scores were maintained in the five patients reviewed at least three years post-operation.

Conclusion: Arthroscopic debridement is simple, safe and effective when compared with other treatment modalities, achieving excellent pain relief and restoration in function in the short term in patients with isolated idiopathic STT arthritis. Longer term follow-up is no doubt required.


PTH Lee MT Clarke A Arora RN Villar

Metal-on-metal (MOM) bearings after total hip arthroplasty are known to elevate the serum concentrations of metal ions, raising concerns about the long-term effects. One potential modifier of ion release is the bearing diameter used. Resurfacing MOM bearings have a large surface area available for corrosion compared to the typical bearing size of 28 mm in total hip replacement (THR) but may benefit from improved lubrication and reduced production of corrodible wear debris. The net effect of these two variables on metal ion release is unknown. In this study, we compared the level of ion release in patients after large bearing MOM hip resurfacing arthroplasty with patient after small bearing MOM THR.

We measured the serum cobalt and chromium levels from 22 patients with large bearing diameter MOM hip resurfacing arthroplasty (Cormet 2000 and Birmingham Hip Resurfacing) and compared them to the serum cobalt and chromium levels of 22 patients with small bearing diameter (28 mm) MOM THR (Ultima). Patients were prospectively matched for activity level, body mass and date after surgery at blood sampling. All were at least 6 months after surgery.

We found the median cobalt and chromium levels after hip resurfacing arthroplasty to be 7.6 times normal (median 38 nmol/L, range 14 to 144 nmol/L) and 10.5 times normal (median 53 nmol/L, range 25 to 165 nmol/ L) respectively. This is compared to 4.4 times normal (median 22 nmol/L, range 15 to 87 nmol/L) for cobalt and 3.8 times normal (median 19 nmol/L, range 2 to 58 nmol/L) for chromium after 28 mm MOM THR (p=0.0021 and p< 0.0001).

Conclusion: Large diameter MOM bearings result in greater release of cobalt and chromium ions than do small diameter MOM bearings. This may be of relevance when the potential effects of long-term exposure to elevated these metal ions is considered.


AP Davies HG Willert PA Campbell CP Case ID Learmonth

Metal-on-metal bearing surfaces have been reintroduced for use in total hip replacement, despite concerns regarding the potential risks posed by metallic by-products. We have compared periprosthetic tissues from metal-on-metal and metal-on-polyethylene hip replacements at revision surgery with control tissues at primary arthroplasty.

Tissues were obtained from 9 control, 25 contemporary metal-on-metal, 9 CoCr-on-polyethylene and 10 titanium-on-polyethylene hip replacement arthroplasties. Each was processed for routine histology with Haematoxylin and Eosin. Quantitative stereological analysis was performed at the light microscopic level.

Metal-on-metal sections showed more surface ulceration and this was correlated with the density of inflammation in the deeper tissues layers. Metal-on-metal tissues displayed a pattern of well-demarcated tissue layers, which were rarely seen in metal-on-polyethylene cases. In metal-on-polyethylene cases, the inflammation was predominantly histiocytic. Metal-on-metal cases by contrast showed a lymphocytic infiltrate with abundant plasma cells. Metal-on-metal tissues showed a striking pattern of peri-vascular inflammation with prominent lymphocytic cuffs especially deep to areas of surface ulceration. Levels of inflammation were higher in cases revised for failure than in those retrieved at autopsy or exploratory surgery. Total replacement and surface replacement designs of metal-on-metal arthroplasty showed similar histological changes. Plasma cells were not seen in any of the metal-on-polyethylene cases. The differences between the patterns of inflammation and cellular infiltration seen in metal-on-metal and metal-on-polyethylene tissues were highly statistically significant.

The pattern and type of inflammation in periprosthetic tissues from metal-on-metal and metal-on-poly-ethylene arthroplasties is very different. Our findings support the conclusion that metal-on-metal articulations are capable of generating a form of immunological response to metallic wear debris that has not been described previously. The incidence and clinical implications of these immunological responses in failed metal-on-metal joints are unknown.


PTH Lee MT Clarke A Arora RN Villar

Elevated serum cobalt and chromium ion levels associated with carcinogenesis and chromosomal damage in animals have raised concerns that metal-on-metal (MOM) total hip replacement (THR) in humans may produce the same effects over time. Considering that the risks may be related to the level of these ions in the body, this study compared the serum cobalt and chromium ion levels in patients with unilateral versus bilateral 28 mm diameter MOM THR.

All patients having THR at our institution were prospectively registered on a computerised database. From our database, we identified 108 patients with Ultima (Johnson and Johnson, Leeds) MOM THR with 28 mm bearing made of cobalt-chromium alloy. After patient review in clinic and before blood results were known, patient matching was performed by date after surgery at blood sampling, activity level and body mass. Using these stringent criteria, 11 unilateral THR could be adequately matched with 11 bilateral THR. Blood serum was taken with full anti-contamination protocols and serum analysed via inductively coupled plasma mass spectrometry.

The serum cobalt ion level after unilateral MOM THR was 4.4 times normal (median 22 nmol/L, range 15 to 37 nmol/L) compared to 8.4 times normal (median 42 nmol/L, range 19 to 221 nmol/L) for bilateral MOM THR (p=0.001). The serum chromium ion level after unilateral MOM THR was 3.8 times normal (median 19 nmol/L, range 2 to 35 nmol/L) compared to 10.4 times normal (median 52 nmol/L, range 19 to 287 nmol/ L) for bilateral MOM THR (p=0.04).

This study has shown that the serum cobalt and chromium ion levels in patients with bilateral MOM THR are significantly higher than those in patients with unilateral MOM THR. With levels of up to 50 times the upper limit of normal, this finding may be of relevance for the potential development of long-term side effects.


K Ho K Gianniakis A Khan JG Andrews DH Sochart

This is a prospective study to determine if we could identify patients who may benefit from preoperative catheterisation in lower limb arthroplasty.

211 consecutive patients undergoing total hip and knee arthroplasty were recruited. There were 131 female (62%) and 80 male (32%), the mean age (+−1 S.D.) was 68+−12 years old. Patients’ demographic details and pre-operative urinary symptoms were recorded. Previous urological surgery and past history of urinary catherisation were also documented. The anaesthetist who was blinded from the study selected the type of anaesthesia and the post-operative analgesia regime. All patients were required to produce mid-stream urine sample before surgery and at post-operation. Urine tract infection was confirmed on a positive microbiological culture. Regression analysis was used to assess various co-variables to identify the high-risk groups.

35 female (56%) and 27 male (44%) were catheterised, the mean age (+−1 S.D.) was 72+/−14 years old. The frequency of catheterisation was unrelated to the surgical procedure, the type of anaesthesia or the postoperative pain control regime. Age over 65 years old and nocturia were significant indicators for urinary catheterisation (p< 0.05). Patients with urinary incontinence and nocturia were strong determinant for urinary catheterisation (p< 0.03). Males over the age 65 years with a past history of urinary catheterisation (p=0.037) were more likely to be catheterised than females of the same group (p=0.947). This has become more evidential if patients have coexisting urinary incontinence and nocturia (p=0.005). Females over the age of 65 years with urinary incontinence were also significant (p=0.013).

The sensitivity for urinary catheterisation in patients over the age of 65 years with previous history of catheterisation, urinary incontinence or nocturia was 89.7%. This group of patients would benefit from pre-operative urinary catheterisation.


N Keong D Ricketts N Alakeson P Rust

To compare the actual with the reported incidence of pressure sores to determine the accuracy of data (classification errors) and completeness of data (differences between manual and computer generated figures), retrospective data was collected regarding pressure sore rates following primary elective total hip arthroplasty operations carried out in 2001. Pressure sores rates were noted by nursing staff and entered into a computer database.

Four consultant orthopaedic surgeons were involved, across 2 sites – 1 NHS (PRH) and 1 local private hospital.

Preliminary audit reports indicated an alarmingly high pressure sore rate across the two units – 17/172 (9.9%) PRH and 23/71 (32.4%) private hospital.

Two major errors were revealed. In terms of accuracy of data, grade 1 areas (erythema without active ulceration) were included at both sites. These are only potential sites of pressure sores and should not have been used to calculate actual pressure sore rate. In terms of completeness of data, manual verification of the number of operations performed revealed a discrepancy between the theatres’ logbook entries and private unit computer figures. 97 rather than 71 operations were performed. There was no such discrepancy at the NHS site.

The data was reanalysed to obtain the actual pressure sore rate. For the NHS unit, grade 1areas were subtracted, causing the rate to fall from 32.4% to 1.0%. The two errors caused a dramatic and significant difference between reported and actual pressure sore rate.

Poor data collection leads to inaccurate audit, leading to inappropriate management. The concern is that similar errors, accumulated across key complication targets and specialities, will have a profound impact on NHS star ratings.


N Ashwood G Bain B Beaumond P Hallam N Wardle

To investigate whether radioscapholunate arthrodesis [RSLA] can provide functional wrist movement with satisfactory pain relief. 19 patients with radio-carpal arthritis underwent RSLA. There were 3 diagnostic groups [post-traumatic osteoarthritis, rheumatoid arthritis and Kienbock’s disease].

The total flexion-extension range decreased. There was a decrease in pain post-operatively. Grip strength increased in Kienbock’s but fell-in patients with osteoarthritis. 95% of patients were satisfied with their result.

The normal ‘functional’ arc is 35 degrees. Pain was reduced in all of our patients, whilst maintaining the functional arc. With only one failure and no complications, we feel the procedure is safe and reliable.


M Waseem JK Stanley J Martin

Distal radioulnar joint surgery has been dominated by different types of partial or complete ulnar head excision. This remains a reasonable option in rheumatoid surgery. However, in the long run, this can create a number of problems. We have used Herbert modular prosthesis to tackle these very difficult situations. This prosthesis comprises of a press fit stem in three sizes and a ceramic head, also available in three sizes.

In Wrightington hospital upper limb unit 61 patients underwent Herbert ulnar head replacement. Fifty-eight were clinically and radiologically reviewed.

Between December 1998 and December 2002 21 male and 27 female patients were operated. The mean age was 49.8 years with a range of 28–72 years. Twenty two left, eighteen right and two bilateral replacements were performed. The mean follow-up was 20.02 months with a range of 3–60 months.

All patients were reviewed by an independent observer using range of motion, grip strength and satisfaction as outcome.

Primary diagnoses included failed Darrach, Bower, Sauve Kapandji and traumatic ulnar head excision. Forty-five patients were satisfied with the outcome. Pain score showed a mean improvement of 4 with a range of 0–10. The grip strength compared to normal side was decreased in 50% of the patients. The range of motion compared to normal side improved by a mean of 10 degrees (range 3–20) in supination and 13 (range 4–23) in pronation.

Radiological review showed new bone (8) and notch formation (9). Stress shielding of 0–19mm was observed in distal ulna with revision or emergency stem.

Complication occurred in eight patients instability (4), RSD (1), implant failure (1) and two others. Twelve patients required further surgery. No loosening was observed at revision.

Conclusion: This is a suitable revision and primary replacement but no long term following is required.


D Kumar S Haidar RS Bassi AK Sinha SC Deshmukh

Displaced comminuted intra-and extra-articular fractures of distal radius require anatomical reduction for optimum results.

To assess clinical, functional and radiological results of volar-ulnar tension band plating of dorsally displaced comminuted fractures of distal radius, we used volar-ulnar tension band plating technique (without bone grafting) and early mobilisation to treat dorsally displaced and comminuted fractures of distal radius in 47 patients with an average age of 48 years (range, 19–76 years).

Volar tilt, radial height, ulnar inclination and volar cortical angles were measured on the unaffected side. AO volar plate was pre-contoured to match the volar cortical angle of the unaffected side. The horizontal arm of the plate was fixed to the distal fragment first. When the longitudinal arm of the plate was brought onto the radial shaft, the displaced distal fragment was levered out anteriorly to restore the normal volar tilt. Adjustment in ulnar inclination and radial height can be made by medio-lateral and cephalo-caudal movement of the longitudinal arm of the plate.

The average follow-up was 26 months (range 12–41 months). According to Gartland and Werley’s system 25 patients had excellent, 15 had good, 7 had fair functional results. The median Disability of Arm, Shoulder and Hand (DASH) score was 10 (range 0–60). Average grip strength as percentage of the unaffected side was 80 %. Average Palmarflexion was 61 degrees, Dorsiflexion 66 degrees, Ulnar deviation 34 degrees, Radial deviation 19 degrees, Supination 74 degrees and Pronation 80 degrees. According to Lidstrom and Frykman’s radiological scoring system 39 patients had excellent and 8 had good anatomical results.

Conclusion: This relatively new technique has given good results in majority of patients. We recommend its use in displaced and comminuted fractures of distal radius in physiologically young patients with high need and demand.


B Singh RG Wetherell J Bland

We identified patients with a poor outcome by examining cases where nerve conduction studies had been repeated after surgery. 168 patients were identified in whom two sets of tests had been performed. 28 were excluded as either they had no pre-operative studies or had insufficient clinical information. Our study group was 140 patients (174 hands) in whom NCS had been performed before and after surgery, with adequate clinical information. Information on the clinical outcome was obtained from postal questionnaires and from hospital records. A proportion of the hands in which two tests had been performed turned out to have been retested because of presentation with symptoms in the other hand, after a satisfactory outcome from surgery on the first side. This accounted for 44 of the 174 hands, and these were used as control group. 130 hands in 92 patients were identified as having a poor outcome from surgery. Of these, 39 underwent a further operation; two went on to a third procedure. Logistic Regression Analysis was used to analyze the data (Stastica).

There was a trend for the poor results to be more common in the elderly, but age was not a statistically significant factor, (p< 0.36). The good results were found mainly in grades 2 to 5 and this was statistically significant, (p< 0.01). A poorer outcome was seen grouped in grades 0, 1, 2 and 6 and this was statistically significant. (p< 0.01). The NCS have been validated, are reproducible and cost about £15 per study. In the group with good outcome, the grade of severity of NCS improved or remained unchanged in the majority. Of the 39 re-explorations, 17 were found to have incomplete division of the ligament. Of these, 10 showed clinical improvement after re-operation. Of the 22 with no evidence of incomplete division, 7 were improved, 10 had persistent symptoms and 5 were worse after revision surgery.

We believe that pre-operative NCS are helpful for two reasons: Firstly, they provide as a baseline for comparison if the patient has unsatisfactory result following decompression. Secondly, we have shown that they are of prognostic value.


RG Turner H Stawick GEB Giddins

Osteoporosis is an increasing problem due to increasing age and inactivity. Distal radial fractures are often the first symptom of this disease. Medical treatment can reduce the risk of further fractures (including hip fractures with the associated mortality and morbidity).

To develop a method for accurate assessment of bone density from routine wrist radiographs:

Various bone substitutes were tested until one was found that gave reasonable density matches with fresh bone over a limited X-ray kV range;

Twenty patients with distal radius fractures had the bone substitute placed beside the wrist being X-rayed.

Wrist and radius thickness were measured from the radiograph. This was combined with the optical density of the distal radius (relative to the bone substitute) to calculate a value for the bone density. The patients subsequently underwent a DEXA scan of the contralateral (uninjured) wrist. [The X-ray calculated bone density and the DEXA density compare well. (R> 0.5]

Conclusion: This technique gives reasonably accurate results. It is not yet ready for clinical practice. A larger study is required to improve the accuracy of this technique, perhaps comparing results with lumbar spine DEXA.


SR Mitchell M Anwar LGH Jacobs CF Elsworth

Day case surgery is commonplace in the field of orthopaedic surgery, being suitable for a wide range of both trauma & elective procedures. It became apparent within our unit that an unacceptably high number of cases were being cancelled for a variety of reasons. We set out to identify these reasons and thereby develop a simple screening process to reduce the number of cancellations.

Initial audit over a 1 year period showed 25% of the 907 day case patients were being cancelled. We subdivided the reasons for these cancellations at both pre-operative assessment and on the day of surgery into avoidable [e.g. no carer / telephone, uncontrolled BP, high BMI and ischaemic heart disease] and unavoidable [e.g. surgery no longer required, patient unwell, list cancelled for emergencies, patient DNA].

The majority of our cancellations fell into the “avoidable” category, predominantly at pre-operative assessment. Accordingly, we devised a simple screening questionnaire to be used by clinicians in out-patients at the time of listing for surgery, based on the RCS guidelines (1985). If any of the questions were answered “Yes”, the patient was not suitable for day case surgery. The patient information letter was also changed, informing patients that non-attendance would result in their removal from the waiting list.

Re-audit of 727 patients over the next 12 months showed a fall in cancellations to only 11%, with the majority of these being for unavoidable reasons.

Cancellations are a source of inconvenience, distress and frustration to both clinician and patient, are a waste of hospital time and resources, and lead to an increase in waiting lists. Our study demonstrates the value of closing the loop in audit, leading to a dramatic reduction in cancellations. Audit is a useful tool to improve patient care, and is not merely a “number-crunching” exercise.


B Theruvil RK Choudhary V Kapoor DG Hargreaves DJ Warwick

Efficient utilisation of the trauma list is an important aspect of trauma care in the NHS. An audit of the trauma theatre time utilisation was done from April 1999 to March 2000. Ideally the first case should start at 8:30 am. However, we found that the first patient was on the operating table only by 9:40 am (mean). The main reasons for the delay were the time required for the anaesthetist to see the patient and the other staff to set up the necessary equipments. We decided to identify the first case of the trauma list the day before, so that the anaesthetist can review the patient the previous day. We felt that this would also give adequate time for the theatre staff to set up their instruments. However, this did not improve the theatre timings.

We introduced the novel idea of performing a carpal tunnel decompression at the beginning of each trauma list to make use of the redundant time without an extra financial burden to the hospital. Carpal tunnel decompression can be performed under local anaesthetic by a basic grade surgeon. This would also give time for the anaesthetist and the consultant surgeon to review the patients on the trauma list.

The theatre time utilisation was re-audited a year following the introduction of carpal tunnel release. The patient for carpal tunnel decompression was on table at 8:44 am (mean). The first trauma case was on operating table at 9:46 am (mean). Therefore, in spite of performing an additional surgery on the list, there was a delay of only 6 minutes. This simple idea has helped us to do an additional case every day with only a 6 minute delay to the trauma list.


MR Utting B Squires I Learmonth

The National Institute for Clinical Excellence (NICE) was set up to provide patients, health professionals and the public with authoritative, robust and reliable guidance on current “best practice”.

To determine how useful for NICE guidelines for Selection of Prostheses for Primary Total Hip Replacement were to patients who were undergoing total hip replacement (THR) and the health professionals who were looking after them. We surveyed 100 patients, 50 Orthopaedic Surgeons, 40 Orthopaedic nurses and posted a questionnaire to GPs, to which 79 replied (56% response rate).

19% of patients had heard of NICE but only 2% were aware of the existence of NICE guidelines on THR and 1% found them useful. Almost all orthopaedic surgeons had heard of NICE and their guidelines for THR, with 74% knowing what the guidelines actually stated but only 14% finding them useful. 78% of surgeons believed that their preferred hip replacement conformed to NICE guidelines, 2% knew that they did not conform and 20% did not know. 27% of general practitioners knew of the guidelines, but only 5% knew what they actually stated and 1% found them useful in their practice. Most nursing staff working in orthopaedic areas had heard of NICE (83%). 43% knew of the NICE guidelines but only 13% knew the actual guidelines and % found them useful.

NICE has failed to communicate its guidelines to both patients and the public. None of the groups found the guidelines useful. NICE has failed to fulfil its mission statement and may instead have other motives, such as empowering centralised regulation of healthcare in the NHS.


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N Ellahee B Levack

All multidisciplinary audit projects from January 1998 to March 2002 involving an Orthopaedic department were assessed to measure their impact on improving clinical practice. Data were derived from reports formulated by the Trust’s Audit department, which listed findings, conclusions and proposals for each project.

Among 41 studies performed, 37 listed a formal proposal of actions. 4 projects had a completed outcome of which 2 closed the loop with re-audit. 9 other projects recommended re-audit but none had been initiated. Although Trusts actively partake in regular audit, it seems more as a service or training commitment, rather than contributing towards improving the quality of healthcare.


R Vhadra K Maclaren

Musculoskeletal conditions are the commonest cause of severe long term pain and account for half of all chronic conditions in the over 65s. The BOA published guidelines on the musculoskeletal undergraduate curriculum in 2001. It suggested that a minimum of 8 weeks be allocated for the musculoskeletal course. However, a survey of medical schools showed that only 3 to 5 weeks are allocated. Our results suggest that the musculoskeletal course in Manchester is not long enough to gain sufficient knowledge. Therefore we feel that these deficiencies need addressing with a change in the taught undergraduate curriculum


CNA Esler WM Harper

The Trent Arthroplasty Audit Group has been prospectively collecting data on primary hip and knee arthroplasties since 1990. Details of 61,000 primary and 4,00 revision arthroplasties have been registered. The Royal College of Surgeons of England. Capital Hip Report (July 2001) concluded that a national joint register could have detected failures of an implant at an earlier stage. We examined data on the register to ascertain why we had been unable highlight a problem with this implant.

The Trent Arthroplasty Register was unable to detect the poor results with Capital hips at an earlier stage than surgeons. A scientific presentation had raised concern before our register could detect a problem. The hips had been listed for revision but were still on a waiting list. Additionally some of the failed hips were not revised as patients were insufficiently fit for surgery.

The stated reason for revision on revision forms was vague and not sufficient to draw conclusions as to the mechanism of failure. Radiological studies have identified a higher radiological failure rate than expected (Charnley & Elite +) but we have shown that outcome scores (Oxford Scores) were not successful at identifying these failures. Since the implementation of the Data Protection Act (1998) consent must be obtained before details are registered, which may lead to further inaccuracy in the creation of survivorship curves.

Joint registers can contain the problem once it is detected but are not a substitute for regular follow-up. Surgical vigilance and a scientific approach is required to ascertain the reason for failure. Revision should not be the only endpoint for registration. Joint registers may be part of the solution but need to be backed up with adequate resources, financial and intellectual, to analyse clinical information, if valid conclusions are to be drawn.


AS Bajwa SA Bajwa S Wilson J Nellis P Finn S Williamson A Port

To evaluate blood transfusion practice in hip and knee arthroplasty, the development of evidence based guidelines, their implementation and prospective analysis of change. An audit was carried out in 4 stages to complete the loop. Stage 1: Retrospective analysis of blood transfusion practice in primary and revision hip and knee arthroplasty. Review of case notes, nursing record, anaesthetic sheet and pathology results from a computer database was carried out. Rates of transfusion, patients’ body weight and height, peri-and post-operative blood loss, use of anticoagulants, drains, surgical approach, type of implant and cement, grade of surgeon and anaesthetist and haemodynamic complications were recorded. Stage 2: Literature search to develop evidence based guidelines for blood transfusion.

The data in stage 1 was evaluated in the light of those guidelines to determine appropriateness of blood transfusion. Stage 3: Dissemination and implementation of guidelines. Anaesthetic, Orthopaedic and audit departments were involved. Guidelines were presented, discussed, finalised and circulated.

Stage 4: Prospective re-evaluation of blood transfusion practice was undertaken. Parameters as in stage 1 plus documentation of reason for blood transfusion by the prescriber were recorded.

For stage 1, 97 Hip arthroplasty (86 primary and 11 revisions) and 119 Total knee arthroplasty procedures (109 primary and 10 revisions) over a period of 26 weeks were studied. Blood transfusion rate was 50.5% (49/97) in hip arthroplasty and 28.5% (34/119) in knee arthroplasty. Evidence based guidelines were developed. 55% transfusions were thought to be inappropriate in the light of guidelines. Following completion of stage 2 and 3, prospective audit of blood transfusion practice was initiated. It was compulsory for the person prescribing blood to document the indication. Data was collected on a daily basis for 15 weeks. In that period 150 joint replacements were undertaken. 77 hip arthroplasty (71 primary and 6 revisions) and 73 knee arthroplasty procedures (66 primary and 7 revisions) were undertaken. Blood transfusion rates for hip arthroplasty decreased to 18% (14/77) and for knee arthroplasty to 5.4% (4/73).

Overall transfusion rates decreased from 83/216 (38.5%) to 18/150 (12%) after implementation of guidelines. This represents an overall reduction of 68%.

Conclusion: A multidisciplinary approach and putting evidence based practice in place has resulted in reduced blood transfusion rates in hip and knee arthroplasty in our institution. We feel this change is an example of implementation of evidence-based practice.


L Campton R Tabbakh A Gregori

Inaccurate positioning of components results in suboptimal knee function, implant wear and early loosening of the prosthesis. Small differences in varus/valgus angulation have been shown not to affect outcome, but, when the prosthesis is more than 3 degrees malaligned from neutral, premature failure rates rise.

Accurate alignment requires proper orientation in the placement of the cutting guides and computer-aided navigation systems have now been developed with the aim of improving this.

We compared the post-operative leg alignment following computer assisted (Orthopilot) versus conventional (IB2 with extramedullary tibial and intramedullary femoral jigs) methods of TKJR using weight-bearing long leg radiographs.

This was a study of 91 consecutive TKJRs (51 IB2s and 40 Orthopilot Search Evolution knees) performed in 70 patients.

A single experienced knee surgeon carried out all these procedures. All these patients had weight-bearing long leg alignment films taken by a single experienced radiographer.

The anatomical centres of ankle, knee and hip were then marked on each film and the tibia femoral angles drawn. Two separate blinded observers then measured the angles of malalignment.

Observer A’s results show that 95% of the Orthopilot knees were within 3 degrees of varus or valgus from neutral. Only 74.47% of the IB2 group were within this range (p=0.011).

For Observer B 87.5% of Orthopilot knees and 70.21% of IB2s were within the range (p=0.052). When we group these finding we see that an average of 91.25% of the Orthopilot and 72.34% of the IB2 knees are within the range (p=0.025).

When the interobserver figures for each group were compared no significant difference was found.

Conclusion: Our results show a significant improvement in postoperative alignment of TKJRs by using the computer-aided navigation system and it should follow that the long-term survival of the prosthesis would be extended.


LA David S Mahroof J Pringle M Bayliss TWR Briggs

This prospective study analyses the histological results of autologous chondrocyte transplantation in patients with articular cartilage defects of the knee joint. Chondrocytes from a non-weight bearing area of the knee were harvested and then cultured in vitro.

Re-implantation involved injection of the chondrocytes into the defect, which was then sealed with a collagen membrane. One year post-op, patients were evaluated by clinical, arthroscopic and histological assessment. A biopsy of the transplanted region was examined by staining with Erlich’s H& E and Safranin 0, polarised light microscopy and by analysis with S100 and immunohistochemistry. Hyaline cartilage content was further assessed by examination of Type IIa & lIb collagen mRNA expression using in-situ hybridisation.

The median age was 31 years. 63 knees were treated. Solitary lesions were treated in 61 knees with two defects being treated in three knees (66 defects in total). The defects were located on the medial femoral condyle in 39 cases, lateral femoral condyle in 14, trochlea in 2 and patella in 11. The defect size ranged from 1–7 cm2 (mean area 3cm2 ). 40 patients had at least one-year follow-up. Using the Brittberg Rating, 11 had excellent results, with 15 good, 10 fair and 4 poor. The mean Lysholm and Gillquist scores improved from 44 pre-op to 77 one-year post-op. Biopsy at one year conftrmed the presence of hyaline cartilage in 22 out of 32 cases (69%). In-situ hybridisation confirmed the presence of Collagen type II in the deep zones of the biopsy with a fibrocartilaginous appearance superficially.

Conclusion: This technique can provide an effective treatment for cartilage defects. The histological results are encouraging and chondrocyte transplantation may be the only procedure to allow regeneration of hyaline like articular cartilage.


A Bonshahi S J Parsons A T Helm D S Johnson R B Smith

The study was established to assess the long-term results and differences between autogenous and synthetic anterior cruciate ligament (ACL) reconstruction.

We randomised 50 patients into 2 groups: 26 (52%) underwent reconstruction with middle third patellar tendon graft (PTG) harvested using the ‘Graftologer’ (Neoligaments) and 24 (48%) underwent reconstruction with the Leeds-Keio ligament (LK).

Subjective knee function was assessed using the Lysholm score, Tegner activity score, IKDC grading, and clinical assessment of anterior knee pain. Laxity was tested clinically, including anterior draw at 20° (Lachman), pivot shift, and arthrometric measurements using the Stryker laxometer.

At five years we have noted no significant difference in Lysholm scoring and Pivot shift between the LK group and patellar tendon group. But there was a significant difference in Tegner activity level and IKDC activity scores with PTG faring better at five years. There is no significance difference in anterior knee symptoms between the groups.

Conclusion: Due to the success of PTG/Hamstring in routine primary ACL reconstruction there does not seem to be a role for artificial ligaments. However, if we just look at functional outcome and patient satisfaction, LK patients seem to be doing as well as PTG at five years. So, there may be a place for the Leeds Keio graft where autologous tissue is unavailable.


AS Bajwa A Lakhdawala P Finn CME Lennox

To investigate whether the harvesting of Hamstring graft in ACL reconstruction results in compromised knee flexion strength and proprioception, and hence knee function?, a prospective study, approved by the local Ethics Committee, to assess the function and strength of the knee joint in patients who had ACL reconstruction done using a four-strand Hamstring graft. The control group was the contra lateral knees. 28 knee joints were studied with mean follow-up of 70.1 weeks (52–156). All operated knees received an extensive set regime of pre-and post-operative physiotherapy. Assessment tools were clinical examination, Laxometer arthrometry for measured anterior draw, Biodex dynamometry and Stabilometry for Hamstring and quadriceps strength and proprioception. The knee function was assessed using a questionnaire incorporating IKDC (International knee documentation committee) performa, Lysholm 2 score, Tegner’s activity scale and Oxford knee score.

Following reconstruction (mean 70.1 weeks postop), objective assessment using Biodex dynamometer showed that mean peak flexion torque around the knee joint was 69.8 N-m and 76.2 N-m in the operated and non-operated knee respectively. There was no difference in flexion torque in both groups. Mean Flexion: Extension ratio around the knee joint was 53.9% in the operated and 53.2% in non-operated sides. Mean stability index, measured using open eye stabilometry, was 3.5 (SD 2.4) in the operated side and 3.1 (SD1.8) in the non-operated side, with no significant difference demonstrable (p< 0.05).

The mean age of patients was 28.3 years (18–44). Mean IKDC score following reconstruction was 74.8 (49–100), SD18.5. Mean Tegner’s activity scale improved from 2.5(3–7) pre-operative to post-operative 5.4(3–7), p< 0.01. Mean Lysholm 2 score improved from 53.4(41–76) pre-operatively to 85(64–100) post-operatively, p< 0.01. Subjective function of the knee on a scale of 0–10 improved from pre-operative 3.1 to post-operative 7.7 (p< 0.01). Arthrometry at 25-degree flexion and 130 N force using Laxometer showed mean anterior laxity 5.3mm on the operated side and 3.1 on the healthy side (side to side difference 2.2mm).

Conclusion: The function of the knee improved significantly following ACL reconstruction both objectively and subjectively. The harvesting of Hamstring as a graft neither compromises the flexion torque nor the proprioception around the knee joint.


SK Chauhan RG Scott W Breidahl RA Beaver

To compare the new technique of computer assisted knee arthroplasty (CAK) against the current gold standard conventional jig based technique (JBK), 75 consecutive patients underwent knee replacement and were randomly allocated to either the CAK or JBK group. The CAK surgery was performed using a freehand technique that avoids violation of the medullary canal. Pre-and post-operative Knee society scores were collected. Post-operative CT scans were performed according to the Perth CT Knee Arthroplasty protocol and pre-and post-operative Maquet views of the limb performed. Intra-operative soft tissue release together with postoperative pain scores and blood loss were also assessed.

CT scans performed show a statistically significant improvement in component alignment when using computer assisted surgery for femoral varus/valgus (p=0.032), femoral rotation (p=0.001), tibial varus/ valgus (p=0.047) tibial posterior slope (p=0.0001), tibial rotation (p=0.011) and femoral-tibial mismatch (p=0.037). Standing Maquet limb alignment was also improved (p=0.004) as was blood loss (p=0.0001). CAK surgery took longer, a mean increase of 13 minutes (p=0.0001).

This is the first controlled study to assess all seven-alignment characteristics of knee arthroplasty in these two groups of patients.

The improvement in alignment resulted in this trial being stopped prematurely as 6 out of 7 of the initial variables had reached significance. It shows a clear improvement in component alignment with computer navigation. The reduction in blood loss in this surgery through not violating the medullary canal will also be beneficial.


SK Gupta KJJ Tayton C Dent S Chatterji

To study the survival analysis of the Accord TKR and to analise the causes for its failure. 111 Accord knees were implanted in 106 patients between 1986 and 1996. All components were cemented. Eighty-seven patients were followed up and assessed according to the Knee Society Clinical Rating System.

Life table analysis of this implant using revision as the end point shows a survival of 25% at 11–12 years.

Of the 87 knees, only 31 were still in situ and of these 7 showed radiographic signs of severe loosening. However, the average knee score for these 31 was only 65/100 and average functional score was down to 42/100.

56 implants have been revised, 21 due to aseptic loosening, 11 due to gross valgus/varus instability, 9 due to deep infection, 8 due to loosening of the patella liner and 7 due to mobile bearing complications.

All 21 (24%) cases of aseptic loosening were found to have a loose femoral component; however, 56% of the total showed significant radiographic osteolysis around the stem of the tibial implants.

Retrieved implants in 5 patients showed significant delamination of the UHMWP at its margins and also revealed a track through the tibial baseplate into the medullary cavity of the tibia.

Conclusion: Early failure of this implant is due to increased debris formation from the UHMWP due to edge loading and early delamination probably as a consequence of the shape of its articulating surface. This situation was significantly aggravated by a design fault in the tibial baseplate, which encouraged unrestricted access of debris into the medullary cavity of the tibia and hence early and severe osteolysis.


N Pradhan AK Gambhir ML Porter

3610 primary and revision total knee replacements were performed at our hospital between 1969 and 1995. We conducted a survivorship analysis of 3234 primary total knee replacements to construct life tables and calculate survival curves. Each knee replacement was entered once only. Revision was defined as the end point. Data was collected both from patient records and by postal questionnaire. Eight types of knee prostheses were evaluated with best-case and worst-case scenarios compared over a 5, 10 and 15 year period.

The evidence suggests that certain types of prosthesis are more liable than others to fail or to fail early. The “Condylar type devices” which include the Total Condylar, Press Fit Condylar (PFC), Kinematic, Kinemax and Anatomic Modular Knee (AMK) have very similar survivorship curves and in the main have performed well up to a 10 year period. The LCS mobile bearing knee performed extremely well at 5 years. The Attenborough knee had an inferior result while the Load Angle Inlay (LAI) which was a very early resurfacing arthroplasty had the poorest results in terms of survivorship.


AK Gambhir S Morgan N Pradham A Gregori ML Porter

Restoration of the mechanical axis is thought to be a critical factor in determining the Outcome of knee replacement surgery. There is strong theoretical evidence that reproduction of this axis improves mechanical loading and hence longevity of the implant. Clinical studies are small in number.

Per-operative use of intra-and-extra-medullary alignment jigs help to determine the distal femoral and proximal tibial cuts. Studies have shown large margins of error using the standard jigs provided with most total knee replacement systems. On this basis computer assisted guidance systems are being introduced such as Orthopilot and BrainLab. These systems allow more accurate placement of the bony cuts and hence improve overall lower limb alignment.

No study has shown conclusively that accurately reproducing the mechanical axis of the lower limb improves survivorship of the implant. Prior to investing in these systems we felt it would be prudent to investigate how critical reproduction of the mechanical axis was in the primary total knee replacement.

We assessed 100 primary kinematic total knee replacements performed in 1990. All case notes were reviewed looking for basic demographics, pathology and clinical outcome.

All cases had a long leg film weight-bearing alignment film taken post-operatively. These were digitised and then analysed using Design CAD 97 software and from this the mechanical axis calculated.

Using these data the patients were divided into two groups. The first were within 3 degrees varus/valgus of the mechanical axis. The second were outside this range. These two groups were then correlated to clinical outcome.

Conclusions: Our results suggest that accurate reproduction of the lower limb alignment and the mechanical axis improves clinical outcome and survivorship of the implant using revision as an endpoint. Our data would support the introduction and use of intra operative computer aided guidance systems.


S.K. Chauhan G.W. Clark R.G. Scott S. Lloyd J.M. Sikorski

Plain radiographs are a poor indication of the overall coronal, sagittal and axial alignment of a total knee arthroplasty (TKA). We describe a new CT method that allows the mechanical axis in both planes to be defined and seven alignment characteristics to be defined.

A GE Light Speed multislice CT scanner performed a high-speed helical scan from the acetabular roof to the talus in 100 patients following TKA. The knees were scanned in a supine position with the legs in a neutral position. The images were reformatted in coronal, sagittal and axial planes and the mechanical and anatomical axes identified. The femoral component (varus/ valgus, flexion/extension, rotation) as well as the tibial – (varus/valgus, posterior slope and rotation) are measured. Coupled femoro-tibial rotational alignment was assessed by superimposition of the femoral and tibial axial images. The accuracy of this technique has been checked by using a mechanical FARO-arm.

The technique has a low intraobserver error rate of 9% (in each case less than 1 degree) and an accuracy of 3mm in a three-dimensional plane, as determined against an independent FARO arm technique. The CT analysis of 100 patients shows normal tibial baseplate rotation to be 8–12 degrees from the tibial tuberosity.

Conclusion: The CT protocol is the first single radiographic investigation that characterizes all the alignment parameters of a TKA. It sets an excellent standard in planning revision knee surgery and provides a valuable tool in assessing alignment of painful knee replacements as well as in outcome measures of TKA.


SK Chauhan RG Scott GW Clark RA Beaver

This study was to assess the accuracy of fixed posterior condylar referencing cutting blocks to the accuracy of combined epicondylar/AP axis referencing in femoral component rotation using a computer navigation system.

Seventy-five consecutive patients undergoing TKRs were randomized into two groups. The first received femoral component rotation by a computerized method that combined the epicondylar axis and Whitesides AP axis measurements to determine rotation. The second group had a zero or three-degree posterior referencing external rotation block, depending on which was closest to the epicondylar axis. All patients underwent axial CT scans of the distal femur to determine component rotation around the surgical epicondylar axis.

Femoral component alignment with the combined method as compared to fixed posterior alignment guides is statistically improved (p=0.001). In the posterior referencing group 43% were correctly rotated to the epicondylar axis but another 43% were malrotated by 3 degrees or more. The mean malrotation was 1.72 degrees (range 0–5) In the combined group 82% were correctly rotated and 11% were malrotated by 3 degrees or more. The mean malrotation was 0.51 degrees (range 0–4).

Conclusion: A combined computerized method of using the surgical epicondylar axis and Whitesides AP axis produces superior results when aiming for neutral femoral component rotation. Fixed posterior referencing blocks will produce errors in malrotation in over 50% of cases.


K Srinivasan P Giannoudis M Agarwal V Patil SJE Matthews

To assess the functional outcome of operative and non-operative treatment of distal humeral fractures in the elderly, patients above 75 years of age were studied. Demographic data including associated injuries and co-morbid conditions were recorded. The minimum follow-up was 16 months (range 16–92 months). Elbow function was analysed according to the OTA rating system. Radiographs were monitored for possible predictors of final functional outcome

Out of 125 patients with distal humeral fractures, 29 were above the age of 75 years. The mean age at the time of admission was 84.6 years (range 75–100). One patient was lost to follow-up. In total there were 28 patients with 29 fractures. 5 of these were open fractures. As per the AO classification, there were 8 type A, 8 type B, and 13 type C fractures. 8 patients were treated non-operatively (3 type A, 2 type B, 3 type C) and 21 (5 type A, 6 type B, 10 type C) operatively. An olecranon osteotomy was performed in 12 cases, 2 underwent triceps tongue reflection, and 7 had triceps splitting. Local complications included 4 cases (1 deep and 3 superficial) of infection and 3 non-unions (including one at the olecranon osteotomy). In the non-operative group the mean loss of extension and mean flexion achieved were 34.0 and 70.0 degrees respectively, whereas in the operative group the corresponding values were 23.0 and 107 degrees.

OTA grading revealed 3 excellent, 9 good, 7 fair and 2 poor results in the operated group whereas in the non-operated group there were 0 excellent, 2 good, 3 fair, and 3 poor results. There was direct correlation between loss of anterior tilt of the distal humerus and adverse outcome.

Conclusion: Our study showed that improved functional outcome can be achieved following surgical treatment in these difficult fracture This study supports the view that we need to re-examine the conventional view of ‘bag of bones’ method as blanket treatment and signifies the need for further studies on similar cohorts of patients.


RR Brown MC Dixon D Parsch RD Scott

There are only a limited number of long term studies of total knee arthroplasty and few with a minimum fifteen year survivorship of a modular fixed bearing posterior cruciate-retaining prosthesis. This consecutive series of 139 total knee arthroplasties (109 patients), using the non-conforming posterior cruciate-retaining Press Fit Condylar (PFC®) system was followed for a minimum of 15 years (range 15.0 to 16.9 years). The patella were resurfaced with an all-polyethylene component in 83% of knees. The tibial component was always cemented, while a porous-coated femoral component was used in 84% of knees. Fifty-nine knees (45 patients) were followed up for a minimum of 15 years. Fifty-seven patients (70 knees) had died and five (8 knees) were too ill to assess. Survivorship of the prosthesis was confirmed for 98.6% of the prosthesis, as only two patients (2 knees) were lost to follow-up.

The mean Knee Society Score and Function Score were 96 and 78 respectively. The total incidence of radiolucent lines was 13%, with 2% around the femur, 11% around the tibia, and 0% around the patella. None of these lines were of any clinical relevance. There was no evidence of progressive radiolucent lines or component loosening, and one case of zone 4 femoral osteolysis.

There were five re-operations for any indication, of which four were for polyethylene insert wear. There was also one loose cemented femoral component after more than 15 years. The survival without need for revision for any reason was 99% at 10 years and 95.6% (worst-case scenario of 94.2%) at 15 years.

This single-surgeon series with a minimum 15 year follow-up shows that the modular fixed bearing posterior cruciate retaining total knee arthroplasty of the PFC system can provide excellent and predictable long term results in tri-compartmental arthritis of the knee.


AR Evans G Gillespie H Dabke M Lewis P Roberts R Kulkarni

Proximal humeral fractures are common and often occur in osteoporotic bone. Suture fixation utilises the rotator cuff tendons as well as bone providing adequate stability and avoids complications associated with metalwork insertion.

Surgical exposure was via a delto-pectoral approach with minimal dissection of the fracture site. Initially a 2 suture technique was utilized with heavy ethibond sutures passed through drill holes either side of the bicipital groove; however, because of concerns about varus instability the technique now uses a third suture placed laterally acting as a tension band to prevent varus collapse. Patients with Neer 2 and 3 part fractures treated with suture fixation were assessed clinically (using the Constant score) and radiologically at a mean of 27 months post fracture.

To date 24 patients have been studied. The average age of the patients in our series was 70.2. All fractures progressed to union with no cases of radiological avascular necrosis. We had 2 cases of mal-union (-one varus and one valgus-), both with a 2-suture technique. One patient had early loss of fixation; re-exploration was performed with stability conferred by a third lateral suture. Active abduction > 120o was achieved in 9 patients with a mean Constant score of 72 compared to 89 on the un-injured contra-lateral side. We have demonstrated that suture fixation of displaced proximal humeral fractures is an effective alternative to fixation using metalwork. The advantages are that minimal soft tissue stripping of the fracture site is required and the potential problems associated with metalwork insertion into osteoporotic bone are avoided. Following one case of varus mal-union with a 2-suture technique we now routinely use a third suture to act as a lateral tension band.


A Rehm W Gaine B Alman

The purpose of this study was to investigate if there is a relationship between the timing of reduction of displaced supracondylar humerus fractures in children and post-operative complications and open reduction rate and to evaluate the usefulness of the definition of early (eight hours or less following injury) and delayed (more than eight hours following injury) treatment used in the literature.

The case notes of children who were treated at our institution for a Gartland grade 2b and 3 supracondylar humerus fracture between July 1995 and June 2002 were reviewed.

We identified 431 patients with a Gartland grade 3 and 141 patients with a Gartland grade 2b fracture. The time from injury to surgery ranged from 2 hours to 13 days. The average time to reduction was 12 hours for grade 3 injuries and 21 hours for grade 2b injuries. None of the patients had an initial closed reduction in the emergency department. 229 patients were treated early with two compartment syndromes, five ulnar nerve, one lateral cutaneous nerve of the forearm, one median nerve - and one radial nerve palsy, one septic arthritis, one pin site infection, six open reductions; one re-manipulation was required for loss of reduction. The delayed group consisted of 343 patients with six ulnar nerve, three median nerve, one radial nerve and one lateral cutaneous nerve of the forearm palsy, three pin site infections, five open reductions; re-manipulation was required in one patient. All nerve palsies recovered post-operatively. The open reduction rate was two percent. The majority of displaced supracondylar humerus fractures in children do not need to be operated on as an emergency. Operation of fractures not associated with a neurovascular compromise within eight hours of the injury does not seem to reduce the rate of significant complications and open reduction rate. In contrary the most severe complication, the development of a compartment syndrome was only seen in the early group. We did not identify an association between complication rateS and a time threshold. Therefore the differentiation between early and delayed treatment used in the literature seems to be arbitrary and not useful.


A Gadgil C Hayhurst N Maffulli JSM Dwyer

Reduction and K-wiring is the most popular form of treating displaced supracondylar fractures of the humerus. Complications including redisplacement of the fracture, cubitus varus, iatrogenic nerve injuries and pin tract infection have been reported following surgery. For successful outcome with K-wiring of supracondylar fractures, strict adherence to protocols and surgical expertise are necessary. We have treated these fractures in straight arm traction since 1995, and the purpose of this study was to audit our practice.

Between January 1995 and December 2000, 112 children with a closed displaced supracondylar fracture of the humerus, without neurovascular deficit, were managed by straight arm traction for a mean duration of 22 days. Final outcome was assessed using clinical (flex-ion-extension arc, carrying angle and residual rotational deformity) and radiographical (metaphyseal-diaphyseal angle and Humero-Capitellar angle) criteria. Our outcomes were compared with those of the recent large studies reporting results of surgical treatment.

71 (63%) patients had excellent, 33 (29%) patients good, 5 (4.4%) patients fair, and 3 (2.6%) patients poor outcome. All patients with fair or poor outcomes were older than 10 years.

Elevated straight-arm traction is safe and effective in children younger than 10 years. It can be effectively used in an environment that has provision of paediatric medical care and general orthopaedic expertise with outcomes comparable to those fractures treated surgically in specialist centres.


V Khanduja L Ng Z Dannawi L Heras

This study investigates the efficacy of the AO Pi-plate in the treatment of complex, unstable, intra-articular fractures of the distal radius.

A retrospective study of 17 patients was carried out who underwent open reduction and internal fixation for dorsally displaced, intra-articular fractures of the distal radius using the AO Pi-plate. All patients were assessed clinically and radiologically post-operatively. The final functional outcome was assessed using the Gartland & Werley scoring system.

The average follow-up period was 34.3 months. 94% (16 patients) of the fractures were classified as AO type C fractures. The wrist movement was restored to a near normal range in all cases. The mean grip strength was 67% of the uninjured hand. The functional outcome as measured by the Gartland & Werley scoring system showed excellent and good results in 88% of the patients. Radiographic assessment revealed an average articular step-off of 0mm post-operatively. The implant removal rate was 29% (5 patients) and the main reason for that was extensor tenosynovitis.

Conclusion: Our study demonstrates that although the functional outcome after using the Pi-plate for complex distal radius fractures is good, there is a significant incidence of extensor tenosynovitis. We recommend that the implant is best used for Type C fractures and be removed electively after fracture union.


S Malek D Atkinson R Gillies M Nicole

To determine the effect of experience of the operator and the effect of type of anaesthesia used on re-manipulation rates of fracture distal radius manipulated in A& E, a retrospective review of distal radius fractures manipulated in A& E between January 2000 and January 2001. Operators were divided into two categories: junior (SHO grade) and senior (higher grade) doctor.

54 patients with fracture distal radius had manipulation in A& E. 15 male and 39 female patients with mean age of 61 years (52 for males and 63 for females) were included.

42 (78%) fractures were manipulated under haematoma block (18 by junior, 23 by senior doctor) and 12 (22%) fractures were manipulated under Bier block (1 by junior, 11 by senior doctor). Operator’s grade was not clearly mentioned in one case. 13 out of 54 patients (24%) needed fracture re-manipulation under general anaesthesia. 12 out of 42 fractures manipulated under haematoma block (30%) needed re-manipulation compared to only one out of 12 fractures (8%) manipulated under Bier block (p=0.25). 9 out of 19 fractures manipulated by junior doctors needed re-manipulation compared to only 4 out of 34 fractures manipulated by senior doctors (p=0.007). Haematoma block was used for 18 out of 19 cases by junior doctors and for 23 out of 34 cases by senior doctors (p=0.038). Average number of fracture clinic follow-ups was 4 (range 2 to 8).

Junior doctors had significantly higher preference for haematoma block and significantly higher re-manipulation rate. Re-manipulation rates were higher with fractures manipulated under haematoma block compared to Bier block.

Adequate training and supervision should be provided for SHOs while performing such procedures in A& E. Use of Bier block as a regional anaesthesia for manipulation of distal radius fractures in A& E should be encouraged.


AR Norrish J Rao MJ Parker

We report the results of a consecutive series of 500 patients treated with a follow-up range from 5–12 years.

Ten patients were lost to follow-up and 398 patients [81%] died. The mean age was 82 years, with 85% being women. Forty-six patients [9.2%] required a second operation of any type, with revision performed in 23 [4.6%]. Of the long-term survivors 66 [81%] had none or minimal pain, whilst 5 [6%] had reported constant pain in the hip.

This is the largest consecutive series, with the following follow-up, reported and for the frail elderly patient this prosthesis can still be recommended.


AO Odumala MI Iqbal RG Middleton

The aim of our study was to determine if the canal flare index of the proximal femur is a dependent factor in prosthetic failure after Austin Moore hemiarthroplasty.

We measured the canal flare index on A-P hip X-rays of 100 and 100 patients with failed and successful Austin Moore hemiarthroplasty respectively. We also measured the canal flare index of a control group of 100 patients without hip fractures. The canal flare index (CFI) is defined as the ratio of the width of the femoral canal at two levels: 20mm proximal to the centre of the lesser trochanter and the canal isthmus. Overall we reviewed 300 radiographs. The study group consisted of 68 males and 232 females. In the failed Austin Moore group there were 62 patients (62%) with loosening, 28 patients (28%) with dislocations and 10 patients (10%) with periprosthetic fractures. The canal flare index of the proximal femur was significantly higher in patients who had persistent thigh pain with radiological loosening in comparison the successful and control groups. (3.3 vs 2.6; 3.2 vs 2.7 respectively: p< 0.001). On the other hand patients with periprosthetic fractures had a lower canal flare index in comparison with the successful and control groups (2.1 vs 2.6; 2.1 vs 2.7 respectively: p< 0.001). However there was no differences in the CFI of patients with dislocations compared with successful (2.4 vs 2.6;p=0.1) and control groups (2.4 vs 2.7;p=0.2). This remained the same when controlled for age and sex in a logistic regression analysis.

Conclusion: The CFI can identify patients prone to persistent thigh pain who present as radiological loosening and to periprosthetic fractures and an alternative cemented prosthesis should be considered in this group of patients


A Upadhayay L Maini P Jain SK Kapoor VK Gautam

Displaced intra-capsular fractures of femoral neck are treated by osteosynthesis in young adults. Using a standard protocol, we have compared the results of internal fixation after closed (CRIF) and open reduction (ORIF) in these patients. We have also studied the risk factors that influence non-union and avascular necrosis (AVN).

Patients in the age group of 15–50 years, who were scheduled for internal fixation within 1 week of injury, were randomized into two groups, one for closed reduction and the other for open reduction. The two groups were compared for factors such as age, gender, time of surgery and posterior comminution as well as union and complications. Using univariate and multivariate methods the factors influencing non-union and AVN were analyzed.

The average duration of surgery in patients undergoing CRIF was less than half of that in the ORIF group. The rates of union (p=0.93) and avascular necrosis at 2 years (p=0.85) were comparable. Rates of complications like deep vein thrombosis and infection were also found to be comparable. Guide wire breakage was found in 2 patients undergoing CRIF. Posterior comminution, poor reduction and improper screw placement were the major factors influencing non-union. An accurate reduction in both the planes and placement of screws parallel or slightly divergent to each other had a positive influence on union. An overall AVN rate of 16.3% (15/92) was encountered and it was not influenced by any of the factors. A delay of more than 48 hrs in surgery did not influence the rates of union or AVN.

Conclusion: Both CRIF and ORIF are credible methods of treatment. Although the duration of surgery in CRIF is less than ORIF, the added time taken in achieving the reduction on the fracture table may actually make the whole procedure longer than ORIF. Posterior comminution, early loss of reduction and convergent screw placement are leading reasons for non-union.


J Kendrew J Varley M Parker

One of the most common early complications after hemiarthroplasty is dislocation, with an incidence of 2 to 4%. After dislocation the mortality and morbidity are significantly increased to in excess of 50%.

It has been claimed that a bipolar hemiarthroplasty has a lower risk of dislocation than a unipolar implant. In addition it has been suggested that patients with either Parkinson’s disease or a previous stroke are at increased risk of dislocation. We investigated these claims by performing a comprehensive literature search of articles published in the last 40 years and data obtained from our own hip fracture database.

From the literature review, 133 reports involving 21,872 patients were retrieved. A further 1235 hip fractures treated by hemiarthroplasty were recorded from our database. 791 (3.4%) dislocations were recorded. Dislocation rate for unipolar prosthesis was higher than bipolar prosthesis (3.9% versus 2.5%). Dislocation rate for posterior surgical approach was higher than for anterior approach (5.1% versus 2.4%). Dislocation rate for cemented prosthesis was 3.6% versus 2.3% in un-cemented prosthesis. However, the effect of the type of implant becomes non-significant on adjusting for the use of cement and surgical approach. The incidence of open reduction after dislocation was increased with bipolar implants. Patients with Parkinson’s disease showed a highly statistically significant increase in dislocation rate (8.7% to 3.4%). The dislocation rate with respect to ipsilateral hemiplegia was 1.6%.

This study indicates there is no difference in the dislocation rate between a unipolar and bipolar prosthesis but if a bipolar prosthesis dislocates, there is an increased risk of failure to reduce the prosthesis by closed means. Patients with Parkinson’s disease are at an increased risk of dislocation but this is not the case for those with a hemiplegia. To minimise the risk of dislocation of a hemiarthroplasty, particularly in those patients with Parkinson’s disease, a unipolar hemiarthroplasty inserted via an antero-lateral approach is recommended.


A Chougle JP Hodgkinson

To determine socket survivorship in DDH based on the severity of hip dysplasia, we carried out a retrospective study of 283 cemented total hip replacements carried out at Wrightington. The hips were classified according to the Crowe and Hartofilakidis classifications. Revision was used as the end point for prosthetic survivorship. The results were analysed statistically using SPSS for Windows

The mean age at time of surgery was 42.6 years with a mean follow-up of 15.7 years. The acetabulum was grafted in 46 cases. The commonest cause for revision was aseptic loosening of the acetabular component (88.3%). 254 procedures were carried out through a transtrochanteric approach with a direct lateral approach used for the remaining mildly dysplastic hips. At 10 years 5.3% of dysplastic, 14.8% of low dislocation and 51.1 % of high dislocation hips were revised.. At 10years 6% of Crowe Type1, 8.5% of Type2, 25.5% of Type3 and 39.2% of Type4 hips were revised. At 20 years 24% of dysplastic, 45% of low dislocation and 88% of high dislocation hips were revised. At 20years 27.3% of Crowe Type1, 29.3% of Type2, 63.3% of Type3 and 84.4% of Type4 hips were revised. The 20 year survival of patients less than 50 years of age at the time of surgery was 61% as compared to 92% survival in patients more than 50 years of age. The mean age of patients in the revised group was 35 years as compared to 45 years in the non-revised group.

Conclusion: This study demonstrates satisfactory results in dysplastic hips following cemented total hip replacements. With increasing severity of hip dysplasia there is a higher rate of premature failure of the acetabular component. There is adverse correlation between age and survival of the acetabular component. There is a dramatic increase in cup failure between 10 and 20 years.


N Pradhan J Hodgkinson P Wood R Vhadra P Wykes

Patients undergoing total hip replacement (THR) often require further orthopaedic surgery including other primary lower limb joint replacements and revision surgery in their lifetime. We analysed the 10-year data of 552 patients who underwent primary total hip replacement between April 1991 and March 1992 at our institute. Data were available for all patients before the index operation. 77% of patients attended their 5-year review and 67% attended their 10-year review. 233 (42%) had had or subsequently had the opposite hip replaced. 30 patients (5%) had a knee replaced and 19 (3%) had both knees replaced. 4.4% underwent revision surgery.

Conclusion: nearly half the total number of these patients will in due course require the opposite hip replaced. 13% will need another major joint surgery (ie revision or TKR). At £6138 for a primary THR and £8500 for revision THR, and the cost of radiographs (£60) and follow-up appointment (£60), the approximate cost implications on a conservative estimate are £13,000.000. These factors including cost implications and human resource requirements will have significant influence on future planning of health care trusts.


S Cutts A Datta A Khalid T Lawrence R Habib

Between January 1996 and July 2002, 60 patients (65 hips) were treated in our unit by 5 consultant surgeons using the Corin Cobalt-Chrome metal-on-metal hip resurfacing. 41 procedures were performed on male patients and 24 female.

All 65 cases used the Cormet Hip resurfacing (Corin, UK). Of these, 12 cases (18.5%) have required revision for mechanical failure. 5 of these patients were male and 7 female. The time to failure was defined as the interval between the date of primary and the date of revision surgery. The mean time to failure was 10.2 months (range 48 hours to 53 months). 8 out of 12 patients required revision within 6 months of the primary procedure. The mean age at the time of revision was 56 years (range 22–71 years).

The commonest mechanism of failure in our series is fractured neck of femur and 4 out of the 6 fractured neck of femur occurred in females over the age of 60. Only 12 of our primary hip resurfacings were women over 60 with the result that 33% of this group were complicated by fractured neck of femur.

In 4 cases, the indication for revision was acetabular loosening. One patient underwent revision surgery for chronic pain of unknown aetiology and one developed progressive avascular necrosis of the femoral head.

Our early results suggest that the procedure is operator-dependent and associated with a steep learning curve. The procedure would appear to be contraindicated in women over 60 and others at risk of osteoporosis.


Y Ahmad M Bishay G Andrew D Pring S Krikler

We present an independent multi-centre follow-up of metal-metal resurfacing from district regional hospitals (DGHs) in a series of ‘young’ patients with implants from a single manufacturer.

Between November 1995 and November 2002, two hundred and thirteen primary total hip resurfacings were performed in six centres. Two hundred and ten patients were followed up with none lost to follow-up. The average age of the patient group was 52.9 years range (21.9–71.3 years). Of these 210 patients 119 were male and 91 were female. There were three bilaterals and five revisions recorded with a revision rate of 2.3% at seven years. The maximum duration of follow-up was 84 months, the minimum was 3 months and the mean follow-up was 43.5 months.

The average Harris Hip score at the latest follow-up review was 78.15 (range 23–100). The Kaplan-Meier Survivorship of Cormet was 95% at 7 years and a survivorship of 97.38% at three years. These results indicate that metal-metal resurfacing meets the NICE guidelines for suvivorship at the three year benchmark in DGHs with local patients and is on course to meet the 10 year benchmark despite the extremely demanding patient group.


MR Acharya WM Harper G Eastwood D Evans

Cerebral micro emboli have been noted to occur during both total hip and knee arthroplasty. These micro emboli have been implicated in the causation of postoperative cognitive impairment. The aim of this study was to determine whether cerebral micro emboli occur during hip fracture surgery.

28 patients undergoing hip fracture surgery had transcranial doppler assessment of the middle cerebral artery to detect cerebral micro emboli. Micro embolic signals (MESs) were recorded during the operative procedure.

Successful monitoring was carried out in 26 patients. MES were recorded in 16 out of 26 patients. 12 out of 16 patients who had MESs had undergone a cemented hemiarthroplasty; the remainder had a sliding hip screw for an extracapsular hip fracture. 75% (9/12) of patients who had a cemented hemiarthroplasty had the majority of MESs after reaming and cementing. MESs in the patients who had a sliding hip screw occurred throughout the operative procedure.

Conclusion: Cerebral micro emboli do occur during hip fracture surgery. These emboli may be responsible for the cognitive dysfunction that occurs in this susceptible group of patients.


RU Ashford A Frasquet-Garcia P De Boer P Campbell

Hip resurfacing is a procedure designed to conserve bone stock in the younger patient and facilitate revision to a total hip arthroplasty if the need arises. The Wagner Hip Resurfacing (WHR) was a metal-on- poly implant introduced in 1978.

The notes and radiographs of 16 patients who underwent 19 WHR procedures performed by a single surgeon between 1980 and 1984 were reviewed.

The mean age at primary surgery was 54 (range 41–68). 16 of the WHRs required revision at a mean time of 45 months (range 1–144 months). 3 WHR had not been revised: one is functioning at 22 years, one functioning well 20 years after implantation when the patient died and 1 non-functional 9 years after implantation due to femoral head reabsorption.

The reason for revision was femoral neck fracture (3), femoral head collapse / avascular necrosis or loosening (8), acetabular loosening (5).

Subsequent problems with the revision were noted in 6 patients (2 dislocations, 2 infections, 1 acetabular loosening and 1 femoral loosening). 3 patients ended with a Girdlestone excision arthroplasty and 2 required re-revision.

Hip resurfacing is designed as a conservative option for the young arthritic hip. This prosthesis not only failed catastrophically at an early stage but had a major subsequent impact on revision surgery and complications associated with it.


VI Shevtsov SI Shved AV Kaminsky KA Giannikas

We report a prospective study of 106 consecutive patients younger than 60 years old who suffered an intertrochanteric fracture of the proximal femur and were treated with an “Ilizarov” external fixator. All surviving patients were assessed with the assistance of the “CITO” evaluation system for fracture outcomes at three months post-injury and 73 patients were either clinically reviewed or contacted by a letter to establish the long-term results.

Complications included one intraoperative death, one case of post-traumatic ankylosis of the hip, two cases that were discharged in varus and one case in valgus of the femoral neck. Other complications included pin-track infections and stiffness at the level of the knee that required a year to resolve. Overall long-term satisfaction was high (76% in reviewed patients and 91% in patients contacted by letter).

The advantages of the “Ilizarov” external fixator include minimal disruption of the tissues and blood loss, capability of closed reduction of the fractures as well as post-operative manipulation of the fracture by gradual adjustments of the frame. This method, however, is time consuming, requires expertise and intense follow-up during the immediate post-operative period.


SKZ Hassan JR Lewis CG Moran R Wenn

To assess the relationship between preoperative urea concentration and mortality in patients with hip fractures requiring surgery, we carried out a prospective observational study of 1230 consecutive patients admitted to a single trauma unit with a hip fracture, required surgery.

Results: The mean age was 80 years (range 17–101) and 931 (77%) were female. 669 patients (54%) had intracapsular fractures, 547 patients (45%) had extra-capsular fractures and 14 patients (1%) had periprosthetic fractures. 760 (62%) patients were admitted from their own homes, 178 (15%) from residential homes, 150 (12%) from nursing homes and 123 (10%) from warden-aided homes. 644 (53%) were independently mobile before injury, 311 (26%) used walking aids, 241 (20%) were mobile with the use of a frame and 24 (2%) were unable to walk. 371 (32%) patients had a mini mental test score of less than 7. 49 (4%) were known to have renal disease and 106 (9%) had diabetes.

The 30-day mortality was 9.8% and the 90-day mortality was 19.9%. The mortality at 1 year was 29.0% and at 2 years was 30.2%. There is a clear relationship between a raised admission urea concentration and mortality at 90 days, 1 year and 2 years. Abnormalities of serum sodium and potassium concentration did not influence mortality.

Conclusion: Mortality is high following hip fracture. Patients admitted with a raised serum urea and treated with operative methods are at increased risk of death at all the time intervals analysed, up to and including 2 years. This group of patients may require a separate care pathway that provides more intensive management of fluid and electrolyte balance.


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A Hussain K Siva RK Prasad

To evaluate one-year mortality rate of hip fractures treated surgically and assess the influence of medical status and ASA grade on this parameter. 212 patients above 65 years (range 65–100, mean 82.7): There were 104 (49.1%) intertrochanteric and 108 (51.9%) femoral neck fractures. A number of surgical procedures, (sliding/compression screw 104 (49.1%), hemiarthroplasty 81 (38.2%), cannulated screws 18 (8.5%) and total hip replacement (4.2%) were used. The one - year mortality rate was obtained from computerised records, case notes and General Practitioners.

One-year mortality rate for the whole group was 28.8% with an exponential increase corresponding to ASA grade. The relationship between ASA grade and mortality for the whole group (P< 0.001), younger age group of 65 – 84 years (P< 0.001), older age group of 85– 100 years (P=0.002), early operation group < 2 days (P=0.001), females (P=0.000), intertrochanteric fractures (P=0.007), femoral neck fractures (P=0.022) and sliding/compression screw (P=0.007) was highly significant. The type of operation per se and time of operation had no predictive value.

Conclusion: Statistically significant mortality is neither dependent on age, nor type of fracture, time of surgery and type of surgery per se, but is essentially a reflection of ASA status.

The extensive dominant influence of ASA grade is a highly significant predictive determinant and final arbiter of surgical risk and mortality in hip fracture.


E. Tsiridis AA Narvani FS Haddad J Timperley GA Gie

To assess the outcome of periprosthetic femoral fractures (Vancouver B3 type) around loose stems treated by impaction grafting revision, 106 B3 fractures were reviewed. To assess the association between those who healed and those who did not for the factors of interest such as stem length, impaction grafting and the combination of the above, odd ratios along with their 95% CI and their p-values were reported. Logistic regression in STATA version 7.0 employed.

75 out of 89 fractures treated with long stem revision and 10 out of 17 with sort stem healed. 74 out of 89 fractures treated with impaction grafting and 11 out of 17 treated without impaction grafting healed.

66 out of 75 fractures treated with long stem and impaction grafting and 9 out of 14 treated with with long stem but no impaction grafting healed. 8 out of 14 fractures treated with short stem and impaction healed. Average healing 8.5 months.

Those treated with long stem are almost four times more likely to heal than those treated with short stem (odds ratio = 3.75 95%CI: 1.21–11.6 p=0.022) and those with impaction grafting are also more likely, but not statistically significant, to heal than those without impaction grafting (odds ratio = 2.69, 95%CI: 0.86– 8.45 p=0.090). Furthermore, those with long stem and impaction are significantly more likely to heal than those without impaction grafting and those with short stem and impaction grafting (odds ratios = 4.07, 95%CI: 1.10 – 15.0 p=0.035 and 5.5, 95%CI: 1.54 – 19.6 p=0.009 respectively).

Impaction grafting is an increasingly popular technique for the restoration of femoral bone stock. It can successfully be applied to periprosthetic femoral fractures but a long stem should be used to bypass the distal fracture line.


G Mundy CNA Esler WM Harper

Approximately 10% of primary hip replacements performed each year for osteoarthritis are in patients aged 55 or less. These patients have a longer life expectancy and a higher activity level than an elder cohort, which may translate to higher revision rates.

We utilized a regional hip register (Trent and Welsh Arthroplasty Audit Group (TWAAG)) to review current surgical practice in this age group. The TWAAG group comprises 118 surgeons working in 31 different hospitals covering a population of 8 million (14.2% of the population).

1 January 2000 to 31 December 2002, we were notified of 7,678 primary THRs for osteoarthritis. 911 (11.7%) were performed on patients aged 55 or less. Age, gender, grade of lead operating surgeon, type of femoral and acetabular prosthesis implanted, fixation method, femoral head size and bearing surfaces were recorded. There were 434 males, 477 females, with an age range of 16–55. Thirty-five femoral and thirty-three acetabular components were identified. 61.7% of femoral prostheses were cemented. 67.4 % of acetabular prostheses were uncemented. 30% of THRs implanted in the group over the study period were hybrid. 50% of implants had a metal/UHMWPE bearing. Other bearing surfaces comprised ceramic/UHMWPE 28.7%, metal/ metal resurfacing 13.8% and ceramic/ceramic 7.5%. Consultants performed 84.5% of procedures.

Femoral prostheses with little or no published data are used and, unless closely monitored, such practices will not be compliant with NICE recommendations. 40% of THRs performed had components implanted that were produced by different manufacturers. At the present time there does not appear to be a clear picture as to what is the ‘gold’ standard for young patients. Continued monitoring of these implants is essential to provide feedback and drive choice.


KL Barker SE Barrington AG Clarkson-Webb S Squires A Racey

The DTC approach to patient management aims to decrease waiting list times and length of stay (LOS). To implement a reduction in the LOS it is imperative that suitable patients are selected. Factors such as co-morbidity and social support are important but other factors may also influence LOS.

To investigate if pre-operative measures of function were predictive of length of stay for patients treated in a Diagnostic & Treatment Centre for elective hip arthroplasty. The first 75 patients treated by the DTC were assessed pre-operatively recording timed measures of function for sit-to-stand, and stair climbing as well as ratings of pain and the WOMAC questionnaire. These measures were compared with the LOS for patients and their functional outcome at 6 weeks after discharge.

Linear regression was used to examine the influence of the measures on LOS. T-tests were used to compare the outcome at 6 weeks for pain and function between patients discharged within 5 days versus > 5 days.

The mean age was 65 years (39 – 80 years SD 8.4); 33 male and 42 female. Mean LOS was 6 days (4–14 SD 1.8), 52 % reached the DTC target of discharge on the 5th day. Regression analysis showed sit-to- stand was the best predictor of LOS (R2 = 46.7%) followed by WOMAC pain and climbing stairs. There were no significant differences in the pain or function scores at 6 weeks for patients discharged at 5 days or later.

Conclusion: There was a linear relationship between pre-operative sit-to-stand and LOS. The timed measures were simple to perform and patients could be tested in their own homes. Early discharge did not result in poorer self-reported outcome at 6 weeks. The routine measurement of sit-to-stand may be useful to clinicians as a prognostic indicator for treatment allocation and planning.


SS Prasad M O’Connor N Pradhan JP Hodgkinson

Recently, there has been a reluctance to perform hip arthrodesis. The number of patients requiring the conversion from hip arthrodesis to arthroplasty has also decreased. We present the functional results following conversion of hip arthrodesis to total hip arthroplasty at a specialist hip centre.

76 patients who underwent conversion of hip arthrodesis to total hip arthroplasty between 1963 and 2000 at the Centre for Hip Surgery, Wrightington Hospital, were included in this retrospective study. 9 patients died of unrelated causes and 7 patients were lost to follow up. The functional scoring was performed using the Merle d’Aubigné and Postel score.

The mean age at the time of surgical hip arthrodesis was 16.7 years and at the time of conversion was 48.7 years. Back pain is the most common indication for the conversion. All the patients were pleased with the clinical outcome following conversion to Arthroplasty. 6 patients had postoperative complications. The mean Merle d’Aubigné and Postel score increased from 8.97 to 13.46 at the latest follow-up. The mean wear rate was 0.06 mm/year. Survival of hip arthroplasty was 92.78 % at 18 years.

Conclusion: Our series demonstrates good outcome and patient satisfaction and high survival of the arthroplasty following the conversion from arthrodesis. Hip arthrodesis could be considered as a holding procedure in selected group of young patients with a later successful conversion to arthroplasty.


T D Lamberton JA Charity PJ Kenny A J Timperley GA Gie

Impaction bone grafting with a cemented polished double-taper stem as a technique for revision of the femoral component was introduced in 1987 at our institution.

As at January 2000, 540 cases in 487 patients had been performed. All procedures have been studied prospectively and there are no patients lost to follow-up. We present the survivorship and outcome data for these patients.

Survivorship at 15 years is 90.6 percent [95 percent confidence interval: 88–93 percent]. Clinical scores show marked and sustained improvement.

There have been 45 failures [8.3 percent]. Technical error contributed to 13 of the 24 non-infective complications, but with improved technique plus the addition of long stemmed impaction grafting, there have been no technical errors since 1996.

Our results show that revision of the femoral component with impaction bone grafting is a reliable and durable technique with an acceptably low complication rate and with excellent survivorship at 15 years.


J Ciampolini MJW Hubble

In the years 1990–1993, in an effort to reduce waiting list time, a small number of patients were sent from Exeter to hospitals in London to undergo elective total hip replacement. No medium- or long-term follow-up was arranged. Our aim was to audit the outcome of these hip replacements.

Review of the records of the referring medical practices, Regional Health Authority, local Orthopaedic Hospital and the distant centres at which the surgery was performed has identified 31 cases. A total of 27 hip replacements in 24 patients were available for clinical and radiological review.

12 (44%) hips have so far required revision surgery, at a mean of 6.5 years. Of these, three (11%) have been for deep infection. A further three hips (11%) are radiologically loose and are being closely monitored. Two patients (7%) suffered permanent sciatic nerve palsy.

Patients whose surgery was performed locally over a similar time period have a published failure rate of only 4.6%. The causes for such a difference in outcome were analysed and include surgical technique, implant selection and absence of follow-up. In the light of this evidence, we would like to urge the government to address waiting list problems by investing in the local infrastructure. Expanding those facilities where properly audited and fully accountable surgeons operate must be the way forward.


G Senthil Kumar M O’Malley N P Geary

To describe a discrete fascial canal containing the medial plantar cutaneous nerve of the great toe in operations of the great toe. Clinical Relevance: The medial plantar cutaneous nerve of the great toe is one of the terminal branches of the medial plantar nerve which itself is the anterior division of Posterior tibial nerve. This branch provides sensation to the dorsomedial aspect of the distal phalanx of the great toe.

Motor branches of the medial branch are given off proximal to the first metatarsophalangeal joint. A medial incision centred over the first metatarsophalangeal and creation of distally based capsular flap is employed in number of operations of the Hallux, e.g. Modified Silver’s McBride, Chevron Osteotomy, Replacement of the MTP Joint. The medial plantar cutaneous nerve is prone to injury if it is not identified and protected, leaving the patient with loss of sensation to the medial surface of the great toe. After dissection of the skin and superficial fascia over the medial side of the 1st MTP joint, a discrete layer of dense connective tissue is seen passing from the medial sesamoid to the medial plantar aspect of the first metatarsal. The closed blades of dissecting scissors can be inserted under this layer proximally to distally and the medial plantar cutaneous nerve can be seen to enter the canal at its proximal end. This fascial layer can then be opened and the underlying nerve thus identified and protected. Opening the tunnel proximally and identifying the nerve ensures nerve is not divided with plantar arm of distally based capsular flap. Identification and protection of this nerve prevents the complication of loss of sensation and the development of a painful neuroma, giving the patients a better outcome following surgery.


PTH Lee MT Clarke PWP Beacroft AHN Robinson

Distal tibial fractures may be satisfactorily held in reduction by fine-wire external fixation techniques, avoiding the need for open reduction and internal fixation. However, as the use of external fixation is associated with pin-site infection, extra-articular placement of the wires is recommended. This study assesses the proximal extension of the capsule of the ankle joint in order to provide information on the safety of wire placement for distal tibia fractures.

We recruited 7 patients who were electively scheduled for an MRI ankle investigation with the suspicion of osteochondral defect and/or meniscoid lesion. Patients with a history of ankle fracture or ankle surgery were excluded from the study. Just prior to MRI, the ankle joint was injected with 5 to 15 ml of contrast solution (1 mM dimeglumine gadopentetate). Selected fat-saturated T1-weighted MRI scans with sagittal, coronal and axial views were obtained. The site and proximal extent of the capsular reflection with reference to the anterior joint line were measured.

All contrast-enhanced MRIs of the ankle joint space were well defined and unambiguous. Proximal capsular extensions above the plane of the anterior joint line were noted at the antero-medial and antero-lateral aspect of the joint (mean 8.9 mm, range 4.9 to 13.4 mm) and at the tibia-fibular recess (mean 18.7 mm, range 13.3 to 23.6 mm), areas that are frequently traversed by wire insertion.

Conclusion: This in vivo contrast-enhanced MRI ankle study demonstrates an appreciable capsular extension above the joint line of the ankle. The proximal capsular extensions at the antero-medial and antero-lateral aspect of the joint and at the tibio-fibular recess run the risk of being traversed during fine-wire placement for distal tibia fractures. Surgeons using these techniques should be aware of this anatomy.


A Ghandour DJ Fagan RH Thomas DP O’Doherty

In a prospective study to evaluate the benefits of radial extracorporeal shockwave therapy (ESWT) in patients with longstanding chronic Achilles tendonitis. 34 cases of non-insertional Achilles tendonitis were treated in 32 patients, using radial shockwave treatment. Symptoms had been present for at least ten months and were resistant to conservative treatments. Patients received three shockwave sessions at weekly intervals. Evaluation was performed prior to treatment, at six weeks and three months after the final session. Patients completed a visual analogue score (VAS) for maximal pain (0–100), the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot Scale and the Victorian Institute of Sport Assessment-Achilles questionnaire (VISA-A).

At short-term review all patients reported an improvement in symptoms. The VAS fell from a pre-treatment value of 74 (+/−15) to 22 (+/−17). An improvement in the AOFAS from of 64 (+/−10) to a post-treatment value of 90(+/−7) was seen, and an average from 30 to 70 in the VISA-A score. No complications from the treatment were reported. Four patients previously listed for surgery have improved sufficiently to be removed from the waiting list.

Conclusion: Short-term results using ESWT for the treatment of longstanding non-insertional Achilles tendonitis are encouraging. Longer-term follow-up subsequent to this prospective pilot study is underway to assess if results are reproducible over a greater time period.


J E Owen K Baker S Palmer P Cooke

The purpose of this study was to investigate the functional outcome of a group of patients following completely neglected tendo-achilles ruptures.

Between July 2001 and July 2002 we identified 6 patients who presented to the Foot and Ankle Service in Oxford with 7 chronic untreated complete ruptures of the tendo-achilles. There were 4 males and 2 females and the average age was 65 years (range 52 to 79). The average time since injury was 12.2 months (range 7 to 24). None of them had undergone any modality of treatment for this condition. From the history, a definite acute injury was confirmed in each patient. All patients had a palpable defect in the tendo-achilles between 4 and 8 cm from the insertion and the defects measured from 10 to 32 mm. In all case the Thompson test confirmed ongoing discontinuity and single leg heel raise was not possible on the affected side. Each patient was assessed using the scoring system of Leppilahti and concentric and eccentric power were assessed using the Kin-Com Dynamometer. The results indicate an average Leppilahti score of 65/100 with 1 excellent, 0 good, 3 fair and 2 poor. The isokinetic strength measurements demonstrated that plantar flexor power was on average 36% weaker than the normal side. These differences were most marked at the higher test speeds, which were on average 16% weaker than at the lowest test speed in the affected leg. Five out of 6 patients were pain free, with only one reporting mild pain. Objective testing demonstrated no differences in the range of movement between the injured and the normal side. All patients were satisfied with the outcome; however, most had some reservations, which related to ongoing weakness that prevented recreational activity.

Conclusion: At one year after injury the completely neglected tendo-achilles rupture in the older population is likely to be pain-free, to have full active ankle movement and to recover two-thirds of the power of plantar flexion compared to the unaffected limb. Ongoing weakness will prevent recreational activity but has minimal affect on activities of daily living including stair-climbing ability. We have established a benchmark of the natural history of this condition in the older patient against which the results of surgical treatment can be compared.


S Kadambande K Hariharan

To compare the intrinsic foot function and pliability of the foot in shoe and non shoe wearing population, measurement on the right foot of 100 randomly selected non-shoe wearing (Indians) and 100 shoe-wearing (British) population was carried out. They had normal body-mass index, age between 25 to 35 years and no previous injury or disability to the lower extremities.

Using a force gauge, force of extension and flexion at 1st metatarsophalyngeal joint, abduction at 5th meta-tarsophalyngeal joint and adduction between 1st and 2nd toe was measured. Pliability Ratio was calculated as follows:

Maximum weight bearing foot length X maximum weight bearing foot length

Maximum non-weight bearing foot length X maximum non-weight bearing foot length.

Using the student test at 95% confidence interval, there was no statistically significant difference in the intrinsic foot function. Multivariate regression analysis showed that after adjustment for other variables like gender and ethnicity, the shoe condition is significant on the pliability ratio. This study shows that although shoe-wearing does not affect the intrinsic foot function it definitely results in stiffer feet. This difference is more marked in women (p=0.0171).

Shoe-wearing can affect the transmission of forces during locomotion especially if the muscles acting across the foot are normal but the joints across which they act are stiff. Shoes have an inbuilt medial arch support and narrow toe boxes. This result in incomplete movement of the transverse and longitudinal arches of the foot leading to stiffer feet and can affect the biomechanics of shod feet.


N Elomrani M Saleh

We report a series of sixty corrections in fifty-five adult patients performed from 1989 to 2001 for complex deformities of the foot and ankle, using circular external fixation, with a mean follow up of 4.4 years. We studied the aetiology, pathophysiology of injury, clinical and radiological evaluation, and the method and outcome of treatment. The patients mean age was 37 years (range 16–65). 37 male. 18 females. 44 deformities were sequel of severe lower limb trauma; the others were due to neurological, congenital and iatrogenic causes. 38 patients had associated proximal pathology including non-union, malunion, shortening and deformities. This required simultaneous correction. In most patients, conventional surgery had failed to achieve correction and many of them were considered for amputation. The aim of surgery was correction of deformity in forty-two occasions and correction of deformity with ankle fusion in eighteen occasions.

For each patient, specific treatment goals were delineated that were realistically achievable. Initial complete correction was achieved in fifty-two patients; there was recurrence of the deformity in fourteen. Forty patients needed corrective osteotomies (16 ankles, 24 tibia and fibula). The results were classified as excellent in six patients, good in thirty-five patients, fair in eight patients, poor in six patients, five of whom had a below-knee amputation. Complications were minor and all resolved with appropriate therapy.

Conclusion: Circular external fixation offer a versatile and effective method of treatment of a variety of complex foot and ankle deformities; however, the surgeon should be familiar with both, their application and subsequent management. If foot and leg deformities coexist consider simultaneous correction. Corrective osteotomies may lead to less recurrence than soft tissue correction alone. Fusion should be considered where muscular imbalance or severe degenerative changes exists. In some cases with severe pathology; the only other option may be amputation.


G S Kumar M Ramakrishnan AEJ Froude NPJ Geary

The aim of the study was to assess the clinical, radiological and paedobarographic outcome following modified Silver’s McBride’s procedure, in the treatment of Hallux Valgus. Between 1997 and 1999, Modified Silver’s McBrides procedure for Hallux Valgus was performed on 38 foot in 28 patients (18 unilateral and 10 bilateral). The median age was 60 years. The median follow up was 26 weeks. Clinical outcome measures consisted of pain, deformity, mobility, walking ability and shoe wear. Radiological outcome measures were Hallux Valgus angle, Intermetatarsal angle, 1st to 5th Metatarsal distance, 1st to 2nd metatarsal distance, and the DMAA (Distal Metatarsal Articular Angle). Paedobarographic (Musgrave) outcome of peak pressure, total force, time from heel strike to toe lift off post operatively were analysed. Preoperative visual analogue pain score was 5–8 and 0–4 postoperatively (p< 0.001). 34 feet had pain on walking preoperatively and only 11 had pain post-operatively. 12 were wearing special shoes pre- operatively and 5 post-operatively. Hallux Valgus angle was 34 pre-operatively and 19 post-operatively (p< 0.001). IMT angle was 14.53 pre-op and 10.88 postop (p< 0.001). 1st-5th MT distance was 67mm pre- op and 63mm post-op (p=0.001). 1st-2nd MT distance was 15 pre-op and 10 post-op (p=0.004). DMAA was 24.7 degrees. 21 foot an obliquity of the 1st tarsometatarsal joint was seen indicating an anatomical cause of metatarsus varus. Foot pressure studies showed a peak pressure of 1.37kg/cm2 , heel to toe off- time was 936.9ms and maximum load was 65.2 kg. There were 3 cases of superficial wound problems. One patient developed Hallux varus deformity, with no functional disability.

Conclusion: Modified Silver’s McBride procedure for the treatment of Hallux Valgus is a soft tissue procedure and is a safe alternative to the commonly practiced osteotomies for correction of this disorder.


L Di Silvio Z Ali A. Narvani A Goodship G Bentley E Tsiridis

Current bone grafts include allograft and autografts, both of which have limitations. Tissue engineering biotechnology has shown considerable promise in improving grafts. A competent graft material should ideally have osteoconductive and osteoinductive properties and comprise of bone forming cells and osteoinductive growth factors. In this study, we have evaluated the in vitro formation of bone and have used human demineralised bone matrix [DBM] and human insoluble collagenous matric [ICM] as scaffolds for mesenchymal stem cells [MSCs] and osteogenic protein [OP-1]. The objective was to determine whether combined addition of OP-1 and MSCs resulted in a superior bone graft substitute by improving the inherent osteoinductive property.

DBM and ICM were prepared and combined with rhOP [1.4 mg/0.25 mg of bone] and MSCs [1 x 105/ ml]. Statistically significant differences in MSC proliferation were seen between materials with and without OP-1 [P< 0.05}, n=8] in DBM on day 1, and both DBM and ICM on day 7 and 14. Enhanced osteogenic differentiation was observed in the presence of OP-1 when compared to DBM alone and on DBM and ICM with OP-1. In conclusion MSCs and OP-1 can be seeded together on DBM and ICM and Von Kossa staining and X-ray analysis confirmed in vitro de novo bone formation, with DBM + MSCs + OP-1 being more successful in this regard.

Conclusion: To date, no other study, to the author’s knowledge, has used MSCs and OP-1 together on a graft material; this funding, therefore, has very important clinical implications.


AS Aster MC Forster RA Rajan KJ Patel R Asirvatham

To assess the reliability of the pre-operative measurement methods used in the management of the hallux valgus deformity, five observers assessed 50 pre-operative standing foot radiographs on two occasions in order to assess the reliability of radiological hallux valgus assessment using the inter-metatarsal angle (IMA), hallux valgus angle (HVA) and joint congruency. Five published methods of angle measurements described by Hawkins, Venning and Hardy, Mitchell, Miller and Nestor were used.

Kappa statistics were used to assess the reliability of the diagnosis of congruency. Regarding IMA and HVA, mean values between the methods were assessed by one-way ANOVA. The differences between the methods and observers were assessed by two-way ANOVA.

Results: Diagnosis of congruency showed good agreement (k=0.608) over two occasions, although this did vary by observer.

The mean IMA and HVA measurements varied significantly between methods on both occasions (p< 0.0001). Mitchell’s method had the lowest and Miller’s the highest mean values.

Analysis of variance showed both method and observer variations were significant for IMA. But HVA measurements differed significantly only by observers.

Conclusion: The reliability of IMA and HVA measurements is poor whichever measuring method is used and these methods are not interchangeable. Study papers should state the measurement method used. For the pre- and post-operative assessment the same method should be used.


SS Prasad T Lake MS Hennessy

Scarf osteotomy is a z-osteotomy of the 1st metatarsal and is proposed to correct anatomical and functional deformities of hallux valgus. This procedure allows early ambulation and early return of function. This study was conducted to evaluate clinical and paedobarographic results following this procedure in a district general hospital.

From August 2000, we prospectively collected the data on 43 feet (32 consecutive patients) followed up for 12 months. We collected the data pre-operatively, 3,6 and 12 months post-operatively using AOFAS score, weight-bearing radiographs and paedobarographs. From the paedobarographs (Musgrave), the forefoot function was evaluated using peak pressure, force time integral and pressure time integrals.

Mean total AOFAS score increased from 45.13 pre-operatively to 94.5 post-operatively (p< 0.001). Postoperatively, the hallux valgus angle decreased from 29.83° to 11.79° and 1–2 intermetatarsal angle decreased from 12.48° to 6.37° (p< 0.001). Post-operatively, peak pressure has increased under the 1st metatarsal head and decreased under the 2nd metatarsal head. Force time integral and pressure time integrals also showed similar changes. We have not noticed significant alteration of forefoot pressures under the lateral part of forefoot.

Using scarf osteotomy, we achieved good correction of the hallux valgus deformity and significant improvement of AOFAS scores. We also noted alteration of the forefoot function with increased pressure under the 1st metatarsal and reduced pressure under the 2nd metatarsal head.

Conclusion: We believe that scarf osteotomy is a versatile and reliable procedure in the management of hallux valgus.


MG McMullan JV Glenn SO O’Hagan G Mclorinan S Valanne DR Marsh S Patrick

The first aim of the study was to investigate if bacteria were implicated in non-union of fractures of the tibia and femur, which had been treated with intramedullary nailing. The second aim was to evaluate the antimicrobial susceptibility of bacteria isolated from the retrieved intramedullary nails.

Forty intramedullary nails removed from tibial and femoral fractures were retrieved for the purpose of the study. Twenty of these nails were from fractures, which had successfully united and 20 were removed from fractures which had failed to unite prior to further operative intervention. There was no evidence of clinical infection in either of the two groups. The nails were subjected to ultrasound in the research laboratory to dislodge adherent bacteria formed as biofilm from the surface of the nail. Using both standard culture techniques and non-culture techniques (Immunofluorescence microscopy and PCR analysis) any dislodged bacteria were isolated and identified.

Isolated bacteria were tested for antimicrobial susceptibility to commonly used antibiotics in orthopaedic practice according to NCCLS guidelines.

Bacteria were detected in 15 out of 20 [75%] of the nails removed from fractures, which had developed a non-union, and in 5 out of 20 [25%] of fractures that had united, using both standard culture techniques and non-culture techniques. The bacterial isolates identified were mainly Staphylococcus epidermidis and the Gram-positive anaerobe Proprionibacterium acnes.

Vancomycin was the most effective antibiotic, with 2 out of 34 [6%] isolates being resistant. Erythromycin was the least effective, with 21 out of 34 [62%] isolates being resistant. Based on overall Minimum Bactericidal Concentrations at which 90% of all strains were killed, Vancomycin was the most active bactericidal agent tested followed in decreasing order by fucidic acid, ciprofloxacin, gentamicin, cefamandole and erythromycin.

Bacteria were detected more commonly in the fracture non-union group than in the union group [p< 0.01]. Of the antibiotic agents tested Vancomycin was the most effective and Erythromycin was the least effective.


AR Norrish M Hanif P Johnston R Sheikh M Gadir

Daycase lumbar microdiscectomy surgery is not widely practised in the UK. We studied the outcome of microdiscectomy as daycase or inpatient surgery.

Data collection was by retrospective case-note review of consecutive patients in each group. Inpatients not suitable for daycase surgery were excluded.

There was no significant difference between patient groups in the rate of recurrent prolapse, wound infection, permanent sensory loss, or persistent postoperative pain. Symptoms resolved and patients returned to normal activities equally in both groups.


E Tsiridis A Bhalla A Narvani A Goodship G Bentley L Di Silvio

Limitations of allografts and autografts for bone repair have increased the demand for a synthetic bone graft substitute for load-bearing and non-load bearing osseous defects. Tissue engineering of bone has thus been implicated to circumvent and eliminate the limitations of existing therapies, with living cell-scaffold constructs ultimately “integrating” with the patients own tissue. Bone engineering requires cells, growth inducing factors and a scaffold for delivery of cells to the anatomic site, creation of 3-D space for tissue formation and mechanical support. In this study, we investigated whether addition of osteogenic Protein-1 (OP-1) enhanced the osseoinductive properties of hydroxyapatite (HA) loaded with mesenchymal stem cells (MSCs). The study was conducted over a fourteen day period and the two groups HA/MSC and HA/MSC loaded with OP-1 were analysed qualitatively by SEM and quantitatively by assessment of proliferation (Alamar blue assay and total cellular DNA) and differentiation marker alkaline phosphatase activity (ALP). HA/MS/OP-1 showed a statistically significant (p< 0.05) increase in cell proliferation (286.52 ± 58.2) compared to the unloaded samples (175.62 ± 23.51). ALP activity (release) was also significantly enhanced (p < 0.05) in the loaded samples at day 14 (12.63 ± 1.58) compared to the control (2.73 ± 1.07).

Conclusion: the osseoinductive potential of HA was markedly improved by the incorporation of MSC’s and OP-1. This type of graft could provide improved mechanical stability at an earlier time point, and may influence future clinical application of HA for load bearing sites.


PA Rust P Kalsi SR Cannon TW Briggs GW Blunn

Bone grafts are frequently used to augment bone healing. Autologous bone graft is the gold standard for osteogenesis but is limited by availability and donor site morbidity. The processing required to lower the immunogenicity of allograft also reduces the osteogeneic properties. Bone marrow contains mesenchymal stem cells (MSCs) which differentiate into osteoblasts, forming bone. Our study examined the use of bone marrow to enhance the osteogenic properties of allograft.

Bioactive proteins within allogenic bone graft stimulate marrow-derived MSCs to differentiate into osteoblasts, thereby increasing the osteogenic nature of the graft.

After informed consent, bone marrow aspirates were taken from five patients during orthopaedic operations. Freeze-dried ethylene oxide treated allograft, from a number of donors, was obtained from the bone bank. MSCs isolated from each marrow aspirate were grown on eight samples of test allograft. Further allograft was heated to 70°C to denature the osteogenic proteins and MSCs from each aspirate were grown on 8 samples, as a negative control. Osteoblastic differentiation of MSCs cultured on the types of allograft was compared.

Scanning electron microscopy confirmed that MSCs covered the allograft after 14 days. Transmission electron microscopy showed that cells on the test allograft were characteristic of osteoblasts and produced collagen extracellular matrix. The levels of osteoblastic proteins, ALP, osteopontin and Type I pro-collagen, produced by cells on test allograft were significantly greater compared with heat-treated control (P< 0.005), after days 7 and 14.

Our study showed that marrow-isolated MSCs could be successfully cultured on allograft. As the levels of osteoblastic proteins increased significantly when MSCs were grown on allograft, osteogenic proteins within allograft caused MSCs to change into osteoblasts. This confirms that autologous marrow MSCs could be grown on allograft to increase its osteogenic prior to grafting, resulting in increased rate of bony healing.


KA Giannikas MT Karski AM Khan J Buckley RA Wilkes CE Hutchinson A Freemont

While the early period of distraction osteogenesis has been extensively investigated, there are very few data describing the long-term morphology of the regenerate. We performed magnetic resonance scans in ten adults (men age 35+− 11 yr), seven of whom had bone transport for an iatrogenic osseous defect while further three had tibial lengthening for limb length discrepancy. Follow-up ranged between 14 and 43 months (mean : 28 + − 10 months) following the removal of the external fixator. The perimeter, cross- sectional area, volume and the mean signal intensity was calculated from the obtained T1 weighted axial images. Values were compared with the contralateral tibia that acted as control. All cases that had bone transport increased the volume of the tibia from 15.3% up to 50.8%. The regenerated segment was noted to have expanded significantly (p< 0.0001) in all cases. Mean signal intensity in the regenerate decreased in seven cases significantly (p< 0.0001) suggesting increase content of unhydrated tissue such as bone and collagen. The cross-sectional surface of the transported segment was increased in all cases (p< 0.008). Finally in cases that underwent bone transport, the docking site was noted to be obstructed by unhydrated tissue. Contrary to previous claims, the post-distraction osteogenesis tibia is far from normal, consisting of areas with potentially different biomechanical properties. Recognition of these changes is essential not only for appropriate pre-operative counselling but also for considering treatment modalities in case of a fracture.


M A El Masry W I El Assuity Y K El Hawary C R Weatherley

Spondylolytic spondylolisthesis is one of the common causes of mechanical low back pain in adults. Conservative treatment of such cases, particularly for the low grade slips, remains the mainstay of management. When patients’ symptoms are marked and not responsive to conservative therapy, the surgical option can be considered. Up to the time of writing this abstract [January 2003], arthrodesis of the affected motion segment with or without instrumentation is the standard surgical option for treating mechanical low back pain. Results of different types of arthrodesis for treating such condition had been reported in literature, including posterior fusion, posterolateral fusion, and posterior and anterior interbody fusion.

Between 1993 and 1998, seventy- five adult patients with grade I or II lytic spondylolisthesis were treated by in situ posterolateral fusion and segmental instrumentation using the Oswestry Pedicle Screw System, with or without extended Gill’s procedure. The indications for surgical intervention in these cases were significant reduction in the quality of life with persistent low back pain and/or leg pain after a minimum of six months conservative therapy. Confirmatory imaging studies consistent with the clinical data should also be obtained before deciding the surgical option. The average operative time was 2.5 hours [range 2–4 hours). The average blood loss was 850 mls (range 300–2300 mls)

After an average follow-up of 60.7 months (range 24–95 months) clinical results were excellent and good in 92%, and radiological union was achieved in 94% of patients. Complications included 2 cases with superficial wound infection, one case with deep wound infection, and four of the patients went to non-union.

In conclusion, with a careful patient selection, patients with instrumental insitu posterolateral fusion gained a satisfactory clinical and radiological outcome and the results were maintained for an adequate postoperative period.


B J C Freeman R D Fraser C M J Cain D J Hall

Intra-Discal Electrothermal Therapy (IDET) has been proposed as a treatment for chronic discogenic low back pain. Reports from prospective outcome studies demonstrate statistically significant improvements, but to date there are no published randomized controlled trials assessing efficacy when compared to a placebo group.

Ethical Committee approval was obtained prior to the study. Patients with chronic low back pain who failed to improve with conservative therapy were considered for the study. Subjects had one or two level symptomatic disc degeneration as determined by provocative CT/discography. Patients were excluded if there was > 50% loss of disc height or previous back surgery. Fifty-seven patients were randomized with a 2:1 (IDET: Placebo) ratio, 38 to the active IDET arm and 19 to the sham procedure (placebo). In all cases the IDET catheter was positioned under sedation to cover at least 70% of the annular tear defined by the CT/discogram. An independent technician connected the catheter to the generator and either delivered electrothermal energy (active group) or did not (sham group). Both surgeon and patient were blinded to the treatment. Patients followed a standard rehabilitation programme.

Low Back outcome score (LBOS), Oswestry Disability Index (ODI), SF-36 questionnaire, Zung Depression Index (ZDI) and Modified Somatic Perceptions Questionnaire (MSPQ) were measured at baseline and 6 months. Successful outcome was defined as: no neurological deficit resulting from the procedure, improvement in LBOS of > 7 points, improvements in SF-36 subsets (pain/disability, physical functioning and bodily pain).

Two subjects withdrew (both IDET). Baseline demographic data, employment and worker’s compensation status, sitting tolerance, initial LBOS, ODI, SF-36, ZDI and MSPQ were similar for both groups. No neurological deficits occurred as a result of either procedure. No subject in either treatment arm showed improvement of > 7 points in LBOS or specified domains of the SF-36. Mean ODI was 41.4 at baseline and 39.7 at 6 months for the IDET group compared to 40.7 at baseline and 41.5 at six months for the Placebo group. There was no significant change in ZDI or MSPQ for either group. No subject in either treatment arm met criteria for successful outcome. Further analysis showed no significant change in outcome measures in either group at six months.

In conclusion, this study demonstrates no significant benefit from IDET over placebo.


A Marsh G Edge J Lehovsky

This study assessed whether spinal fusion surgery could be performed safely in patients with Duchenne’s muscular dystrophy (DMD) and a low (less than 30%) predicted forced vital capacity (PFVC).

Patients were identified with a diagnosis of scoliosis secondary to DMD who underwent spinal fusion procedures at the Royal National Orthopaedic Hospital, Stanmore between January 1990 and December 1999. Their notes and radiographs were reviewed and a standardised data collection form was completed.

Thirty patients with a mean age of 14 years 8 months at surgery underwent posterior spinal fusions. All were discharged from hospital alive and self-ventilating on average 22 days post-operatively (range 13–62 days). Thirteen patients had a PFVC less than 30%. The mean pre-operative curve was 61 degrees (range 30 to 90) and the mean number of levels fused was 15 (i.e. T3 to sacrum). The mean correction was 36 degrees (range 16 to 61). Two patients required temporary tracheotomies, one with a PFVC of 34% and one with a PFVC of 20%. Both were removed successfully after 39 days and 27 days respectively. There was no association between PFVC and operative time, blood loss, length of time on ventilatory support, time intubated, incidence of complications or length of admission.

Historically, only curves of greater than 20–35 degrees have been considered suitable for surgery, as the progression of the curve is associated with a marked decline in respiratory function. Considering the currently used criteria for surgery, the group of 13 with low PFVCs normally would have been denied surgery.

We conclude that spinal fusion surgery can be safely performed in DMD patients with a low PFVC.


L Ng P Sell

To evaluate prognostic factors that influence outcome particularly those related to duration of symptoms in surgery for lumbar radiculopathy, #2

In primary care 75% of patients are pain free after the onset of sciatica within 28 days. The optimum timing of surgery for unresolved leg pain secondary to herniated lumbar disc is unclear.

#2 We prospectively recruited 113 patients in this study and at one year, the follow up was available on 103 (91%). We investigated the prognostic value of a number of variables. These included the duration of sciatic symptoms, age at operation, Modified Zung Depression Score (MZD) and Modified Somatic Perception Score (MSP) using multiple regression analysis. The outcome was measured by the change of the Oswestry Disability Index (ODI), Low Back Outcome Score (LBOS) and of the Visual Analogue Scale (VAS). Patients with contained and non-contained herniated disc were compared.

The change in ODI is statistically significantly associated with the duration of sciatica symptoms (p=0.05) with a one-month increase in the duration of symptoms being associated with a decrease in the change of ODI of 0.6% (95% CI, −1.014 to −0.187). The duration of sciatica and the MZD are associated with significant reduction in LBOS (p=0.034 and 0.028 respectively). VAS was not significantly associated with all the prognostic factors investigated.

A shorter duration of sciatic symptoms was associated with a greater degree of patients’ outcome satisfaction. Non-contained herniated disc had a shorter duration of symptoms and a better functional outcome compared to contained herniated disc. Unemployment and smoking were not risk factors for poor surgical outcome.

Conclusion: Our study indicates that the duration of radicular pain of more than 12 months has a less favourable outcome. Patient’s satisfaction is greatest if surgery occurs within one year.


ML Costa L Shepstone ST Donell TL Thomas

The aim of this study was to test the efficacy of shock-wave therapy for chronic Achilles pain. Forty-nine patients with Achilles tendon pain for a minimum of 4 months were included in the study. Patients were randomised to either shockwave therapy (n=27) or placebo control (n=22). The treatment group were given 2000 shocks at up to 1500 mJ/mm2 per shock. The control (sham) treatment was applied using the same parametres but the shockwaves were dispersed before they reached the patient. Each patient was treated once a month over 3 months. The primary outcome measure was pain on walking indicated on a 100mm visual analogue score (VAS) at 3 months. The walking pain scores were very similar at baseline between the two groups. In the treatment group the mean (standard deviation) was 55.5 mm (30.6) and in the control group 55.6mm (26.5). By 3 months, the pain scores had reduced in both groups to a mean (standard deviation) of 34.5 mm (34.2) and 50.3 mm (36.3). Although lower in the treatment group this difference was not statistically significant at the 5% level (t-test, p=0.127, 95% CI : −4.7 to 36.2). Two elderly patients in the treatment group sustained spontaneous rupture of the tendon after falls during the course of the trial. The results of this trial provided no evidence for the use of shockwave therapy in the treatment of patients with chronic Achilles tendinopathy. However, a treatment effect cannot be ruled out since the 95% confidence interval included a potential clinically relevant difference. The two cases of rupture suggest extreme caution in treating the elderly.


J Wilson-MacDonald G Burt D Griffin C Glynn

To assess whether epidural steroid injection [ESI] is effective in the treatment of nerve root pathology caused by compression in the lumbar spine secondary to either spinal stenosis or disc prolapse, we carried out a prospective randomised controlled trial; patients were randomised either to ESI or Intramuscular steroid injection, with minimum two year follow-up.

Ninety two patients with symptoms, signs and radiological findings consistent with lumbar nerve root compression suitable for surgical decompression.

The main outcome measures were the Oxford Pain Chart over the first month, Oswestry Disability Index, and the need for surgery.

There was a significant reduction in pain early on after ESI compared with controls [p=< 0.004] between 10 and 35 days. There was no difference in the long term between the two groups and the rate of surgery in the two groups was not significantly different. Indeed the rate of surgery was higher in the ESI group than the control group [41% vs.31%] but this was not significant. A second ESI did not change the likelihood that surgery would be required.

Conclusion: ESI is effective for early pain relief for lumbar nerve root compression. However it does not change the natural history of the condition and does not reduce the ultimate need for surgery. It is probably effect to “buy time” in acute sciatica until improvement occurs naturally.


P Johnston AR Norrish T Brammer N Walton NP Coleman TA Hegarty

The objective of our study was to assess the efficacy of infection control measures (pre-admission screening and patient segregation) on reducing inpatient exposure to methicillin-resistant Staphylococcus aureus (MRSA).

A prospective case-control study was undertaken, analysing all admissions to three wards over an 83-month period from September 1995 to July 2002 inclusive (a total of approximately 34 000 patients). An orthopaedic ward with active infection control measures was compared with two controls, an orthopaedic ward with no measures and a general surgical ward with no measures. A statistical analysis was performed of the difference between the 3 wards in numbers of new cases of MRSA infection or colonisation. There was a statistically significant difference in numbers of new cases between the ward with the active infection control measures and the two control wards.

The infection control methods described are shown to reduce the exposure of patients to MRSA, which is of importance in orthopaedics, and has further benefits that may be applied in other surgical specialties, notably the choice of antibiotic used with the associated risk of side-effects of the specific anti-MRSA agents, the cost for surgical prophylaxis and patients’ confidence in the admitting surgical unit. As a useful by-product, such segregated inpatient beds are effectively ring-fenced, ensuring availability even during a hospital bed-shortage.


D Griffin M Dunbar H Kwong P Upadhyay D Morgan M Lwin D Damany C Barton G Surr

Hip and knee arthroplasty has been associated with relatively high rates of thromboembolic events and the majority of UK orthopaedic surgeons use at least one form of prophylaxis. Of the many different subgroups of thromboembolic rates that are commonly presented in the literature, symptomatic proximal deep vein thrombosis (spDVT) and fatal pulmonary embolism (fPE) are perhaps the most important clinical outcomes.

To determine the effectiveness of common chemical and mechanical prophylactic methods in preventing spDVT and fPE in patients undergoing primary hip and knee arthroplasty. A systematic review of the literature from 1981 to December 2002 was performed. Predetermined inclusion and exclusion criteria were applied. Studies where more than one method of prophylaxis was used were excluded from analysis. For each individual method of prophylaxis, data was extracted, combined and converted to give estimates of the rates of spDVT, fPE and major bleeding events. Absolute risk reduction estimates for spDVT, fPE and major bleeding events were calculated by comparing the thromboembolic rates for each method of prophylaxis with using no prophylaxis of any kind.

992 studies were identified of which 162 met the inclusion criteria. No method of prophylaxis was statistically significantly more effective at preventing spDVT and fPE than using nothing. There were at least as many major bleeding complications as spDVTs. The number of fPEs prevented was very small.

When complications such as major bleeding are considered, the evidence behind the use of any prophylaxis is unconvincing.


SR Mitchell K Hinduja R Samuel P Hirst

Problem-based learning medical courses are now in the majority in the UK. This type of teaching, based on research by Barrow in the 1960s, seeks to integrate basic sciences and clinical teaching, leading to the acquisition of an integrated knowledge base that is readily recalled and applied to the analysis and solution of problems. We noticed an apparent difference in the core anatomical knowledge in a group of 4th year medical students during their orthopaedic placement, some of whom had been taught a traditional course and some a PBL course. We set out to quantify this difference.

60 simple anatomy questions were asked, with 30 minutes allowed, and no negative marking. 33 students were PBL taught, and 27 by a traditional course, with a roughly equal male: female ratio. The average score in the PBL group was 39.2% (range 11–52%), whereas the traditional group averaged 73.7% (range 63–79%).

A second study was undertaken on two groups of 80 second year medical students, at 2 different UK universities with comparable teaching standards and entry requirements, both being well-established courses. Again, a simple 50-question anatomy paper was used, without negative marking. The traditional course students scored a mean of 37.5 (25–46), and the PBL group scored a mean of 32.3 (18–45). The results were statistically significant (p< 0.0001).

Our results suggest that the difference between the two groups with regard to core anatomical knowledge increases with progression through training. This has significant implications due to PBL courses being in the majority. During the usually short orthopaedic attachment, it will become increasingly difficult for clinicians to teach effectively due to the lack of this knowledge.


SK Saraf V Logani OP Sharma

Ultrasound detects fracture healing earlier than conventional radiographic methods; however, its clinical applicability is limited by subjective nature of interpretation. An ultrasonographic scoring system was developed to quantify fracture healing objectively.

Fifty closed traumatic diaphyseal fractures of less than three weeks, treated by IM Nails, were subjected to serial radiographic and USG examinations (2–24 weeks) by LOGIQ 500 USG machine using 7.5MHz linear transducer. USG parameters included were Echogenecity (EC), Visibility of IM Nail (VIMN), Bridging Callus (BC), and Continuity of Cortex (CC). Marks were allotted from 0–3 for each parameter in the three fracture zones. Three portals were used and mean was obtained. Disorganized echopattern was also defined by us. The results were statistically analyzed and compared with radiological findings using Bone Formation (BF) score.

At 2 weeks, 94% had EC score of < 3, increasing significantly at each follow-up. Defective unions had EC less than 3 at all the times. BC score of 9 was obtained by 94% at 2 weeks increasing to 100% at 8 wks. In non-union score remained 0. VIMN did not provide any statistically significant information. CC were significant only 12 weeks onwards.

USG Score parallels the appearance and progressive mineralization of callus in the fracture gap. Healing pattern can be predicted more definitely in the earlier stages where EC score has more positive predictive value and statistical significance than radiological BF score. EC> 3, BC> 3 and absence of DE was considered an essential USG criteria to conclude fracture union. The advantage over radiological assessment is lost after 12 weeks. We also conclude that a fracture will probably end up in delayed union nonunion if, at 6–8 weeks, the fracture has EC score < 1 or does not show bridging callus in any of the sonographic portals (BC score < 3) or has a disorganized echopattern in any of the sonographic portals.


B.J Fourie J Stothard R Madhock J Hovenden

We set out to ascertain if there is a consensus in elective orthopaedic practice for the screening and management of MRSA. A questionnaire was distributed to all British Orthopaedic Association Linkmen, with prepaid return envelopes.

A response rate of 60% (159 of 250) was recorded. 62% do have a screening policy in practice: all admissions (44%), high risk patients only (22%), only patients for joint replacement (12%), both patients for joint replacement and patients at high risk of carriage (21%). Eradication therapy is used in a MRSA - positive patient prior to joint replacement surgery by 91%, following which the MRSA status would be checked by 88%. The efficacy of eradication would be confirmed by obtaining: one set (29%), two sets (13%), and three sets (49%) of negative swabs, prior to proceeding with surgery. A 2nd generation Cephalosporin (77%), followed by Teicoplanin/Vancomycin (16%) are in routine use for antibiotic prophylaxis.

The majority of responders have adopted a practice of screening patients; however, significant differences exist in the population that is selected for screening. Eradication in MRSA positive patients is a common practice, but there is variation in the number of subsequent screens performed. Cephalosporins remain the antibiotic of choice for prophylaxis but first line therapeutic agents are also being used which may have implications for resistance. These variations can be partly attributed to the lack of evidence from which practical guidelines can be drafted, as highlighted by national guidelines published in 1998. Until further research is done into the cost effectiveness of screening and the further management of MRSa we have to rely on strict adherence to infection control practices, and appropriate use of antibiotics.


CH Wong LW Khin KS Heng KC Tan CO Low

Early operative debridement is a major determinant of mortality in necrotizing fasciitis. However, early recognition is difficult. The aim of our study is to develop a novel scoring system for distinguishing necrotizing fascitis from other soft tissue infections based on routine laboratory findings on admission.

The developmental cohort consisted of 89 consecutive patients with necrotizing fasciitis treated between January 1997 and August 2002. Control patients (n=225) were randomly selected from patients admitted with the diagnosis of cellulitis or abscesses during the same period. Their haematological and biochemical results done on admission were analyzed.

Total white cell count, haemoglobin, sodium, glucose, creatinine and C-reactive protein were selected as predictors. The final constructed model was reliable and discriminated well between patients with necrotizing fascitis from those with other benign soft tissue infections (Area under the receiver-operating characteristic (ROC) curve, 0.98). The LRINEC score was derived from this model and was validated in a separate cohort of patients from a different hospital (56 patients with necrotizing fasciitis and 84 control patients). Based on the calculated probability we stratified patients with soft tissue infections into 3 risks categories: high (LRINEC score _8), intermediate (LRINEC score 6–7) and low (LRINEC score _ 5) risks groups.

The LRINEC score is a robust score capable of detecting even clinically early cases of necrotizing fasciitis. On admission, patients in the intermediate and especially the high risks groups should be subjected to a frozen section biopsy or MRI scans with an aim of early diagnosis, debridement and ultimately


C Rajasekhar S Das A Smith

We report the outcome of 135 knees with medial compartment osteoarthritis treated by Oxford meniscal-bearing unicompartmental arthroplasty. They have been performed in a Distict General hospital by a single surgeon. All the knees had an intact anterior cruciate ligament, a correctable varus deformity and the lateral compartment was uninvolved or had minor osteoarthritic changes. At review 29 knees were in patients who had died and 106 were in those who were still living. The mean elapsed time since operation was 5.82 years (range 2–12 yrs).

Using revision as the end point the outcome for every knee was established. Five knees have been revised, giving a cumulative prosthetic survival rate at ten years of 94.04% (95% confidence interval 84.0 to 97.8). The causes for revision were aseptic loosening in three, progressive valgus deformity in one and dislocation of the bearing in one. Knee rating and patient function were assessed using the modified Knee Society Scoring system. The mean Knee score was 92.2 (51–100), and mean Functional score was 76.2 (51–100). 90% of the patients did not require blood transfusion. Two patients had deep vein thrombosis and three knees had superficial wound infection that responded to antibiotics. Intraoperatively, one patient had fracture of the proximal tibia which was fixed with two partially threaded cancellous screws.

92% of patients were fully satisfied with the procedure and 91% of them said that they would undergo a similar procedure in the opposite knee.

The implant survival is comparable to that reported by the designers of the prosthesis and not significantly different from those for total knee replacement. Uni-compartmental knee replacement with all its advantages offers a viable alternative in patients with medial gonarthrosis. Appropriate patient selection and good surgical technique are the key factors.


PTH Lee MT Clarke CP Roberts J Gray GS Keene N Rushton

Prior studies have compared the bacterial load observed in laminar flow operating theatres (LFOTs) and standard operating theatres (STOTs) by wound culture and air sampling during surgery. However many organisms responsible for low grade infection after THR are not readily identified on routine culture and may be detectable only by more sensitive techniques such as the poly-merase chain reaction (PCR). This study assessed the wound contamination rate during THRs and compared the results in STOT with that in LFOTs using PCR.

We recruited patients undergoing primary THR for osteoarthritis. Surgery was performed in either STOTs or LFOTs, using identical skin preparation solutions, surgical drapes and operating attire. Specimens of the deep tissue, taken at the beginning and end of surgery, were each immediately separated into two sterile containers, one sent for culture (aerobic, anaerobic and enriched meat broth) and the other frozen at minus 80 degrees Celsius for PCR at a later date.

In each theatre type, 40 specimens from 20 THRs were analysed by both PCR and culture. Using PCR, bacterial DNA was identified on 12 of 40 specimens (30%) from STOTs, of which 3 were taken at the start of surgery and 9 at the end of the surgery, giving a 45% wound contamination rate (9 of 20). Two specimens (5%), both taken at the end of surgery, were positive on enriched culture. In LFOTs, bacterial DNA was identified by PCR on 8 of 40 specimens (20%), of which 2 were taken at the start of surgery and 6 at the end of surgery, giving a 30% wound contamination rate (6 of 20). No specimens were positive on enriched culture.

Wound contamination of primary THR occurs frequently in both STOTs and LFOTs. Although STOTs showed evidence of more frequent wound contamination than LFOTs, with the numbers available, no significant difference was detected. These data remind us the importance of aseptic surgical technique as significant wound contamination can occur despite the use of ultra clean air operating theatres.


T M Lawrence R Wenn C White C G Moran

The aim of this study was to determine the incidence of second hip fracture.

A prospective cohort study include 2682 patients aged 50 years or more admitted with a hip fracture over a 4 year period. Mortality data were available for all patients and survival analysis was performed to determine the incidence of second hip fracture. The mean age-specific incidence rates of primary hip fracture in the population were calculated to serve as a baseline.

95 patients (3.5%) sustained a sequential, contralateral hip fracture within the study period. The mean age at first hip fracture was 82 years and the mean interval between fractures was 316 days. Fracture morphology was similar on both sides in 69% of cases. Survival analysis demonstrated that the incidence of second hip fracture at 1 year was 2.8% (95% CI: 2.0–3.6), 2 years was 5.7% (95% CI: 4.3–7.1) and 3 years was 7.3% (95% CI: 5.4–9.2). The relative risk of hip fracture in patients who had already sustained one hip fracture was 2.4 times above that of matched controls. Assistance with activities of daily living was identified as a risk for second hip fracture (p=0.026, 95% CI: 1.058, 2.466). The odds ratio for sustaining a second hip fracture compared with the incidence of primary hip fracture in the normal population aged 55–64 years was 47.5 xs; 65–74 years was 15 xs; 75–84 years was 3.7x and 85+ years was 1x.

The risk of sustaining a second contralateral hip fracture is substantial. In younger patients preventative measures can be targeted at the individual who has sustained a fracture whereas in more elderly patients, preventative measures need to address the population as a whole.


A Misra MRA Hussain NJ Fiddian G Newton

129 knees suitable for a standard PCL retaining cemented total knee replacement were randomised into two groups, one in which PCL was retained in the normal way, the other group having the PCL fully resected. Both groups received a PCL retaining implant. The two groups were well matched with a predominance of females and a mean age of 67 years.

There was no statistically significant difference in the HSS scores at an average of 57 months (range 56–60 months) in the two groups. Pain relief, deformity correction, range of motion, stability and strength were comparable in the two groups. A radiological assessment revealed femoral rollback in approximately 20% of cases with a slightly higher incidence in the PCL sacrificed group. There was no significant loosening detected in either of the categories at two years review.

At five years one TKR in the PCL retained group has been revised due to an infection and one each in the two groups are awaiting revision surgery for loosening. Our findings have shown that there is no significant difference in the 5 year results of a PCL-retaining total knee replacement if the PCL is excised or preserved. This suggests two significant points:

the PCL is not functional in most patients with a total knee replacement even when retained:

patients with excised PCLs show good results with PCL retaining implants, thereby questioning the need for posterior stabilised designs in all such cases.


RV Patel J Stygall J Harrington M Harrison SP Newman FS Haddad

To quantify the intraoperative cerebral microemboli load during primary total knee arthroplasty (TKA) using transcranial Doppler ultrasound and to investigate whether a patent foramen ovale influences cerebral embolic load in general.

Patients undergoing primary TKA, with no history of stroke, TIA, ongoing CNS disease or alcoholism were included. All operations were carried out under a standardised general anaesthetic and performed by two consultant orthopaedic surgeons. Microemboli l oad was recorded, using transcranial Doppler ultrasound (TCD), onto VHS tape for subsequent playback and analysis. Patent foramen ovale detection was performed using bolus intravenous injection of agitated saline followed by valsalva manoeuvre technique and TCD. Timing of specific surgical steps was recorded for each operation and emboli load calculated for that period.

Results: 50 TKA patients were studied (31 females, 19 males); 28 right and 22 left TKAs were performed. Cerebral microembolisation occurred in 19 patients (42%). Mean microembolic load was 3.56 per patient (range 0–21). PFO was detected in 9 patients (18%). Two thirds of PFO positive patients displayed cerebral microemboli. However, 36.6% (n=15) of PFO negative patients also displayed microemboli intraoperatively. Deflation of the tourniquet was followed by a larger microembolic load than the other phases of the operation.

Conclusion: Intraoperative cerebral microembolisation occurs in a significant proportion of patients during total knee arthroplasty. The presence of a patent foramen ovale does not appear to influence the incidence microemboli intraoperatively. Specific surgical activities are associated with generating greater embolic loads. These questions will be comprehensively assessed in the larger study currently underway.


A Bennett CNA Esler WM Harper

The Trent Arthroplasty Audit Group has been prospectively collecting data on primary knee arthroplasty since 1990 and revision procedures since 1992. Details of 27 000 primary and 1300 revision knee arthroplasties have been registered. In 2001 hospitals in Wales joined the group, increasing the catchment population to 8 million (14% of the UK population). The register has enabled evaluation of changes in the demography and surgical practice of knee arthroplasty in the Trent region over the past 13 years.

Over this period there has been a steady increase in the number of arthroplasties registered, from 1330 cases in 1990 to 2855 in 2002. Whilst there has been a slight increase in the proportion of men undergoing surgery, the age distribution remains consistent (mean age 69 years). PFC/Sigma is currently the most commonly used prosthesis in the region.

Since 1990 the number of patients registered with rheumatoid arthritis has fallen by almost 50%. During this period there has also been a slight decrease in the proportion of uncemented joints and a decline in the number of bilateral simultaneous procedures taking place.

The ratio of primary to revision knee arthroplasty has not changed significantly since 1992 but there is some evidence of specialisation of revision knee surgery. There has been no significant change in patient satisfaction rates since the start of the registry, with 80% of patients reporting that they are satisfied with their joint replacement at 1 year.

Conclusion: It is reasonable to assume that these findings reflect practice across the UK as a whole, given the diversity of hospitals contributing and the large population base of the Trent & Wales register.


MJ Radford S Curry D Wood

Patella instability can be a disabling condition predominately affecting younger patients, restricting activity and potentially leading to premature osteoarthritis. We describe and evaluate a new technique of stabilising the joint.

Between November 2000 and January 2002 we operated on 24 unstable knees (belonging to 23 patients). All patients had failed a course of conservative treatment and the average number of dislocations pre-operatively was 7. All patients had an extra-synovial lateral release and stabilisation by harvesting the semitendinosus tendon which was then tunnelled through a vertical hole in the patella, under the vastus medialis, wrapped around the adductor magnus and tied to itself at the lower border of the patella.

The patients were assessed clinically and radiologically at an average of 19 months, following the procedure.

There were 19 knees assessed: 13 female /6 male, 10 left /9 right, average age 22 years. 13 patients had retro-patella chondral damage none had meniscal or cruciate pathology. The visual analogue score increased from 4 pre-op to 7.5 after operation. The Kujala patello-femoral score was 74 post procedure. 53% of patients described their knee as excellent, 47% as good. Only one patient has re-dislocated to date (single event). There were no specific risk factors.

Conclusion: Stabilisation of an unstable patello-femoral joint with a semitendinosus loop is a highly successful procedure with good patient satisfaction. We are also happy to use this procedure in the skeletally immature as its use does not preclude a later realignment procedure, should it be indicated.


N Pradhan AK Gambhir P Kay ML Porter

Fifty-seven revision total knee arthroplasties were performed in our hospital using the TC3 system between 1995 and 1997. Twelve patients died. Forty-five patients were followed up for an average of 5.6 years (range 4 – 7 years). No patients were lost to follow-up.

All patients were clinically and radiologically evaluated. A postal patient satisfaction questionnaire was completed. Two patients were revised; one for infection and one for instability. Survivorship using revision as the end point was 93.3% at 7 years.

Indications for revision were infection (4;9%), instability (38;84%), pain and stiffness (3;7%). 32 (71%) patients were satisfied with their outcome, 7 (16%) were noncommittal and 6 (13%) were disappointed at 5 years. We have analysed the 13 dissatisfied patients and highlight the lessons learned.

Pain and stiffness are not good indications for revision; insert thickness of more than 17.5mm is suggestive of elevation of the joint-line; instead the femoral component should be distalised; step wedges should be used in preference to angular wedges; Always long stem the tibial implant if augments are used; stems should be canal filling with adequate grip on the diaphysis.

We suggest the above lessons we have learned from our initial revision arthroplasty learning curve may correlate to the clinical outcome of this small group of dissatisfied patients.


H Prem S Aravindan MAS Mowbray A Newman-Sanders

70 patients who underwent dynamic MRI scanning for chronic anterior knee pain were retrospectively evaluated. All patients had been symptomatic for over a year. 43 patients had been treated conservatively and 27 had undergone surgical procedures (arthroscopy -13, lateral release- 9, tibial tubercle transfer 5). The extent of subluxation, tilt and cartilage abnormalities on MRI scans, during resisted extension were assessed. Functional scoring (Oxford, Lysholm and Tegner scores) was done through questionnaires and correlated with the radiological findings.

54 (77%) patients were found to have some patellofemoral abnormality on the scans. Subluxation was the most common finding with mild subluxation in 30, moderate in 18 and severe in 17 knees. Mild tilt was seen in 26 knees and moderate to severe tilt in 14 knees. Tilt was found in association with subluxation except in 8 cases. Grade 1 and 2 cartilage wear were seen in 13 knees and Grade 3 and 4 in 21 knees.

The “Tibial Tubercle to Trochlear Groove distance” (TTD) was measured in all knees and correlated with subluxation. The average distance was 13.5mm, 13.6mm and 18.8mm for mild, moderate and severe subluxation respectively. All patients with a TTD _ 20mm had moderate or severe subluxation. The specificity of a TTD _ 20mm for severe maltracking was 100% but the sensitivity was only 42%.

The TTD appears to be the single most significant parameter determining patella tracking. We have proposed an algorithm for the surgical and non-surgical treatment of chronic anterior knee pain. We recommend lateral release for those with moderate and severe subluxation and a tibial tubercle transfer as well in those with a TTD _ 20mm. The functional scores did not zshow a significant correlation with the grading of subluxation.


A Singh CNA Esler WM Harper

We sought to determine the incidence of complications and re-operation up to one year following primary total knee replacement in a single health region.

The Trent Arthroplasty Audit group collects prospective data on all knee replacements performed within this health region (population 5.2 million). All patients are sent a validated, self-administered questionnaire one year after surgery. The questionnaire addresses patient satisfaction and any complications and re-operations following surgery. We analysed the returned questionnaires of 5352 patients [5896 knees] who had their primary knee arthroplasty between 1998 to 2000. Responses were received from 4169 patients [4592 knees] (response rate 80%). Clinical records were also examined to gain further information.

516 patients reported complications in 546 knees. Complication rate of (12%) and 3.5% had a further operation on the joint within one year. Complications were highest following knee replacement for trauma (36%) followed by osteoarthritis (12%) and lowest for rheumatoid arthritis (8%). We have no knowledge of the complexity of the surgery but 60% of the complications occurred in patients operated on by a Consultant, 29% by a Specialist Registrar and 10% by an Associate Specialist & Staff Grade. On the whole Consultants performing fewer than 10 joint replacements per year registered a higher complication rate (21%) as compared to Consultants performing more than 25 joints per year (12%), but they performed 18% of the arthroplasties. The incidence of complications, as stated by the patient was as follows: Pain 7%, Stiffness 2%, Superficial infection 1%, Swelling 0.7%, Deep infection 0.7%, DVT 0.4%. 1.2% (infection 0.4%: Instability 0.7%: Patellar resurfacing 0.2%), Manipulation (1.3%), Arthroscopy (0.7%), ORlF of Peri-prosthetic fracture (0.06%). 12 % of the patients who had a primary knee replacement in Trent region between 1998 and 2000 considered that they had a complication. Complications rates appear to be higher for surgeons performing less than 10 joint replacements per year. Only 43% of Consultants performed more than 10 knee arthroplasties themselves in any one of these three years. The deep infection rate was 0.4% and one-year post surgery the revision rate, for all causes was 1.2% and the manipulation rate was 1.3%.


WJ Hart R Spencer Jones

To review the outcome of patients with deep infection using a new 2-stage revision technique.

A management plan consisting of initial debridement, insertion of antibiotic spacers and 2 weeks of intravenous antibiotics is currently used. No further antibiotics are given systemically. If blood tests are satisfactory at 12 weeks, reimplantation occurs. Patients are encouraged to partially weight-bear and perform a range of motion exercises with their spacers in place. The necessary data has been prospectively collected to identify predictors of success.

Thirty four patients have been identified and fully followed up for more than 1 year. 27 patients have over 2 years of follow-up. When looking at all of the patients we have achieved an 82% success rate. For patients whose only previous major surgery was their arthroplasty this rises to 90%. Where multiple surgeries have been undertaken this falls to 73%. All of the peri-operative investigations have been reviewed and whilst they have a good negative predictive value they are not specific enough to alter practice.

Conclusions: Short courses of parenteral treatment can produce comparable results to previously- published series when treating deep infection after knee replacement. There seems to be a failure rate that is difficult to avoid associated with chronic, multiple revision cases.


R Mittal PP Kotwal S Rastogi M Farooque

The rate of nonunion of shaft of humerus ranges from 0 to 15%. The management of this problem becomes difficult when it is complicated by osteoprosis, bone defects and previous surgeries. We treated 24 such cases. There were sixteen males and 8 females. Age ranged from 28 to 65 years and averaged 46 years. Ten fractures were in the middle third and 14 were at the junction of middle and lower thirds. The average duration of nonunion was 8 months. Eight cases were previously treated with plating, 4 were treated with intramedullary nail and 2 with external fixator. Ten cases were treated with slab or cast. All cases were treated with removal of old metalwork (if any), open reduction, placement of fibula autograft in the medullary canal of humerus, plating and cancellous onlay grafting. The length of the fibula autograft in the humerus exceeded the plate length over each fragment. Anterior approach was used in 22 cases. In 2 cases posterior approach was used because of a previously posterior placed plate. U-slab was given in the postoperative period. It was discarded when there was clinical and radiological evidence of union. Physiotherapy was given to all patients after union. 22 humeri united and 2 failed to unite. 21 patients could carry out their daily activities and return to their profession. There was no postoperative radial nerve palsy. 1 case had fibula donor site pain. The follow-up period was 12 to 26 months and averaged 20 months.

Conclusion: This method is a very useful way to manage difficult nonunions of shaft of humerus. We conclude that anterior approach to shaft of humerus is easy and physiological; intramedullary fibula helps to improve the screw purchase, abolishes the stress risers, acts as internal splint, substitutes for absent cortex and provides bone graft.


A Kulkarni H Ahrens A Abudu SR Carter RM Tillman RJ Grimer

Non-union of long bone fractures can be a challenging problem. There are several methods of treatment and they depend upon various patient factors, biology of non-union, and presence of infection. When faced with failure of treatment with biological reconstructive procedures patients have little choice. At our institute we have treated 10 such patients with radical excision and reconstruction using tumour endoprostheses as a last attempt to save the limb.

Median age of the patients was 71 years (25–85). 2 patients were male and 8 were female. Median follow-up was 49 months (8–229). 5 had infected non-union. Resection and massive endoprosthetic reconstruction involved the distal femur in 4 patients, proximal femur 3, distal humerus 2 and total Humerus in 1 patient. Time from diagnosis of non-union to treatment was 0 to 96 months (median 11 months) and patients had had 0 to 6 (median 3) previous operations 5 infected non-unions were operated as 2 stage procedures and received long term antibiotics. 4 out of 5 infected non-unions were salvaged. There were 5 complications, namely periprosthetic fracture, infection, a dislocated shoulder, radial nerve palsy, suture of bosing.

All the patients achieved immediate mobility and stability. Extendible prosthesis allowed partial correction of limb shortening.

Conclusion: Resection of established non-union and reconstruction with endoprostheses is a good salvage operation for elderly and low demand patients in whom time consuming biological reconstruction is not desirable.


SS Madan DS Feldman S Shin KJ Koval

To determine the effectiveness of six-axis analysis deformity correction using the Taylor Spatial Frame for the treatment of post-traumatic tibial malunions and non-unions, the study design was a retrospectively reviewed, consecutive series. Mean duration of follow-up: 3.2 years (range 2–4.2 years). All patients had been referred to a tertiary referral centre for deformity correction. Eighteen patients were included in the study (11 mal-unions and 7 nonunions). All deformities were post-traumatic in nature. The mean number of operations prior to the application of the spatial frame was 2.6 (range 1–6 operations). All patients completed the study. Six-axis analysis deformity correction using the Taylor Spatial Frame (Smith & Nephew, Memphis, TN) was used for correction of post-traumatic tibial malunion or nonunion. Nine patients had bone grafting at the time of frame application. One patient with a tibial plafond fracture simultaneously had deformity correction and an ankle fusion for a mobile atrophic nonunion. Two patients had infected tibial nonunions that were treated with multiple debridements, antibiotic beads, and bone grafting at the time of spatial frame application. A rotational gastrocnemius flap was used to cover a proximal third tibial defect in one patient. The average length of time the spatial frame was worn, time to healing, was 18.5 weeks (range 12–32 weeks). The main outcome measurements involved assessment of deformity correction in six axes, knee and ankle range of motion, incidence of infection, and return to preinjury activities.

Results: Seventeen of the 18 patients treated with the Taylor Spatial Frame, with adjunctive bone graft as necessary, achieved union and significant correction of their deformities in six axes, i.e. coronal angulation and translation, sagittal angulation and translation, rotation, and shortening. Fifteen of the 18 patients returned to their pre-injury activities at last follow-up.

Conclusion: Six-axis analysis deformity correction using the Taylor Spatial Frame is an effective technique in treating post-traumatic malunions and nonunions of the tibia, with several advantages over previously used devices.


P Armstrong R Dhamarajan E Breuning S Abudu

Complication rates are an increasingly topical issue. Figures are widely published in elective surgery. We were unable to find any overall rates published solely for trauma surgery involving metal implants. We wanted to identify our overall rate as a matter of good practise and to produce a figure for others to compare against.

We wanted to identify the overall infection rate and study those infections in terms of fracture healing, implant survival and chronic soft tissue infection.

A wound infection was any wound where there was a positive culture, prolonged pus drainage with or without a sinus or presence of pus at further surgery with or without a positive culture. Metal implants were any metalwork covered primarily or secondarily with soft tissue. 708 implants were inserted over the 11 month period studied.

The causative organism was staphylococcus aureus in 65% of cases and a third of these were MRSA. Other organisms included coliforms, acinobacter, pseudomonas and bacillus.

Of 52 patients who had a wound infection, 6 (11.5%) had no treatment with no detrimental effect, 34 patients had antibiotics alone and 27 had no further problems. 2 died from sepsis related causes, 3 died from other causes, 1 had delayed union but no evidence of continuing infection and 1 had chronic soft tissue discharge but bony union.

12 patients had further surgery and antibiotics. 6 retained their metal work and of these 3 died from sepsis related causes, 1 had no further problems, 1 tibial nailing became a chronic discharging osteomyelitis and 1 olecrannon fracture became an uninfected non-union. For the 6 patients who had their metalwork removed 2 died, 1 from sepsis, 2 had successful revisions and 2 were continuing treatment at most recent follow-up.

Conclusion: overall deep wound infection rate was 7.3%. Most deep wound infections were treated with antibiotics alone with a satisfactory outcome. Re-operation rate for deep wound infection was 1.7%. There is very little information available on overall deep wound infection rates for implants in trauma surgery; we offer our findings as a comparison for future reference.


L M Jeys O Wall G Radcliffe S J E Matthews

Human recombinant bone morphogenic protein type 7 (BMP 7) is now available commercially for clinical use. In our trauma unit it has been used since September 2001 for patients with established intractable non-unions. We present the early results.

All consecutive patients receiving BMP 7 were reviewed regularly following treatment. All patients had established non-unions previously treated with a variety of methods. The patients were assessed for clinical evidence of fracture union (using stability and pain). Treatment episodes will be categorised as failures if there is no evidence of fracture union at 1 year following BMP 7 treatment. Plain x-rays were assessed by 2 independent radiologists and categorised into: Radiological evidence of fracture union; encouraging progression towards union; little evidence of fracture healing; atrophic non-union, hypertrophic non-union.

A total of 12 separate non-union sites have been treated in 10 patients (all male) to date. The mean age of the patients at follow up was 45 years. The series included 5 tibial non-unions, 3 femoral non-unions, 3 ulna non-unions with a mean of 3.3 treatments (range 1–7 treatments) and had endured symptoms, from initial injury to treatment with BMP 7, with a mean of 8.3 years (range 2 months-10.4 years). To date, the mean follow-up is 18 weeks (range 6–48 weeks).

Currently, 2 fractures have clinical & radiological union, 2 treatments have failed (implant failure and patient opted for amputation), 3 fractures are below 3months follow up, 5 fractures have a radiological classification as “encouraging” progression towards of union ( 4 with clinical union).

In a very difficult treatment group, we have encouraging early clinical results. Radiological evidence to compare to initial clinical results will be available shortly.


R Bommireddy Y Shenava O Keast-Butler A Shetty S Phillips AFG Groom

We retrospectively reviewed 19 femoral non-unions. Age group ranged from 17–72 yrs with mean of 40 yrs. 12 were men and 7 were women. 11 fractures involved diaphysis and 8 involved supracondylar area. 5 cases were infected non-unions. Time from fracture to defini-tive treatment varied from 5 to 88 months (mean 21 months). Open technique was used in 18 cases. In 8 cases we have used autogenous cancellous bone graft and in 3 cases BMP7 was used in addition to bone graft. 9 cases were treated with Ilizarov frame without bone graft, 6 with plate & bone graft, 3 with intramedullary nail and 1 with bone graft alone. Internal bone transport was carried out in 5 cases to achieve limb length equality. Fracture union was achieved in 16 patients with 7 excellent and 8 good results as per ASAMI criteria. 15 cases achieved excellent to good functional results. Because of persistent infection, 2 distal femoral non-unions required transfemoral amputation. Treatment was discontinued due to psychiatric illness in 1 patient with Ilizarov frame. Two of the patients in Supracondylar group developed knee stiffness. Pin tract infection is a common complication in Ilizarov group.

Adequate reduction & stabilization is key to success. Non-unions without any complications can be treated with exchange nail or open reduction and plating. Ilizarov method is effective for non-unions complicated by distal location, infection and bone loss. Psychological assessment is important before considering Ilizarov method of treatment.


P Meda PB Machani I BraithwaiteI C Sinopidis P Brownson SP Frostick

A prospective study was carried out over a period of 4 years. 31 patients with a mean age of 49 years were treated using the clavicular hook plate. The mean follow up was 28.34 months. 23 patients were operated primarily and 8 patients were operated for symptomatic non-union.

All the patients achieved clinical and radiological union in a mean 12.71 weeks. According to Constant scoring the mean was 94. According to HSS (Hospital for Special Surgery) scoring 9 patients had excellent, 21 had good.

The clinical results of the clavicular hook plate were good leading to good shoulder girdle function.


M Agarwal K Tzafetta SL Knight PV Giannoudis

Between 1990 and 2000, 15 patients with open 3C fractures of the lower extremity were treated at our institution. Demographic data such as age, sex, associated injuries and co-morbidities were recorded. The mechanism of injury, ISS [Injury Severity Score] and MESS [Mangled Extremity Severity Score] were ascertained. The minimum follow up was 2 years. All the fractures were classified according to the AO system. The patients received a combined treatment by the orthopaedic and plastic surgeons and when necessary by the vascular surgeons. Treatment options, were based on the extent of soft-tissue damage and the configuration of the fracture. Intra-operative details including arteries and nerves involved, type of flap cover, quality of fixation and need for fasciotomy were recorded and analysed. A final follow up was carried out at a special clinic and the outcome was analyzed using SF-36 and EUROCOL. MESS and ISS were analyzed for possible predictors of final functional outcome.

The patients were predominantly males. The main mechanism of injury was due to a road traffic accident and 6 of the patients had associated injuries in other parts of the body. In two thirds of the patients the fracture site was in the tibia, and in 3 cases there was a combined fracture in femur and tibia. The posterior tibial artery was involved in the vast majority of the cases, which was either disrupted or avulsed. The Salvage and reconstruction was carried out in 13 patients, which accounted for 77% of the cases and 2 patients underwent immediate amputation. Both had a Mangled Extremity Severity Score of 10. The bone fixation was mainly achieved by plating, or nailing. Half of the patients underwent fasciotomy, in the rest the compartments were decompressed due to the nature and extent of the injury. All the patients required secondary procedures, the mean total number of operations was 2.6.

Although only one-fifth of the patients had some problems with self care, half experienced some problems with mobility. Anxiety and depression was a problem in two thirds of the patients, and about the same proportion of patients experienced moderate to severe pain. The mobility was correlated to the MESS score.

Conclusion: the functional outcome was most closely related to the severity of injury and the injury-surgery interval. Our study showed that improved functional outcome is possible following surgical treatment of these challenging injuries especially when prompt response is instituted by combined ortho/plastic/vascular surgical teams.


J Conroy M Agarwal PV Giannoudis

32 consecutive patients who suffered open [Gustilo grade IIIB] distal tibial [AO type 43B and C] ‘Pilon’ fractures were prospectively studied in order to assess long-term functional outcome. All patients had radical debridement with immediate [within 24hrs] skeletal stabilisation and early soft tissue cover with a vascularized muscle flap as per our hospital’s protocol for management of severe open tibial fractures. The minimum follow-up was one year [range 1–8 years]. The superficial infection rate was 13% [4/32], deep infection rate was 6% [2/32] and the amputation rate as 6% [2/32]. There were no long-term problems with union and none of the patients required an ankle fusion. Patients were assessed using the SF-36 questionnaire. There were sig-nificant differences from the US norm in physical function score [p< 0.01], role physical score (p< 0.05) and physical component score (p< 0.01). Physical component score of 38.5 was significantly better (p< 0.01) when compared with amputees from severe lower extremity trauma. Our protocol for management of severe open pilon fractures resulted in a good functional outcome with low infection and amputation rates.


B Thornes A Walsh F Shannon P Murray E Masterson M O’Brien

A new apparatus and technique of syndesmosis fixation is tested in a prospective clinical study. Buttons on both sides of the ankle anchor a strong suture under tension following syndesmosis reduction. This syndesmosis suture acts like a tightrope when under tension. Implantation is simple with a minimally invasive technique, as the medial side is not opened. It allows physiological micromotion whilst resisting diastasis, does not require routine removal, and allows patients to weight-bear earlier.

Sixteen patients with Weber C ankle fractures with a syndesmosis diastasis underwent suture-button fixation and the results compared to 16 consecutive patients with syndesmosis screw fixation. Patients were, in effect, quasi-randomised according to surgeon preference. Mean A,O,F,A,S, ankle scores were significantly better in the suture-button group at three months post-op (91 vs 80, p=0.01, unpaired t-test) and at twelve months (93 vs 83, p=0.04, unpaired t-test). Return to work was also significantly faster (2.6 months vs 4.6 months, p=0.02, unpaired t-test). No suture-buttons required implant removal. Axial CT scanning at three months showed implants to be intact with maintenance of reduction, as compared to the uninjured contralateral side.

Suture-button syndesmosis fixation is simple, safe and effective. It has shown improved outcomes and faster rehabilitation, without needing routine removal. Although the apparatus design may undergo further refinement, we believe this technique will become the treatment of choice in Weber C ankle fractures with a syndesmosis injury.


RJ Pacheco M El-Shazly M Saleh

To review the results of the treatment of pilon fracture with percutaneous internal fixation and extrarticular ring fixation in neutralization, twenty-two fractures in twenty-one patients were included in the study. The mean follow-up time was 5.3 years. Five fractures were classified Ruedi-Algower type I, six were Ruedi-Algower type II and eleven Ruedi-Algower type III. Six were open fractures (3 Gustilo type III) and there were 19 associated fibular fractures (five were internally fIxed). Thirteen fractures (60%) were associated with metaphysealdiaphyseal dissociation (MDD). The majority of fractures were high energy (18 out of 22). General health outcome was assessed with the use of the SF-36 and functional outcome was evaluated with AOFAS score and Bone’s criteria.

The average AOFAS score for the study population was 79.4. The AOFAS scores decreased as the severity of the fracture increases and these differences were statistically significant between the Ruedi-Algower types I and III. The pilon fractures population scored lower in all SF-36 categories but mental health and energy and vitality when compared to an age matched population but statistically significant differences were only found in the categories of physical function and limitation due to health problems. 65% achieved excellent or good results according to Bone’s criteria. No significant differences were found in the union times in the MDD group (253 days) when compared to the fractures with no MDD (224 days), but this can be due to the high incidence of autograft in the MDD group (7 out of 13). All patients achieved full weight bearing at 6 weeks. Fourteen patients had superficial pin site infections (one needed screw removal) that settled with oral antibiotics. There was one case of non-union and two varus heels.

Conclusion: Good results are achieved treating pilon fractures with minimal internal fixation and the Sheffield ring fixator in neutralization but quality of life and functional scores significantly worsen in the most severe Ruedi-Algower type III fractures.


MC Forster KS Kumar ID Hyde MI Adelman

The aetiology of Panner’s disease is unknown. Thrombophilic states have been implicated in Perthes’ disease but remain controversial. The relationship, if any, between thrombophilia and Panner’s disease is not known.

A 7 year old boy presented with pain and restriction of motion in one elbow with no history of trauma. Radiographs confirmed Panner’s disease. A thrombophilia screen showed an abnormal activated protein C resistance test consistent with the presence of Factor V Leiden in the heterozygous state. Thrombophilia may predispose to thrombotic venous occlusion in bone leading to intramedullary hypertension, anoxia and avascular necrosis. This may explain the aetiology of some cases of Panner’s disease. Resistance to activated protein C is a common heritable thrombophilia. The incidence in the UK is around 1.75%. It is caused by a CGA to CAA substitution at position 1691 of the Factor V Leiden gene. This blocks the binding of activated protein C to prothrombotic Factor V producing thrombophilia. Factor V Leiden carriers are three times more likely to experience clinical venous thrombosis than non-carriers. Whilst this risk does not warrant lifelong anticoagulation, thromboembolic events are more likely to cause problems than Panner’s disease which is essentially self-limiting. Affected patients should avoid other risk factors such as smoking or the combined contraceptive pill.

As Factor V Leiden is common in our population, its presence in this patient may be incidental. Thrombophilia screening should be considered for patients with Panner’s disease. This enables appropriate counselling if a thrombophilic condition is found.


SS Madan H van Bosse DS Feldman DE Ruchelsman KJ Koval WB Lehman

The aim of our study was to assess the efficacy and complications of treatment of limb deformities using six axes deformity analysis and the Taylor TM Spatial Frame [TSF]

Between January 1997 and March 2000, we treated 75 lower limbs in 66 patients with deformities. Patients were divided into four groups. The groups were Blount’s disease, congenital deformities, traumatic deformities, and a miscellaneous group. The data was prospectively collected. This was a consecutive series of the first 66 patients treated at our institution with the TSF. Deformity correction using the TSF is done with the aid of computer software.

The mean age of the 66 patients was 18.7 years (range 0.5 to 72 years). The average frame time was 18.6 weeks (range 9 to 49 weeks). There was shortening present in 31 limbs with a mean of 18.6 mm (range 5 to 50 mm). Deformity correction with distraction osteogenesis was begun 7 days after the osteotomy. The mean length of time until correction was 6.7 weeks (range 3 to 13 weeks). There were a total of 10 complications (13.3%) in the series.

27 tibiae in 23 patients underwent correction with the TSF for Blount’s disease. There were 11 infantile and 16 adolescent forms. Correction of congenital deformity was performed in 20 tibiae and 8 femurs in 18 patients. There were 9 males and 9 females. There were 13 male and 8 female patients with traumatic lower limb injuries. There were 11 malunions and 10 nonunions (including 2 infected nonunions) that were corrected with the TSF.

The TaylorTM Spatial Frame is an effective technique in treating deformity. Angulation, translation, shortening and rotation can be corrected simultaneously.

Based on our results, we conclude that the TSF allows safe, gradual correction that is accurate and well tolerated.


SS Madan DE Ruchelsman DS Feldman

We utilized a dry-bone model of the pelvis and proximal femur, set upon transparent Lucite plates with four mounting screws and adjustable struts, allowing measurable and reproducible pelvic tilt and rotation. Our protocol for osteotome placement at each of the osteotomy sites strictly followed the technique described by Ganz. A 30°, 15 mm bifid osteotome was used for imaging at the initial ischial osteotomy at the infracotyloid groove. A 30°, 2 cm straightedge osteotome was placed 4 cm below the pelvic brim to image the retroacetabular osteotomy on the quadrilateral plate. Various osteotome placements were imaged with the C-arm image intensifier to better define the risks of inferior and posterosuperior intraarticular osteotomies at each of these sites, respectively. A 600 osteotome oriented at 500 to the quadrilateral plate was also utilized.

In addition, violation of the inferior quadrant of the joint as well as posterolateral slipping of the osteotome blade along the posterior column, were appreciated on all images of pelvic flexion and rotation. The false-profile view always confirmed the perpendicular orientation of the osteotome blade. The false-profile view allowed for accurate evaluation of the positioning of the 30°, 2-cm straightedge osteotome along the retro-acetabular osteotomy site. In the views obtained, the blade could be seen aligned parallel to the posterior surface of the acetabulum, while respecting the posterosuperior joint space with optimal step-off from the posterior column. False-profile and posterior judet views provided optimal visualization of the 60° osteotome on the quadrilateral plate. In addition, pelvic flexion and rotation did not impact the ability to visualize the inferior margin of the acetabulum in evaluating the potential for creating an inferior intraarticular osteotomy. The results of our study indicate that awareness of the appearance of ideal osteotome placements at each osteotomy site on AP and false profile C-arm image intensification will decrease the incidence of iatrogenic osseous and therefore neurovascular complications reported in the literature and reduce post-operative patient morbidity.


G Dewnany P Radford J Hunter

Prophylactic stabilisation with internal fixation of the asymptomatic hip in unilateral slipped capital femoral epiphysis is controversial.

The incidence of bilaterality varies from 20–80% depending on the length of follow-up. The opposite hip has 2335 times higher incidence of developing a slip in cases of a unilateral slip at presentation and there is no chemical, anatomic or radiological feature which can predict a slip.

The arguments regarding prophylactic fixation are based on risks of AVN, chondrolysis, and problems with implant removal and joint penetration

We present a retrospective analysis of sixty-five patients who had prophylactic fixation of the uninvolved hip at the same time as their opposite slipped femoral physis. None had an underlying systemic or endocrine disorder and the average age was 12.5 years (range 11–15 years).A single 7.0 mm cannulated screw was used in all cases. The average time to fusion was 18 months (range 6 to 36 months) and duration of follow up ranged from 3–8 years (mean 4.5 years).

None of the patients had implant removal and at latest review did not show any evidence of chondrolysis, avascular necrosis, premature physeal arrest or secondary arthrosis in the prophylactically fixed hip. There were a couple of cases of inadvertent wire penetration into joint, which were recognised and rectified immediately, and a correct length screw inserted. Both these patients had an uneventful post-operative course with no problems of chondrolysis etc at latest follow-up (5 years). One patient (1.5%) developed a superficial wound infection, which cleared up with antibiotics.

Conclusion: This study demonstrates the safety of prophylactic fixation using a single cannulated cancellous screw and is recommended for prevention of delayed slip and hence secondary osteoarthrosis.


S Patil DA Sherlock

Femoral head deformity with flattening and lateral protrusion can occur secondary to epiphyseal dysplasia or avascular necrosis of any aetiology in childhood. This causes painful impingement of the lateral femoral head on the acetabular lip, a phenomenon known as hinge abduction. We aimed to review our experience of valgus extension osteotomy in the treatment of hinge abduction in children and young adults with avascular necrosis.

Twenty patients undergoing valgus osteotomy for hinge abduction performed by a single specialist were clinically and radiologically reviewed. The aetiology was Perthes disease in 16 patients and treatment of DDH in 4 patients. The indication for the procedure was pain and limited abduction. The mean follow-up was 4.5 years. Patients were assessed using modified Iowa hip scores at final follow-up. The procedure corrected some leg shortening and improved the abduction range of the affected hip. Overall 80 % of patients did well. The mean Iowa hip score in Perthes group was 84 at final follow-up.

Four patients preoperatively had cysts/ defects in their femoral head. These were seen to fill up during their postoperative follow-up. Poorer outcome was associated with preoperative hip stiffness and surgery before stabilisation of the avascular process.

Conclusion: Valgus osteotomy is an effective procedure for relieving hinge abduction with associated additional benefits including improvement of leg shortening and improvement in hip abduction. The procedure should be avoided in stiff hips.


SS Madan DE Ruchelsman J Jeong WB Lehman DS Feldman

The role of femoral and acetabular version in correction of dysplasia of the hip has been undereported. Between June 1995 and September 2000, a Bernese periacetabu-lar osteotomy (BPO) was performed in 25 patients (26 hips) by the senior author with an average follow-up of 3.7 years (range 2-5 years). The mean age of the patients (24 female, 1 male) at the time of surgery was 29.4 years (range, 11.5 to 45 years). Only patients with a primary diagnosis of acetabular dysplasia were included in this series.

The average Harris hip score increased from 55.1 (range 34–75) preoperatively to 92.9 (range 72–100) at the latest follow up (p< 0.0001). The mean pre-operative Merle d’Aubign score increased from 13.5 (range 1015) to 17 (range 15–18) at the latest follow up. The mean lateral centre edge angle of Wiberg increased from 13.10 (range 00–200) pre-operatively to 52.60 (range 200-740) at latest follow-up (p< 0.0001). The anterior centre edge angle averaged 10.90 (range 4-170) pre-operatively and improved to 490 (range 210–760) at latest follow-up (p< 0.0001). The Mckibbin instability index is the sum of femoral and acetabular version (normal range 200–500). There were 6 hips with low instability index and 11 hips with high instability index pre-operatively. At the latest follow-up there were only 2 hips with low instability index and there were no patients with a high instability index. Our clinical results showed fi fteen patients with excellent results, eight good results and one fair and one poor results. Thus, overall good to excellent results were obtained in 92% of our patients. It is therefore possible that we had higher success rate in our series than that reported in other series because of the correction of version of the hip in addition to the coronal and sagittal defi ciency of the hip.


R Thonse GV Johnson

Of the 30585 births (from 1997–2002) in the population served by our NHS trust, 2742 babies (8.96%) were referred to the hip screening clinic by the neonatologists and general practitioners. They were examined clinically and by US scans by the specialist consultants. The findings were documented prospectively. 233 hips were identified as abnormal by ultrasound scans (Graf). 45% (106) of these were normal on clinical examination. None of the hips identified as abnormal on clinical examination were normal on US scans. In 38% (88) clinical examination could not be reliably performed as the babies were tense.

Of the 1862 hips which were clinically normal, 106 (5.69%) had abnormal ultrasound findings. Furthermore, of the 841 babies who were tense on clinical examination, 88 (10.46%) babies had abnormal ultra-sonographic findings.

Ultrasound scanning of hips in at-risk babies by an experienced paediatric radiologist will identify all the abnormal hips. This will release the paediatric orthopaedic surgeon from routine clinical examination of all these babies. This time can be utilised for running other clinics. Babies found to have abnormal hips on US scanning may be seen by the orthopaedic surgeon for treatment and follow-up. Parents of babies with normal hip US scans may be reassured by a nurse practitioner or a paediatric physiotherapist.


RMD Meek NV Greidanus DS Garbuz BA Masri

The purpose of this study is to evaluate the effect of prosthetic patellar resurfacing on outcome of revision total knee arthroplasty in a matched cohort study.

From January 1997 to December 1999 126 patients who underwent revision of total knee arthroplasty were identified. The status of the patella was ascertained post revision as to the presence or absence of patellar prosthesis. At a minimum of two years follow-up, pain and function were assessed by questionnaire for WOMAC, Oxford-12, SF-12 and patient satisfaction data. Co-morbidity, surgical exposure, HSS knee scores and ROM were also collected. Univariate and multivariate analysis were performed. Follow-up was obtained in 110 patients (52 with patellar component, 58 bony shell), matched for age (mean 70 and 67 years), sex and co-morbidity scores and followed for a minimum of two years. There was no significant difference between the two cohorts with regards to outcomes of WOMAC pain scores (mean 66 and 74, p=0.14), WOMAC function scores (mean 59 and 65, p=0.22), Oxford- 12 scores (mean 57 and 64, p=0.17), and satisfaction score outcomes (57 and 68, p=0.14). It remains controversial whether the patient’s pain, function and satisfaction are affected in revision total knee arthroplasty by patellar prosthetic resurfacing. Insufficient patellar bone stock may preclude prosthetic resurfacing in which case patel-loplasty is performed. From this series, the presence or absence of a patellar prosthesis does not appear to sig-nificantly affect pain, function, or satisfaction outcomes following revision total knee arthroplasty.


R Thonse GV Johnson

The aim of this study was to ascertain the results and effectiveness of targeted screening of babies.

All the newborn babies (30585 births from 1997 to 2002) in the geographical area served by our trust were assessed by the paediatricians (neonatologists) and general practitioners (GP). They were assessed for abnormal hip examination finding including clinical instability and risk factors for DDH. The risk factors were positive family history, abnormal lie or presentation other than vertex during pregnancy or at birth, oligohydramnios or other congenital abnormalities. On referral, they were assessed clinically and by ultrasound (US) scan in a special Hip screening clinic.

The data were obtained prospectively. Over the period of these six years, 2742 babies were examined in the clinic. Many had more than one risk factor or abnormal hip examination finding (15.9% of babies with abnormal hips and 7.4% of babies with normal hips). Only five babies presented at or after 4 months of age (delayed presentation). They had been treated by the GP (1 patient), at a private hospital (1 patient) or were from outside our area (3 patients). All had abnormal hips on clinical examination. Of these, 3 were 3A or 3B Graf grade (US scan), 1 was 2B and another 2A+.

Screening of babies with above risk factors has identified all patients with abnormal hips in our area, thus avoiding late presentation of DDH. Raising awareness of GPs and paediatricians about these factors should also reduce the number babies to be seen in the hip screening clinic to minimum yet safe levels.


SS Madan DE Ruchelsman DS Feldman WB Lehman

To evaluate the correction of complex congenital deformities of the lower limb by six axes deformity analyses and computer assisted correction using the Taylor TM Spatial Frame (TSF), from 1998 to 2000, the authors performed corrections of multiple congenital deformities in 24 lower limbs in 18 patients. There were 9 males and 9 females. There were a total of 29 bone segments, (8 femurs, 21 tibiae) in the 24 lower limbs that were corrected with application of the TSF. Our series included the following diagnoses and deformities: unknown skeletal dysplasia (2), achondroplasia (3), pseudoa-chondroplasia (1), multiple epiphyseal dysplasia (2), spondyloepiphyseal dysplasia (2), fibular hemimelia (3) tibia hemimelia (1), hypophosphatemic rickets (3), and posteromedial bowed tibia (1).

The mean age of the patients was 15.4 years (range 0.5 to 35 years). The mean frame time until correction was 20.1 weeks (range 9 to 49 weeks). The mean follow up was 2.4 years (range 2 to 3.4 years). The apex of the deformity was directed posteromedial in 7, anterolateral in 6, medial in 5 and anteromedial in 5 patients. The mean coronal and sagittal plane deformities were 14.60 (range −230 to 400) and 70 (range, −400 to 280), respectively. The average magnitude of the deformity was 21.70 (range 90 to 470), and the plane of the deformity to the coronal plane was −23.30 (range −800 to 400). Eight patients had a mean lower extremity shortening of 12.3 mm (range 5 to 50 mm). One patient had 15° of internal rotation. With application of the TSF and the principles of distraction osteogenesis, we were able to reduce the coronal and sagittal plane deformities to 3.10 and 1.40 respectively. The overall mean magnitude of the deformity was decreased to 3.40. Shortening was corrected to an average of 3 mm. We experienced only 4 complications in the 24 limbs (16.7%). Complications in this patient group included one female patient with hypophosphatemic rickets who had residual deformity with significant lateral mechanical axis deviation due to inadequate translation. In addition, there were two superficial pin tract infections and one delayed union.

Computer-assisted six axes deformity planning and TaylorTM Spatial Frame application effectively and safely correct complex congenital and developmental limb deformities and offer significant advantages over the well-established Ilizarov technique.


JB Wood

Avascular necrosis (AVN) of the immature femoral head is the final common pathway of the Legg-Calve-Perthes (LCP) disease. Since cigarette smoking has been linked to the development of vascular disease, a study was performed to see if there was any association between parental smoking and LCP disease.

The biological parents of 97 children with LCP disease were questioned on their smoking habits, which were compared to a control group of parents with unaffected children. Further comparison was made with respondents from the Perthes’ Association website who completed an on-line questionnaire.

Parents were classified as being smokers or non-smokers on the basis of their smoking habit pre-pregnancy, during pregnancy and at the time of diagnosis of LCP being made. There was a higher proportion of children in the LCP group who had parents who smoke (N=67/97, 69%) compared to the control group (N=14/87, 16%). Further analysis showed that the highest rate occurred when both parents smoke before pregnancy (N=37/97, 38%) followed by when only the father smoked (N=23/97, 24 %). Maternal smoking alone appeared to have the least association (N=7/97, 7 %).

In the control group the non-smoking rate was 58/87 [67%]. The changes in smoking patterns with respect to the pregnancy concerned were also noted.

Fisher’s Exact test was used to determine any difference between the study group and the control group. There was a significant difference between the Perthes’ SE group concerned to the controls in all respects except maternal smoking.

Comparison made with data obtained from the Perthes’ association website showed no difference between the two Perthes’ groups.

Conclusion: These results support an association between parental smoking and the development of disease LCP disease.


SS Madan JA Fernandes JF Taylor

Thirty-four patients were studied through the whole of the Perthes’ disease in Alder Hey Children’s Hospital, Liverpool. The acetabular changes included osteopaenia of the roof, irregularity of its contour, and decrease in the depth. These changes were proportional to the femoral head involvement. The purpose of the study was to know the effect of the morphological changes of the femoral head on the acetabulum and its outcome.

Radioisotope scans of the hip were examined in fourteen children with unilateral Perthes’ disease and comparison was made with the contralateral hip. These scans showed increased uptake on the lateral part of the acetabulum and no uptake over the avascular part of the femoral head. Average follow-up was ten years and on an average children were followed up from six years to fifteen years of age. Six readings of the measurements of various dimensions of the acetabulum and the femoral head were done. CT scan also showed irregularity in the acetabulum. Statistical tests lead to the conclusion that the decrease in the depth of the acetabulum was secondary to the femoral head involvement and the extent of its dimensional changes affected the final congruity between the femoral head and the acetabulum. Also the remodelling potential of acetabulum decreases as the child grows older. Therefore containment procedures could be done by femoral osteotomy in younger children and acetabular osteotomy may benefit older children.


JE Owen MC Watts PT Myers

This study reports our long-term results of arthroscopically assisted meniscal suture using an inside-out technique.

Between January 1990 and July 1997, 112 patients underwent 121 meniscal repairs in 112 knees. The average follow-up is 8.7 years (range 5.4 to 12.9 years). Repairs consisted of interrupted sutures using 2.0 PDS. Sutures were placed arthroscopically using a suture shuttle system and tied behind the capsule after making a small postero-medial or posterolateral incision. The meniscus and bed was prepared using a Rasp or hand-held instruments. Fibrin clot techniques were not used. 79% of patients had associated ACL reconstruction in addition to meniscal suture. All surgery was carried out by our senior author (PTM). Rehabilitation involved non-weight-bearing in an extension splint for 3 weeks and partial weight-bearing for a further 3 weeks followed by a progressive rehabilitation programme.

The average age at surgery was 23.9 years (range 12.2 to 57.7 years). The average time from injury to surgery was 13.5 months (range 0 to 60 months). There were 74 males and 38 females. 51% of patients were professional or semi-professional athletes. Repair involved 79 medial menisci, 42 lateral menisci. The average number of sutures used was 3.8 (range 1 to 12). Operative findings and procedure were entered prospectively into a database. Patients were assessed clinically until recovery and long-term follow-up consisted of a detailed postal questionnaire.

The average Lysholm scores were 86.4, with 59% excellent, 16% good, 17% fair and 8% poor. IKDC subjective scores averaged 82.0, with 40% excellent, 21% good, 27% fair and 12% poor. Confirmed failure of meniscal repair (as indicated by MRI or re-arthros-copy) has been identified in 11.8% of patients. A further 10.8% have a probable failure based on a recurrence of mechanical symptoms. Of the failures 73% were professional or semi-professional sportsman. Their average return to sport after surgery was 9.5 months (range 3 to 18 months). Failure was reported at an average of 29.3 months after surgery (range 0 to 84 months).

With an aggressive approach towards meniscal preservation we have achieved a success rate of 77.4% at an average follow-up of 8.7 years.

The majority of these tears are vertical posterior horn or large bucket handle and associated with an ACL reconstruction. The majority of patients are young and involved in a high level of sporting activity.


P Li J Forder R Ganz

To investigate the proportion of dysplastic hips which are retroverted. We studied the radiographs of over seven hundred patients with dysplastic hips who had had a periacetabular osteotomy in the period 1984–1998. We excluded patients with neuromuscular dysplasia, Perthes’ disease of the hip, post-traumatic dysplasia and proximal focal femoral deficiency. We selected 232 radiographs of patients with congenital acetabular dysplasia. A number of parameters were measured including lateral centre-edge angle, anterior centre-edge angle, acetabular index of weight-bearing surface, femoral head extrusion index and acetabular index of depth to width. Also recorded were acetabular version and congruency between femoral head and acetabulum.

The lateral centre-edge angle of Wiberg had a mean value of 6.4° (SD 8.9°), the mean anterior centre-edge angle was 1.3° (SD 13.5°) and the acetabular index of weight-bearing surface of the acetabulum had a mean value of 24.5° (SD 9.7°). The majority (192, 82.8%) of acetabula were anteverted as might be expected. However, a significant minority (40, 17.2%) were retroverted. The mean anterior centre-edge angle in retroverted hips was 6.7° (SD 9.4°) compared with 0.4° (SD 13.3°) in anteverted hips.

The authors have shown that, in a typical group of patients with congenital acetabular dysplasia significant enough to warrant periacetabular osteotomy, the majority of hips as expected have anteverted acetabula. However, a significant minority are retroverted. This finding has an important bearing on the performance of the osteotomy. We have also found that most if not all the information required prior to and following periac-etabular osteotomy can be obtained from an orthograde view of the pelvis.


R Samuel P Dunkow M Smith D Lang

Radiological examination is a useful tool in assessing osteoarthritis (OA) in the knee. We have compared the extent of osteoarthritis in the knee graded on radiographs and by intraoperative observation to determine if there is significant difference with relevance to preop-erative planning.

Radiographs for fifty-eight patients were graded for OA under blind conditions using the Ahlback classification system and direct measurement of the medial and lateral joint spaces. Intraoperative assessment of the corresponding joint surfaces was performed under blind conditions by a separate surgeon and graded using the Outerbridge classification system.

OA was found to be more common in the medial compartment than the lateral, both on radiographs and intraoperatively. Spearman correlation coefficient for the medial compartment comparing joint space narrowing and intraoperative assessment was −0.545. For the lateral compartment the Spearman correlation coefficient was lower at –0.406. Positive predictive values for OA in the medial and lateral compartments on radiography were 90% and 66.67% respectively. Negative predictive values for OA in the medial and lateral compartments on radiography were 44.74% and 34.69% respectively.

Conclusion: We have demonstrated that although radiographs have reasonable to good accuracy at showing OA in both compartments the absence of OA on radiographs does not correlate well with the absence of OA in the knee. This is of importance when planning operations, particularly unicompartmental knee replacement, as intraoperative findings of bilateral disease will change the operation required.


M Hockings J Borrill PJ Rae

Patients were followed up retrospectively by a combination of clinical review, mail and telephone questionnaires. The Lysholm knee (LS) and the Tegner activity (TA) scores were recorded.

From July 1991 until February 1999 75 meniscal repairs were carried out in 70 patients by a single surgeon (PJR). The average age of the patients was 26yrs 8 months, 52 male and 18 female. 14 patients (18.6%) were lost to formal follow-up. Lysholm Score (LS) and Tegner Activity (TA) scores were available on 58 repairs for analysis. The average follow-up was 6 yrs 4 months (range 3 yrs 4 months to 10 yrs 9 months), Average scores were LS=89.2, TA before surgery=6.2, TA after surgery=5.7. 9 patients had menisectomy following retear due to further injury. The overall success rate was 86.9%, with 74.1% scoring clinically good or excellent on the Lysholm Score.

There was a trend of improved results for patients over 30 yrs; those with longer tears and lateral repairs did slightly better. Those with ACL laxity had a significantly better result. The time interval to repair following injury did not make a difference. With an overall success rate of 86.9% the authors would recommend this traditional technique in light of the more recent techniques presently in use.


AP Davies PA Campbell CP Case ID Learmonth

Cobalt chrome-on-cobalt chrome bearing surfaces have been re-introduced despite some concerns regarding potential risks posed by soluble metallic by-products. We have investigated whether there are metal-selective differences between the levels of genetic damage caused to a human cell line when cultured with synovial fluids retrieved from various designs of orthopaedic joint replacement prostheses at the time of revision arthroplasty.

Synovial fluids were retrieved from revision hip and knee arthroplasty patients with bearings made from cobalt chrome-on-cobalt chrome, cobalt chrome-on-polyethylene and stainless steel-on-polyethylene. Control synovial fluids were retrieved from primary arthroplasty cases with osteoarthritis. Synovial fluid was cultured with human primary fibroblasts for 48 hours in a cell culture system under standardised conditions. The “Comet” assay was used with an image analysis system to measure levels of DNA damage caused by the various synovial fluid samples.

Synovial fluids from cobalt chrome-on-cobalt chrome and cobalt chrome-on-polyethylene joint replacements both caused substantial levels of genetic damage as detected by the Comet assay. Synovial fluids retrieved from stainless steel-on-polyethylene joints caused low levels of damage. The difference between these groups was highly statistically significant (p< 0.001). Control synovial fluids from osteoarthritic joints caused minimal changes. Atomic absorption spectroscopy demonstrated that the metal-on-metal synovial fluids contained the highest levels of cobalt and chromium. Different alloys used in orthopaedic implants are associated with different levels of DNA damage to cultured human cells in vitro. We are able to demonstrate that this damage is attributable at least in part to the metal content of the synovial fluid samples. We have no evidence for any long-term health risk to patients with such implants.


A Blom G Hughes T Lawes J Cunningham A Goodship I Learmonth

Restoration of bone stock is the single greatest challenge facing the revision hip surgeon today. This has been dealt with by means of impaction grafting with morsellised allograft from donor femoral heads.

Alternatives to allograft have been sought. This study investigates the use of a porous biphasic ceramic in impaction grafting of the femur.

Impaction grafting of the femur was performed in four groups of sheep. Group one received pure allograft, group two 50% allograft and 50% BoneSave, group three 50% allograft and 50% BoneSave 2 and group four 10% allograft and 90% BoneSave as the graft material.

Function was assessed by measuring peak vertical reaction forces. Changes in bone mineral density were measured by DEXA scanning. Loosening and subsidence were assessed radiographically and by examination of explanted specimens.

All outcome measures showed no statistically significant difference between the four groups after eighteen months of full function.

Conclusion: When used as allograft expanders, Bone-Save and similar porous biphasic ceramics perform as well as pure allograft in impaction grafting of the femur.


N Roy H Mirza NR Fahmy

Full thickness skin grafting has been used following dermo-fasiectomy for Dupuytren’s contracture. We have used a conservative approach following excision of the contracture. Following radical excision through Brunner’s incision, an elliptical full thickness skin graft is harvested from the volar aspect of the wrist. This is applied to the wound on the volar aspect of the proximal phalanx to cover the gap with the finger held in extension. Patients who have undergone primary Dupuytren’s excision between 1990–1998 were recalled and evaluated in special clinic. Clinical notes were reviewed for pre-operative deformity, wound problems if any and recurrence of deformity at annual follow-up. Patients were reviewed for present status of deformity, ROM, sensation, 2-point discrimination, evidence of recurrence and patient satisfaction.

One hundred and six fingers were evaluated in 80 patients. Average duration of follow-up was 52 months. Sixty-five patients had bilateral disease and 29 patients had family history of Dupuytren’s disease. Average pre-operative flexion deformity of the PIP joint was 68.6 degrees and 12 patients had deformity of the DIP joint. Mean flexion deformity at review of the PIP joint was 26.4 degrees. 29 patients reported sensitivity to cold. Two-point discrimination was abnormal in 24 patients. Skin tightness was noted in 8 fingers and 7 cases had recurrence. In 2 fingers the recurrence was away from the graft and in remaining 5 fingers it was proximal to the graft not crossing the grafted area. Thirty-three patients had progressive disease in the adjacent fingers away from the operated area. There was no case of graft loss. Seventy patients were satisfied with the end results of the operation.

Our study has shown a very low incidence of recurrence following radical dissection and similar result as dermo-fasciectomy, and the skin graft acting as a barrier in cases of recurrence. Also graft harvested from the wrist matches the colour of the palm with increased patient satisfaction.


MA El Masry WI El Assuity D Chan

To provide short- term follow-up data on the surgical success and patient outcome following early anterior cervical fusion in this particular type of injury. A prospective study of 10 consecutive patients.

Stage I compressive extension injury of the cervical spine, as described by Allen and Ferguson, is not always a stable injury. The combined unilateral failure of the posterior structures under compression together with failure of the anterior structure under tension will lead to a rotationally unstable segment. Various treatment options are available including halo vest immobilization, posterior stabilization with plating and anterior fusion and plating.

10 consecutive patients diagnosed with stage I compressive extension injury (fracture subluxation of the cervical spine). All subjects presented with a neurological deficit and vertebral subluxation. All patients were investigated with CT scan of the involved segment; in addition 2 patients had MRI scans.

The surgical protocol consisted of early reduction followed by anterior cervical fusion using a tricortical iliac graft, and stabilization, using locking plate fixation. Follow-up was by radiographs and clinical examination.

Intraoperative assessment revealed disc injury in all patients. Anatomical realignment was achieved together with a solid fusion in all of the patients. All patients showed improvement in the neurological deficit. One patient remains with some residual weakness in his triceps and another patient required removal of a prominent screw.

Early anterior fusion and plating for this type of injury is a safe procedure


JM Wilkinson

Aseptic loosening arises when periprosthetic bone loss results in mechanical failure at the host-implant interface, and is the main factor limiting implant survival after total hip arthroplasty (THA). The aims of this study were to determine whether genetic variation is a risk factor for loosening, explore the metabolic mechanisms of periprosthetic bone loss, and determine whether bisphosphonates may prevent bone loss and enhance implant mechanical stability after THA. In a genetic association study (J Bone Mineral Res2003; 18:1995–2001) we found that carriage of the −238A allele within the promoter region of the TNF gene was an independent risk factor for aseptic loosening. A subsequent reporter gene assay showed differential TNF gene responsiveness between the –238A and –238G alleles to polyethylene particule stimulation (Calcified Tissue Int 2003; 72: 251-273). In a cross-sectional study (J Orthop Res 2003; 214: 691–696) we found that subjects with aseptic loosening had lower bone mineral density (BMD) in the region of the femoral calcar and higher urinary excretion of cross-linked collagen breakdown products than their counterparts with fixed femoral implants. In a randomised controlled trial we found that a single dose infusion of a bisphosphonate (pamidronate) reduced femoral bone loss over 2 years after THA, but did not affect pelvic bone loss or implant migration (J Bone Miner Res2002; 17: 1328). Transient increases in bone turnover markers occurred after surgery and were highly predictive of later femoral BMD change. The main predictor of early implant migration was patient age, but not periprosthetic BMD change. In summary, genetic as well as environmental factors affect implant survival after THA. Aseptic loosening is associated with regional changes in bone mass and turnover as well as focal osteolytic lesions. Bisphosphonate therapy is well tolerated after THA and has a clear biological effect. However, the impact of preventing early bone loss on late aseptic loosening remains unclear and awaits long term study.

[Winner, Robert Jones Gold Medal and Association Prize, 2003]


HA Mann NJ Goddard CA Lee

Haemophilia care has steadily improved over the years and especially so during the last decade. The routine use of prophylactic treatment has undoubtedly resulted in a significant improvement in the life-style, quality of life and life expectancy of these patients, and bodes well for the future.

The knee is the most common joint affected in patients with severe haemophilia (approx 50%) and despite best efforts there is still a group of young adults who have a severe degree of knee joint destruction as a result of repeated articular bleeding episodes during their early years.

The indications for operation are primarily disabling pain that is unresponsive to medical treatment. Deformity and poor functional range of motion, particularly a severe flexion contracture of the knee, are relative indications and may in themselves justify joint replacement. Equally joint contractures and flexion deformity pose various surgical challenges for the surgeon. The introduction of continuous replacement clotting factor has facilitated the operation and in our experience has reduced the complications of TKR. We have found that it permits earlier rehabilitation and in our present series the outcome in this group of patients almost comparable to TKR performed in the general population.


M Moran P Walmsley A Gray IJ Brenkel

There is little evidence describing the influence of body mass index on the outcome of Total Hip Replacement (THR). There are concerns that an increasing BMI may lead to increased blood loss, infection and venous thromboembolism. 800 consecutive patients undergoing primary cemented THR were followed for a minimum of 18 months. The Harris Hip Score (HHS) and SF-36 were recorded pre-operatively and at 6 and 18 months post-operatively. In addition other significant events were noted, namely death, dislocation, re-operation, superficial and deep infection and blood loss. Multiple regression analysis was performed to identify whether BMI was an independently significant predictor of the outcome of THR.

No relationship was seen between the BMI of an individual and the development of any of the complications noted. The HHS was seen to increase dramatically post-operatively in all patients. BMI did predict for a lower HHS at 6 and 18 months, and a lower physical functioning component of the SF-36 at 18 months. This effect was small when compared with the overall improvements in these scores.

Conclusion: THR provides good symptomatic relief irrespective of BMI. On the basis of this study we can find no justification for withholding THR solely on the grounds of BMI.


P Dunkow B Muddu

We conducted a prospective randomised controlled trial. 45 patients (total of 47 elbows) underwent either a formal open release or a percutaneous tenotomy (24 open, 23 percutaneous). All patients had pre-operative assessment by the DASH (Disability of the Arm, Shoulder and Hand) scoring system. The surgery was performed by 1 surgeon (BN Muddu). Both groups were followed up for a minimum of 12 months and re-assessed using the DASH scores, time for return to work and patient satisfaction. Statistical analysis using Mann-Whitney and repeated measures ANOVA were performed.

The groups were similar in respect of demographic and pre-test variables. Statistical analyses using Mann-Whitney showed significant differences for patient satisfaction (p=0.012), time to return to work (p=0.0001), improvements in DASH Score (p=0.002) and improvement in sporting activities (p=0.046). There was a trend to improvement in work related activity. Repeated measures ANOVA comparing the pre-operative data for each group were also significant for standardized DASH scores (p=0.0082) and sporting activities (p=0.043).

Our study has shown that there is a significant difference in outcome in the two patient groups. Those patients undergoing a percutaneous release returned to work on average 3 weeks earlier and their symptoms as shown from their DASH scores improved significantly more than those undergoing an open procedure. The percutaneous procedure is a quicker, simpler procedure to perform than an open procedure. Our study has shown that patients have significantly better outcome measures after a percutaneous procedure.


A Langston SH James MD Holt

The South Wales Air ambulance is a charity-funded helicopter service that started functioning on 1 April 2001. There are 10 staff involved in the running of the service, including pilot and paramedics. The territory covered is the South and Mid-Wales regions. The service costs on average £500 per flight and the net cost per year is approximately £750,000.

A retrospective study was performed to evaluate the extent and appropriateness of the air-ambulance call-outs over a 12-month period. The guidelines for call-out are based on medical and non-medical criteria. During this period the helicopter made 315 sorties. On 159 occasions the helicopter was stood down once airborne or following landing at the scene. £80,000 has been spent on non-patient -carrying call-outs. Of the 156 patient-carrying sorties 70% were transferred to Mor-riston Hospital, Swansea. 67% of these patients were categorised as trauma patients. Transfer distance averaged just 15 miles (range 2.6-41.2 miles). The majority of trauma cases were categorised as spinal soft tissue injuries or soft tissue injuries. 52% of patients were discharged by A& E staff without requiring orthopaedic assessment. 59% of trauma transfers were deemed to be inappropriate for helicopter transfer by the senior author.

Our study concludes that the air-ambulance is used inappropriately in at least 50% of the call-outs. The call-out criteria require amending and should place more emphasis on pick-up location rather than the nature of the casualty. It is not used cost effectively and is not always clinically effective.


WJ Harrison CP Lewis CBD Lavy

The study sought to compare infection and union rates in HIV positive patients sustaining severe open tibial fractures, with those in healthy controls.

In a prospective study, consecutive adult patients with Gustilo grade 2 or 3 open tibial fractures who consented to enter the study were enrolled and treated according to a standard regime. The regime consisted of intravenous antibiotics, emergency wound excision and irrigation, wound left open, fracture stabilisation by external fixation, wound inspection at 48 hours and closure if clinically indicated. 27 patients with 28 fractures entered of whom 7 patients were HIV positive.

At 3 months, 2 of the HIV positive cases had satisfactory wound healing, while 5 were infected. In the HIV negative controls, 17 had satisfactory wound healing while 4 were infected (p=0.020, Fishers exact test).

At 6 months 4 HIV positive patients were united, 3 were ununited. At the same time, 16 HIV negative patients were united, 1 ununited, and 4 lost to follow-up (p=0.059, Fishers exact test).

Open tibial fractures in HIV positive patients are prone to wound sepsis and may show a tendency to delayed or non-union.


R Raman S Cooke SJE Matthews PV Giannoudis

Firearm injury is a potentially increasing public health problem worldwide. It is increasingly the subject of media and public attention. We aim to analyze the epidemiology, pattern and outcome as experienced.

Data such as age, sex, race, scene and nature of injury, firearm used, alcohol and drug factors, anatomy involved, surgical requirements, transfusion details, ICU/HDU stay, complications, deaths, and outcome were collected from medical notes, WYMAS and Coroners office of all patients who presented with firearm injuries from January 1995 to December 2001. Seventy-eight cases presented to our institution. There were 19 fatalities at the scene of injury. 69 were male. 51 sustained injuries in public places, 20 at their homes and 7 in outdoor areas. Low velocity firearms were involved in 49 cases. 50 were crime related. Alcohol was identified in 34 patients and illicit drugs in 6 cases. 19 cases had bony injury with associated vascular injury in one case. Primary neurological injury was diagnosed in 5 cases. Lower extremities and upper limb injuries accounted for 59% and 26%. 3 had head and neck wounds. 4 patients had thoracic trauma and 5 had abdominal injury. 86% required surgical intervention. 11 patients had a total of 16 complications, the most common being secondary infection. 6% of patients died at the emergency department and 3 after. Chest injuries caused 5 deaths and head wounds caused 3 deaths illustrating criminal intention to cause fatal body harm.

Conclusion: Males in younger age groups are disproportionately affected and the majority were crime- related injuries. Alcohol and other drugs were identified as a significant factor. There has been no significant decrease in the reported cases of firearm injuries or firearm-related deaths after the amendment made in the Firearm Rules in September 1998 (No:1941). The incidence of non-fatal firearm injury is comparable to centres involving similar population.


SD Deo C Loucks PA Blachut PJ O’Brien HM Broekhuyse RN Meek

The long-term results of patients with multiple knee ligament injuries, i.e. at least 3 ligament ruptures, including both cruciates, in patients entered prospectively onto the trauma database between 1985 and 1999, were reviewed. Forty patients with this injury had modified Lysholm scores at long term follow-up a mean of 8 years post-injury. The mode of operative treatment fell into 3 groups: direct suture or screw fixation of avulsions (Group 1), mid-substance ruptures treated with cruciate reconstruction with hamstring tendons (Group 2), or suture repairs of mid-substance ruptures (Group 3). All operative procedures were undertaken within 2 weeks of injury. Non-operative treatment involved a cast or spanning external fixator (2–4 weeks) followed by bracing. Statistical analysis was performed on the Lysholm scores.

The 40 patients in the study group were predominantly young males, 40% had polytrauma, 33% had isolated injuries. Thirteen patients (33%) had non-operative management, the remainder had early operative treatment of their ligament injuries, tailored to the type of ligament injuries identified.

Long-term patient outcome data shows statistically significant differences (p< 0.05) between the best results, in patients with direct fixation of bony avulsions (mean = 89), followed by those who had early hamstring reconstruction (mean = 79), followed by those who underwent simple ligament repairs (mean = 65). There was a statistically significant difference (p< 0.05) between the overall scores for the operative group (mean = 80) compared with the non-operative group (mean = 50).

Operative treatment of multiple ligament injuries, particularly fixation of avulsions and primary reconstruction of the posterior cruciate ligament appears to yield better results than non-operative or simple repair in the long term follow-up in this group with significant knee injuries.


D Chakravarty MJ Parker A Boyle

This study was conducted to find out whether blood transfusion was an independent risk factor for mortality and wound infections after hip fracture surgery.

A retrospective cohort study analysed prospectively collected data for 3571 hip fracture patients undergoing surgery over the last 15 years in one institution. Out of these 1068 patients underwent blood transfusion.

There were no significant differences in the mortality values at 30, 120 and 365 days and in the rates of infection (superficial and deep) in the two groups (transfused and non-transfused).

Conclusion: Blood transfusion does not significantly increase mortality or infection following hip fracture surgery.


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S Ravinder HS Gill JPS Walia BS Brar TS Nagra

Skin and soft tissue loss is very common in modern high velocity trauma. Such wounds pose problem of coverage. We present a good alternative to skin grafting & flaps i.e. SINGH’S skin traction device for wound closure in these patients.

The technique is based on the principle of tissue expansion and makes use of viscoelastic properties of the skin i.e. creep and stress relaxation. 100 cases with 116 wounds with skin and soft tissue loss were treated. Two parallel kirshner wires (1.5mm) were passed through the dermis on either side of the wound margins and interconnected by compression device consisting of threaded rod having two blocks and compression knob. Gradual compression approximated the wound margins. Patients ranged in age from 15 to 65 years with average age of 30.5 years. Main modes of injury were roadside accidents and machinery accidents. Average operating time was about 20 minutes. 50 amputation stump wounds were also treated.

Excellent results were observed in 48 (41.4%), good in 42 (36.2%), fair in 14 (12%) and poor in 12 (10.4%) wounds. Main complication was cutting through of wires.

We found that this technique is simple, economical and effective. No special training and instruments are needed and can be done by junior surgeon at small centres. It provides full thickness cover to the wound which matches the surrounding normal skin in quality, sensations and colour. Above all this technique can be successfully used in infected wounds and wounds with exposed bone and tendons. Careful gradual compression judged by pain and blanching gives better results and fewer complications.


CWC Tong JF Griffith GE Antonio KM Chan

[Hong Kong Orthopaedic Association, Travelling Fellow]

Glenoid bone loss predisposes to further dislocation and failure of arthroscopic Bankart repair in patients with recurrent shoulder dislocation. This study investigates quantification of glenoid bone loss in anterior shoulder dislocation using computerized tomography (CT).

CT was performed in 40 patients (average age 31 years, range 16–82 years) with anterior shoulder dislocation. Of this group, 42 shoulders with anterior dislocation and 38 contralateral normal shoulders were examined. In addition, twenty shoulders in ten normal subjects were examined. CT technique comprised 1mm acquisition, pitch 1.0, simultaneously of both shoulders. Reformatted images en face to the glenoid fossa were obtained. Ten different measures of the glenoid fossa were obtained including cross sectional area, maximum height, and width and flattening of the anterior curvature of the glenoid.

In normal subjects, maximum side to side difference in cross-sectional area was 14% and maximum glenoid width 4.1mm. For dislocating shoulders, flattening of the anterior edge of the glenoid fossa and a reduction in maximum glenoid width were the best objective criteria of bone loss. Flattening of the anterior glenoid curvature was a feature of 95% dislocated shoulders though was only seen in 1.5% of normal shoulders. Glenoid cross-sectional area was not a useful measure of glenoid bone deficiency.

Variable glenoid bone loss is a measurable feature of anterior shoulder dislocation. CT can be used to objectively assess this preoperatively. This should help when deciding on whether to perform an arthroscopic Bankart repair or open bone block procedure.


S Sharma LA Rymaszewski

The purpose of this study was to demonstrate the beneficial effects of elbow arthrolysis.

This was a prospective study on 88 patients with post-traumatic elbow stiffness with a mean follow-up of 51 months (1 year - 11 years), who had failed to improve their range of movement at a mimimum period of 6 months after their injury. All patients had an open arthrolysis. Post-operatively patients received continuous passive movement (CPM) for 48 to 72 hours. This was facilitated by good analgesia afforded by a continuous brachial plexus block. All patients received no physiotherapy thereafter and were advised to actively mobilise their elbow. ROM was assessed using a goniometer and function assessed using the Mayo elbow performance index.

The ROM improved from a mean of 56 degrees pre-operatively to 106 degrees post-operatively. This improvement in ROM was reflected in the improvement of pre-operative flexion from 107 to 138 degrees and improvement of extension from 60 to 31 degrees. Function improved from a mean of 65 to 85 on the Mayo elbow performance score. 95% of the patients were satisfied with the outcome. Complications included ulnar nerve paraesthesia in 3 patients, 1 triceps avulsion and 1 superficial infection. 3 patients required a manipulation of the elbow in the postoperative period. This was performed within 2 weeks of the operation. There were no cases of elbow instability or heterotopic ossification in this series.

Conclusion: Open elbow arthrolysis combined with continuous brachial plexus block and CPM in the postoperative period is a safe, reliable and durable procedure for improving ROM and function in patients with post-traumatic elbow stiffness.


AM Richards ND Citron

The aim of this study is to assess the clinical outcome following latissiumus dorsi transfer for massive irreparable tears of the rotator cuff.

Between 1996 and 2002 seven patients with massive irreparable rotator cuff tears were treated by transfer of the latissimus dorsi by a single surgeon. Their mean age at time of surgery was 65 years. Five patients were female, five were primary procedures and two were revisions. Patients were assessed with MRI pre-operatively; the decision to plan a transfer was made clinically.

At time of operation all were found to massive irreparable tears of the cuff including Supraspinatus and Infraspinatus, Subscapularis was intact in all cases. Five of the transfers were implanted to a bone trough, one was sutured to a tendon stump, and one was augmented with a Teflon patch.

Mean time to follow up was 21 months. All patients were assessed by the lead author or by his Specialist Registrar. Six patients had a good result, one had a poor result this was a revision procedure resulting in deltoid origin detachment.

Functional outcome significantly improved post-transfer. Constant score 62.1% vs 36.1% (p< 0.0005, Paired t-test), Pain was also significantly reduced post-transfer, both when active 7.1 vs. 2.2 p (< 0.005) and when at rest 3.7 vs. 1.2 (p< 0.005).

Conclusion: These results are compatible with those published for Latissimus Dorsi Transfer. Latissimus Dorsi Transfer can be effective in restoring shoulder function and reducing pain following massive irreparable tears of the rotator cuff.


DJ Watkinson M Waseem DG Hargreaves

A prospective study of early operative treatment of unstable elbow dislocations using a surgical algorithm, we present the early results of nine such injuries including five terrible triads of the elbow and four elbows which redislocated in plaster. All except two were high energy injuries. The lateral collateral ligament complex was found to be avulsed proximally in all cases and was reattached using a bone anchor. The common extensor origin was also torn to a variable extent in all cases and was repaired end to end. In the terrible triads, the coronoid fracture as fixed with a transosseous suture and the radial head reconstructed or, in one case with gross comminution, replaced. In the four redislocations, full stability was only restored when the medial collateral ligament was also reattached. Mobilization without a hinged external fixator was allowed from day one, but the elbows were protected in a hinged splint in between exercise sessions. Patients were assessed for stability, ROM, and functional disability using the DASH score at an average of 12 months.

No elbows redislocated post-operatively and no patients complained of instability. Mean extension was 18° (95% CI 7° – 28°), flexion 131° (124° – 137°), pronation 76° (56° – 96°), and supination 82° (75° – 90°). Mean DASH score was 14.6 (95% CI 0.7 – 28.5) though this result was skewed by one patient who developed RSD and had a DASH score of 67.2. This was however the only complication.

Early operative intervention with reconstruction of unstable elbow dislocations, including the terrible triad, prevents the poor results which are commonly found following non-operative treatment of such injuries. An external fixator is not usually required in the acute setting.


S Thomas A Wilson A Chambler I Harding M Thomas

The Copeland Shoulder Arthroplasty is a cementless, pegged humeral head surface replacement. The design is based on the principle of minimal bone resection and has been in clinical use since 1986. The only published series to date, that of Levy and Copeland, reported results for 103 patients which were comparable to those obtained with stemmed implants. We report the outcome at our institution using the same prosthesis with a hydroxyapatite coating.

81 shoulders (74 patients) underwent resurfacing hemiarthroplasty through an anterior deltopectoral approach. Preoperative diagnoses were: osteoarthritis (39), rheumatoid arthritis (29), rotator cuff arthropathy (1), post-traumatic arthrosis (2). They were followed for an average 28 months. 10 were lost to follow-up (8 deaths).

Constant scores improved from a mean preoperative figure of 15.7 to 54.0 (p< 0.01) at last follow-up. For rheumatoid arthritis and osteoarthritis the scores improved from 15.2 to 50.4 (p< 0.01) and 16.0 to 55.4 (p,< 0.01) respectively.

There was a 13% complication rate with one case requiring revision for loosening to a stemmed implant. Most were cases requiring subsequent acromioplasty. In one case the glenoid rim was fractured during head dislocation. There was a low rate of perioprosthetic radiolucency (4.2%) which may relate to the hydroxyappatite coating within the shell of the prosthesis. Ipsilateral stemmed elbow replacement was performed in some cases without a double stress riser effect. Periprosthetic humeral neck fracture as managed non-operatively with uneventful union.

Conclusion: The good outcome reported in Copeland’s own series has been replicated in the early to medium term at our institution. The surface replacement system is simpler, accurate and preserves bone stock.


DPS Baghla JC Angel M Siddique A McPherson P Johal W Gedroyc G Blunn

Interventional MRI provides a novel non-invasive method of in-vivo weight-bearing analysis of the talo-calcaneal joint. Six healthy males (mean 28.8 years) underwent static right foot weight bearing MRI imaging at 0o, 15o inversion, and eversion. Using known radiological markers the motion of the talus and calcaneum were analysed.

The calcaneum externally rotates, plantar-flexes and angulates into varus. The talus shows greater plantarflexion with similar varus angulation, with variable axial rotation. Relative talo-calcaneal motion thus involves, 6o relative talar internal rotation, 3.2o flexion and no motion in the frontal plane. Concurrently the talus moves laterally on the calcaneum, by 6.5mm, with variable translations in other planes.

The calcaneum plantar-flexes, undergoes valgus angulation, and shows variable rotation in the axial plane. The talus plantar-flexes less, externally rotates, and shifts into varus. Relative motion in the axial and saggital plane reverses rotations seen during inversion. The 8o of relative valgus talo-calcaneal angulation is achieved through considerable varus angulation of the talus, in a direction opposite to the input motion. This phenomenon has not been previously reported. From coronal MRI data, comparative talo-calcaneal motion in inversion is prevented by high bony congruity, whereas during eversion, the taut posterior tibio-talar ligament appears to prevent talar valgus angulation.

We have demonstrated that Interventional MRI scanning is a valuable tool in analysing the weight-bearing motion of the talo-calcaneal joint, whilst approaching the diagnostic accuracy of stereophotogammetry. We have also demonstrated consistent unexpected talar motion in the frontal plane. Talo-calcaneal motion is highly complex involving simultaneous rotation and translation, and hence calculations of instantaneous axes of rotation cannot effectively describe talo-calca-neal motion. We would suggest that relating individual and relative motion of the talus / calcaneum better describes subtalar kinematics.


RK Choudhary B Theruvil GR Taylor

Arthrodesis of the first metatarsophalangeal joint (MTPJ) has been recommended for various big toe deformities. We present a new technique of internal fixation for achieving dynamic compression at the first metatarso-phalangeal joint arthrodesis using memory compression staples. The memory compression staple is fabricated from equiatomic Nickel-Titanium (Ni-Ti) alloy. This alloy has a property by virtue of which it becomes easily malleable at a low temperature and reverts back to its original shape at a higher temperature. This property is known as the Shape Memory Effect. This principle is employed to provide compression at the arthrodesis site. Thirty feet were operated in 27 patients. There were 24 females and 3 males with a mean age of 61.2 years. Two memory compression staples were used at right angles to each other to achieve compression at the fusion site. The post-operative regime allowed full weight-bearing in a rigid sole shoe. A standard questionnaire was used for the subjective assessment, which included questions regarding level of pain, ambulation and patient satisfaction. Objective assessment was performed by a clinical and a radiological examination. Post-operatively there was a reduction in the pain score from 4.6 to 1.6 (p< 0.0001). Ambulation ability improved from 4 to 2.5 (p< 0.0001). There was 96.7% of radiological fusion with an average fusion time of 8.2 weeks. Patients reported 86.6% excellent to good results. The only significant post-operative complication was a single non-union.

We advocate memory compression staples for the internal fixation of the first metatarsophalangeal joint arthrodesis, which is a low profile implant, does not require post-operative cast immobilisation and has a predictable success rate comparable to previously reported methods.


M Freudmann S Hay

A comprehensive postal questionnaire was sent to 164 orthopaedic consultants, all members of the Brit-ish Elbow and Shoulder Society. Questions were asked about the initial reduction, investigations undertaken, timing of any surgery, preferred stabilization procedure, arthroscopic or open, detail of surgical technique, period of immobilization and rehabilitation programmes instigated in first-time and recurrent traumatic dislocators. The response rate was 83% (n=136)

The most likely treatment of a young traumatic shoulder dislocation:

It will be reduced under sedation in A& E by the A& E doctor.

Apart from x-ray, no investigations will be performed

It will be immobilised for 3 weeks, then given course of physiotherapy

Upon their second dislocation, they will be listed directly for an open Bankart procedure (with capsular shift as indicated) during which subscapularis will be detached and metallic bone anchors used

Following surgery, they will be immobilised for 3 to 4 weeks, before being permitted full range of movement at 2 to 3 months and allowed to return to contact sports at 6 to 12 months

On the other hand, 54% of surgeons indicated they would investigate prior to surgery, 16% said their first choice operation would be arthroscopic stabilisation, the number of dislocations normally permitted before surgery ranged from 1 to more than 3, and the period of immobilisation post operation from nil to 6 weeks.

The results reveal a wide variation in practice and no clear consensus on how to best manage these patients. Open stabilisation remains the firm favourite. Does this mean arthroscopic stabilisation is regarded as an experimental procedure?


M. Karski K. Giannikas A. Khan H. Maxwell

We present our technique for arthrodesis of the failed Keller’s excisional arthroplasty and the results of postoperative follow-up in a series of eight patients [nine feet].

Arthrodesis of the first metatarsophalangeal joint was performed with a tricortical interposition bone graft stabilised between the first metatarsal and proximal phalanx with a mini dental plate. In all cases the indication for the procedure was for chronic pain at the first meta-tarsophalangeal joint and transfer metatarsalgia of the lateral rays. Post-operative follow-up ranged from 13– 70 months and patients were evaluated using a custom-made satisfaction questionnaire, clinical examination and evaluation of pre-and post-operative x-rays.

All patients were female. The mean age of the patients was 53.2 years [range 32–69]. The post- operative questionnaire revealed that five patients [six cases] were highly satisfied with the surgery. However, we do report complications associated with the procedure including one case of deep infection and four cases in total of radiological non-union of the graft.

The majority of patients were highly satisfied with the surgery, but this technique for the revision of failed Keller’s procedures has a significant risk of complications, so patients should receive appropriate counselling pre-operatively. Although the mini dental plate was low profile, its decreased rigidity may have been responsible for the four cases of non-union.


H Sharma G Shah J De Leeuw F Denolf

Does the type of implant have any correlation with critical fusion time of hallux metatarsophalangeal joint? There are few cadaveric biomechanical studies published in the literature assessing the strength and rigidity of different fixation methods. Although it is still unclear whether the amount of metal affects the fusion rate, the aim of this study was to assess whether using a supplementary dorsal ¼ tubular plate in addition to a compression screw gives any added rigidity to the fusion area leading to an earlier fusion.

A retrospective analysis was conducted on the first metatarsophalangeal joint fusion in 26 consecutive patients (34 feet) between April 1998 to February 2002 comparing using single screw versus a screw supplemented with a dorsal ¼ tubular plate. There were 18 females and 8 males with a mean age of 51.5 years and a mean follow-up of 2.9 years. The final fusion was assessed clinically and radiologically by trans-articular trabeculation.

There was a fusion rate of 97%. All patients except one had solid fusion. One case had non-union. Four cases had superficial wound infection, which settled down with appropriate antibiotic therapy. Paraesthesia over the dorso-medial aspect of the big toe in three patients and transfer metatarsalgia in two patients were documented.

The type of implant did not show any direct correlation with the complication rate. There is no evidence to suggest in this study relating the amount of implant to final outcome. Therefore the choice of implant fixation can be at the discretion of the operating surgeon.


BC Knight ME Lovell

This study assessed the effect of litigation on the long-term outcome and recovery of ankle inversion injuries. 167 patients from an accident and emergency database were contacted by telephone. Thirty participants were litigating and these candidates were randomly matched with 30 non-litigating patients with respect to mechanism of injury. Each group had 27 patients with ankle sprains because of falls/trips and 3 after road traffic accidents. Radiographs when available of each participant were examined and the degree of soft tissue swelling over the lateral malleolus was assessed.

76.6% of litigants reported incomplete recovery compared to 26.7% of non-litigants. The median period of sleep disturbance, swelling, limping and non-weight-bearing was 1.5 days, 2.0 weeks, 2.0 weeks and 1.0 weeks for the non-litigants. This compares to 3.5 days, 10.0 weeks, 8.0 weeks and 8.0 weeks for the litigants using the same variables (p< 0.0001 in all cases). Where ankle radiographs had been taken swelling was equal in each group (9.0mm over lateral malleolus (30% of litigants incorrectly suggested an ankle x-ray had been taken, when it had not)). The majority of litigants (65%) thought that physiotherapy would not be beneficial in rehabilitating their ankle (35% non-litigants)

It appears that litigation has a negative effect on the outcome and recovery of ankle sprains.


S. Mannion S. Chimangeni C. Lavy

Gap defects in the tibial shaft can arise as a consequence of auto-sequestrectomy in chronic osteomyelitis. Whilst bone transport techniques can be utilised to treat defects, the skills and equipment necessary for such procedures are seldom available in the developing world. An alternative, and more freely available method of reconstruction is to use ipsilateral vascularised fibular transfer.

Approach to the fibula is postero-lateral. Muscle attachments to the lateral and antero-medial surfaces of the bone are released but care is taken to maintain the posterior proximal vascular pedicle, arising from the peroneal artery and to keep the periosteum intact. The fibula is then osteotomised proximally and distally and then transposed, by translation and rotation into a pre-prepared graft bed spanning the tibial defect. Some form of fixation and stabilisation may then be required and cancellous bone graft applied.

Over the past 12 months 5 cases of ipsilateral vas-cularised fibular transfer have been performed. Mean age of the patients was 6.4. In three cases stabilisation was by a trans-calcaneal, intramedullary K-wire. In the remainder interfragmentary screws were used at the proximal and distal ends of the graft, supplemented by external fixation. Cancellous bone grafting was only performed in those cases also undergoing external fixation.

In all cases the graft united satisfactorily at both the proximal and distal ends. No further procedures were necessary to effect this union. Particularly in the younger patients compensatory hypertrophy of the fibula, in response to the increased weight-bearing demand, was both marked and rapid. All five cases have completed treatment and need no mobility aids when walking.

In conclusion we feel that the ipsilateral vascular-ised fibular graft is a useful method for treating tibial gap defects of osteomyelitic origin. Few specialised resources are required and thus it is a suitable technique for the developing world.


S Aravindan JG Kennedy AJ McGuinness TC Taylor

High complication rates and technical difficulties of intramedullary fixation in children with osteogenesis imperfecta have prompted the modification of existing rod systems. The Sheffield telescoping intramedullary rod system was introduced to reduce the complications. It has a T-piece which is permanently fixed to prevent its separation and is expanded to reduce the migration. This study analyses the outcome of this rod system over a 12-year period in two specialist centres.

Sixty rods were inserted in the lower limbs of 19 children with osteogenesis imperfecta. All children had multiple fractures of the bones before rod insertion. 39 rods were inserted into the femur, of which 3 were exchange and 4 revision procedures. 21 rods were inserted in the tibia. Eight children had intramedullary rodding of all the four lower limb long bones. The outcome was measured in terms of mobility status, incidence of refractures and rod-related complications.

Our series demonstrates that there is significant reduction in refractures and improvement in the mobility status in children with osteogenesis imperfecta following intramedullary fixation. The frequent complication of T-piece separation and the need for reoperation has been overcome with the Sheffield modification of rod design. But the extracortical and metaphyseal migration of the rod continues to be a problem and further improvement in the design is desirable.


CK Yiannakopoulos AD Kanellopoulos

Between 1999 and 2002 14 children with femoral shaft fractures were treated with closed, locked intramedullary nailing. There were 11 male and 3 female patients, aged 11–16 years (mean 14.4 years). All fractures were closed. There were 9 transverse, 1 pathologic, 1 bipolar, 1 malunited and 2 spiral fractures. The fractures occurred following MVA or falls from height. All fractures were reduced and closed locked intramedullary nailing was performed using small diameter titanium nails without reaming. The entrance of point of the nail was created at the tip of the greater trochanter and no traction was used intraoperatively. The mean hospital stay was 2 days and immediate partial weight-bearing was permitted.

All fractures united according to clinical and radiological criteria within 9 weeks. The maximum patient follow-up was 24 months (mean 17 months). Hip and knee mobility was full and no case of femoral head osteonecrosis, infection or malunion was ascertained.

Closed, locked intramedullary nailing in adolescent patients provides immediate fracture immobilization combining safety and limited morbidity. Meticulous adherence to the surgical technique is necessary respecting the developing upper part of the femur.


JR. Greenslade EO Sullivan R Carare-Nnadi G Bowyer

The “Knot of Henry” was dissected in 16 embalmed cadaveric feet to reveal the complex interconnections between flexor hallucis longus (FHL) and flexor digi-torum longus (FDL) tendons. Three distinct anatomical patterns were observed.

Tension was applied manually to FHL or FDL proximal to the Knot. Digit movement was different depending on the anatomical pattern.

FHL or FDL tendon transfer is an accepted technique to prevent progression of acquired plano-valgus deformity. In order to minimise donor deficit, we suggest the use of either FHL or FDL should be based on assessment of the anatomical pattern at the time of surgery.


HS Gill S Ravinder JPS Walia BS Brar

Lisfranc injury is named after Jacques Lisfranc, a field surgeon in Napoleon’s army.

Based on Columnar classification of Lisfranc fracture dislocation, study of injury to medial column was carried out as they have the potential to be a severe cause of residual disability in the foot if not properly treated at the initial stage. Importance of Medial column is that it forms the highest point of longitudinal arch and may be injured in isolation or in association with lateral and middle column. Complex deforming forces may cause unusual pattern of medial column injuries at more than one level. There is renewed interest in this injury over past decade as modalities of treatment have changed over a period of time from conservative to fixation with K-wires to rigid fixation with screws to fixation with absorbable screws or combination of above.

We present 21 cases of medial column injuries in Lis-franc fracture-dislocation. Age ranged from 18 to 65 yrs. All were male. Four fixed with compression screws,12 fixed with K-wires, 2 managed conservatively, 3 were neglected cases. Post-operatively POP back splint was given, K-wire removal at 8 weeks, screw removal after 12 weeks and partial weight bearing started at 8-12 weeks. Follow-up ranged from 3 months to 3 years.

They were graded on basis of residual pain, foot shape, and movements. Best results were seen in cases where rigid intertarsal / intercolumnar stability was achieved by screw fixation. There was residual inter-cuneiform subluxation in 4 cases, which were fixed with K-wires, and this led to residual pain. Conservative/neglected cases had poor results.

Intercolumnar / intertarsal instabilities should be primarily recognized and stabilized under compression. Stabilization should not only be within the 3 columns but also intercolumnar, thus maintaining the relative length of 3 columns and hence reconstitution of medial longitudinal arch.


P Haslam M Morris I Lasrado JA Fernandes

CTEV is a difficult condition to treat with chances of recurrence, re-operation rate and over correction. Recent literature based on evidence is favourable with the Ponseti management. The aim of the study was to review our surgical results over a 5-year period using the Cincinnati approach.

Children with failure of conservative serial stretching and casting for 6 months underwent open release. The records and radiographs were reviewed retrospectively from 1997–2002. 60 patients were identified with 92 feet undergoing primary sub radical releases using the Cincinnati approach in 40 male and 20 female children. The mean age at surgery was 10 months. 55 patients were idiopathic with 3 syndromal and 2 teratological.

Consultants performed > 75% of operations, with k-wire stabilisation done in 46 patients and primary wound closure in 25; the majority of wounds were left open. The timing of plaster change varied, with the majority at 2 weeks. Wound problems occurred in 4 patients (significant in 2). All patients but one wore splints for an average length of 13 months. Complication rate was 20% comprising infection, over- correction and recurrence. Re-operation rate for early recurrence was 12%. Further surgery in the form of tibialis anterior transfer and derotation osteotomy was performed on 15% and 10% of feet respectively. 6 feet in 4 patients showed signs of significant over correction.

Wound healing by secondary intention of the Cin-cinnati approach is safe. Results and complications are comparable to other series, but not to the Ponseti non-operative management. Practice is now changed to the latter based on evidence.


S Mannion S Chimangeni A Mawa P Chirombo

Clubfoot is one of the commonest congenital abnormalities and is 2–3 times commoner in African populations than Caucasian. From December 2000 in Lilongwe, Malawi, the Ponseti method was used for treatment of this condition combined with the Colombian Clubfoot Score. Over the study period 150 patients were treated, with an average age on presentation of 5.5 months. 43% of cases had completed the manipulation and casting part of treatment and 5.5 months. 43% of cases had completed the manipulation and casting part of treatment and had been braced, but 75% of these were no longer attending regular follow up. We believe that the method is useful for treating CTEV in Africa, but that the intensive nature of the therapeutic regime leads to compliance difficulties.


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KAN Saldanha JA Fernandes MJ Bell M Saleh

To review the results of limb lengthening and deformity correction in fibular hemimelia, fifty-five patients with fibular hemimelia underwent limb reconstruction at Sheffield Children’s Hospital. According to Achter-man and Kalamchi classification, twenty-six were classified as Type IA, six as Type IB and twenty-three as Type II fibular hemimelia. All patients had at least some shortening of ipsilateral femur but forty-nine had sig-nificant femoral deficiency. Lengthening of tibia and in significant cases femur was done using De Bastiani or Vilarrubias or Ilizarov methods. Ankle valgus and heel valgus were corrected through osteotomies either in the supramalleolar region or heel. Equinus was corrected by lengthening of tendoachelis with posterior soft tissue release and in severe cases using Ilizarov technique.

The average length gained was 4.2 cm (range 1 to 8) and the mean percentage of length increase was 15.82 (range 4.2 to 32.4). Mean bone healing index was 54.23 days/cm. Significant complications included knee subluxation, transient common paroneal nerve palsy, and recurrence of equinus and valgus deformity of foot. Overall alignment and ambulation improved in all patients. Knee stiffness due to cruciate deficient subluxations needed prolonged rehabilitation. Presence of 3-ray foot gives a better functional result and cosmetic acceptance by patients. The Ilizarov frame has the advantage to cross joints and lengthen at the metaphysis.

Limb reconstruction in fibular hemimelia using limb lengthening and deformity correction techniques improve functional status of involved lower limb.


RW Paton A Bonshahi W Kim

We describe a successful modified operative procedure at an average 19 months follow-up in 3 patients with congenital dislocation of the patella and compare its merits to the other procedures already reported in the literature.

Congenital dislocation of the patella may be associated with other congenital conditions or syndromes i.e. Down’s syndrome, congenital vertical talus and cerebral palsy. Numerous operative techniques have been described in the literature which may be divided into 3 basic groups. A modification of the Langenskiold & Ritsila procedure is described. The original procedure describes an extensive lateral release with detachment and medial transfer of the patellar tendon through a curved incision. The tendon is routed through a fold of synovium medially and fixed distally to bone with sutures through drill holes in the proximal tibia. We found at surgery this synovium was too fragile to hold the transferred tendon and the use of drill holes unnecessary. The main alterations include a limited and straight anterior skin incision, a fashioning of a ‘buckle’ of the transferred distal patellar tendon to a distally based flap which avoids drill holes in the growing bone. This modification of the Langenskiold procedure was used successfully in 3 cases, including a revision of a failed Goldthwaite- Roux procedure in a mentally handicapped child. The results at average 19 months follow-up are successful. The early results confirm that the patella remains located and tracks normally. The valgus and flexion deformities have significantly improved.

This modification of the Langenskiold & Ritsila procedure requires less dissection than other operations, with no bony surgery and a cosmetic scar. The Langen-skiold & Ritsila procedure has been successful and we feel that this modification simplifies and improves on the original technique.


M Bhatia P Housden

We assessed two simple radiological methods of predicting redisplacement of forearm fractures in children: a) Cast Index (ratio of sagittal to coronal cast width at the fracture site), and b) Padding Index (ratio of padding thickness at the fracture site in the plane of the deformity to the maximum interosseous width).

Case records and radiographs of 100 children who underwent a manipulation under general anaesthesia for a displaced fracture of forearm or wrist were studied. Redisplacement was defined as more than 15 degrees of angulation and/or more than 50 percent of translational displacement on check radiographs at 1–2 weeks.

Angulation (in degrees) and translation displacement (in percentage) were measured on the initial and check radiographs. Cast index and Padding index were measured on the check radiographs. Good intra and inter observer reproducibility was observed for both these measurements. The cast index was validated in an experimental study.

Redisplacement was seen in 29 cases. Of these 21 cases underwent a secondary procedure for redisplacement. Initial displacement, cast index and padding index were the three factors which were significantly higher in the redisplacement group (p< 0.05). The means and 95% Confidence intervals for cast index and padding index were 0.88 (0.84, 0.90) and 0.48 (0.39, 0.62) in the redisplacement group whereas were 0.71 (0.69, 0.72) and 0.11 (0.09, 0.12) in the group with no redis-placement respectively. No statistically significant difference was seen for age, fracture location, initial angular deformity and seniority of the surgeon.

Conclusion: cast index and padding index are simple and reliable radiographic measurements to predict the redisplacement of forearm fractures in children. A plaster with a cast index of> 0.9 and padding index of > 0.3 is prone to redisplacement.


KAN Saldanha M Saleh MJ Bell JA Fernandes

To review the results of reconstruction of pseudoar-throsis and/or significant varus with retroversion of proximal femur in congenital longitudinal lower limb deficiencies, twenty-three of ninety-five patients with lower limb deficiencies underwent proximal femoral reconstruction at the Sheffield Children’s Hospital. All twenty-three underwent valgus derotation osteotomies to correct coxa vara and retroversion of femur. Seven patients also had pseudoarthrosis of the neck of femur. Three of these were treated with valgus derotation osteotomy and cancellous bone grafting, two with fibular strut grafts, one King’s procedure and one with excision of fibrous tissue and valgus derotation osteotomy. A variety of internal fixation devices and external fixator were used.

Seventeen of the twenty-three patients had valgus osteotomies repeated more than once (average 2.3) for recurrence of varus deformity. Average initial neck-shaft angle was 72 degrees, which improved to an average of 115 degrees after reconstruction.

All seven patients with pseudoarthroses underwent multiple procedures (average 3.3) to achieve union. Cancellous bone grafting was repeated twice in two patients to achieve union but all three with cancellous bone grafting underwent repeat osteotomies to correct residual varus. Two patients achieved union after fibu-lar strut grafting. One patient, who underwent excision of pseudoarthrosis, achieved union but had to undergo further valgus osteotomy. No particular advantage of any one-fixation device over the others was noted in achieving correction.

Early axis correction using valgus derotation oste-otomy is important in limb reconstruction when there is significant coxa vara and retroversion, although recurrence may require repeated osteotomies. Pseudoarthro-ses needed more aggressive surgery to achieve union.


A Kulkarni A Abudu RM Tillman SR Carter RJ Grimer

130 consecutive patients with metastastic tumours of the extremity bones treated with resection with or without major endoprosthetic reconstruction were studied retrospectively to determine the indication for surgery, complications, clinical outcome and oncological results of treatment.

The mean age at diagnosis was 61 (22 – 84). The tumours originated from a variety of organs. Lower extremity was involved in 104 and upper extremity in 26. Metastatic disease was solitary in 55 patients and multiple in 75 at the time of surgery. The median follow-up possible from the time of operation to review was 48 months (0-103).

The indication for surgery was radical treatment of solitary metastases with curative intent in 33, pathological fracture in 46, impending fracture in 27, failure of prior fixation devices in 17, painful swelling or extremity in 37. Surgical treatment included excision of expendable bones without reconstruction in 20 patients and resection with endoprosthetic reconstruction in 110 patients. 7 patients received adjuvant chemotherapy and the majority received adjuvant radiotherapy.

At the time of review, 58 patients had died at a mean time of 23 months (0–90) from surgery (53 from progressive metastatic disease and 5 from other causes). 72 were alive at mean follow-up of 22 months (1–103) from surgery. 36 patients (28%) were alive at 2 years post-surgery and 8 (6%) at 5 years. One patient died intra-operatively. Post-operative complications occurred in 32 patients (25%). 18 patients required further surgical procedures for dislocation, infection haematoma, stiff joint, plastic surgical procedures. All the patients had control of pain and 90% achieved desired mobility.

There was no difference in the survival of patients who presented with solitary and multiple metastases, renal and non-renal metastases, and upper or lower limb metastases.

Conclusion: Selected patients with bone metastases can benefit from resection and major bone reconstruction with acceptable morbidity. We have not identified predictable prognostic factors in these selected patients.


V Kapoor B Theruvil SE Edwards GR Taylor NMP Clarke MG Uglow

The majority of diaphyseal forearm fractures in children are treated by closed reduction and plaster immobilisation. There is a small subset of patients where operative treatment is indicated. Recent reports indicate that elastic intramedullary nailing (EIN) is gaining popularity over plate fixation. We report the results of EIN for diaphyseal fractures of the forearm in 44 children aged between 5 and 15 years during a three-year period. The indications were instability (26), redisplacement (14), and open fractures (4). Closed reduction and nailing was carried out in 18 cases. A single bone had to be opened in 16 cases and in 10 cases both bones were opened for achieving reduction. Out of the 39 both bone forearm fractures, 35 patients had stabilisation of both radius and ulna and in 4 cases only a single bone was nailed (Radius 3, Ulna 1).

Union was achieved in all the 44 cases at an average time of 7 weeks with one delayed union. All patients regained full flexion and extension of the elbow and wrist. Pronation was restricted by an average of 20° in 30% patients.

Complications were seen in 10 patients (20%). 4 patients had prominent metal work which required early removal. There was refracture in one case, which was treated by nail removal and re-fixation. Two patients developed post operative compartment syndrome requiring fasciotomy. EIN of the radius alone in a patient with fractures of both the bones of forearm, led to secondary displacement of the ulna. This resulted in ulnar malunion and a symptomatic distal radio-ulnar joint subluxation. This was successfully treated by ulnar osteotomy.

Compared to forearm plating EIN involves minimal scarring, easier removal and less risk of nerve damage. We therefore recommend EIN for the treatment of unstable middle and proximal third forearm fractures.


M Ramakrishnan G Kumar SS Prasad RW Parkinson

To report the experience with the new device, the Long Proximal Femoral Nail (Long PFN) in patients with impending pathological femoral fractures to identify the advantages and complications associated with its usage. This is the first in the series on the use of Long PFN for patients with femoral metastases.

Between April 2000 and September 2001, twenty-five consecutive patients with femoral pathological lesions were prophylactically stabilised using Long PFN. The nailings were performed using a percutaneous closed technique. Lateral femoral Line (LFL) technique was used for location of the entry point and easy insertion for the nail. Only the proximal one-fifth of the femur was reamed to accommodate the 17 mm diameter of the proximal part of the nail.

We had technical problems in three patients. The overall mobility of the patients improved in twenty patients and the mobility remained the same as pre-operative level in five patients. Good to excellent pain relief achieved in eighteen patients. The pain relief was fair in five patients and poor in two patients. We had no mechanical failure of the implant in our series.

Long PFN, a modified reconstruction nail, can be inserted percutaneously and has an easy operation technique. Our early experience with Long PFN in the management of impending femoral fractures has been favourable.


A Kulkarni F Fiorenza RJ Grimer SR Carter RM Tillman

Only 1% of all primary bone tumours are situated in the distal humerus. Destruction of the distal humerus by tumour is rare and reconstruction of the distal humerus is challenging. Because of the amount of bone loss following tumour excision, excision arthroplasty or arthrodesis is impossible and hence some form of reconstruction is usually required. Allograft reconstruction and hemiarthroplasty are uncommon and lead to an unpredictable outcome.

Ten patients underwent endoprosthetic replacement of the distal humerus for bone tumours over a thirty one-year period. There were 8 primary and 2 secondary tumours and male to female ratio was 2:3. Average age of the patients was 47.5 years (15–76 years). Mean follow up was 8 years (9 months - 31 years). Four patients required further surgery, three having revision for asceptic loosening and two of these and one other later needing a rebushing. There were no permanent nerve palsies, infections, local recurrences or mechanical failures of the implant. Four patients died of their disease between 12 and 71 months after operation, all with their prosthesis working normally.

Average flexion deformity was 15 degrees (0–35) and average flexion of these patients was 115 degrees (110–135). The average TES Score for these patients was 73% (29% to 93%). The activities which the patients found to be no problem (TES score more than 4.5 out of 5) were: brushing hair, drinking from a glass, putting on make up or shaving, picking up small items, turning a key in a lock, doing light household chores and socialising with friends, whilst activities that proved difficult (TES score less than 3 out of 5) were: gardening and lifting a box to an overhead shelf. Pain was not a problem and only 1 of the surviving patients reported ever having to use regular analgesics.

Conclusions: Endoprosthetic replacement of the distal humerus and elbow joint is a satisfactory method of dealing with these unusual tumours in the long term.


L Jeys R Suneja S Carter R Grimer

To identify the incidence of a cortical breech on the initial presentation X-rays of patients with distal femoral GCTs, and whether this lead to a higher rate of local recurrence of tumour, a prospective database is kept of all patients seen in the unit. Initial presentation X-rays on 54 patients with distal femroal GCTs were reviewed. The size of the tumour was estimated by measuring the largest dimensions of the tumour (depth, breadth & height). The volume of the distal femur was estimated using the same X-ray and computer programme. The X-rays were then carefully studied for evidence of a cortical breach. The records were also checked for evidence of subsequent locally recurrent disease and subsequent surgery.

X-rays were reviewed on 54 patients (29 male, 25 female), range of 18–72 years. All patients had a biopsy-proven GCT of the distal femur, X-rays (prior to biopsy) were reviewed. 34 (63%) patients with a cortical breech on X-ray. The mean tumour volume: distal femoral volumes (TV:DFV) was statistically greater between those patients with a cortical breach and those without, using ANOVA (p< 0.0001). There were 13 patients with local recurrent disease but no statistical difference in subsequent local recurrence rates between the two patient groups. There was also no statistical differences between the number of operations for those who presented with a cortical breach or without. There was no evidence that more radical surgery was required if a patient presented with a cortical breach.

The risk of cortical breech in patients with GCTs of the distal femur is dependant upon the tumour volume to distal femur volume ratio. If the ratio is above 54% then present with a cortical breech on X-ray is likely (95% confidence interval).There is no evidence those patients with a cortical breach have a higher rate of local recurrence, an increased number of operations or more radical surgery.

Conclusion: The risk of cortical breech in patients with GCTs of the distal femur is dependent upon the tumour volume to distal femur volume ratio.


AA Narvani E Tsiridis M Ramachandran TW Briggs SR Cannon A Saifuddin R Mitchell

The aim of this study was to compare the accuracy of image guided (ultrasound or CT) percutaneous needle biopsy to percutaneous needle biopsy without image guidance in diagnosis of soft tissue tumours.

Eighty-eight consecutive patients with soft tissue lesion who were referred to the soft tissue tumour unit underwent percutaneous needle biopsies of their lesion either with image guidance or without. Sixty-one out of these 88 patients subsequently underwent excision of their lesion and the excised specimen was then subjected to histological examination. The accuracy of image guided percutaneous needle biopsy and percutaneous needle biopsy without image was then calculated by comparing the histological results of the needle biopsy to that of excision biopsy.

The diagnosis accuracy of image guided percutaneous needle biopsy was 92% (34 out 37) compared to 79% (22 out of 28) for percutaneous needle biopsy without image. In 3 out of the 28 patients who had percutaneous needle biopsy without image guidance, there was insufficient material obtained from the needle biopsy to allow a histological diagnosis. This was not the case with any of the patients who had image guided percutaneous needle biopsy.

Conclusion: Using image guidance, either USS or CT scan, improves the diagnostic accuracy of percutaneous needle biopsy and should be the gold standard technique in management of soft tissue tumours. However, if the lesion is palpable and not mobile, the accuracy of percutaneous needle biopsy without image guidance can be up to 79%.


JAM Bramer H Ahrens SR Carter RM Tillman RJ Grimer A Abudu

Pathological fracture occurs in 5–10% of all primary malignant bone tumours. It is thought that they unfavourably influence survival, because the fracture haema-toma may contaminate adjacent tissues. Management is often more aggressive and one is less inclined to consider limb saving surgery.

Aim of this study was to determine whether the presence of pathological fracture had an effect on rate of limb salvage surgery, role of adjuvant treatment and survival.

A retrospective study was done on all patients with a pathological fracture through localised Ewing’s sarcoma, treated between 1979 and 2001. Of 289 patients with localised Ewing’s sarcoma, 27 had a pathological fracture. Eighteen presented with fracture, in 9 fracture occurred after biopsy. All were treated with chemotherapy according to protocol. Two fractures were already treated by osteosynthesis elsewhere, the rest healed with conservative treatment. After chemotherapy, 20 patients were treated surgically: 19 with limb saving surgery, 1 with amputation. Apart from chemotherapy, treatment was surgery alone in 15, surgery and radiotherapy in 5, and radiotherapy alone in 7 patients. Indications for radiotherapy were close margins, poor chemotherapy response, or pelvic tumours. Surgical margins were wide in 16 patients, marginal in 2, and intralesional in 1 patient. Local recurrence occurred in 2 patients, primarily treated with chemotherapy and radiotherapy alone. Five year survival was 60%, metastasis free survival 59%, both comparable with rates reported in literature.

Conclusion: Chemotherapy allows fractures to consolidate with conservative treatment. Adequate surgical margins can be achieved in the majority of patients with limb saving surgery. Adjuvant radiotherapy does not seem necessary if margins are wide. Survival is not negatively influenced by pathological fracture. The survival rate following limb saving surgery in these patients is similar to that of patients in literature where amputation is done. Limb saving surgery seems a safe option.


K Ho J Harrison DH Sochart

To assess the cost involved and whether orthopaedic patients with Methicillin-resistant Staphylcoccus aureus (MRSA) infections were being managed according to national guidelines, retrospective survey of all MRSA infections over a 26 months period was performed. Demographic details and risk factors were identified. Infection control measures were compared with national guidelines. Total length of hospital stays, treatments received and cost were noted.

In total, 78 patients were diagnosed with a MRSA infection (31 male and 47 female) with a mean age 66.4 years +/− 20.8 SD. MRSA infections occurred in 75 (97%) trauma patients and in 2 (3%) elective patients. MRSA infections were isolated from wounds in 62 patients, others sites include sputum, blood, urine and skin colonization. The average time of diagnosis after admission was 20.6 days +/− 16.6 SD. Major risk factors were internal fixation of fractures (97%), previous antibiotics (97%), nursing home residents and hospital transfers (50%). Normal national guidelines were followed in 86% of the cases. Antibiotics were used in 67 patients after microbiological confirmation; this additional cost exceeded £19,000. The mean hospital stay was 50.7 days and the cost of hospitalization per patients exceeded £19,700 (£388.60 per day). Incidence of MRSA infection in trauma and elective patients were 2.4% and 0.1% respectively. Infection control policies were strictly followed in 86% of the cases. Long hospitalization and antibiotics were a significant risk factor for developing MRSA infections. Considering the low incidence of MRSA infection in elective surgery, segregation of trauma and elective patients is an important measure in reducing the incidence and cost of MRSA infections. Substantial saving can be achieved with firmer antibiotics policies.


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PM Lewis AR Evans PR Roberts R Kulkarni

Private companies now offer risk assessment packages to Trusts. Data are collected using ICD coding and complication rates for individual surgeons are calculated and published. A risk assessment document was recently published at the Royal Gwent Hospital presenting complication rates and misadventures on league tables of specialty and consultants. Serious concerns were raised about the quality of the data. We undertook a study to independently evaluate the accuracy of data used to calculate these complication rates.

Two Orthopaedic Surgeons with the highest published complication rates were studied. The notes of patients who had suffered complications were retrieved and the published complication data was compared with the clinical interpretation of the actual complication. One hundred and fifty reported complications were analyzed.

In most cases data accuracy was woefully inadequate. For example revision procedures were counted as complications for the revision surgeon irrespective of who carried out the primary procedure. The normal work-up of these patients including procedures to investigate the presence of infection are recorded as complications with some patients being recorded as having up to four separate complications. Misadventures published for surgeons included dural tap during epidural anesthesia. The results of this study highlight the potentially devastating consequences of data inaccuracy. Inaccurate published data on complications, used to form league tables for individual surgeons, can be career- jeopardizing. We advocate that consultation with the clinicians involved should always occur before data are published so that these inaccuracies can be picked up and the potentially damming consequences of falsely high complication rates can be avoided.


D Sunderamoorthy S Ahuja A Grant

Patients admitted to trauma wards are routinely screened for MRSA pre-operatively. The majority of them have implant surgery before the screening results were available. The aim of our study was to identify the incidence of MRSA wound infection in these patients and their outcome following it.

We randomly reviewed 40 patients who were colonised with MRSA pre-operatively and have had implant surgeries. The case notes, drug charts and the microbiology were reviewed to identify the incidence of MRSA wound infection and its outcome in these patients. The place of residence, site of colonisation and the treatment given were also considered.

70% of the patients were admitted from home and 20% had previous admission within one year. The commonest site colonised is the nose (50%) followed by the perineum in 20%. Multiple sites were colonised in 10% of the patients. Only 50% of them with positive nasal MRSA were given nasal bactroban and chlohexidine wash was given in only 70% of them with MRSA colonisation in other areas. 22.5% (9/40) of the patients developed MRSA infection post operatively and they were treated with vancomycin or teicoplanin. Wound debridement and washout were done in 67.5%. 75% of the MRSA infected wound healed well with no MRSA in the wound site after treatment. 25% of the MRSA infected wounds had persistent MRSA in the wound.

As per our study the incidence of MRSA wound infection in patients colonised pre-operatively is about 22.5%. Most cases seem to heal well without much complication with appropriate antibiotics and wound care.


SK Kapoor

An osteochondroma is a benign tumour and multiple hereditary osteochondromatosis [MHO] is an auto-somal dominant skeletal disorder in which there are numerous cartilage-capped excrescences. The true incidence of malignant change of osteochondromas is not known, as many osteochondromas, especially solitary lesions, are asymptomatic and usually not reported.

Between the years 1995 to 2002, 11 patients with a secondary chondrosarcoma developing in osteochon-droma were found, out of 300 cases of musculoskeletal tumours treated at our institution. All the patients were treated surgically, The mean follow up of the patients was approximately 2 years [range from 3 months to 4 years]

In radiographs, evidence of malignant change was seen in all the cases. In the cases where MRI was carried out [6 out of 11 cases], the average cartilage cap thickness was 5.0 cm [ranging from 2 to 12 cm].

It is important to recognize the features suggesting malignant change, namely pain, continued growth of the lesion after skeletal maturity, thick bulky cartilaginous cap, and soft tissue mass with or without calcifications. Six of our cases had Grade I chondrosarcoma. High-grade chondrosarcomas occur with greater frequency in patients of multiple hereditary osteochondromatosis. Grading of chondrosarcoma is considered to have prognostic significance. However, the rate of local recurrence is primarily dependent on the adequacy of the primary surgical therapy, rather than the histological grade. In our series we had 3 cases wih local recurrence. In 2 of these cases, intralesional debulking had been done and in 1 case of marginal excision was done. Therefore primary resection [with a cuff of normal tissue] or radical excision appears to be the treatment of choice for these lesions.


MC Oliver PW Skinner

To evaluate the performance of this institution in its delivery of care to elderly patients with a hip fracture over an 11-year period and to establish recommendations to improve practice.

Regular prospective audits of a cohort of 50 patients have been undertaken between 1990 and 2000. A larger and more comprehensive retrospective audit of 100 patients was performed in 2001. Goals were set regarding time to admission, time to surgery and to discharge in close accordance with the best practice guidelines devised by the Royal College of Physicians in 1989.

There has been an alarming decline in standards in key areas.

Time from A& E to admission: at best 78% of patients within 3 hours, 4% in 2001.

Time from admission to surgery: at best 89% within 24 hours, 31% in 2001.

Persistence of significant morbidity for patients delayed to surgery for non-medical reasons: 65% of these patients developed a post operative complication and 20% died within 30 days of admission.

Delay to discharge: at best 13 acute bed days, now 18 (2001).

Current practice is less than ideal. Clinical governance involves a dual responsibility – of the clinician to maintain high standards and of the management to provide adequate resources. Both need addressing to reverse the current trend.


L Audigé D Griffin M Bhandari J Kellam T Rüedi

We applied the technique of path analysis to investigate the effect of potential prognostic factors, including injury characteristics and treatment choices, on the risk of delayed healing or non-union after operative treatment of tibial shaft fractures.

Data were collected in a prospective observational study of 41 Swiss hospitals over two years, and analysed by regression models and path analysis. Path analysis is a technique to visualize the most important associations between clinical factors and outcome in a ‘causal path diagram’ that summarises the most likely cause and effect relationships.

Factors having a direct relationship with the occurrence of delayed healing or non-union included open fracture (RR 6.7), distal shaft location (RR 2.2), and initial treatment with an external fixator (RR 2.8). There were many other significant inter-relationships within the final diagram. For example, the choice of treatment was related to factors such as fracture aetiology, AO classification, location and skin injury. Fracture classification was not associated with delayed healing and non-union after adjustment for other factors including treatment choice.

The association of hypothesised risk factors, such as soft tissue injury and fracture location, with delayed healing or non-union was confirmed and measured. This study suggested that the use of an external fixator had a direct, negative effect on outcome, and that the use of nails or plates might contribute to delayed healing or non-union by their association with post-operative diastasis. These observations support this first use of path analysis in orthopaedics as a powerful technique to interpret data from an observational study.


PA Rust SA Black F Arnold CRR Corbertt MH Patterson

It is likely that league tables will to some extent determine hospital finance in the future. The major indicator used in league table calculations in orthopaedics is mortality rates following surgery. Therefore, our study audited the accuracy of mortality data.

A previous audit of our department by an external audit company was found to show an apparent excess mortality rate, due to the company’s failure to distinguish between true operations and certain procedures, i.e. urethral catheterisation. We were concerned that these flawed results may find their way into the publicised tables of the Department of Health (DH). We thus audited deaths in 2000/1 and compared the results with DH data.

DH league table figures combine the mortality numbers for all surgical specialities. Our analysis was based on DH criteria [www.doh.gov.uk/performancer-atings/2001), death within 30 days of operation, following non-elective admission and excluded certain procedures. PAS was used to identify deaths and all case notes were reviewed.

From review of the notes, the criteria for post-operative death were fulfilled by 54/131 deaths (41%). By speciality, these included 14/33 deaths in orthopaedics, general surgery (25/73) and neurosurgery (15/25). The DH identified 64 post-operative deaths in this period. DH calculations were applied to compare our postoperative mortality results (54 deaths) with those of the DH (64 deaths). Although there was no significant difference between our observed death rate and the DH’s, using our results the hospital’s ranking improved from twelfth to sixth place in 42 small acute hospitals.

The observed mortality rate in our hospital is very close to that published by the DH and the national average. From the results of our study, we are confident that the flawed data from the external company did not enter the system and distort the DH’s league tables.

Therefore, hospitals should not wast money on audits by external companies.


N.V. Greidanus R.M.D. Meek D.S. Garbuz B.A. Masri C.P. Duncan

Patient satisfaction is not uniform or consistent following revision total knee arthroplasty. This study evaluates ninety-nine patients with a self-administered patient satisfaction questionnaire at a minimum of two years following the revision procedure (1997–99) to determine differences between satisfied (sixty-six patients) and dissatisfied patients (thirty-three patients). Univariate analysis revealed that patients satisfied with their results were significantly different (p< .05) than dissatisfied patients with regards to post op scores including those of the WOMAC pain and function, oxford, and SF-12. Patients were not different with regards to (p> .05) age, comorbidity score, surgical approach, or sepsis as a reason for the revision procedure. Regression analysis demonstrated that gender, post-op WOMAC score, and pre-op arc of motion were significant determinants of satisfaction.

The purpose of this study is to evaluate determinants of patient satisfaction following revision total knee arthroplasty.

Patient satisfaction with revision knee surgery is most strongly associated with both pre and post-operative descriptors of knee function as well as gender.

Understanding the variables associated with satisfaction/dissatisfaction following revision knee arthroplasty may further assist ongoing research efforts to improve the outcomes of this procedure.

Univariate analysis revealed that patients satisfied with their results were significantly different (p< .05) than dissatisfied patients with regards to WOMAC pain and function score, oxford knee score, and SF-12. Patients were not different with regards to (p> .05) age, comorbidity score, surgical approach, or presence of sepsis as a reason for the revision procedure. Regression analysis demonstrated that gender, post-op WOMAC score, and pre-op arc of motion were significant determinants of satisfaction (p< .05).

A self-administered patient satisfaction survey was completed by ninety-nine patients at a minimum of two years following revision total knee arthroplasty. Fifty-nine patients were females and forty were males. Sixty-six patients were satisfied and thirty-three patients were dissatisfied with the outcome of their surgery at two years post-op. Univariate analysis and multivariate regression suggest that pre and post-operative joint function and gender are the most significant determinants of patient satisfaction


P. Zalzal B. Petrisor M. Bhandari F. Smith

A retrospective study of one hundred and nineteen unicompartmental knee arthroplasties was performed. Outcome measures were the Oxford twelve-item knee questionnaire, the Short Musculoskeletal Functional Assessment (SMFA) and the WOMAC. Regression analysis was performed in order to determine predictors of outcome. After an average follow up period of four years, the mean scores indicated a good to excellent functional outcome. The only predictor of outcome identified was gender, with women obtaining a better functional outcome than men. Other variables that did not influence functional outcome included age, weight, stage of disease, previous HTO and bilateral procedures.

The purpose of this study was to determine

the functional outcome of unicompartmental knee arthroplasty and

predictors of outcome.

Although unicompartmental knee arthroplasty is becoming more widely accepted as a treatment option for degenerative osteoarthritis, there are very few studies in the literature that systematically investigate the predictors of outcome for this procedure.

This is a retrospective study of one hundred and nineteen unicompartmental knee arthroplasties perfomed at a university hospital by a single surgeon. The outcome measures used were the Oxford twelve-item knee questionnaire, the Short Musculoskeletal Function Assessment (SMFA) and the Western Ontario and McMaster (WOMAC) functional indices. Multiple regression analysis was performed to determine predictors of outcome from chart derived variables.

After a mean follow-up of four years the mean Oxford Knee Score was thirty-nine and the mean SMFA and WOMAC functional scores were eight and seven respectively, indicating a good to excellent functional outcome. Regression analysis revealed gender as a predictor of outcome however other variables including age (range 49–84 yrs), weight (range 55–225 kgs), previous ORIF, preoperative varus/valgus (range 0–16 degrees), joint subluxation (range 0–13mm), radiographic stage of disease (Kellgren and Lawrence), as well as previous HTO and bilateral (simultaneous or staged) unicompartmental knee arthroplasty were found to not correlate with functional outcome.

Good to excellent functional outcome scores can be achieved with unicompartmental knee replacement. Previous HTO or bilateral procedures as well as weight, pre-operative varus/valgus < sixteen degrees or radiographic stage of disease were not predictive of outcome.


K.J. Deluzio J.A. Astephen

The objective of this study was to determine if pre-operative gait patterns could predict which patients selected for unicondylar knee replacement (UKR) actually received a UKR or a total knee replacement (TKR). At the time of surgery, ten of the twenty-two UKR candidates presented with extensive degenerative changes and received total knee replacements. We analyzed gait, radiographic, and anthropometric data with a pattern recognition technique designed to detect biomechanical differences between the two groups. The groups were indistinguishable clinically, and radiographically, yet the pattern recognition technique identified features that completely separated the two groups based on the biomechanical differences.

The objective of this study was to determine if pre-operative gait patterns could predict which patients selected for UKR actually received a UKR or a TKR.

The UKR and TKR groups were indistinguishable visibly, clinically, and radiographically, yet the pattern recognition technique employed in this analysis identified features that completely separated the two groups.

Biomechanical differences between the pre-operative groups could lead to more accurate diagnosis of unicompartmental knee OA as well as further understanding of the pathomechanics of knee OA.

Twenty-two patients were initially diagnosed with unicompartmental knee OA of the medial side, and prescribed to receive unicompartmental knee replacements (UKR). At the time of surgery, ten of the twenty-two UKR candidates presented with more extensive degenerative changes and received total knee replacements (TKR). We measured gait data including knee joint angles forces and moments, velocity, stride length, stance percentage, and stance time as well as body mass index. Furthermore radiographic measures were taken including the Hip Knee Ankle (HKA) angle, the standing knee flexion angle, and the medial and lateral condyle joint spaces.

The data were analysed using a pattern recognition technique that used principal component analysis to extract features from the data and discriminant analysis to separate the two groups.

The discriminant function completely separated the UKR and TKR patients based on their pre-operative data. The most discriminatory feature represented a difference in early swing phase in the knee internal rotation moments.


J.F. Rudan P. Costigan S. Lynn H. Grant

Successful total knee arthroplasty design is related to the joint dynamics imposed by the design. This study examined the clinical and biomechanical performance of patients who received a PFC Sigma total knee implant (posterior cruciate substituting design). Radiographic, strength testing, gait pattern and clinical survey data were collected. Pre-operative and post-operative outcome measures were compared. Statistically significant differences were found on the pain, stiffness and physical function scales of the WOMAC as well as the knee and total score parameters of the Knee Society Score. Significant improvements were also seen on several gait pattern parameters.

Factors such as implant design and surgical technique have been found to influence knee kinematics and kinetics thereby effecting patient function and implant survival after total knee arthroplasty. Numerous gait studies have reported a lack of normal gait pattern for TKA patients (Wilson et al., 1996; Andriacchi, 1993; Jevsevar et al., 1993). There is debate in the literature as to which design best improves patient function and implant survival, the posterior cruciate (PC) substituting or PC-retaining. The purpose of this study is to determine the clinical outcome and biomechanical performance of patients who receive PFC Sigma total knee arthroplasty.

The PC substituting implant design provided significant improvements in clinical and gait outcomes at two years post-op in this patient sample.

Patients experience significant pain and stiffness relief, and better functional outcomes.

A cohort of eighteen total knee replacement patients were followed for two years post-operatively. Radiographic, strength testing, gait pattern and clinical survey data (SF36, WOMAC, Knee Society Score) were collected. Paired sample t-tests, repeated measures general linear modeling and principle component analyses comparing aged matched normals were conducted to evaluate pre-operative and post-operative outcomes. Statistically significant differences were found on the pain, stiffness and physical function scales of the WOMAC as well as the knee and total score parameters of the Knee Society survey. There were also significant improvements found on gait pattern parameters. Findings like these point to a need for larger population studies of patients with PC-substituting TKA.

Funding: Funding for this study was provided by Depuy Orthopaedics, Inc.


P. Thistlethwaite J. Ronsky H.S. Gill

Roentgen stereophotogrammetric analysis (RSA) is a tool that can provide quantitative information for objective evaluation and comparison of implant migration. The purpose of this study was to develop and validate a new method to determine the position and orientation of an implant with RSA that does not require the implant modification or acquisition of accurate 3D implant models. This method utilizes information from certain common features of implant geometry. This method has demonstrated in-vitro precision and accuracy of 0.005 !0.059 mm in position and 0.09 ! 0.166° in orientation which is equivalent to both marker and model based RSA methods

Roentgen stereophotogrammetric analysis (RSA) is a tool that can provide quantitative information for objective evaluation and comparison of implant migration. RSA measures have demonstrated the ability to both predict premature implant failure before clinical or standard radiological signs appear, and to elucidate implant wear which is considered a major causal factor in failure. To provide this functionality, RSA requires either the modification of each implant by the addition of spherical markers or the acquisition of accurate 3D models of each implant. These approaches can significantly limit the application of the RSA method. The purpose of this study was to develop and validate a new method to determine the position and orientation of an implant with RSA that does not require the modifying or acquiring accurate 3D models of each implant. This method is based on the geometric inter-relationship between the pair of RSA images and geometric information from the projected outlines of certain paired (visible in both views) features of implant geometry. Evaluations were performed on a metallic acetabular cup modified with spherical markers. The implant features used in this case where the hemispherical shell and the planar circle at the base of the acetabular cup. This method has demonstrated an average in-vitro precision and accuracy of 0.005 !0.059 mm in position and 0.09 ! 0.166° in orientation which was equivalent to that achieved with the marker based method and equivalent to published model based RSA results.

Funding: NSERC, GEOIDE, University of Calgary.


O.L. Huk D.J. Zukor J. Antoniou F. Mwale A. Petit

The aim of this study was to analyze in human macrophages the effects of Co2+ and Cr3+ ions on the activity of caspase-8 and caspase-3, initiator and executioner of apoptosis, respectively. Caspase-3 and -8 activities were measured by colorimetric assays. Results show that Co2+ ions induced caspase-3 activity in a time-dependent manner. Co2+ had no effect on caspase-8 activity. The activation of caspase-3 by Cr3+ was time-dependent while caspase-8 activity reached a maximum after eight hours and decreased thereafter. Since caspase-8 is primarily activated by membrane-associated events, our results suggest that Cr3+ interacts with cell membrane components to induce macrophage apoptosis, whereas Co2+ seems to stimulate apoptosis most likely through intracellularly located mechanisms.

Because of their potential for improved wear performance, there has been a revived interest in metal-metal bearings, made of cobalt-chromium-molybdenum alloys, as an alternative to the use of conventional metal-polyethylene bearings. However, metal ion toxicity remains a major cause for concern. Previous studies suggested that both cobalt (Co2+) and chromium (Cr3+) ions induce macrophage apoptosis. The interest in apoptosis lies in the fact that it offers specific targets for therapeutic intervention.

The aim of this study was to analyze the effects in human macrophages of Co2+ and Cr3+ ions on the activity of caspase-8 and caspase-3, initiator and executioner of apoptosis, respectively.

U937 human macrophages were exposed to 0–10 ppm Co2+ (CoCl2) and 0–500 ppm Cr3+ (CrCl3). Caspase-3 and caspase-8 activities were measured by colorimetric assays based on the recognition of specific amino acid sequences (DEVD and IETD, respectively).

Results show that Co2+ ions induced caspase-3 activity with a significant increase after four hour incubation and a maximal 2.65-fold increase reached after twenty-four hour with 10 ppm. Co2+ had no effect on caspase-8 activity.

Cr3+ ions significantly stimulated caspase-3 activity after four hours with a maximal 1.75-fold stimulation reached after twenty-four hours, reaching only 50% of that observed with Co2+. Caspase-8 activity was significantly increased after two hours incubation, peaking at eight hours with a 2.2-fold increase, and decreasing thereafter.

Since caspase-8 is primarily activated by membrane-associated events, our results suggest that Cr3+ interacts with cell membrane components to induce macrophage apoptosis. On the other hand, Co2+ seems to stimulate caspase-3 activity and apoptosis most likely through intracellularly located mechanisms.


R. El-Hawary S.E. Roth J.C. Harwood J.A. Johnson G.J.W. King D.G. Chess

A load cell, capable of measuring medial and lateral loads independently, was used to evaluate current methods of ligamentous balancing in total knee arthroplasty. Ten cadaveric knees were randomized with the surgeons blinded or unblinded to the load cell’s output. Before ligament resection, there were differences between medial and lateral forces (p< 0.05). Balance improved in both groups following ligamentous releases. There was a trend for superior balance (medial-lateral compressive force) with load cell feedback provided: 30°(11.1 vs. 44.4N), 60°(7.1 vs. 36.9N), and 90°(3.0 vs. 8.7N). Further in-vivo studies with this device may improve load transfer and the longevity of TKA.

The purpose of this study was to employ a tibial load cell to assess current methods of ligamentous balance during total knee arthroplasty, and to determine whether the load cell can improve load distribution between the medial and lateral compartments.

Current methods achieve imperfect load balance, however this may be improved with the assistance of an intra-operative load cell.

Intra-operative assessment and quantification of load balance with a load cell may improve the longevity of TKA.

TKA was performed on five pairs of cadaveric knees which were randomly assigned into one of two groups based upon whether the surgeons were blinded or unblinded to the load cell’s output. A validated tibial load cell, capable of measuring medial and lateral loads independently, was inserted. Compartment forces were recorded at discrete flexion angles prior to ligamentous balancing and again after soft tissue balancing with final components cemented into position.

Initially, there were significant differences between the loads in the medial and lateral compartments (p< 0.05). With soft tissue release, there was improved balance. There was a trend for superior balance (medial minus lateral compressive force) in the unblinded group at 30°: 11.1N unblinded vs. 44.4N blinded, 60°: 7.1 vs. 36.9N, and 90°: 3.0 vs. 8.7N.

Failure to achieve ligamentous balance results in instability and unequal load distribution. Current balancing techniques are not perfect, but appear to be improved with the use of the load cell. Further in-vitro and in-vivo studies are needed to improve the load distribution following TKA.


R.M.D. Meek N.V. Greidanus D.S. Garbuz B.A. Masri

This study evaluated the effect of prosthetic patellar resurfacing on outcome of revision total knee arthroplasty. One hundred and twenty-six patients who underwent consecutive revision of total knee arthroplasty were identified. The status of the patella was ascertained post revision as to the presence or absence of patellar prosthesis. WOMAC, Oxford-12, SF-12 and patient satisfaction data were obtained at a minimum of two years follow-up. Follow-up was obtained in one hundred and ten patients. There was no significant difference between the two cohorts with regards to outcomes. A patellar prosthesis does not appear to significantly affect pain, function, or satisfaction outcomes following revision total knee arthroplasty.

The purpose of this study is to evaluate the effect of prosthetic patellar resurfacing on outcome of revision total knee arthroplasty in a matched cohort study.

The presence or absence of a patellar prosthesis does not appear to significantly affect pain, function, or satisfaction outcomes following revision total knee arthroplasty.

Attempting to resurface the patella in revision cases may not be worthwhile.

Follow-up was obtained in one hundred and ten patients (fifty-two with patellar component, fifty-eight bony shell), matched for age, sex and co-morbidity scores and followed for a minimum of two years. There was no significant difference between the two cohorts with regards to outcomes of WOMAC pain (mean seventy-two and sixty-five, p=0.17), WOMAC function (mean sixty-four and fifty-nine, p=0.26) scores, Oxford −12 (mean sixty-three and sixty-seven, p=0.2), SF-12 (mean forty and thirty-six, p=0.27) and satisfaction outcomes (mean eight and nine, p=0.07), (power of 0.8, beta=0.2).

From January 1997 to December 1999 one hundred and twenty-six patients who underwent consecutive revision total knee arthroplasty were identified. The status of the patella was ascertained post revision as to the presence or absence of patellar prosthesis. At a minimum of two years follow-up, pain and function were assessed by questionnaire for WOMAC, Oxford-12, SF-12 and patient satisfaction data. Co-morbidity, surgical exposure, HSS knee scores and ROM were also collected. Univariate and multivariate analyses were performed.

It is questionable whether patient’s pain, function and satisfaction are affected in revision total knee arthroplasty by patellar prosthetic resurfacing.

Funding: One or more of the authors has received funding from a commercial party. This was DePuy, Inc, Warsaw, IN.


C.S. Bailey S.G. Sjovold M.F. Dvorak C. Fisher T.R. Oxland

The purpose of this study was to investigate the strength profile of the thoracolumbar endplate. Indentation testing was performed on the T9, T12, and L2 endplates of six fresh-frozen human cadaver vertebrae. Indentations were performed in a standardized rectangular grid pattern of seven columns and five rows. There was an incremental increase in the strength of each row moving anterior and posterior from the central row. The relative strength of the anterior regions of the endplate increased with rostral ascent into the thoracic spine.

The purpose of this study was to map the strength profile of the thoracolumbar endplates using indentation testing.

Indentation testing was performed on the T9, T12, and L2 endplates of six fresh-frozen human cadaver spines using a materials testing machine (Dynamight, Instrom Corporation, Canton, MA). A minimum of twenty-five indentations was performed in a rectangular grid (seven columns by five rows). A 3mm hemispherical indendor was lowered at 0.2mm/s to a depth of 3mm producing endplate failure.

The failure load significantly varied with the AP and LAT positions (p< .0001). Each row was significantly stronger than the rows anterior to it (p < 0.04), except for the most row. The most lateral columns were stronger than the central (range: p = .04 – .0002). The mean strength of the L2 posterior row was greater than that for the thoracic endplates (p< .01), while no difference existed between levels within the two anterior rows. The ratio of the mean strength for the posterior row compared to that of the anterior row was significantly different across level (P< 0.036). The ratios for L2, T12, and T9 were 1.35, 0.97, and 0.91 respectively.

The periphery of the thoracolumbar endplate is stronger than the centre. The interaction identified between position and level suggests a relative strength increase in the anterior aspect of the endplate with rostral ascent into the thoracic spine.

This knowledge may assist in preventing intervertebral inplant subsidence by influencing implant positioning and design.

Funding: Canadian Institutes of Health Research Please contact author for figures and/or graphs.


J.L. Jaremko D. Hill M. Moreau R.F. Zernicke

Recent studies have shown that scoliotic deformity can be estimated accurately from deformity of the full three hundred and sixty degrees torso shape. However, acquisition of these data requires an expensive multi-scanner system. If it was possible to estimate accurately scoliosis from the back surface shape alone, a single scanner and simplified analysis methods could be used. Here, we estimated the Cobb angle within ten degrees in 84% of forty-six patients from back surface data, compared to 99% within ten degrees for a previous, larger study using the entire torso shape. These results suggested that both back-surface and full-torso models for Cobb angle estimation should be pursued for their potential merits.

The surface deformity of scoliosis, often the primary patient complaint, progresses non-linearly with the underlying spinal deformity. If it was possible to estimate reliably the degree of scoliosis from the surface, adolescent patients with non-progressing scoliosis could be spared harmful X-ray radiation. Some of us have previously estimated the scoliotic Cobb angle from three hundred and sixty degrees torso surface deformity. Here, we tested how accurately the Cobb angle could be estimated from back surface data alone, which are easier and less expensive to obtain than full-torso data.

A genetic algorithm selected the clinical parameters to be used by a neural network to estimate scoliosis deformity from back surface deformity. We had forty-six consecutive patients with right-thoracic curves (Cobb angles eleven to ninety-seven degrees), in whom fifteen indices were available including age, height, bracing status, scoliometer reading, back surface rotation, and cosmetic score of landmark asymmetry. Those data were used by a neural network to estimate the Cobb angle within ten degrees in 84% of patients, a 30% improvement over regression-model accuracy, though less accurate than use of the three hundred and sixty degrees torso shape which estimated up to 99% of curves within ten degrees in a previous study.

Neural network predictive accuracy was better when using the full three hundred and sixty degrees torso shape, but the simpler and more economical acquisition of back surface data alone also gave promising results. This pilot comparison study suggested that both models (using back surface data alone vs. using three hundred and sixty degrees torso data) should continue to be developed in attempts to optimize surface estimation of scoliosis.


T.R. Turgeon W. Dust S. Sanche K. Mochoruk

The twelve matte and twelve polished surfaces of hemi-arthroplasties were contaminated with Staph. epidermidis and then irrigated with bulb or pulse irrigation. The surfaces were then quantitatively cultured using a standardized swabbing technique. Results are expressed as the percentage of contaminant bacteria recovered. The matte finish groups showed median values of 1.46 and 2.88x10−2 while the polished finish groups showed 1.49x10−3 and 2.83x10−6 with bulb and pulse irrigation, respectively. The difference between irrigation types was significant (p=0.002) for both matte and polished surfaces. Pulse irrigation was more effective than bulb irrigation in removing contaminant bacteria from the prosthetic surfaces studied.

Tremendous suffering is associated with infection following total joint arthroplasty. To reduce infection risk, some surgeons use pulse irrigation prior to wound closure. This practice is based on the assumption that pulse irrigation will more effectively remove adherent bacteria. However, there has been no study of the effectiveness of pulse irrigation in clearing bacteria from prosthetic surfaces. The hypothesis of this study is that pulse irrigation is more effective than bulb irrigation in removing intra-operative bacterial contaminants from prosthetic surfaces.

The matte and polished surfaces of hemiarthroplasties were studied separately. Each surface was contaminated with Staph. epidermidis and then irrigated with pulse or bulb irrigation. A third group without irrigation was also studied. The surface was then swabbed three times using a standardized technique. The swab tips were quantitatively cultured.

Twelve matte and twelve polished surfaces were examined using both irrigation types with corresponding non-irrigation reference values. Results are expressed as the percentage of contaminant bacteria recovered. The matte finish groups showed median values of 1.46 and 2.88x10−2 while the polished finish groups showed 1.49x10−3 and 2.83x10−6 with bulb and pulse irrigation, respectively. The difference between irrigation types is significant (p=0.002) for both matte and polished surfaces.

Pulse irrigation was more effective than bulb irrigation in removing contaminant bacteria from the prosthetic surfaces studied.

Funding: Hip Hip Hooray, Zimmer-Sadler


S. Xing E. Boynton

The effect of conditioned media from implant revision membranes on tartrate resistant acid phosphatase (TRAP) secretion following PE exposure was investigated. Human Monocytes were cultured on PE/collagen coverslips, and 50 uls of culture media, conditioned media from implant revision membranes, or conditioned media from synovium was added. Cultured media were collected, and analyzed for TRAP activity. Statistical analysis showed significantly greater release of TRAP in the media with the supplement of the conditioned media from implant revision membranes, indicating that the unknown factors in the conditioned media could accelerate monocyte-macrophage TRAP secretion. Identifying and blocking of the factors would be beneficial for long-term implant performance.

The purpose of this study was to investigate the effect of conditioned media from implant revision membranes on monocyte-macrophage tartrate resistant acid phosphatase (TRAP) secretion.

Conditioned media from implant revision membranes significantly enhanced monocyte-macrophage TRAP secretion following PE exposure in vitro.

Since TRAP has been related to bone resorption, identifying and blocking factors stimulating monocyte-macrophage TRAP section would be beneficial for preventing peri-implant bone resorption.

Monocytes isolated from human blood were cultured on PE/collagen coverslips, and 50 uls of fresh culture media, conditioned media from implant revision membrane, or conditioned media from synovium was added at time zero, day two and four. Cultured media were collected at day two, four and six, and analyzed for TRAP activity. As previously reported the conditioned media from the revision membranes contained TRAP activity greater than synovial membranes. Therefore the accumulative TRAP activity after culturing macrophages with PE was corrected by subtracting TRAP activity measured in the conditioned media prior to DNA normalization. Statistical analysis showed significantly greater release of TRAP in media with addition of the conditioned media from implant revision membrane when compared with either conditioned media from synovium or fresh culture media (p< 0.01, n=3). This result indicates that certain unknown soluble factors in the conditioned media from implant revision membrane could accelerate monocyte-macrophage TRAP secretion. Since TRAP enzyme has been related to bone resorption, greater TRAP secretion could lead to peri-implant osteolysis and subsequent implant loosening. Identifying and blocking of those factors would be ultimately beneficial for implant long-term clinical performance.

Funding: Canadian Orthopaedic Research Foundation and Arthritis Society


G. Grimard G. Lacroix H. Labelle B. Poitras

The aim of this study is to compare the adulthood quality of life of subjects with adolescent idiopathic scoliosis who have had surgery to subjects without. Inclusion criteria were being operated or having not operated but having a scoliosis with a Cobb angle ≥ 35° at the last visit. Self-administered questionnaires (five) were sent to all eligible patients. A total of two hundred and four had surgery. The mean Rolland score for subjects was significantly higher for the group who had surgery. The only variable affecting physical component of the SF-36 was the alcohol consumption. The EuroQol score was predicted by the marital status, people being married having a better score. In conclusion, there is not significant difference in the quality of life in adulthood between the subjects with AIS whether they had surgery or not. Subjects who had surgery tend to be less in pain than people not operated on.

The aim of this study is to compare adulthood quality of life of patients with AIS who have had surgery to subjects without.

Overall, there is not significant difference in the quality of life in adulthood between the subjects with AIS whether they had surgery or not. Subjects who had surgery tend to be less in pain than people not operated on.

This preliminary study will help the health professionals involved with the management of patients with AIS make clinical decisions and better understand the long-term quality of life in idiopathic scoliosis.

Among the two hundred and ninety-nine AIS responding, two hundred and four had surgery and ninety-five none and their mean Cobb angle was respectively fifty-eight and forty-four degrees. All patients had a follow up more than twenty years. There was no significant difference as for sex, life status, education, working areas, alcoholism, smoking habits, chronic illness and reproductive health between the two groups. Same proportion of subjects in both groups had no back pain (≅30%); but more non-operated subjects had physiotherapy and/or chiropractic treatments (p< 0.001). The mean Rolland score for subjects was significantly higher for the group who had surgery (p = 0.02). Using multiple regression analysis, the only variable affecting physical component of the quality of life measured with the SF-36 was the alcohol consumption whereas the psychological of the SF-36 was predicted by alcohol consumption as well and the gender. The quality of life measured by the EuroQol was predicted mainly by the marital status, people being married having a better score.

The study was designed as a comparative retrospective cohort study. Subjects referred for Adolescent Idiopathic Scoliosis between 1960 and 1979 to Sainte-Justine Hospital were entered into the cohort. Inclusion criteria were being operated or having not operated but having a scoliosis with a Cobb angle ≥ 35° at the last visit.

A self-administered questionnaire was sent to all eligible patients. The questionnaires that were used were all reliable and valid. More specifically the instruments used were the Oswestry, Roland, SF-36, Quebec Back Pain Disability Scale, Scoliosis Research Society and the EuroQol-5D.


J.M. Mac-Thiong H. Labelle M. Charlebois M.P. Huot J.A. de Guise

This study evaluated the sagittal alignment of the spine and pelvis in adolescent idiopathic scoliosis. The pelvic configuration influenced the lumbar lordosis but was not associated with the thoracic kyphosis or with the curve type. The pelvic incidence in adolescent idiopathic scoliosis was higher than that reported in the literature for normal adolescents and was closer to the values of pelvic incidence found in adults. The role of the PI in the pathogenesis of AIS needs to be explored in a comparative study involving AIS patients and normal adolescents.

The purpose of this study was to evaluate the sagittal alignment of the spine and pelvis in adolescent idiopathic scoliosis (AIS) based on the curve type.

Five sagittal parameters were retrospectively evaluated on lateral radiographs for one hundred and sixty AIS patients: thoracic kyphosis (TK), lumbar lordosis (LL), sacral slope (SS), pelvic tilt (PT) and pelvic incidence (PI). The patients were classified according to their coronal curve type. ANOVA was used to compare the parameters between the curve types and Pearson’s coefficients were used to investigate the relationship between all parameters.

The TK was significantly lower for King I, II and III curves as compared to lumbar curves. The LL was higher for lumbar curves, although not significantly. No significant change between the groups was observed for SS, PT and PI. The PI was significantly correlated to LL, SS and PT for all groups. The LL was strongly related to the SS in all cases but not with the TK, except for thoracolumbar curves.

The TK mostly depended on the spinal deformity while the LL was mainly influenced by the pelvic configuration. The scoliotic curve type was not associated with a specific pattern of sagittal pelvic configuration. The PI was significantly higher than that reported in the literature for normal adolescents.

The role of the PI in the pathogenesis of AIS needs to be explored in a comparative study involving AIS patients and normal adolescents.

Further study is needed to evaluate the prognostic value of the PI in AIS.

Funding: This research was funded by the Canadian Institute of Health Research.

Please contact author for figures and/or diagrams.


J.S. Tan B.K Kwon M.F. Dvorak C.G. Fisher T.R. Oxland

A biomechanical study assessing pedicle screw fixation with three different augmentation methods was performed in human cadaveric vertebrae. Precision opto-electronic measurement of screw motion assessed motion magnitude and patterns, ie translation and/or rotation. Physiological cyclic loads were applied as opposed to the simple pull out test. Augmentation with wires, hook or cement decreased overall motion. There were no significant differences in motion magnitude between the three augmentation methods. Motion patterns for screws with cement augmentation were mainly rotational and differed from the other two methods. Rigid body translations were observed with wires or hook augmentation, suggesting a loosening behaviour. Augmentation with cement resulted in better fixation than wires or hook.

Augmentation of loosened pedicle screws in poor quality bone is often necessary. The purpose of this study was to contrast the kinematics of loosened pedicle screws augmented with laminar hooks, sublaminar wires or calcium phosphate cement.

Cyclic tests of pedicle screws with compressive force and bending moment were carried out on forty-eight screws in twenty-four cadaveric vertebrae (L3-L5) augmented with hooks, wires or cement. Motion at the screw tip and screw head were measured using an optoelectronic camera system and the magnitudes compared in a paired manner using non-parametric statistics. Motion patterns of the screws were determined for each augmentation method.

Augmentation with hook, wire or cement decreased screw motion. There was no significant difference between augmentation methods when the magnitudes of motion, described as ranges and offsets, were compared. Augmentation with cement resulted in mainly rotations of the screws while there were rigid body translations with wires or hooks.

Comparing magnitudes of motion at the screw head and screw tip were insufficient. The screw head and screw tip could be moving in synchronous, indicating rigid body translations. Using simple pull out tests would not detect such differences.

The method used in this study contrasted pedicle screws motion with different augmentations. While there was no detected significant difference in motion magnitude of the pedicle screws, the motion pattern of the screws suggested better augmentation with cement.

Motion of pedicle screws in situ had not been described in the literature. Previous work comparing pedicle screws fixation used the pull out test, while the current method applied physiological loads.

Funding: Funding from the Canadian Institutes for Health Research, Funding from Synthes

Spine Please contact author for diagrams and/or graphs.


S. Kaspar D. Bednar J. Dickey

In this biomechanical study of isolated porcine C2 vertebrae, antero-posterior forces were applied to potted specimens. Bipedicular fractures were generated in 25.4% of fifty-nine specimens (others fractured mostly through laminae). Bipedicular fractures were subsequently fixed under direct vision with trans-pedicular lag screws. These fixed specimens were then tested again. The mean ultimate tensile strength of the construct was 27.1% compared to the native bone’s fracture strength in the same specimen. This is a good model for hangman’s fracture, and is relevant to newer constructs that utilize C2 pedicle screws as part of a larger instrumentation procedure.

Hangman’s fracture rarely needs internal fixation. However, if fixation is indicated the fracture can sometimes be directly fixed with trans-pedicular screws rather than fusing C1-C2 and committing to a great loss of neck range of motion. To our knowledge, the actual pullout strength of pedicle screws in C2 is previously unreported. Hence, we developed a laboratory model of hangman’s fracture by applying antero-posterior tensile force in fifty-nine porcine specimens that were stripped of soft tissues. The failure strength of the bone averaged approximately 3200 N, and subsequent fixation averaged to 27.1% of this value. Regardless of pre-hoc expectations, these values indicate that the screw purchase is strong enough to consider continued use of the procedure in repair of hangman’s fracture, fixation to C2 of multi-level constructs, and so forth. Multiple anterior and posterior screw procedures have been tested in the past, but to our knowledge the pullout strength of C2 pedicle screws has not been examined. Because the usage of C2 pedicle screws is growing in popularity, this biomechanical information is pertinent to work in traumatic, degenerative, and reconstructive procedures. Some limitations of the present study are that the specimens were porcine rather than human, and that only fixation to single vertebrae was examined.

Funding: Dr Kaspar holds academic research grants from McMaster University and from The Physicians’ Services Incorporated (PSI) Foundation, the former of which was used to finance this project. There are no commercial grants or conflicts of interest.


F. Al-Khalifa A. Lawendy A. Yee J. Finkelstein

A predictive model for final kyphosis was tested by evaluating the radiographs of forty-three patients with traumatic burst fractures. Since clinical outcomes are related to final kyphosis in the ambulatory patient rather than on the initial supine injury radiograph, the ability to predict final kyphosis is beneficial in determining treatment. This study demonstrated that in the appropriately selected patient for conservative care, the limit of final-kyphosis(Kf) can be predicted from the intial-kyphosis(KI) , such that Kf= < KI+.5KI . Outliers from this equation were patients who had unrecognized posterior column fractures, superior and inferior end-plate fractures, and/or multiple level of injury.

The purpose of this study was to define a prediction model that afforded clinicians the ability to define final kyphosis from initial supine films in order to guide the management of stable burst fractures.

This study has demonstrated that as a rule of thumb, the final absolute kyphosis for stable burst fractures can be expected to be up to Ki (initial absolute kyphosis) + 1.5Ki. Outliers were found to be fractures with unrecognized posterior element injury, both superior and inferior endplate fractures and multiple level injuries.

The final kyphosis is clinically more relevant than the initial kyphosis in terms of functional outcome after conservative management. A prediction model for final kyphosis based on initial injury films can help guide the clinician for optimal management.

Retrospective radiographic analysis was performed on forty-three patients with a minimum follow up six months. All patients suffered traumatic burst fractures, which were deemed stable as to be satisfactorily managed in a brace. Serial radiographs were used to determine initial (Ki) and final (Kf), Kyphosis angles. Predicted Kf was determined using the equation Kf =Ki + 1.5 Ki. The initial absolute kyphosis was the measured kyphosis using the Cobb technique and including the loss of the expected normal lordosis of that spinal segment. Inclusion criteria included burst fractures at between levels T10 – L3 in the neurologically intact patient.

The equation accurately predicted the final outcome , Kf, in 70 % of the cases. In 20% of the cases, the Kf was less than expected. (Acceptable clinical result). In 10% of the cases, Kf was greater than predicted or achieved a clinically unacceptable kyphotic angulation requiring secondary surgery. In this group of outliers, post-hoc analysis identified unrecognized posterior element injury, both superior and inferior endplate fractures and multiple level injuries.

In traumatic burst fractures, the goal of management is to protect the spine during healing while maintaining an acceptable alignment, which will not lead to late pain and deformity. A final absolute kyphosis angle, Kf, from twenty to thirty degrees has been variably regarded as a threshold to obtain a good clinical outcome. Criteria for stability have been previously documented, however variables are based on initial presentation. Aside from careful classification of the fracture type, the current “rule of thumb” prediction model for Kf may further help the clinician with management decisions.


S.E. Roth P. Mousavi G. Cheung E. Chow J. Finkelstein C. Whyne

The impact of cement leakage during percutaneous vertebroplasty has not been well characterized. This study aimed to quantify and compare cement leakage and its clinical significance in osteoporotic and metastatic vertebrae treated with vertebroplasty. Cement leakage was quantified using semi-automated thresholding of digital CT scans for fouteen metastatic and nineteen osteoporotic vertebrae and compared to pain scores. Cement leakage was present in 90.9% of vertebrae. Cement leaked predominantly into the disc in the osteoporotic vertebrae but yielded more diffuse leakage patterns in the metastatic cases. Despite cement leakage, there was significant improvement in pain immediately following vertebroplasty for all patients.

This study aimed to quantify cement leakage in osteoporotic and metastatic vertebrae post-vertebroplasty and to determine whether leakage has clinical significance at follow-up.

Despite high incidences of cement leakage, both osteoporotic and metastatic patients experienced significant immediate pain relief post-vertebroplasty.

Cement leakage is investigated as a possible rationale for the higher rates of pain relief seen in osteoporotic vs metastatic patients undergoing percutaneous vertebroplasty.

Cement leakage was present in 90.9% of the vertebrae treated. The percent volume of cement leakage was 11.6±10.6 in the osteoporotic vertebrae and 19.4±19.1 in the metastatic vertebrae (p=0.144). Cement leaked predominantly into the disc in the osteoporotic vertebrae whereas leakage was more diffuse in the metastatic vertebrae. Pain scores were high prior to vertebroplasty and decreased significantly following the procedure in both groups irrespective of leakage (p< 0.05).

Digital CT scans were retrieved for osteoporotic (n=19) and metastatic (n=14) patients treated with percutaneous vertebroplasty. Volume of cement injected directly into the vertebral body and location of cement leakage (pedicle, disc, periphery, canal) was quantified using semi-automated thresholding techniques. Pain scores were collected at four stages of treatment (pre, immediately post, one day post, one week post-vertebroplasty).

Disruption of the endplate in the osteoporotic spine provides an easily accessible pathway for the leakage of cement into the disc. Elevated pressurization during cement injection into metastatically involved vertebrae may account for the more diffuse cement leakage seen in the metastatic group. Clinically, pain scores improved irrespective of leakage.


Y.R. Rampersaud J.H.T. Pik D. Salonen

Using post-operative CT analysis the clinical accuracy of computer-assisted fluoroscopy for the placement of thoracic (n=69) and lumbosacral (n=271) pedicle screws was assessed. All screws were placed using the Fluoro-Nav™ system (Medtronic Sofamor Danek, Memphis, TN, USA). Screw position was completely intrapedicular in 86.5%. There were no clinically significant screw misplacements. Pedicle breaches with a potential for neurological injury (> 2 mm; medial) was 0.6%. The overall pedicle screw misplacement rate in this study is less than or comparable to reported misplacement rates using other techniques. The use of computer-assisted fluoroscopy may improve the safety of pedicle screw placement.

The purpose of this prospective study is to evaluate the clinical accuracy of computer-assisted fluoroscopy for the placement of thoracic (T) and lumbosacral (LS) pedicle screws.

The overall thoracic and lumbar pedicle screw misplacement rate in this study is less than or comparable to reported misplacement rates using other techniques.

The use of computer-assisted fluoroscopy may improve the safety of pedicle screw placement.

Postoperative computed tomographs (CT) of three hundred and forty pedicle screws were independently reviewed. All screws were placed using the Fluoro-Nav™ system (Medtronic Sofamor Danek, Memphis, TN, USA). The relative position of the screw to the pedicle was assessed and graded as follows – A- completely in; B – < 2mm breach; C – 2–4mm breach; D – > 4–6mm breach. If an osseous breach occurred, the direction of the breach was further classified.

Overall screw position was graded A in 86.5% (294/340) of screws (91.1 % (24/271) -lumbosacral and 68.1.0% (47/69)-thoracic). Forty-six pedicle breaches occurred (24 medial; 22 lateral). Thirty-five percent (16/46) of breaches were unavoidable secondary to a pedicle screw that was larger than the size of pedicle (thoracic-13). Pedicle breaches were Grade B in 11.8%, Grade C in 1.5% and Grade D in 0.3% of screws. There were no clinically significant screw misplacements. Pedicle breaches with a potential for neurological (> 2 mm; medial) or vascular injury was 0.6% and 0% respectively.

FluoroNav™ appears to be a safe and practical adjunct for the placement of thoracic and lumbosacral pedicle screws.

Funding: Medtronic-Sofamor Danek – research support


J.M. Buchowski V. Sinkov K.M. Kebaish J.P. Kostuik

A prospective study was conducted to determine the functional and radiographic outcome of sacroiliac arthrodesis. Twenty patients were enrolled and the mean follow-up period was 4.6 years. SI joint instability was the most common etiology. Seventeen of twenty patients (85%) went on to a solid fusion. Statistically significant improvement was noted postoperatively in five of eight SF-36 categories (PF, RP, BP, SF, and RE), with a positive trend in the others. We conclude that sacroiliac arthrodesis is successful in the treatment of sacroiliac disorders, however its success is dependent on careful patient selection.

The purpose of this study was to determine the functional and radiographic outcome of sacroiliac joint arthrodesis.

Twenty consecutive patients were enrolled with an average age of 45.1 years. Plain radiographs and SF-36 Health Surveys were obtained prior to surgery and during the follow-up period.

Mean duration of symptoms was 2.6 years and mean follow-up was 4.6 years. SI joint instability was the most common etiology and was present in twelve patients. Seventeen of Twenty (85%) patients went on to a solid fusion. Of the three patients who did not fuse, two remained symptomatic and required revision surgery. Fifteen of twenty patients (75%) completed pre- and post-operative SF-36 forms. Improvement was noted in all SF-36 categories. PF improved from 31.8±31.0 to 50.7±34.5 (p< 0.030). RP improved from a 0.0±0.0 to 31.3±41.5 (p< 0.012). BP improved from 15.6±11.1 to 35.7±24.7 (p< 0.009). SF improved from 37.5±21.0 to 61.5±24.1 (p< 0.028). Finally, RE improved from 46.2±48.2 to 66.7±44.9 (p< 0.012). Improvement was also noted in GH, VT, and MH from 52.2±23.5, 30.8±21.7, and 56.0±28.3, respectively to 56.1±20.5, 44.6±25.8, and 61.3±26.3, respectively, however these were not significant (p values 0.345, 0.064, and 0.220, respectively).

In this prospective study, a fusion rate of 85% was achieved, and statistically significant improvement in functional outcome was observed in five of eight SF-36 categories with a positive trend in the others.

Sacroiliac arthrodesis is successful in the treatment of SI joint instability, arthritis, spondyloarthropathy, and dysfunction, however, its success is dependent on careful patient selection.


S. Frost K. Summers B. Singh D. Chess R. McCalden R. Bourne C. Rorabeck S. MacDonald

The pathogenesis of osteolysis in failed total hip arthroplasty is not fully understood. The purpose of this study is to identify CD4+CD25+ Regulatory T cells in periprosthetic tissues in failed total hip replacements secondary to osteolysis. Intra-operative tissue samples and peripheral blood were collected from patients undergoing revision total hip arthroplasty surgery. Regulatory T cells were present in the tissues, and significantly increased in the peripheral blood in patients with failed total hips compared to normal controls. Further characterization of these regulatory T cells are warranted as they may play a role in osteolysis in loose total hip replacements.

Osteolysis remains the most common complication following total joint arthroplasty. To date, no authors have investigated the role of CD4+CD25+ regulatory T cells (TREG) participating in the osteolytic pathogenesis. The purpose of this study is to quantitate the presence of TREG cells in periprosthetic tissues in failed total hip replacements secondary to osteolysis.

Fifteen consecutive patients booked for revision total hip arthroplasty secondary to osteolysis were included. Tissue samples were collected: peripheral blood (PB), synovial fluid (SF), synovial tissue (ST), and interface tissue (IT) between the failed component and the bone defect. Total lymphocytes were isolated and analyzed using fluorescent-tagged antibody cell sorting (FACS) for the presence of TREG cells. Frozen sections of ST and IT were analyzed with immunohistochemistry for TREG cells.

TREG cells were significantly upregulated (p< 0.01) in the PB (68%) of revision hip patients compared to normal controls PB (44%). In the synovial tissue (ST) and interface tissue (IT), 57% of the lymphocytes isolated were TREG cells. The presence of TREG cells in the ST and IT were confirmed with immunohistochemistry.

TREG cells are upregulated in the peripheral blood of patients with failed total hips secondary to osteolysis. The TREG cells are also present in the synovial tissue and interface tissue.

Evidence for involvement of regulatory T cells contribute to our understanding of this complex biologic response to artificial wear particles.

Functional studies of these TREG cells are warranted as they are upregulated in patients with loose total hip replacements.


J.L. Howard A.J. Hui R.B. Bourne C.H. Rorabeck S.J. MacDonald R.W. McCalden

The purpose of this study was to determine contact patterns in cementless acetabular cups using a novel computed tomography (CT) scan analysis technique. Eighteen embalmed cadaveric hemipelvis specimens were randomly assigned to receive one of three cup designs. A custom CT platform was designed to optimize imaging of the acetabular cups. After cup implantation, specimens were mounted on the platform and imaged in a spiral CT scanner. Contact analysis was preformed using custom-developed imaging software. The hemisphere, dual geometry and spiked cup designs analyzed using this CT analysis technique demonstrate differences in the amount and distribution of bone pros-thesis contact.

The purpose of this study was to determine contact patterns in cementless acetabular cups using computed tomography (CT) scan analysis.

Eighteen embalmed cadaveric hemipelvis specimens were randomly assigned to receive a hemispherical cup, a dual geometry cup, or a spiked cup. After radiographic templating, an experienced orthopaedic team prepared the specimens and implanted the acetabular cups. A custom CT platform was designed to optimize imaging of the acetabular cups. After cup implantation, specimens were mounted on the platform and imaged in a spiral CT scanner. Contact analysis was preformed using custom-developed imaging software. Contact was defined as a bone-prosthesis distance of 0.5 mm or less.

The mean amount of cup contact was 40.4% (SD=8.2%) in the hemisphere group, 24.7% (SD=2.3%) in the dual geometry group, and 29.7% (SD=9.5%) in the spiked group. Colour mapping of the bone-prosthesis gap was used to identify contact/non-contact regions along the acetabular contour for all cup designs.

Preliminary work with this CT analysis technique demonstrates differences in the amount and distribution of contact in the acetabular cup designs. Future work will involve development of an imaging phantom to clarify error, use of the technique with different cup designs and reaming techniques, and comparison of this technique with conventional CT scan techniques.

This study outlines a novel CT analysis technique for quantitatively determining bone-prosthesis contact for cementless acetabular cups.

The hemisphere, dual geometry and spiked cup designs analyzed using this CT analysis technique demonstrate differences in the amount and distribution of bone prosthesis contact.

Funding: Smith and Nephew


O.L. Huk I. Catelas D.J. Zukor J. Antoniou F. Mwale C. Tkaczyk A. Petit

Metal particles and ions are liberated from the articular interface of metal-metal (MM) total hip arthroplasties. To better understand their cellular effect, we analyzed the internalization of these metal particles and ions by macrophages in vitro. Macrophages were exposed to metal particles isolated from MM prostheses cycled in a hip simulator and to metal ions. Cells were processed for transmission electron microscopy analysis. Results reveal the internalization of metal particles and Cr3+ ions in specifically localized cytoplasmic areas. This study is the first to reveal that metal particles of clinically relevant size and Cr3+ ions are internalized by an apparently active process.

In order to minimize articular interface wear, metal-metal (MM) hip implants have been considered as an alternative to conventional metal-polyethylene bearings. While the local histological effects of the metallic particles and ions appear to be similar to that seen with metal-polyethylene hip replacements (i.e., a foreign-body macrophage response), little is known about the cellular effects of these metal particles and ions.

The purpose of this study was to better understand the cellular effect of metal particles and ions, we analyzed their internalization by macrophages in vitro.

J774 mouse macrophages were exposed to metal particles isolated from serum of MM prostheses cycled in a hip simulator and to Cr3+ (CrCl3) and Co2+ (CoCl2) ions. Cells were then processed for transmission electron microscopy analysis.

Micrographs revealed the internalization of metal particles and Cr3+ ions in specifically localized cytoplasmic areas, suggesting that they are phagocytosed via an active pathway. Energy disperse X-ray analysis spectra of macrophages incubated with Cr3+ revealed a chromium phosphate composition. The same structure and composition were also observed when Cr3+ ions were incubated in culture medium without cells, suggesting that they were formed outside the cells. Co2+ ions did not form visibly agglomerated structures.

This study is the first to reveal that metal particles of clinically relevant size are internalized by an apparently active process and that Cr3+ ions can be internalized by macrophages after binding to phosphorus or phosphoproteins. Kinetic studies are now necessary to better understand the mechanism of phagocytosis and the ultimate outcome of these particles and ions in macrophages.


N. Mahomed J. Wright G. Hawker A. Davis P. Coyte G. Naglie E. Badley

The purpose of this study is to compare the efficacy of home based vs. inpatient rehabilitation following total joint arthroplasty (TJA). Primary outcome was the self-reported WOMAC pain and function score that was used to evaluate a stratified random sample of two hundred and thirty-two patients. Despite concerns about early hospital discharge there was no difference in functional outcomes at the primary endpoint (twelve weeks post TJA) between the group receiving home based vs. inpatient rehab. Given that home- based rehab is less expensive; we would recommend the use of home based rehab protocols following elective primary TJA.

Home- based rehab is increasingly utilized to save costs but concerns have been raised about early hospital discharge and adverse clinical outcomes. The aim of this RCT was to compare the efficacy of home based vs. inpatient rehab following Total Joint Arthroplasty (TJA).

Despite concerns about early hospital discharge there was no difference in functional outcomes twelve weeks post TJA between the group receiving home based vs. inpatient rehab.

With no significant difference in functional outcomes, less expensive home based rehabilitation protocols are recommended following elective total joint arthroplasty.

We randomized two hundred and thirty-two patients to either home based or inpatient rehab following TJA using block randomization techniques. All patients at a tertiary referral centre and large volume community hospital undergoing primary elective total hip or knee arthroplasty for osteoarthritis or inflammatory arthritis were eligible. Standardized care pathways were followed for both procedures. All patients were evaluated at baseline (two weeks prior to surgery) and twelve weeks post surgery using standardized questionnaires including history, physical exam, demographics and WOMAC pain and function (the primary endpoint). In total one hundred and fifteen received a total hip and one hundred and seventeen a total knee arthroplasty; there were eighty-five men and one hundred and forty-seven women with a mean age of sixty-seven (range thirty-eight to eighty-nine) years. The groups were similar at baseline for patient demographics and WOMAC scores. At follow-up (twelve weeks post TJA) there was no statistically significant difference in WOMAC scores.


J.P. Waddell X. Chen K.A. Griffith J. Morton E.H. Schemitsch

Fifty-five patients undergoing isolated acetabular revisions in fifty-seven hips were available for review. In thirty-three of fifty-seven hips there was no significant acetabular deficiency; of the remaining twenty-four hips twenty underwent allograft reconstruction and four autogenous bone grafting. Mean follow-up was four years with a range of three to seven years; there have been no femoral loosening, and three further surgical procedures for hip instability. All acetabular components at last review were soundly fixed with the exception of one patient who underwent excision arthroplasty at twelve months for deep infection.

The purpose of this study was to review the functional outcome and the fate of the femoral stem and revised acetabular component following isolated ace-tabular revision.

Findings of the current study demonstrate that isolated acetabular revision does not compromise the final functional nor radiographic outcome in acetabular revision in appropriately selected patients; the fate of the femoral component is not adversely influenced by this procedure.

There is no need to remove the femoral component at the time of acetabular revision if the femoral component is well fixed and stable by pre- and intra-operative assessment.

Prospectively entered data on fifty-seven hips (fifty-five patients) who have undergone isolated acetabular revision without femoral revision was available for review. All patients were assessed pre-operatively and post-operatively on an annual basis by means of physical examination, x-ray, SF-36 and WOMAC questionnaires.

In thirty-three of fifty-seven hips there was no significant acetabular deficiency; of the remaining twenty-four hips, one had a segmental defect, thirteen had a cavitary defect and ten had a combined segmental and cavitary defect. Osteolysis existed in the proximal femur of two hips.

Bone grafting in twenty-four hips consisted of morselized allograft in nine; combined structural and morselized allograft used in eleven and autogenous bone used in four acetabular defects. Autogenous bone grafting was done in two femoral osteolytic lesions.

Mean follow-up was four years with a range of three to seven years. The mean duration of arthroplasty prior to revision was fourteen years (range four to twenty-three years).

There were no nerve palsies, vascular injuries or intra-operative fractures in this patient group. All ace-tabular components at latest review were soundly fixed with the exception of one patient who underwent excision arthroplasty at twelve months for deep infection. Twenty-one of the twenty-four hips with bone grafting demonstrated positive radiographic signs of incorporation; the remaining threehips have a stable interface but no evidence of bone ingrowth. Three of the fifty-seven hips presented with hip dislocations after revision arthroplasty; two were managed by closed reduction; the third by open reduction and soft tissue repair.


S. Kaspar J. deBeer D. Petrucelli

There has never been a study of whether intra-articular steroid injections of arthritic hips can alter the outcomes of subsequent arthritis management, particularly total hip arthroplasty (THA). In this study forty patients with a history of steroid injection of the hip and subsequent THA are examined retrospectively for infections, revisions, and prospectively-gathered hip scores, as compared to matched non-steroid controls. The steroid group had an increased incidence of pain, infectious workup under usual care, and two revisions for deep infection within three years. We suggest that steroid injections of hips should be avoided in patients who are candidates for THA.

Despite the lack of demonstrated efficacy of intra-articular steroid injections for hip arthritis, the procedure is often utilized for diagnostic differentiation from spine pain, and attempted therapeutic management of painful hip arthritis. However, in the era of total hip arthroplasty (THA) the safety of this practice must be evaluated in the context of whether the injections pose any potential for complicating subsequent surgery, particularly with regard to infection. In this study, forty patients who underwent THA and had a history of previous steroid injection were compared retrospectively to forty carefully-matched patients who underwent THA in the same time period but had no history of prior steroid injection. Outcome measures included whether there was a septic workup under usual care, and this occurred in 20% of steroid patients within the first thirty-six months post-THA, as opposed to 0% in the controls. Furthermore, in a detailed analysis of Harris and Oxford scores, there was in the steroid group a higher incidence of night pain, increased severity of pain, and reduced function with activities of daily living at one year. There were two revisions for deep infection in the steroid group, and one revision for dislocation in each of the steroid and control groups. Pending the completion of the study, we provisionally suggest that steroid injection of hips may be ill-advised in a patient who will be a candidate for THA in the future. This suggestion is based primarily on the incidence of pain and infectious complications in the first postoperative year.

Funding Dr Kaspar holds academic research grants from McMaster University and from The Physicians’ Services Incorporated (PSI) Foundation, the latter of which was used to finance this study and the continuation thereof. There are no commercial grants or conflicts of interest.


J.S. Theodoropoulos E.J. Harvey C. Séguin A. Passeriello J. Kassis L. Busque

Avascular necrosis is poorly understood. The etiological factors have not been fully delineated. This disease process had a huge cost impact on the health system due to surgical treatment. Patients with avascular necrosis seen at a single institution underwent DNA extraction and analysis, coagulation-related analysis and buccal smears with DNA analysis. In this patient group 60% tested positive for at least one thrombophilic or hypofibrinolysis factor. We make recommendations depending on the defect in the cascade, allowing for potential non-surgical management of osteonecrosis in patients undergoing therapy with known antagonistic medications (i.e. corticosteroids).

The etiology and pathogenesis of nontraumatic AVN need to be better elucidated.

Our study identifies the potential association of thrombophilic and hypofibrinolytic factors and osteonecrosis of the hip, particularly genetic markers as identified through DNA markers

The significance of this study:

Osteonecrosis is a devastating musculoskeletal condition;

Tends to occur in young people;

Treatments are suboptimal mostly palliative and not curative;

currently unable to identify persons at risk for AVN;

cannot reverse the process once AVN has developed.

60% of patients had at least one tested thrombophilic or hypofibrinolysis factor positive. Most patients never had a thrombotic event.

Genetic screening, multiple hematological paramteres were tested on patients with avascular necrosis.

hypercoagulability plays a role in the development of AVN of the hip, mainly at the microvascular level;

an impairment at the level of the fibrinolytic system through high PAI-1 levels is a potential mechanism responsible for the development of AVN;

a genetic predisposition is implicated, at least in part, in the development of AVN of the hip.

most patietns had a multifactorial problem and genetic screening and blood testing will lead to recommended therapy (medical) for those patients at risk.


H. Frei P. Mitchell B.A. Masri C.P. Duncan T.R. Oxland

Impaction allografting is increasingly used for the treatment of failed total hip replacements. In six human cadaveric femurs the impaction allografting procedure was performed to comprehensively describe the postoperative morphology of impaction allografting. After the procedure, the specimens were sectioned and prepared for histomorphometric analysis. The graft porosity was lowest in Gruen zone four (52%) and highest in Gruen zone one (76%). At the level of Gruen zone six and two, virtually the entire cross-section was filled with bone cement. The presented data will serve as a baseline for future investigations of the impaction allografting.

Impaction allografting is an attractive procedure for the treatment of failed total hip replacements. The purpose of this study was to comprehensively describe the morphology of impaction allografting post operatively to form a baseline for further investigations.

Three experienced surgeons performed the impaction allografting procedure on six cadaveric femurs. After the procedure, the femurs were cut in 6mm thick transverse sections and processed for histomorphometric analysis.

The porosity of the impacted graft was highest proximally in Gruen zone one (76%) and lowest in Gruen zone four (52%). Below the tip of the stem (Gruen zone four), the mean cement penetration was significantly lower compared to the proximal part of the femur. The averaged residual impacted graft layer in Gruen zone six and two was (0.5mm SD 0.4mm) significantly thinner compared with Gruen zone’s one, 7/1, and four.

In the region of Gruen zone six and two the entire cross-section was penetrated with bone cement with almost no residual graft layer (Figure). Even the simulated lytic defects in this region were filled with the graft cement composite which may not be remodelled by the host bone.

The graft porosity was found to be highest proximally and lowest distally. In the region of Gruen zone six and two the entire cross-section was penetrated with bone cement with almost no residual graft layer.

This investigation will serve as a baseline for future studies of the mechanical and biological processes that make the impaction allografting a successful procedure.

Funding: Stryker Howmedica and DePuy for provided implants and instruments.

Please contact author for figures and/or diagrams.


N. Mahomed S. Schulz D. Laing

The purpose of this study is to evaluate prospectively the comprehension of a specific, detailed and fully informative consent in a standardized manner using a validated tool. The Deaconess Informed Consent Comprehension Test, a set of standardized questions related to eight domains of informed consent was used to survey nearly one hundred patients in a randomized controlled trial (RCT) over a year. The results of our survey demonstrate the lack of comprehension of respondents regarding most of the domains of “informed” consent. This study highlights the limitations of informed consent and the need of alternative concepts, such as entrustment/valid consent.

The purpose of this study was to evaluate prospectively the comprehension of a specific, detailed and fully informative consent in a standardized manner using a validated tool.

The results of our survey clearly demonstrate the lack of comprehension of the respondents regarding most of the domains of the “informed” consent. We are therefore concerned about the moral value of such consent.

This study highlights the importance of discussing the limitations of informed consent and the need of alternative concepts, such as entrustment and valid consent.

We surveyed nearly one hundred patients enrolled in a randomized controlled trial (RCT) over a year. All received their own copy of a specific, detailed, fully informative explanatory letter, the consent form and a patient’s guide to medical research. The Deaconess Informed Consent Comprehension Test, a set of standardized questions related to eight domains of informed consent, was used to evaluate the comprehension of research participants. Although over half of the research participants had retained a copy of the explanatory letter, the consent form and the guide, nearly 40% did not understand the purpose of the RCT. An overwhelming majority (greater than 90%) failed to identify the risks/discomforts associated with the study, while almost 60% of respondents could not identify potential benefits of their participation in the RCT. A mere 56% could provide a clear explanation of randomization. However, over 75% could identify the appropriate persons/process in case they had queries or concerns about the study.


C.M. Haydon R. Mehin C.H. Rorabeck R.B. Bourne R. McCalden S.J. Macdonald

One hundred and thirty-one cemented femoral stems inserted during revision total hip arthroplasty were reviewed to determine component survival. Harris Hip scores and complete radiographs were analysed. Survival at 10.5 years was 86.9%. Radiographically, 76.9% of the remaining components were classified as stable or possibly loose. Chi-square analysis of demographic and surgical factors determined age < 60 years, male gender and stems > 200 mm in length contributed significantly to failure (p < 0.05). Contrary to published results, we found that longer stems were more susceptible to failure. Revision femoral THA to a cemented component is an effective procedure that exhibits good long-term survival.

The purpose of this study was to determine the long-term survival of cemented femoral components in revision total hip arthroplasty (THA) and to identify factors significant to implant failure.

Cemented femoral components demonstrate good long-term survival and remain a suitable option for revision THA for hips with an intact cortical tube.

We report high long-term survival for this increasingly popular procedure, and contradict published results regarding the relationship between stem length and failure.

A consecutive series of one hundred and thirty-one THA revisions using a cemented femoral component were reviewed. Ninety-four hips in eighty-five patients alive > six years post-operatively were studied with a mean follow-up of 10.5 years. Hips excluded from analysis were thirty deceased and seven lost to follow-up before six years post-operatively. Implant success was graded radiographically and by comparing pre-operative to recent Harris Hip scores.

Of the ninety-four hips, fifteen (16%) femoral components were subsequently revised; nine (9.6%) for aseptic loosening, three (3.2%) for periprosthetic fracture, and one (1.1%) for each of stem fracture, instability, and sepsis. Survival at 10.5 years was 86.9% for all reasons and 91.0% for aseptic loosening as an endpoint. 76.9% of the retained components were radiologically classified as stable or possibly loose at follow-up. Factors significant for failure included age at revision < sixty years (p = 0.003), male patients (p = 0.036) and stems > 200 mm in length (p = 0.024).


J. Antoniou P. Roughley M. Aebi T. Steffen F. Mwale

Hyaline cartilage and immature nucleus pulposus possess similar macromolecules in their extracellular matrix, and there is no unique molecular marker to distinguish the two tissues. We show that in normal disc (fifteen to twenty-five years old), the GAG to hydroxyproline ratio (proteoglycan to collagen ratio) within the nucleus pulposus is approximately 28:1. However, the GAG to hydroxyproline ratio within hyaline cartilage of the same group is 2.5:1. This information is important in identifying stem cell conversion to a nucleus pulposus cell phenotype rather than a chondrocyte phenotype for tissue engineering of intervertebral disc.

Tissue engineering of intervertebral discs (IVDs) using mesenchymal stem cells (MSCs) induced to differentiate into a disc-cell phenotype has been considered as an alternative treatment for disc degeneration. Since there is no unique marker for disc tissue, and because cartilage and immature nucleus pulposus (NP) possess similar macromolecules in their extracellular matrix, it is currently difficult to recognize MSC conversion to a disc cell. In this study, we compare the proteoglycan to collagen ratio in the NP of normal disc to that of the hyaline cartilage of the endplate within the same group of individuals.

To distinguish between a normal NP and hyaline cartilage phenotype for tissue engineering of IVDs.

Human lumbar spine specimens were harvested from fresh cadavers, aged twelve week to seventy-nine year. Discs and endplates were examined for total collagen using the hydroxyproline assay and glycosaminoglycan (GAG) content using a standard assay.

In a mature disc with no degeneration (fifteen to twentyfive years), the GAG to hydroxyproline ratio within the NP is approximately 28:1. However, the ratio within the hyaline cartilage endplate of the same group is 2.5:1.

A high proteoglycan to collagen ratio can be used to distinguish NP cells from chondrocytes. The lower NP collagen content is probably responsible for its gelatinous nature rather than the firm texture of hyaline cartilage, and this is essential for normal disc function. This information is crucial in identifying a NP-like phenotype when MSCs are induced to differentiate into a disc cell as opposed to a chondrocyte, for tissue engineering of IVDs.


T. Rajwani R. Bhargava R. Lambert M. Moreau J. Mahood J. Raso K.M. Bagnall

Vertebral growth remains a mystery, especially with regards to the contribution of different growth plates and the mechanisms of growth after closure of these plates. As an example of vertebral growth in general, the growth of the vertebral canal was assessed in a rat model using fluorochromes. Although 80–90% of vertebral canal growth was due to growth plates, the remaining canal growth occurred via periosteal absorption and deposition. This is contrary to the traditional idea that periosteal mechanisms do not change the shape or dimensions of bone and suggests that the vertebrae exhibit a different model of growth than typical bones.

Vertebral growth remains largely a mystery. The contributions of different growth plates and the mechanisms of growth after closure of these plates requires further exploration. As an example of vertebral growth, vertebral canal growth was assessed in a living rat model using fluorochromes.

Vertebral canal growth and presumably vertebral growth in general occurred by different mechanisms at different phases of development. Growth plates accounted for the majority of growth although periosteal mechanisms also resulted in changes in the size and shape of the vertebrae. This is contrary to the traditional concept of periosteal growth and suggests that vertebrae may exhibit a different model of growth than typical bones.

The growth of the vertebrae in a particular dimension and during a particular phase of development is dependent on different mechanisms of growth, which may play a role in interpreting vertebral growth anomalies.

The interspinous junction closed by the end of the first week, whereas the neurocentral junction closed between weeks three and four. By four weeks, the vertebral canal had achieved 80–90% of its growth in area and diameter. After growth plate closure, the canal continued to grow by periosteal mechanisms and was displaced posteriorly.

Thirty-six Sprague-Dawley rats (age one week-seven weeks) were injected with tetracycline and alizarin using a dosing interval of four days. Thoracic vertebrae were sectioned using a cryostat and examined under a fluorescence microscope. In addition to noting fluoro-chrome deposition, the dimensions of the growth plates and canal were noted.

Funding: Edmonton Orthopaedic Research Association and University of Alberta Department of Radiology and Diagnostic Imaging


C.L. Hubley-Kozey W.D. Stanish

Spinal stabilization through appropriate neuromuscular responses to external perturbations is important in the prevention and rehabilitation of low back pain (LBP). Muscle synergism, coordination and imbalances are terms used to describe the neuromuscular strategies considered important to actively maintain spinal stability. We recorded surface electromyographic (EMG) recordings from healthy controls (CON) and those with chronic, mechanical low back pain during performance of an exercise model that dynamically challenged lumbar-pelvic stability. Those with LBP showed greater variation in amplitude in response to the perturbations imposed by the exercise model, and demonstrated a lack of synergistic and antagonistic coactivation compared to the CON group.

The purpose of this study was to compare the neuromuscular control strategies used by those with LBP and those without to complete a standardized task aimed at dynamically challenging stability of the lumbar spine and pelvis.

Those with LBP activated their muscles in a more asynchronous manner than normal controls, illustrating an alteration in neuromuscular control that should be a focus of therapeutic intervention strategies aimed at prevention and rehabilitation of LBP.

These data illustrate a need for neuromuscular retraining, focusing on muscle coactivation in response to dynamic perturbations rather than a single perturbation.

Surface EMG recordings from two trunk extensor and five abdominal muscle sites were recorded from twenty-four men without LBP and fourteen men with chronic LBP while they performed a task that dynamically challenged lumbar spine and pelvis stability. The EMG amplitudes recorded from the upper and lower rectus abdominus sites were significantly (p< 0.05) lower for the LBP compared to the CON group. The temporal EMG profiles were compared using a statistical pattern recognition technique. This analysis showed that the LBP group used different patterns of synergistic muscle coactivity compared to the highly coordinated manner in which all seven muscles were recruited for the CON.

These results quantify the neuromuscular control differences between the two groups providing a foundation for developing an objective classifier of neuromuscular control impairments associated with LBP. In future this approach could assist in directing therapeutic interventions in particular those aimed at muscle reeducation.


S.E. Roth D. Stephen H. Kreder C.M. Whyne

Intramedullary nailed high proximal tibial fractures rely on the proximal screw-bone interface to provide stability, which can be insufficient in low-density bones. This study investigated the biomechanics of proximal screw cement augmentation in intramedullary nailing of high proximal tibial fractures. Mechanical stability in flexion/extension, varus/valgus and torsion was tested on six pairs of cadaveric proximal tibiae, with/without cement augmentation. Cement augmentation significantly increased construct stability in torsion and demonstrated a trend towards improved varus/valgus stabilization. Surprisingly, cement augmentation significantly decreased stability in flexion/extension, suggesting the potential benefits of cement augmentation may be limited in intramedullary nailed high proximal tibial fractures.

This study assessed the biomechanical effects of augmenting proximal screws with cement in intramedullary nailing of high proximal third tibial fractures.

While increased biomechanical stability was seen in torsion and varus/valgus, the reduction in stability in flexion/extension suggests that there may be limited benefit in cement augmentation in the nailing of high proximal tibia fractures.

High proximal tibial fractures fixed with intramedullary nailing rely primarily on proximal screw fixation to provide stability. Cement augmentation of the proximal screws may provide needed increased construct stability in low-density tibiae.

Cement augmentation provided a significant increase in construct stability in torsion (37.5% ± 8.0%, p< 0.05), with a trend toward increased stability in varus/valgus (25.5% ± 36.2%, p=0.08). Conversely, stability in flex-ion/extension was significantly decreased with the use of cement (25.9% ± 13.0%, p< 0.05).

Reamed intramedullary nails (Zimmer, MDN) were implanted into six pairs of elderly cadaveric fresh-frozen proximal tibiae and secured using four proximal screws (two transverse, two oblique, 4.5mm diameter). Bone cement was injected into the screw holes just prior to screw insertion to augment the bone-screw interface in one tibia from each pair. Specimen stability was tested in flexion/extension and varus/valgus loading to 12Nm and in torsion to 7Nm. Displacement data was generated and analyzed using a repeated measures design.

We hypothesized that intramedullary nail-bone construct stability would be increased with cement augmentation, particularly in low-density specimens. While construct stability was improved in torsion and varus/valgus, surprisingly stability consistently decreased in flexion/extension.


M. Volesky E. Harvey R. Reindl P. Guy

Non-unions of pilon fractures are difficult Orthopaedic problems. Significant bone loss and infection can lead to amputation. Joint stiffness in conjunction with disuse osteopenia make stabilization in this area challenging. We present the use of a custom blade plate design that offers sufficient stability for successful treatment in six successive cases. With a mean follow-up of thirty-three months, all fractures treated with this method healed. The five infected cases healed without recurrence of infection. With average scores of 70.7 on the Maryland Foot Score, and sixty-eight on the Foot and Ankle Society Ankle-Hindfoot Scale, the patients overall had satisfactory results.

The purpose of this study was to describe a new technique of treating non-unions of distal tibia pilon fractures using a custom blade plate design. A report of successful outcomes in six consecutive cases.

A retrospective analysis of fifty-six pilon fractures treated over a three- year period revealed six patients with significant complications related to their fractures. Of these, all had significant bone loss and five were infected. All six failures were revised using a custom blade plated design with oblique locking screws for triangular fixation of the distal pilon. The average follow-up period was thirty-three months. These patients were evaluated with the Maryland Foot Score (MFS) and the Foot and Ankle Society Ankle-Hindfoot Scale (AHS).

All of the six patients treated with the proposed method went on to heal without recurrence of infection. Three patients required additional surgical interventions including bone grafting, debridement and hardware removal to achieve the final result. Their average MFS and AHS were 70.7 and sixty-eight respectively.

Stable fixation is an absolute necessity for a successful outcome in the failed pilon fracture. A custom blade plate design with oblique interlocked screws offers sufficient long-term stability, despite infection and disuse osteopenia, for healing of the non-united fracture to occur. As shown by our series, satisfactory clinical results can be expected and amputation can be avoided in complicated cases using this surgical technique.


C.S. Bailey C. Fisher M.F. Dvorak

This study examined the occurrence of type II (Beta) error in the spine surgical literature. A literature search from 1966 until present identified twenty-nine randomized control trials, which had a two-group parallel design and reported a non-significant difference in the primary outcome measure. We determined whether these trials had sufficient sample size to detect a 25% and 50% relative change in the primary outcome. Nine studies specifically identified a primary outcome. Four studies reported a sample size calculation. Therefore, twenty-five trials were at risk of committing a type II error.

The purpose of this study was to determine the frequency of potential type II error in randomized controlled trails reported in the spine surgical literature.

A literature search was conducted of the Medline, Pubmed, and the Cochrane databases using the keywords of “spine” and “surgery”, between 1967 until present to identify randomized controlled trials involving spine surgery. Trials were included in this study if they were of a two-group design, with at least one of the groups being a surgical cohort, and that reported a non-significant difference in the primary outcome. We determined the frequency for which the primary outcome and sample size calculation was reported. The sample size was assessed to determine whether the trial had sufficient subjects to detect a 25% and 50% relative difference in the primary outcome for a power of 80%.

Twenty-nine studies satisfied the inclusion criteria. Nine studies specifically identified a primary outcome. All others reported multiple outcomes with no specified primary measure. Four studies reported a sample size calculation. Of the remaining twenty-five that did not, three had sufficient power and the rest were at significant risk of committing a type II error.

The spine surgical literature is plagued with a high potential for type II errors in the published trails with a non-significant outcome.

In the spine surgical literature, a randomized controlled trial that fails to reject its null hypothesis, requires careful scrutiny of its methodology to prevent misinterpretation of the results.


D.R. Pichora S. Csongvay R.E. Ellis

Previously, we have described a novel, computer assisted technique of osteotomy for distal radius malunion. Laboratory and clinical results demonstrate excellent realignment of the articular fragment, but incomplete correction of the radioulnar convergence and loss of radial bow. This study describes an innovation whereby both the proximal and distal fragments of the malunited radius are manipulated in 3D relative to an external template. Two case studies demonstrate the improve restoration of anatomy with this technique.

The purpose of this study was to develop a method of computer-assisted planning and image guided surgery to restore the normal bow to the malunited radius.

Manipulation of a virtual model of a distal radius malunion can only restore the full anatomical bow to the radius if both the distal and proximal fragments are corrected to match a normal template.

This is a novel method of restoring normal anatomy in which both fragments of a malunited bone are corrected relative to an external normal template.

A previously developed CT-based research software system for conducting computer-assisted distal radius osteotomy allowed three-dimensional manipulation of the distal fragment only, to restore the alignment of the distal articular surface. Results of the first six cases demonstrated that this system did not fully correct the convergence of the radius and ulna with persistent loss of radial bow, although it does provide excellent realignment of the articular fragment. The system was modified to include the ability to manipulate the proximal fragment of the radius. This fragment is rotated and translated to match an external reference template derived from a mirror image CT surface mesh of the opposite forearm. Results of two case studies are evaluated, demonstrating the computer models and post-operative radiographs confirming improved restoration of radial anatomy compared to the previous system.


M. Blankstein M. Nakane A. Bang J. Freedman R. Byrick R. Richards D. Bell E. Schemitsch

This study was undertaken to assess the contribution of pulmonary fat embolism caused by intramedullary femoral canal pressurization to the development of acute lung injury in the presence of resuscitated hemorrhagic shock. Twenty-seven NZW rabbits were randomly assigned into one of four groups: resuscitated hemorrhagic shock and fat embolism, resuscitated hemorrhagic shock, fat embolism, and control. Fat embolism was induced via intramedullary cavity with a 1–1.5 ml bone cement injection. Only the animals that underwent resuscitated shock and fat embolism displayed amplified neutrophil activation and alveolar infiltration. These findings suggest that the combination of resuscitated shock with fat embolism initiates an inflammatory response, which may play a role in the development of fat embolism syndrome.

The objective of this study was to assess the contribution of pulmonary fat embolism caused by intramedullary femoral canal pressurization to the development of acute lung injury in the presence of resuscitated hemorrhagic shock.

Only the animals that underwent resuscitated shock and fat embolism displayed amplified neutrophil activation and alveolar infiltration.

These findings suggest that the combination of resuscitated shock with fat embolism initiates an inflammatory response, which may play a role in the development of fat embolism syndrome.

CD11b mean channel florescence was only significantly elevated in the HR/FE group at two and four hours post knee manipulation. Moreover, greater infiltration of alveoli by leukocytes was only significantly higher in the HR/FE group as compared to controls.

Twenty-seven NZW rabbits were randomly assigned into one of four groups: resuscitated hemorrhagic shock + fat embolism (HR/FE), resuscitated hemorrhagic shock (HR), fat embolism (FE), and control. Hypovolemic shock was induced via carotid bleeding for one-hour prior to resuscitation. For fat embolism induction, the intramedullary cavity was drilled, reamed and pressurized with a 1–1.5 ml bone cement injection. For evaluation of neutrophil activation, blood was stained with antibodies against CD45 and CD11b and analyzed with a flow cytometer. Animals were mechanically ventilated for four hours post surgical closure. Postmortem thoracotomy was performed, and three stratified random blocks of each lung were processed for histological examination.

Our findings suggest that FE by itself does not cause lung injury, as there were no apparent differences between the control and FE animals. Only the HR/FE animals revealed a higher number of infiltrating neutrophils into alveolar spaces and greater neutrophil activation.


K.A. Hildebrand C. Sutherland

We describe the natural history of a rabbit knee model of permanent post-traumatic joint contractures. Twenty-four skeletally mature female NZW rabbits had five-mm-squares of cortical bone removed from both femoral condyles. An extra-articular K-wire immobilized the knee joint in flexion. The K-wire was removed eight weeks later and the rabbits were divided into four groups depending on the remobilization time. The average extension loss for the experimental knees in the zero, eight, sixteen and thirty-two weeks remobilization groups was thirty-eight, thirty-two, twenty-one and twenty degrees, respectively. The motion loss stabilized in the later time intervals suggesting permanent contractures had developed. The contralateral unoperated knees average extension loss was nine degrees.

The purpose of this study was to develop a rabbit knee model of post-traumatic contractures.

A simulated intra-articular fracture plus eight weeks of immobilization leads to a permanent joint contracture even after thirty-two weeks of remobilization.

This animal model of human post-traumatic joint contractures will allow further studies investigating mechanisms underlying the process.

Twenty-four skeletally mature female NZW rabbits had 5 mm squares of cortical bone removed from both femoral condyles. An extra-articular Kirschner wire (K-wire) immobilized the knee in flexion. A second operation was performed eight weeks later to remove the K-wire. The rabbits were divided into four groups. Hind limbs were dissected, preserving the joint capsule. A device allowing six degrees-of-freedom coupled to a material testing system which applied a 0.2 Nm torque measured joint angles. Statistical analysis was performed using ANOVA with a posthoc Student-Newman-Keuls test. Data are presented as mean ± SD.

The loss of extension for the experimental knees in the zero and eight weeks remobilization groups was significantly greater than the values of all contralateral unoperated knees. The loss of extension for the experimental knees in the sixteen and thirty-two weeks remobilization groups was also greater than the contralateral knees, although it was not statistically significant (p = 0.07). With this model, the severity of the contracture decreased with time of remobilization. However, the degree of contracture stabilized between sixteen and thirty-two weeks of remobilization, suggesting that the joints had developed a permanent contracture. This mimics the human scenario of permanent post-traumatic joint contractures.

Funding: has not been received from a commercial party. This work was supported by The Alberta Heritage Foundation for Medical Research.

Please contact author for tables and/or graphs.


G.R. Wohl K.B. Muldrew N.S. Schachar L.E. McGann R.F. Zernicke

Osteochondral allografts (frozen uncontrolled, or cryo-protected with dimethyl sulfoxide) were transplanted into medial femoral condyles of eighteen sheep. Cores from the ipsilateral graft site served as autografts for the contralateral limb. Analysis of graft and host cancellous bone microarchitecture by μCT at three months post transplant demonstrated no significant differences among the treatment groups. Dramatic bone resorption at the graft–host interface, however, occurred in up to 1/3 of condyles from all treatment groups, including fresh autografts suggesting that factors other than donor source or tissue storage played an important role in the bone incorporation of osteochondral grafts.

The purpose of this study was to study the effect of different freezing protocols on periarticular cancellous bone architecture after osteochondral allograft transplantation.

There were no significant differences in graft or host cancellous bone architecture among the groups (autografts, frozen allografts, cryopreserved allografts). Dramatic resorption of graft bone in condyles from all treatment groups suggested that factors other than donor source or tissue storage played important roles during incorporation of osteochondral grafts.

Graft positioning, graft orientation, and recipient bed necrosis may play significant roles during incorporation of osteochondral graft bone.

Osteochondral allografts (10 mm diameter) were transplanted into medial femoral condyles of eighteen skeletally mature Suffolk ewes. Allografts were frozen (–80°C) without cryoprotectant (FROZ) or treated with dimethyl sulfoxide (cryoprotectant) and frozen (–80°C at 1°C · min−1) (CRYO). Osteochondral cores removed from ipsilateral graft sites served as fresh autografts (AUTO) for the contralateral medial femoral condyles. Condyles were harvested at three months and scanned (micro computed tomography –μCT). Three dimensional μCT data of graft and host cancellous bone regions were analyzed for bone volume fraction, trabecular thickness, bone surface–volume ratio, and trabecular anisotropy. No morphological differences were found among treatment groups. Excessive bone resorption of graft and interface precluded analysis of some samples from each group (ALLO — 2/9, CRYO — 3/9, AUTO — 6/18). Dramatic bone loss did not correlate with poor graft orientation, placement, infection, or recipient–bed necrosis, but a combination of these factors may contribute to excessive cancellous bone resorption in osteochondral grafts.

Funding: Medical Research Council of Canada, Canadian Institutes of Health Research, No commercial funding

Please contact author for figures and/or diagrams.


G. Goplen J. Astephen K. Delusio R. Leighton

The purpose of our study was to compare the performance of a new intramedullary reaming device to a contemporary reaming system. The new intramedullary reaming device was the Synthes Reamer/Irrigator/Aspirator reamer (RIA) which differs from contemporary reaming devices in that it has a built-in irrigation and aspiration system to reduce the intramedullary pressures and temperatures associated with reaming. An in-vivo cadaver model was developed to quantify intramedullary pressure, temperature, speed and force of reaming. The results showed significant differences in intramedullary pressures with no significant differences in speed and force of reaming.

The purpose of our study was to compare the performance of a new intramedullary reaming device to a contemporary reaming system.

The Synthes Reamer/Irrigator/Aspirator reamer (RIA) produced significantly lower peak and average intramedullary pressures during reaming with no significant differences in speed and force of reaming.

A reaming system with a built-in irrigation/aspiration could possibly reduce the morbidity and mortality associated with the reaming of long bone fractures. There were significantly lower minimum, maximum and average proximal and distal intramedullary pressures with the RIA reamer. There were no significant differences in force or speed of reaming. No temperature changes were noted with either reaming system.

A cadaveric model was developed to compare the RIA reaming system to a contemporary reaming system. Pressures were measured with pressure transducers inserted proximally and distally. Temperatures were measured with thermocouples inserted adjacent to isthmus. Force of reaming was measured with a load cell distally. Speed was calculated from data collected from a linear voltage displacement transducer. Fifteen, matched pairs of frozen, unpreserved femurs were reamed using both reaming systems and the data collected. Canals were reamed to a diameter two centimeters greater than the templated canal size. Data was collected and analyzed with paired t-tests (p< .05).

Embolic material within the cardiovascular system has been shown to increase morbidity and mortality in susceptible individuals. Embolization is related to increased intramedullary pressures. The RIA reamer, as a result of its built-in irrigation/aspiration capacity, produces lower intramedullary pressures. This may have clinical significance.

Funding: This work was supported by Synthes (West Chester, PA)


M. Bhandari P.J. Devereaux M.F. Swiontkowski P. Tornetta W. Obremskey K.J. Koval S. Sprague E.H. Schemitsch G.H. Guyatt

In a meta-analysis of fourteen trials (N=1901 patients) in patients with displaced hip fractures, we identified significant reductions in the risk of revision surgery with internal fixation compared to arthroplasty. A trend towards increased mortality with arthroplasty was identified.

The purpose of this study was to determine the effect of arthroplasty (hemi-arthroplasty, bipolar arthroplasty and total hip arthroplasty) in comparison to internal fixation for displaced femoral neck fractures on rates of mortality and revision surgery

Arthroplasty for displaced femoral neck fractures, in comparison to internal fixation, significantly reduces the risk of revision surgery at the cost of greater infection rates, blood loss and operative time, and a possible increase in early mortality.

Over 220,000 fractures of hip occur per year in North America representing an annual seven billion dollar cost to the health care system. Current evidence suggests internal fixation may reduce mortality risk at the consequence of increased revision rates. A large trial is needed to resolve this issue.

We searched computerized databases (MEDLINE, COCHRANE and SCISEARCH) for published clinical studies from 1969–2002 and identified additional studies through hand searches of major orthopaedic journals, bibliographies of major orthopaedic texts and personal files. We found a non-significant trend toward an increase in the relative risk of dying with arthroplasty when compared to internal fixation (relative risk=1.27, 95% confidence interval, 0.84–1.92, p = 0.25; homogeneity p= 0.45). Arthroplasty appeared to increase the risk of dying when compared to pin and plate, but not in comparison to internal fixation using screws (relative risk= 1.75 vs 0.86, respectively, p< 0.05). Fourteen trials provided data on revision surgery (n=1901 patients). The relative risk of revision surgery with arthroplasty was 0.23 (95% confidence interval, 0.13–0.42, p = 0.0003, homogeneity p = < 0.01).


J. Astephen K. Deluzio

The pathogenesis of knee osteoarthritis is complex and involves many correlated factors that can be measured with gait analysis. Important biomechanical factors may lie in the interrelationships between variables. This study demonstrated the use of a multidimensional gait data analysis technique that simultaneously considered multiple time varying and constant measures. The gait patterns of normal and knee osteoarthritic subjects were successfully separated with a misclassification error rate of < 6%. One of the most discriminatory features identified an important knee osteoarthritis difference during the loading response phase of the gait cycle.

The objective of this study was to detect biomechanical factors of knee osteoarthritis with a multidimensional gait data analysis technique.

A multidimensional gait data analysis technique detected a very discriminatory feature that described a knee osteoarthritis difference during the loading response phase of the gait cycle.

The combination of variables involved in the loading response feature may be important to the onset and development of knee osteoarthritis.

Discriminatory gait features associated with knee osteoarthritis were identified with a misclassification error rate of < 6%. In a very discriminatory feature, the loading response phase of the gait cycle was completely isolated as important. Body mass index (BMI) was the greatest contributing factor to the loading response feature.

Three-dimensional gait analysis was performed on fifty elderly patients with severe knee osteoarthritis and sixty-three elderly asymptomatic subjects. Three components of knee joint angles, moments and forces were calculated. Body mass index (BMI), radiographic measures and stride characteristics were also measured. A multivariate statistical technique extracted important features from the data and a discrimination procedure defined the optimal separation between the two groups.

The importance of loading response had been hypothesized previously, and this study quantitatively identified a very discriminatory gait pattern difference during loading response. The difference described was multidimensional. Although BMI was the largest contributing factor, there was no univariate difference in BMI between the two groups.

Funding: NSERC


B.J. Sawatzky W.O. Kim I. Denison

The purpose of this study was to investigate the effects of varying tire pressures on rolling resistance of pneumatic wheelchair tires and compare the rolling resistance of pneumatic versus solid wheelchair tires.

Our study demonstrated that, statistically significant increases in rolling resistance occurred at and below 50% of the recommended tire pressures (RTP) for the pneumatic tires tested. Also, solid tires performed worse than pneumatic tires at 25% (RTP).

Shoulder pain among the spinal cord injured wheelchair users is reported between 60–100%. Despite the shoulder problems, it’s not uncommon to see WC users with low or flat tires. To reduce the need for regular inflating of tires, people have switched to the popular solid tire. Unfortunately, based on our results, the use of the popular solid tires may still contribute to repetitive strain disorders in wheelchair users.

Compared to the recommended tire pressures the pneumatic tires showed statistically significant decreases in rolling distance at 25% and 50% RTP. The rolling distances of the two solid tires performed similarly to 25% RTP of the pneumatic tires.

This prospective study measured the differences in rolling resistance of five types of commonly used wheelchair tires (three pneumatic: two solid: under four different tire pressures (100%, 75%, 50% and 25% RTP) using a standardized roll down test ramp and a wheelchair with a 56 kg load. Four samples of rolling distances (five per tire pressure per sample) were measured for each tire type and analyzed (repeated measure ANOVA).


K.J. Deluzio C.S.N. Landry J.J. Chu C.L. Hubley-Kozey J.W Kozey G.E. Caldwell W.D. Stanish

Modern gait analysis offers a unique means to measure the biomechanical response to diseases of the musculoskeletal system during activities of daily living. The objective of this on-going study is to quantify the biomechanical environment of the knee joint in subjects with moderate knee osteoarthritis (OA). We collected 3-D motion, ground reaction force, and electromyographic data from seven normal subjects and five subjects with moderate knee OA. There were no differences in stride characteristics or joint motion patterns between the two groups. In contrast, we found differences in knee joint kinetics between the moderate OA subjects and the normal control subjects.

The objective of this on-going study is to quantify the biomechanical environment of the knee joint in subjects with moderate knee osteoarthritis (OA). Our goal is to identify biomechanical characteristics related to treatment interventions.

The moderate knee OA patients walked with a visibly normal gait as measured by stride characteristics and joint angles. Differences were detected in the joint loading (ie adduction and flexion moments).

The biomechanical differences between normal and osteoarthritic knees will provide the basis upon which to design and evaluate non-invasive treatments for knee OA.

Subjects performed, in random order, five trials of their normal selected speed, and a fast walk (150% of the normal speed). Three-dimensional motion and force data were used to calculate three dimensional joint angles, moments and forces.

There were no differences in stride characteristics (walking speeds, stride lengths, or stride times) between the two groups. The moderate OA patients walked with normal knee joint motion patterns. In contrast, we found differences in knee joint kinetics between the moderate OA subjects and the normal control subjects. The magnitude of the adduction moment during stance was larger for the moderate OA patients at both walking speeds (p< 0.05). We also identified differences in the pattern of the flexion moment, but only at the higher walking speed (p< 0.05).

Gait analysis can provide insight into the mechanical factors of knee osteoarthritis by quantifying the dynamic loading and alignment of the knee during activities of daily living


S.J. MacDonald A. Kirkley S. Griffin J. Ashley C. Griffin

Patients with moderate to severe osteoarthritis of the knee, on a waiting list for total knearthroplasty, were recruited to a double-blind, randomized clinical trial evaluating neoprene knee braces containing high-power static magnets or sham magnets. Patients wore the brace for a minimum of six hours per day and were evaluated at baseline, two, six, twelve and twenty-four weeks. The subjective outcomes (MACTAR, WOMAC, KOOS, SF-36) and functional outcomes (six minute walk, thirty second stair climb) showed no statistically significant differences between the groups at any of the follow-up time periods.

The purpose of this study was to compare the effectiveness of neoprene knee braces containing high-power static magnets to sham magnets in the management of osteoarthritis of the knee

No statistically significant difference in patient-related quality-of-life and objective functional evaluation was found between groups.

This study provides patients and doctors with evidence as to the efficacy of this type of therapy. It will allow those individuals on fixed incomes to utilize their resources to the best advantage to minimize their symptoms related to osteoarthritis of the knee.

A prospective double-blinded randomized clinical trial was conducted. Ninety-five patients with moderate to severe osteoarthritis of the knee were randomized to receive a Magnet (M) or Sham (S) knee brace. Both groups were equal with regards to age (M = 71.1 yrs, S = 66.8yrs), severity of disease, gender and all baseline measures. No statistically significant difference in patient-related quality-of-life and objective functional evaluation was found between groups at any time interval.

All study patients were recruited from a knee arthroplasty waiting list. At baseline and at two, six, twelve and twenty-four weeks each patient completed a WOMAC, MACTAR, KOOS quality-of-life questionnaire, SF–36 global health measure, and six minute walk and thirty second stair climb after which they were asked to determine their general fatigue, pain and shortness of breath on a 100mm VAS scale. Patients were instructed to wear their brace at least six hours per day and when active (walking, shopping, golfing).


K. Latendresse E. Dona P.J. Scougal M. Gillies W. Walsh

Lacerations of the FDP tendon in zone one may be reattached to bone with a modified Bunnell pullout suture or with suture anchors. Eleven cadaveric fingers were submitted to cyclical testing of five hundred cycles with either a modified Bunnell pullout suture of 3-0 polypropylene or a micro-Mitek suture anchor with 3-0 Ethibond. Gap formation was 6.6mm in the modified Bunnell group and 2.0mm in the micro-Mitek group (p< 0.001). Load to failure was 37.6N in the pullout group and 28.5N in the anchor group (p< 0.005). Gap in the pullout group and low failure load in the anchor group are of concern.

Distal zone one FDP tendon lacerations are usually re-attached to bone by a modified Bunnell pullout suture of 3-0 polypropylene. This treatment may lead to moderate to severe losses of DIP joint motion in up to 50% of patients. Suture anchors have recently been introduced as a fixation alternative. Cyclical testing simulating five days of a passive mobilisation protocol was used to compare the Micro-Mitek anchor to the modified-Bunnell pullout suture in FDP tendon fixation.

Eleven cadaveric fingers FDP tendons were repaired to bone using a modified Bunnell pullout suture of 3-0 polypropylene or a micro-Mitek anchor with 3-0 Ethibond. Testing was done from 2N to 15N at 5N/sec, for a total of five hundred cycles. Gap formation at the tendon bone interface was measured. Load-to-failure was performed on all specimens.

No specimens failed during cyclic testing. Gap formation was 6.6mm (SD 1.2, range 4.9–8.2mm) and 2.0mm (SD = 0.4, range 1.7–2.7mm) for the pullout technique and the micro-Mitek anchor repair respectively (p< 0.001). Load to failure data was 37.6N (SD 4.7, range 31.8–45.1N) for the pullout group and 28.5N (SD 4.0, range 21.8–33.4N) for the micro-Mitek group (p< 0.005).

This data suggests that both fixation techniques may be adequate to sustain five days of simulated passive rehabilitation therapy. Significant gap formation in the modified Bunnell pullout group is of concern although this needs to be correlated in the clinical setting. The lower failure rate of the micro-Mitek group may leave a narrow margin of safety for passive rehabilitation.


C.L. Hubley-Kozey J. S. McNutt K.J. Deluzio J.W Kozey J.J. Chu G.E. Caldwell W.D. Stanish

The objective of this study was to determine if abnormal neuromuscular patterns exist in individuals with knee Osteoarthritis compared to those with healthy knees. We collected surface electromyographic signals during preferred speed and fast walk conditions from seven muscles crossing the knee joint. We found differences between the two groups that could lead to differences in joint loading, with the OA group having higher coactivity between hamstrings and quadriceps during initial loading. Further investigating these differences is warranted in particular given the trend for lower external extensor moments for the OA group at the fast walking speed.

The purpose of this study was to compare neuromuscular control of knee joint motion during walking between those with moderate Osteoarthritis (OA) and those with healthy knees (CON).

Moderate OA neuromuscular control patterns differed from those with healthy knees.

Detecting neuromuscular alteration associated with mild to moderate knee OA is important to direct therapeutic strategies aimed to slow down or possibly reverse disease progression.

Surface electromyographic (EMG) recordings were collected from seven muscles crossing the knee joint of CON (n=7) and those with moderate OA (n=4) during preferred speed and a fast-paced walks. A pattern recognition technique was applied to the EMG profiles. No differences (> 0.05) were reported between the two groups for spatial and temporal gait parameters or knee joint kinematics. Statistical differences were found (p< 0.05) in muscle activation patterns between the two groups and the differences were more prominent at the faster walking speed. The two vasti muscles had double peaks during stance and higher amplitudes at heel strike for the OA group. There was higher activity in the two hamstring muscles at heel contact and a burst of activity during late stance for the OA group.

The disproportionately higher knee flexor coactivity at heel strike may reflect a guarded response to pain, whereas the burst during weight transfer may reflect a stabilizing response as the knee moment changes from a flexor to an extensor moment. At normal walking speeds the neuromuscular control patterns were similar between groups, but differences were exaggerated when the system was stressed at higher speed.


P. Zalzal M. Papini D. Petruccelli J. de Beer M. Winemaker

A ligament tensioning device was used during total knee arthroplasty procedures to determine the effective stiffness of the soft tissue envelope around osteoarthritic knees. This information was used to calculate the resting forces on polyethylene components in well balanced knees. Various patient and implant factors were investigated to see if they correlated with the stiffness of the soft tissues around arthritic knees. The effective stiffness of the soft tissues was found to be higher when the posterior cruciate ligament was preserved compared to when it was sacrificed.

The purpose of this study was to determine, in vivo, the effective stiffness of the soft tissue envelope around the knee and to estimate the resting force on the implanted polyethylene component during total knee arthroplasty (TKA). A ligament tensioning device was used to measure displacement between the tibia and the femur versus load during eighty-six consecutive TKA procedures. A maximum of five measurements were made in both flexion and extension. The measurements were taken after bone cuts were made and soft tissue balancing was performed. The effective stiffness of the knee soft tissue envelope was determined in flexion and extension. Post- operative range of motion was measured while the patient was still under anesthetic. There was no significant difference in the average effective stiffness between men and women or between flex-ion and extension. Age did not appear to correlate with effective stiffness. The average effective stiffness was significantly higher in posterior cruciate retaining knees compared to those in which the posterior cruciate was sacrificed. There was no statistical significance between the average resting force on the polyethylene in men versus women, in flexion versus extension, or in posterior cruciate retaining knees versus posterior cruciate sacrificing knees. The immediate post-operative range of motion did not correlate with the resting force on the implanted polyethylene


M. Blankstein M. Nakane A. Bang J. Freedman R. Byrick R. Richards E. Schemitsch

This study was undertaken to assess the contribution of pulmonary fat embolism to systemic platelet activation in a rabbit model of fat embolism. Fifteen NZW rabbits were randomly assigned into one of two groups: fat embolism and control. Fat embolism was induced via intramedullary canal pressurization with a 1–1.5 ml bone cement injection. Only the animals that underwent fat embolism displayed consistent platelet activation, as demonstrated by platelet degranulation and procoagulatory surface expression. These findings suggest that fat embolism plays a role in platelet activation and in the overall activation of hemostasis following trauma.

The objective of this study was to use a recently developed rabbit model of fat embolism to assess the systemic hemostatic response to pulmonary fat embolism.

Our findings demonstrate platelet activation following forced liberation of bone marrow contents into the circulation only in the FE group, as demonstrated by CD62P elevation (a marker of platelet degranulation) and annexin V elevation (a marker of procoagulatory surface expression). Platelet activation also coincided with significantly lower platelet counts in the FE group at two and four hours post embolism, suggesting platelet aggregation.

These findings suggest that fat embolism plays a role in platelet activation and in the overall activation of hemostasis following trauma.

Platelet count decreased significantly at two and four hours post knee manipulation only in the FE group. Annexin V expression increased significantly in the FE group at two and four hours post knee manipulation. Lastly, CD62P expression only increased significantly in the FE group at two hours post knee manipulation

Fifteen New Zealand White male rabbits were randomly assigned into one of two groups: control and fat embolism (FE). In FE group (n=8), the intramedullary cavity was drilled, reamed and pressurized with a 1–1.5 ml bone cement injection. In the control group (n=7), a sham knee incision was made, exposing both femoral condyles, but was immediately closed without further manipulations. All animals were mechanically ventilated for an additional monitoring period of four hours post-surgical closure. For flow cytometric evaluation of platelet activation, blood samples were stained with fluorescence-conjugated antibodies against CD41 (FITC), CD62P (P-selectin) and annexin V (FITC). Platelet events were identified by their characteristic CD41 staining and size and were analyzed using a flow cytometer. All animals were mechanically ventilated for four hours post surgical closure.

The implications of platelet activation following fat embolism are numerous, ranging from adherence and aggregation, to secretion of key components of both the coagulation and inflammatory cascades.


P. Zalzal M. Papini M. Bhandari

A novel, validated three dimensional finite element model of the femur was used to characterize the stress concentration in the bone at the proximal end of a fracture fixation plate. A supracondylar fracture of the distal femur fixed with a plate was modeled utilizing physiologic load patterns simulating several phases of a cycle of gait. The relative maginitude and length of the zone of increased stress was characterized. The effects of varying plate geometry and material in the attempt to decrease stress concentration at the end of the plated were investigated.

The exact nature and distribution of stresses around femoral fracture fixation plates remains unclear making it difficult to determine how close to existing hardware a distal femoral plate can be implanted. Our objective was to use a novel, validated finite element (FE) model to examine the stress distribution at the proximal end of the plate.

The von Mises element stresses in the bone without the implant were compared to those with the implant. Additionally, we determined the effect of metal (titanium versus stainless steel), and plate taper (ten, thirty and forty-five degrees) on stresses at the proximal end of the plate.

The peak von Mises stress in the plated bone occurred below the corners of the plate, and was approximately four times that in the un-plated case (thirty-eight MPa versus nine MPa). We identified a distance of 34 mm (approximately one bone diameter) beyond the edge of the plate before stresses returned to within 1% of the un-plated control. The choice of metal did not affect the state of stress distribution in the bone beyond the proximal edge of the plate. In addition, the stress concentrations decreased proportionally as the taper angle decreased from forty-five to ten.

Utilizing this FE model we report the following:

Stresses are concentrated at the end of plates and return to within normal limits approximately one bone diameter beyond the edge of the plate.

The stress concentrations decrease proportionally as the taper angle decreases.

Titanium plates offer no added advantage in stress reduction at the end of the plate.

Funding: The authors gratefully acknowledge the financial support of Materials and Manufacturing Ontario (MMO) and the Dean’s New Faculty Seed Grant at Ryerson University.


P. Mousavi L. Chin H. Ahn S.E. Roth J. Finkelstein A. Vitkin C. Whyne

In percutaneous vertebroplasty, clinically significant complications occur predominantly in patients with spinal metastases. This higher rate of complication may be associated with increased pressurization that has been reported due to the presence of lytic tissue during vertebroplasty. To date, there has been no research investigating techniques aimed at reducing this pressurization. This study investigated the potential of tumour volume reduction using laser induced thermo therapy ablation within the metastatic spine. This novel technique proved to be capable of efficient tissue shrinkage (average 60%) with little or no pressurization (average 1.3mmHg) and moderate levels of temperature elevation (average increase of 15.1°C).

This study aims to investigate the potential of minimally invasive tumour volume reduction using laser induced thermo therapy ablation within the metastatic spine.

Volume reduction of tumour tissue prior to cement injection may provide a method to reduce pressurization, reduce the likelihood of tumour extravasation and improve cement fill during percutaneous vertebroplasty.

In percutaneous vertebroplasty, clinically significant complications occur predominantly in patients with spinal metastases (10%).

Laser-induced thermo therapy condensed and coagulated the simulated tumour. Volume shrinkage of the tumour tissue averaged 60%. Pressures generated within the vertebral body only rose an average of 1.3mmHg during the procedure. Maximum temperatures on the posterior body wall increased by 15.1°C, with average temperatures 6.8°C above the baseline.

A simulated lytic defect created using breast tissue was introduced into the vertebral body of a calf spine to model a metastatically involved vertebra. A pre-charred surgical fibre coupled to a diode laser delivering 1750J of energy was inserted through an eleven-guage needle into the centre of the tumour using an intrapedicular technique. During treatment, the temperature at the posterior body wall and intravertebral pressure were measured. Following ablation, the volume of the remaining tissue was measured.

The results suggest that this novel technique is capable of reproducible, uniform, and effective tissue destruction with little to no pressurization and moderate levels of temperature elevation. Both pressures and temperatures generated during our study were lower than reported values during percutaneous vertebroplasty and suggest little risk of complications.


T. Rajwani E.M. Huang C. Secretan R. Bhargava R. Lambert M. Moreau J. Mahood J. Raso K.M. Bagnall

This study was designed to examine the components of the MR image of the neurocentral junction (NCJ) and to explore the discrepancy between the age of closure of the NCJ as determined by anatomic and imaging studies. MR images of one hundred and fourteen porcine NCJs were correlated with anatomic and histologic sections. Whereas gross anatomic visualization did not reveal the NCJ site, MRI was sensitive for cartilage detection and accurately determined the age of NCJ closure although it overestimated the extent of closure. Based on this study, MRI characterization of the NCJ appears reliable and the NCJ cartilage does not close until adolescence.

This study examined the composition of the MR image of the neurocentral junction (NCJ) and the discrepancy between the age of closure of the NCJ as determined by anatomic and imaging studies.

MRI was sensitive for cartilage detection and accurately determined the age of NCJ closure (i.e. absence of cartilage on histologic examination).

MRI underestimated the extent of NCJ closure, with NCJs in the process of closure often presenting as completely open on MRI.

MRI and histologic characterization of the NCJ provided better description of closure patterns than anatomic examination.

Disparate NCJ development has been implicated as a potential cause of adolescent idiopathic scoliosis. Whereas autopsy studies have refuted this theory by suggesting that the NCJ closes before adolescence, MRI studies have resurrected this idea by suggesting later closure. MRI-histologic correlation suggests that the NCJ cartilage remains present until adolescence and therefore further exploration of the disparate growth hypothesis is required.

Gross anatomic visualization did not reveal the NCJ site, even after removal of the periosteum. In contrast, the presence or absence of an NCJ image correlated with the presence or absence of cartilage although MRI overestimated the extent of this cartilage.

Vertebrae were grossly examined for any evidence of the NCJ site. Sagittal and transverse MR images of one hundred and fourteen porcine NCJs in various stages of development (thirty-eight open, sixty-four closing, twelve closed) were correlated with anatomic and histologic sections acquired at the same position.

Funding: Edmonton Orthopaedic Research Association and University of Alberta Department of Radiology and Diagnostic Imaging


C.E. Tschirhart A. Nagpurkar C.M. Whyne

Spinal metastatic disease can result in burst fracture and neurologic compromise. This study aims to examine the effects of tumour location, shape and surface texture on burst fracture risk in the metastatic spine using a parametric poroelastic finite element model. Tumours were found to be most hazardous in the posterior region of the vertebral body, whereas the multiple tumour scenarios reduced risk. Tumour shape may affect the mechanism of burst fracture. Serrated and smooth outer tumour surfaces yielded similar trends. These results can be used to improve guidelines for burst fracture risk assessment in patients with spinal metastases.

This study aims to examine the effects of tumour location, shape and surface texture on burst fracture risk in the metastatic spine.

Both tumour location and shape are important factors in assessing the risk of burst fracture in the meta-static spine.

Improving risk prediction may reduce burst fracture in patients with spinal metastases.

Vertebral bulge increased over 30% when the tumour was moved posteriorly. Conversely, for the multi-tumour scenarios, vertebral bulge and axial displacement decreased by 41% and 35% in comparison to a single central tumour. Anterior and lateral movement demonstrated only small effects. Vertebral bulge increased proportionally to mediolateral tumour length and axial displacement increased proportionally to superior-inferior tumour length. Similar trends were seen with smoothed and serrated tumour surfaces.

Using a parametric poroelastic finite element model of a metastaticaly involved T7 spinal motion segment, fourteen single and two multi-tumour scenarios were analyzed, each comprising approximately 24% tumour volume. Ellispoidal tumours were positioned in central, anterior, posterior and lateral locations. Tumour shape was altered by adjusting tumour radii for a centrally located tumour. Tumours were modeled using smoothed and serrated outer surface configurations. Burst fracture risk was assessed by measuring maximum vertebral bulge and axial displacement under load.

Tumours were found to be most hazardous in the posterior region of the vertebral body, whereas the multi-tumour scenarios reduced risk. Modeling of tumour surface texture did not impact shape or location effects. Tumour shape may affect the mechanism of burst fracture.

Funding: This study was supported by the National Science and Engineering Research Council.


K.A. Hildebrand M. Zhang D.A. Hart

The objective of this report was to evaluate myofibroblast numbers in human elbow anterior joint capsules. Joint capsules were obtained from six patients with post-traumatic contractures and from six elbow joints of age-matched organ donors. Frozen sections were labeled with α-smooth muscle actin (α-SMA), a marker of myofibroblasts. Myofibroblasts were identified in both experimental and control tissues. Myofibroblast numbers and percentage of total cells were significantly elevated in the capsules of patients (919 ± 187; 36 ± 0.04%) when compared to organ donor control tissue (485 ± 335; 9 ± 0.04%). Future work will look at the expression of myofibroblast modulators in human elbow joint contractures.

The purpose of this study was to determine whether myofibroblasts are associated with human elbow joint contractures.

Myofibroblast numbers and percentage of myofibroblasts to total cells were significantly increased in anterior elbow joint capsules of patients with post-traumatic contractures.

Methods to alter myofibroblast expression may be strategies to prevent or treat post-traumatic elbow joint contractures.

Joint capsules were obtained from six patients (age 33±13 yrs, preoperative flexion-extension arc range of motion 58°±15°) and from six elbow joints of organ donors free of contractures (age 26±15 yrs). Frozen sections were double labeled using monoclonal antibodies to α-smooth muscle actin (α-SMA) with peroxidase conjugated secondary antibodies, and affinity purified antibodies to laminin with Elexa Fluor 488 conjugated secondary antibodies. The laminin antibodies label components of blood vessels, to differentiate between α-SMA expression associated with blood vessels or myofibroblasts. Endogenous peroxidases were quenched and 10% normal goat serum was used as a blocking agent. DAB/peroxide substrate was added for thirteen minutes. DAPI was applied to label nuclei. Cell nuclei associated with α-SMA and not with laminin were counted as myofibroblasts.

Myofibroblast numbers and percentage of total cells were significantly increased (t-test, p < 0.05) in the joint capsules of the patients when compared to organ donor control tissue. Total cell numbers were not significantly different in the patient and control tissue.

Modulators of α-SMA expression and myofibroblast formation include growth factors and matrix molecule components. Future work will look at the expression of these modulators in human elbow joint contractures.

Funding: Funding has not been received from a commercial party. This work was supported by The Alberta Heritage Foundation for Medical Research.

Please contact author for tables and/or diagrams.


I. Weller H. Kreder E. Wai S. Jaglal J. Schatzker

We compared the mortality of hip fracture patients treated in teaching versus community hospitals in Ontario. Hip fracture patients ≥ 50 yrs were identified from the Canadian Institute for Health Information Hospital Discharge Abstracts Database and linked to the Registered Persons Database for death information. Logistic regression analyses were done to assess the relation between hospital type and both mortality and complications after surgery. Covariates examined include sex, age, Charlson-Deyo index, time to surgery and their interactions. Although patients treated in teaching hospitals have more comorbidities and complications they have lower mortality than those treated in community hospitals.

The purpose of this study was to compare the mortality of hip fracture patients treated in teaching versus urban and rural community hospitals in Ontario.

Although patients treated in teaching hospitals have more comorbidities and complications they have lower mortality than those treated in community hospitals.

This finding will have far-reaching implications for health policy in this province. Hip fracture (ICD-9 code 820) patients ≥ 50 yrs treated in Ontario between 1993 and 1999 were identified from the Canadian Institute for Health Information Hospital Discharge Abstracts Database. These were linked to the Registered Persons Database for death information. Logistic regression analyses were done to assess the relation between hospital type and both mortality and complications after surgery. Covariates examined include sex, age, Charlson-Deyo index, time to surgery and their interactions.

Patients treated in teaching hospitals and rural community hospitals were more likely to have a major complication than those in urban community hospitals, adjusted OR (95% CI) 1.37 (1.29–1.45); 1.28 (1.06–1.55) respectively. Patients in teaching hospitals had more comordities than those in community urban or rural hospitals. Nevertheless, patients treated in teaching hospitals have lower mortality (in hospital, and at three, six and twelve months post-surgery) than those in urban community hospitals, adjusted OR (95% CI) 0.76 (0.60–0.96), 0.90 (0.85–0.96), 0.91 (0.86–0.96), 0.92 (0.88–0.96) respectively. The difference between rural and urban community hospitals was not statistically significant, however there was a trend to higher mortality in rural institutions, adjusted OR (95% CI) 0.79 (0.63–1.00), 1.13 (0.95–1.36), 1.16 (0.98–1.36), 1.13 (0.97–1.32) respectively.


J. Maurer J. Ronsky B. Loitz-Ramage M. Andersen R. Zernicke J. Harder

The relations among tissue quality, socket discomfort, gait characteristics, and socket pressures are not well established for the unilateral below-knee amputee population. These relations were evaluated for six amputees at seventeen regions of interest on the residual limb. Pressure sensors were placed directly on the residual limb. Peak dynamic socket pressures were not directly related to peak joint moments. However, increases in ground reaction forces (GRFs) related to increases in socket pressures.

The relations among tissue quality, socket discomfort, gait characteristics, and socket pressures are not well established for the unilateral below-knee amputee population. The purpose of this study was to evaluate these relations for six amputees. A thorough understanding of pressure distribution between the residual limb and prosthetic socket is critical to socket design and limb health. The subjects ranged in age from thirty to seventy-two years of age. The inclusion criteria were male, unilateral transtibial amputation, ability to ambulate independently, non-diabetic, no debilitating health conditions, non-recent amputee. Tissue sensation and socket discomfort were evaluated at seventeen regions of interest on the residual limb. Tissue sensation was assessed using Semmes-Weinstein monofilaments to test light touch/deep pressure sensation, tuning fork to test vibration sensation, and pinprick to test pain sensation. Socket discomfort was assessed using 10 cm Visual Analogue Scale. Gait characteristics were recorded during walking using a Motion Analysis System. Socket pressure measurements were made using F-socket pressure sensors in conjunction with I-Scan software program. Pressure sensors were placed directly on residual limb. Gait characteristics and socket pressures were compared across three different testing days. The site-specific tissue sensitivity scores did not correlate with the socket discomfort scores. In addition, site-specific discomfort scores did not correlate with peak socket pressures recorded at subject’s normal walking speed. Significant day-to-day pressure differences were found at four of the seventeen areas of interest. Peak dynamic socket pressures were not directly related to peak joint moments. Two subjects demonstrated direct relations between ground reaction forces (GRFs) and socket pressure on the different test days.

Funding: NSERC, Workers’ Compensation Board (Alberta), University of Calgary


K.D. Gordon C.E. Dunning J.A. Johnson G.J.W. King

The influence of the supinator and pronator quadratus (PQ) muscles on distal radioulnar joint stability were evaluated using a joint simulator capable of producing forearm rotation, before and after ulnar head excision. Multiple pronation trials were conducted with incremental loading of the PQ relative to the pronator teres; supination trials were similarly conducted with the supinator and biceps. Incremental supinator muscle loading did not alter forearm kinematics. Increased PQ loading did not affect intact kinematics, but did alter joint motion following ulnar head excision. PQ activation will likely aggravate forearm instability following ulnar head excision; suggesting rehabilitation should incorporate immobilization in supination.

The purpose of this study was to study the effect of pronator quadratus (PQ) and supinator loads on forearm kinematics in both an intact distal radioulnar joint (DRUJ) and following ulnar head excision.

The PQ muscle appears to aggravate instability of the DRUJ following ulnar head excision, while incremental loading of the supinator muscle had no effect.

Patients with DRUJ instability and/or who have undergone surgical removal of the ulnar head should be rehabilitated in supination to limit the influence of the PQ muscle.

Eight cadaveric upper extremities were tested in a custom joint simulator employing motion and load-controlled tendon loading to produce forearm rotation. Pronation was achieved via loading of the pronator teres and PQ muscles. Repeated trials were conducted in which the ratio of the PQ load was increased incrementally relative to the pronator teres load. Supination trials were similarly conducted using the biceps and supinator muscles. Testing was conducted in the intact forearm and following ulnar head excision. An electromagnetic tracking device was used to record motion of the radius and ulna. Kinematic data was analyzed with a planar analysis that measured dorsal palmar displacements and diastasis of the DRUJ.

Greater diastasis and dorsal translation of the radius relative to the ulna were noted under increased PQ loading following ulnar head excision (p< 0.05). Increased supinator load had no effect on kinematics before or after ulnar head excision. This effect is likely due to the location of the two muscles. The effect of PQ muscle loading was only noted in neutral to full pronation. These results suggest that rehabilitation of the forearm following ulnar head excision should be conducted with the forearm in supination to minimize joint instability.

Funding: Natural Sciences and Engineering Research Council of Canada, The Arthritis Society (Canada)


H.J. Kreder I. Weller E. Wai

The purpose of this study was to evaluate mortality following delay to surgery in hip fractures in the province of Ontario. All patients undergoing a surgical procedure for a hip fracture between 1993 and 1999 were identified using administrative databases. For every day that surgery was delayed, the adjusted odds of in-hospital mortality increased by a factor of 1.12 times (95%CI), with similar results at three months and one year. A significant relationship exists between delay to surgery and mortality in elderly hip fracture patients. Every effort should be made to avoid non-medical delays in providing operative treatment for hip fractures.

A significant relationship exists between delay to surgery and mortality in elderly hip fracture patients. Every effort should be made to avoid non-medical delays in providing operative treatment for patients with fractured hips.

This finding will have far reaching implications for the allocation of health resources in the future.

All patients undergoing a surgical procedure for a hip fracture between 1993 and 1999 in the Province of Ontario were identified using administrative databases and the provincial mortality database. Multivariable logistic regression models were used to adjust for age, gender, medical comorbidity, type of hip fracture, and teaching status of the treating hospital.

For every day that surgery was delayed, the adjusted odds of in-hospital mortality increased by a factor of 1.12 times (95% CI). The adjusted odds of in-hospital mortality increased as the delay to surgery lengthened from a factor of 1.2 [95% CI] with a one day delay to a factor of 1.5 [95% CI] for a delay over two days as compared with patients operated within twenty-four hours. Similar relationships were observed at three months and one year. Even when considering only healthy patients, < 70 years old with no comorbid conditions, the relationship between mortality and surgical delay remained significant (p < 0.0001), suggesting that surgical delay was unlikely to be caused by patient factors alone.


J. Golisky E.H. Schemitsch H.J. Kreder C. Borkhoff D. Stephen M. McKee

Fracture of the femoral head usually results from high-energy trauma, particularly motor vehicle accidents. These fractures are often associated with poor functional outcomes. SF-36 and MFA scores were obtained for twenty-five femoral head fractures. The mean SF-36 scores was 57.2 (22.6 to 82) and the mean MFA score was 37.6 (10–72). As expected the scores were negatively correlated (−0.587, p=0.005). The presence of an ipsilateral posterior acetabluar wall fracture negatively affected functional outcome. Fragment excision was associated with a higher functional outcome when compared to internal fixation. Posterior surgical approach resulted in higher scores than patients who underwent an anterior procedure.

Fracture of the femoral head is a rare but severe injury. The purpose of this study is to determine the functional outcome of and prognostic factors associated with femoral head fractures.

Acetabular wall fracture, surgical approach, and method of surgical treatment are prognostic factors of functional outcome as measured by the SF-36 and the MFA.

There is currently no consensus on the management of femoral head fractures and treatment practices have evolved on the basis of a limited series of studies. Functional outcome following femoral head fracture has been evaluated using Epstein’s criteria in several studies, however, only one study has been conducted using a validated outcome measure.

Twenty-five femoral head fractures in twenty-four patients were identified from the trauma and orthopaedic databases of two major trauma centres. The patient with bilateral femoral head fractures was not included in the analysis. After obtaining informed consent, the patients’ medical records were reviewed. Functional outcome was assessed using two validated, patient-based outcome measures, the Short Form (SF)-36 and the Musculoskeletal Functional Assessment instrument (MFA). The average age of the patients was 36.8 (std. dev. 11.1) and the mean length of follow-up was 41.4 months (minimum twelve months). Three factors were identified using non-parametric analysis that significantly affected the functional outcome scores:

The presence of an ipsilateral posterior acetabluar wall fracture negatively affected functional outcome (p=0.08).

Fragment excision resulted in significantly higher scores when compared with the patients treated by internal fixation (p=0.067).

A posterior surgical approach resulted in a better functional outcome than the anterior approach (p=0.013).


T. Vasarhelyi W. Long D. Mayman J. Rudan D. Pichora R. Ellis

A fluoroscopic based computer enhancement system was designed for accurate insertion of guide wires for hip fracture fixation while decreasing fluoroscopy time. A saw bone model was created. The femur was imaged with fluoroscopy and a three-dimensional computer model was created. The femur, fluoroscopy drum, and drill were tracked with an optical tracking device. Guide wire position was planned on the computer model. Using a tracked drill the guide wire was inserted. The number of fluoroscopic images was decreased by 85% and the number of passes required to place the guide wire in acceptable position was decreased by 60% using computer enhanced technique.

A fluoroscopic based computer enhancement system was designed for accurate insertion of guide wires for hip fracture fixation while decreasing fluoroscopy time.

The number of fluoroscopic images and passes required to place the guide wire in acceptable position were decreased using computer enhanced technique. Final guide wire position was not different between the two groups.

Orthopedic surgeons are exposed to radiation from fluoroscopy on a daily basis. This system allowed us to insert guide wires using substantially less fluoroscopy, without compromising accuracy.

An average of 13.5 images were taken for each standard technique trial compared to two images for each computer enhanced trial, representing a reduction in fluoroscopy of 85%. One pass was used for each computer enhanced trial. An average of 2.4 trials was used for standard technique. Average final error was 3.6mm using standard technique and 3.8mm using computer technique.

A saw bone model with a soft tissue sleeve was created. A DRB (dynamic referencing body) was fixed to the femur. The DRB, fluoroscopy drum, and drill were tracked with an optical tracking device. The system created a 3D model from two orthogonal fluoroscopic images. Guide wire position was then planned on the computer model. Using a tracked drill the guide wire was inserted.

Computer enhanced trials were compared to standard techniques in regards to number of fluoroscopic images taken, number of trials to obtain acceptable guide wire position, and accuracy of guide wire placement. Guide wire position was measured on AP and lateral x-rays.

Funding: This project was funded in part through a grant from the Canadian Foundation for Innovation


S. Pirani M. McKee

In five teaching hospitals, seventy-two patients with seventy-three bicondylar tibial plateau fractures were prospectively randomized by envelope to treatment either by AO methods (group A) or ring fixator methods (group B). Outcome measures included clinical and radiographic parameters, & HSS knee scores.

Results: Re-intervention was necessary within six months in ten group A & seven Group B patients. Forty-three procedures were performed (thirty-three Group A-ten Group B) I& D 12- 3: STSG 3-0: Quadricepsplasty 1-0; Manipulation 2–4; Muscle flap 2–0; Above knee amputation 1–0; Revision ORIF 5–1; Revision Rings 0–1; Bone graft 2–1; Bead pouch 3-0; Synovectomy 1-0; Sequestrectomy 1-0.

More patients had more septic and wound complications resulting in more need for re-intervention following ORIF.

Conclusion. For bi-condylar tibial plateau fractures (OTA 41.C) six-month HSS scores are significantly higher after treatment with Ring Fixator methods. Reintervention rates for deep sepsis/wound problems are higher with AO methods. Wound and infection complications occurring after AO treatment are more severe and require multiple procedures for control.

We have conducted a prospective randomized trial to determine the outcomes of treatment by

Open reduction and internal fixation or

Closed reduction and ring fixation for the treatment of bi-condylar tibial plateau fractures (OTA 41.C)

We report our early findings on re-intervention rates for complications.

In five teaching hospitals, seventy-two patients with seventy-three bi-condylar tibial plateau fractures were prospectively randomized by envelope to treatment either by AO methods (group A) or ring fixator methods (group B). Outcome measures included clinical and radiographic parameters, & HSS knee scores. Randomization gave the following demographics

Re-intervention was necessary within six months in ten group A & seven Group B patients. Forty-three procedures were performed (thirty-three Group A-ten Group B) I& D 12- 3: STSG 3-0: Quadricepsplasty 1-0; Manipulation 2-4; Muscle flap 2-0; Above knee amputation 1-0; Revision ORIF 5-1; Revision Rings 0-1; Bone graft 2-1; Bead pouch 3-0; Synovectomy 1-0; Sequestrectomy 1-0.

More patients had more septic and wound complications resulting in more need for re-intervention following ORIF.

For bi-condylar tibial plateau fractures (OTA 41.C) six-month HSS scores are significantly higher after treatment with Ring Fixator methods. Reintervention rates for deep sepsis/wound problems are higher with AO methods. Wound and infection complications occurring after AO treatment are more severe and require multiple procedures for control.

Please contact author for pictures and/or diagrams.


H. Vasan C. Cooke E. Schemitsch L. Wild P. O’Brien M.D. McKee

Bone transport/limb lengthening with circular external fixation has been associated with a prolonged period of time in the frame and a significant major complication rate following frame removal. We examined the results of bone transport in fifty-one limbs using the “monorail” technique and found a dramatically improved lengthening index (24.5 days/cm. – time in frame /cm. of length gained) and an absence of refracture or angulatory deformity following fixator removal. This technique is our treatment of choice for limb lengthening/bone transport.

We sought to determine patient oriented outcome and complication rates following b one transport using an external fixator placed over an intramedullary nail (the “monorail” technique).

Bone transport using the monorail technique is associated with a dramatically improved lengthening index and a lower major complication rate than traditional ring fixator methods. Patient satisfaction with the procedure was high.

Our study confirms the significant advantages of the monorail technique for bone transport/limb lengthening. The time in the fixator is dramatically reduced, and complications associated with earlier techniques such as angulatory deformity or refracture were not seen.

We identified forty-nine patients (fifty-one limbs) who had undergone bone transport using the monorail technique (external fixator placed over an intramedullary nail). There were thirty-five men and fourteen women with a mean age of thirty-five years (range 17–50). Pre-operative diagnoses included post traumatic length discrepancy/bone defect (forty-one), congenital short stature (six) and other (four). All patients had a unilateral fixator placed over an implanted intramedullary nail. Once length correction was achieved, the fixator was removed and the nail “locked”. The mean amount of lengthening was 5.5 cm. (range 2 – 18 cm.). The lengthening index was 24.5 days /cm. (duration of external fixation/cm. bone length gained), with a range from ten to fifty days /cm. There were nineteen complications (thirty-seven percent): nine premature consolidations, four infected pin sites, two hardware failures, two osteomyelitis, one DVT, one nonunion. There were no refractures, angulatory deformities or cases of intramedullary sepsis.


H.J. Kreder D. Stephen M. McKee E. Schemitsch

5207 patients treated for a calcaneous fracture in Ontario between 1993–1999 were identified from population datasets and were reviewed to evaluate regional practice variation and complication rates for operatively and non-operatively managed calcaneous fractures. There was considerable geographic variation in treatment. Individuals in some parts of Ontario were almost eight times more likely to receive operative treatment than others. The majority of calcaneous fractures in Ontario are treated non-operatively, however the large observed practice variation suggests that there is disagreement among treating clinicians. Primary subtalar fusion has a high risk of post-operative infection and should therefore be considered very cautiously.

The purpose of this study was to evaluate regional practice variation and complication rates for operatively and non-operatively managed calcaneous fractures.

The majority of calcaneous fractures in Ontario are treated non-operatively, however the large observed practice variation suggests that there is disagreement among treating clinicians. Primary subtalar fusion has a high risk of post-operative infection and should therefore be considered very cautiously.

Given the observed regional variation in management of calcaneous fractures more work needs to be done to address this issue.

5207 fractures of the calcaneous in Ontario between 1993–1999were identified from population datasets. Regional variations in treatment and complication rates were computed. Multiple linear regression was used to identify factors associated with complications.

There was considerable geographic variation in treatment. Individuals in some parts of Ontario were almost eight times more likely to receive operative treatment than others. General surgeons or general practitioners definitively treated 30% of patients (almost all closed). Overall rate of complications was low, however there was a 13.4 percent infection rate following immediate subtalar fusion. Infection was 5.3% following ORIF and 0.6% following closed treatment. Infection risk was increased in multiple trauma patients and those with open fractures. Subsequent subtalar fusion rates (within the study period) were higher in multiple trauma patients, but were not associated with treatment (open or closed). Amputation was 22.5 times more likely following open calcaneous fractures but the overall amputation rate was only 0.17%. No relationship between surgeon experience and the rate of complications following operative treatment was identified.


K.G. Vince R. Berkowitz S.R. Kantor

To reduce the reported 1% mortality rate in the first month because of embolism and cardiopulmonary complications, intraoperative Swan Ganz catheter monitoring has become routine at our institution for patients undergoing bilateral total knee arthroplasties. By calculating the pulmonary vascular resistance, patients at risk for fat embolism syndrome can be identified after the first of single-stage, sequential bilateral total knee arthroplasties prior to proceeding to the second arthroplasty. This study evaluates the reliability of quantitative parameters for canceling the second side.

The purpose of this study was to evaluate the reliability of quantitative criteria for proceeding with the second side of single-stage, sequential bilateral total knee arthroplasties.

Our experience did enable this procedure to be performed in a consistently safe manner. Bilateral total knee replacements have a reported 1% mortality rate in the first month largely because of embolism and cardiopulmonary complications. Adhering to a monitoring protocol that allows this risk to be minimized enables surgeons to offer this treatment to the many patients with bilateral gonarthrosis.

One hundred and sixty-three consecutive patients who had one-stage, sequential, bilateral total knee arthroplasties were monitored prospectively with a pulmonary artery Swan Ganz catheter. The pulmonary vascular resistance was calculated before skin incision, ten minutes after deflation of the tourniquet following completion of the first arthroplasty, and again after the second knee replacement. The second knee replacement was cancelled in seventeen patients because the pulmonary vascular resistance after the first arthroplasty had either doubled from baseline, or was above 200 dyne/second/cm5. Of those who had their bilateral arthroplasties performed, 2% developed signs of fat embolism syndrome, while in the group in whom the second side was cancelled, a 6% incidence was observed. The mortality rate for the entire cohort was 0%. Intraoperative monitoring with a pulmonary artery catheter reliably indicates which patients are at increased risk for pulmonary vascular compromise after one total knee replacement and therefore are not eligible for a second total knee replacement at the same operation.


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D.A. Bednar J. Salem

Retrograde nailing of femoral shaft fractures has been a routine trauma practice option for approximately five years and may be technically advantaged in many situations. Earlier review of our antegrade experience revealed that 30% of standard nails are recognized to frequently cause pain (30%) and/or heterotopic ossification at the hip; knee pain of unclear etiology was found frequently as well (13%). This review of our preliminary experience with retrograde nails found a 30% frequency of nonspecific knee pain complaints at a mean of thirty-four months. No ectopic ossification was seen and no nails had been removed.

The purpose of this study was to review the experience of patients who have undergone retrograde femoral nailing with regard to possible knee pain complaints.

Chart and imaging records were reviewed retrospectively. Patients were contacted and interviewed by telephone to determine late pain complaints.

From January 2000 through February 2002, eighteen patients were treated for twenty-two femoral shaft fractures. The group included ten males and and eight females of mean age 54.5 years (range, nineteen to ninety years). Treatment was with Synthes retrograde femoral nails, reamed and statically locked, inserted under fluoroscopic control on a radiolucent table using a Tenet™ leg holder. At thirty-four months, all fractures had healed primarily with no appreciable malalignment, no infections and no nonunions. No intraarticular free bodies or ectopic ossification were seen. Eleven patients were asymptomatic with regard to the index injured extremity. Five had mild to moderate pain, generally localized anteriorly, without associated articular symptoms and not requiring any analgesia. Two had severe symptoms of diffuse knee pain with radiographic degenerative changes noted, but these were cases with associated complex tibial plateau fractures to account for it. Even eliminating these two patients, fully five of sixteen patients (30%) without associated periarticular trauma at the knee had mild to moderate nondisabling anterior knee pain complaints after retrograde femoral nailing.

The frequency of anterior knee pain complaints after retrograde femoral nailing is significant.

Previous authors have found knee pain complaints in 27–29% of cases. We found no evidence of articular derangement in our patients undergoing retrograde femoral nailing in the absence of associated periarticular trauma at the knee, we confirm a 30% frequency of nonspecific knee pain complaints persisting at almost three years after injury.

Patients should be made aware that, at intermediate-term follow-up, mild to moderate knee pain may be a result of this fracture treatment.


R. Jenkinson D. Sanders M. MacLeod A. Domonkos

This study is designed to evaluate intra-operative stress testing on detection of syndesmosis injuries. We evaluated forty patients with ankle fractures requiring surgery. Their ankles were subjected to stress examinations after each stage of fixation. These were compared to the contralateral side. Biomechanical criteria were used to predict need for syndesmosis fixation. In 42% of the fractures, intra-operative fluoroscopy found an unpredicted syndesmosis injury. In 8% the syndesmosis was intact despite prediction. Medial malleolar fixation was not adequate for syndesmosis fixation as shown by stress testing. These findings may have implications for future diagnosis and treatment of syndesmosis injuries.

This study is designed to evaluate the utility of intra-operative fluoroscopic stress testing in diagnosing tibio-fibular syndesmotic injuries.

Forty skeletally mature patients with unilateral external rotation ankle fractures requiring open reduction and internal fixation were prospectively recruited. Intra-operatively the injured ankle was examined fluoroscopically using external rotation, valgus and anterior drawer stress tests, as well as static antero-posterior, mortise, and lateral ankle views. Stress testing was performed using a standardized force of 37.5 N. Stress testing was done after each stage of fixation (lateral, medial, and syndesmotic). The uninjured contralateral limb was examined as a control, and a 1 mm side to side difference was defined as a positive stress examination.

Intra-operative fluoroscopy detected unpredicted syndesmotic injuries in 42 % of ankle injuries. In all cases, fixation of the medial malleolus did not restore syndesmotic stability. In 8 % of ankle injuries, a syndesmotic injury was predicted but stress testing revealed the syndesmosis intact.

Intra-operative fluoroscopy is a more sensitive modality for detection of otherwise unpredicted syndesmotic injuries compared to criteria based upon static radiographs. Medial malleolar fixation did not add stability to syndesmotic injuries in this study.

Injuries involving the distal tibio-fibular syndesmosis are difficult to detect. Previously, the decision to stabilize the syndesmosis in ankle fractures was based upon biomechanical criteria and static radiography. This and other recent studies challenge this, suggesting fluoroscopic stress testing is a better diagnostic method for these poorly tolerated injuries.

Funding: Synthes Canada, Smith Nephew Richards Inc.


P. Morin R. Reindl T. Steffen E. Harvey P. Guy

In our cadaver study plating the fibula in addition to nailing the tibia decreased the mean rotation across the tibial osteotomy site compared to nailing the tibia alone. Although this is statistically significant (p=0.0034) it may not be clinically relevant as the mean values for ROM were 19.10 and 17.96 degrees respectively. Plating the fibula resulted in no statistically significant difference in the mean vertical displacement, angulation or neutral zone.

Therefore, we may conclude that plating the fibula in a combined distal third tibia and fibula fracture does not enhance the stability of tibial IM nailing.

The purpose of this study was to determine if combined distal third tibia and fibula fractures are more stable when fibular fixation is added to the standard tibial IM rodding.

In combined distal third tibia and fibula fractures, plating the fibula does not enhance stability of intramedullary tibial nailing.

No additional incision or soft tissue stripping is required for plating of the fractured fibula.

The average range of motion in rotation was 19.1° for tibial and fibular fixation combined, and 18.0 ° for tibial fixation alone with a difference of 1.1°, which was clinically significant ( p=0.0034). The mean differences in vertical displacement, angulation, and neutral zone were not statistically significant.

Five matched pairs of embalmed cadaveric lower limbs were dissected and stripped of soft tissue. Each tibia received a 9mm solid titanium nail that was locked proximally and distally. Fibular fixation consisted of a seven- hole LCDCP. A 1.5 cm section of tibia and a 1.0 cm section of fibula were removed. Testing was accomplished with an MTS machine. Vertical displacement was tested with an axial load to 500 N, rotation was tested with an internal and external torque of 5 Nm, and angulation was calculated from the vertical displacement data. All displacement data was measured across the osteotomy site.

The mean range of motion in rotation was the only statistically significant finding. However, considering the average range of motion with and without fibular plating of 17.96° and 19.10° respectively, this finding is likely not clinically relevant.

Funding: Tibial nails, bolts, fibular plates and screws provided by Synthes (Paoli, PA, USA)


N.V. Greidanus D.S. Garbuz D. Wilson G. McAlinden B.A. Masri C.P. Duncan

The prospective evaluation of two hundred and seven symptomatic total knee arthroplasties presenting for revision total knee arthroplasty is reported. On univariate analysis patients who had infection differed significantly (p< .001) from those without infection with regards to: elevated ESR, CRP, positive aspiration, and history of; revision procedure less than two years since last surgery, early wound problems, ongoing pain since index procedure, and discharging wound. On multivariate analysis elevated ESR or CRP, positive aspiration, pain since index procedure and early wound complications were significant predictors of infection (p< .05). These variables were then used to formulate an evidence-based multivariate predictive algorithm to assist the clinician in decision making prior to surgery.

Differentiating septic from aseptic failure of total knee arthroplasty on the basis of clinical features and diagnostic tests can be troublesome for the clinician. The purpose of this paper is to describe significant differences between cases of septic and aseptic failure of total knee arthroplasty. The incorporation of these variables into a practical multivariate clinical prediction algorithm can provide assistance in establishing the diagnosis of infection prior to revision knee arthroplasty.

A simple clinical prediction algorithm can assist in the diagnosis of infection in patients with painful total knee arthroplasty. Patients with five of five criteria have a 99% probability of infection whereas patients with zero of five criteria have a 1% probability of infection.

This is the first multivariate evidence-based clinical prediction algorithm presented for use in decision making prior to revision total knee arthroplasty. The surgeon can use the information derived from clinical and laboratory assessment to compute an approximate pre-operative probability of infection prior to surgery (see table).

On multivariate analysis elevated ESR or CRP, positive aspiration, pain since index procedure and early wound complications were significant predictors of infection (p< .05). These variables were then used to formulate an evidence-based multivariate predictive algorithm to assist in clinical decision making.

Prospective data was collected on two hundred and seven symptomatic knee arthroplasties presenting for revision arthroplasty. A multivariate logistic regression model was used to determine the probability of infection using five significant variables. Combinations of these five variables can provide the clinician with an estimate of the probability of infection prior to revision knee arthroplasty.

Please contact author for tables and/or charts.


S.E. Gowans A. Silaj A. Chu M.A. Neary L. Corrigan E. MacLean N. Mahomed

This study examined the effect of seven vs. five day physiotherapy on hospital LOS for total joint replacement (TJR) patients. 1055 consecutive TJR patients were studied. Seven day PT significantly reduced LOS for TJR patients (0.73 days) and the subgroup of total hip replacement patients (0.80 days). Decreases in TJR LOS reduced hospital costs by $100,000. Older patients and patients with greater co-morbidities had a longer LOS with both five and seven day PT, but their LOS was less with seven day PT. This study provides strong evidence for providing seven day PT for TJR patients.

The purpose of this study was to determine the effect of five vs. seven day/week physiotherapy (PT) on acute care, length of stay (LOS) for TJR patients.

The inpatient discharge abstract database was used to retrospectively identify TJR patients who were admitted on January 1, 2000 or later and discharged by March 31, 2002 or earlier. Patients were excluded if they died in hospital or were discharged to another acute care facility. PT was enhanced from five to seven days/week on March 10, 2001. This date was used to divide patients into PRE and POST (enhanced PT) groups. Differences in LOS (PRE vs. POST) were analyzed for all TJR, and separately for THR (total hip replacement) and TKR (total knee replacement) patients, using t-tests. Potential interactions between group (PRE, POST) and age (young < 70 yrs, old ≥ 70 yrs), gender, and co-morbidity were analyzed with two-way ANOVA’s (group x other variable). LOS acute care savings were calculated using the unit-specific per diem cost.

1055 patients were studied. LOS was significantly reduced for TJR (0.73 days) and THR (0.80 days) patients. TJR decreases in LOS reduced acute care costs by $100,000. Age and co-morbidity had significant main effects but no interaction on LOS.

LOS and hospital costs were reduced for TJR patients with seven day PT. The fact that a decrease in LOS was seen in a large sample, in both young and old patients and patients with and without comorbidities, provides strong evidence to support seven day PT for TJR patients.


S.H. Freter M. Dunbar M. Morrison H. MacLeod

Perioperative delirium (POD) is not uncommon in orthopaedics. We prospectively followed one hundred and thirty-two arthroplasty patients and thirty hip fracture patients using POD as the outcome. Patient interviews, chart reviews and application of the Mini Mental Status Exam (MMSE) were used to identify risk factors for POD. Having two or more risk factors or low scores on the MMSE was predictive of POD. Development of POD significantly increased patient length of stay. It may be possible to identify “at risk” patients for POD and intervene preoperatively so as to improve outcomes.

The purpose of this study was to identify risk factors for delirium in arthroplasty and hip fracture patients among routinely collected data.

Risk factors for perioperative delirium (POD) in arthroplasty and hip fracture patients can be identified. In elderly hip fracture patients, cognitive impairment as measured by preoperative performance on the Mini Mental Status Exam (MMSE), appears to have a strong association with development of POD.

As delirium is associated with adverse outcomes, it may be possible to target interventions to reduce the incidence of POD in patients who are at greatest risk, and potentially improve outcomes.

The incidence of POD was lower in elective orthopaedic patients (13.6%) than in fracture patients (40%). Among elective arthroplasty patients, having two or more risk factors was associated with an eight-time increase in the incidence of delirium and increased length of stay (9.5 days versus six days). Length of stay was considerably higher in hip fracture patients with two or more risk factors (18.9 days vs. 9.9). A low score on the MMSE was the best predictor of developing POD in hip fracture patients.

We recorded age, sensory impairment, functional status, history of previous POD, and use of alcohol or benzodiazepines, in one hundred and thirty-two hip or knee arthroplasty patients, and thirty elderly patients awaiting surgery for hip fracture. All patients completed the MMSE preoperatively.

Delirium was documented prospectively by the Confusion Assessment Method.

POD has an adverse effect on outcomes and is not uncommon in orthopaedics. Risk factors have been identified that could be used for preoperative screening and intervention.


T. Yousif M. Dunbar A. Hennigar D. Amirault

A retrospective chart review of three hundred and eighty-seven PFC© and PFC Sigma© total knee replacements performed by a single surgeon over a seven-year period was completed. During that time, there were fourteen revisions for polyethylene failure. Survival analysis indicates a failure rate of 8%. Previous reports in the literature of the survivorship of the original PFC design demonstrated a five percent failure rate over a ten-year period. Gamma sterilization in air of the PFC polyethylene and the locking mechanism of the articular surface have been implicated in premature wear and failure of this prosthesis.

The purpose of this study was to determine the revision rate due to polyethylene failure for a cohort of PFC© and PFC Sigma© total knee prostheses implanted by a single surgeon.

The early to mid-term revision rate (8%) of the PFC© and PFC Sigma© polyethylene component appears to be abnormally high. The early failure of this tibial articulating component may be related to faulty polyethylene inserts and/or failure of the locking mechanism. Attention to preparation of the polyethylene and locking mechanism of the tibial insert may need to be addressed.

Three hundred and eighty-seven total knees were performed in a cohort of three hundred and twenty-two patients (64% female; mean age = 70 ± 9 years; mean BMI = 31 ± 6). Mean follow-up was forty-one months (± 23). The revision rate at seven years was 8%. At time of revision most prostheses were solidly fixed with no overt signs of loosening of the tibial component. However, there was movement of the polyethylene in the tibial tray in both the mediolateral and AP direction with obvious surface and backside wear. Marked synovitis with evidence of osteolysis, particularly on the femoral side, was also noted. Bone graft was required in almost all cases.

A retrospective chart review was conducted for PFC© and PFC Sigma© total knee systems implanted by a single surgeon between 1995 and 2002. Collected data included patient demographics, age, gender, body mass index, and reason for surgery. The amount of synovitis and osteolysis was documented during revision surgery.

During the routine follow-up of this cohort, patients were identified with marked synovitis and increasing pain in the knee even though there was no gross mal-alignment of the tibial or femoral component.


M. Dunbar A. Al-Hibshi G. Reardon D. Amirault

The demand for knee arthroplasty (TKR) is increasing yet there are no established criteria for prioritizing patients. We investigated surgeon inter-observer reliability and factors that influenced their prioritization of patients by having three surgeons each independently consult on twelve randomly selected patients waiting for TKR. Surgeons had high reliability and were most influence by the patient’s pain and gait pattern when assigning priority. Surgeon assigned priority also correlated with common subjective outcome metrics. Formalized gait assessment may allow for more objective prioritization of patients waiting for TKR.

The purpose of this study was to investigate the inter-observer reliability of surgeons assessing the priority of patients waiting for elective total knee arthroplasty (TKR) surgery, and to assess the discriminative methodology surgeons employ when assessing patients.

Surgeon’s can reliably assign a priority to their patients waiting for TKR. Surgeons generally consider the patients pain and gait pattern when assigning priority.

Wait lists for elective TKR are increasing and the demand will continue to grow. Objective criteria for prioritizing patients would allow for rational delivery of limited surgical resources.

Surgeons have high inter-observer reliability when assigning patient priority (ICC = 0.86). Pain and gait pattern have a significant impact on the surgeon’s assessment of priority (p=0.25 and p< 0.001, respectively). The oxford twelve most closely correlated to the surgeon’s prioritization (r=0.80).

Twelve patients waiting for TKR were randomly selected from three surgeons wait lists. Each surgeon independently examined all twelve patients and recorded their assessment of the patient’s acuity (priority) on a visual analogue scale. The impact of various aspects of the patient’s presentation on the surgeon’s assessment, such as pain control, function, gait, joint contracture and radiographic appearance, were recorded. All patients completed the SF-36, Oxford twelve and WOMAC questionnaires. Linear regression and Intra-Class Correlation Coefficients were used to assess the data.

Through the complex patient-surgeon interaction during a standard consultation, surgeons are able to prioritize their patient’s with high reliability. Improved objective metrics for prioritizing patient’s may be possible by more formalized methods of gait assessment.


J. de Beer D. Petruccelli R. Gandhi M. Winemaker

A retrospective review was conducted to evaluate short-term (one year) outcomes of primary total knee arthroplasty (TKA) patients receiving Ontario Worker’s Safety and Insurance Board Benefits (WSIB) compared to a matched cohort of non-WSIB patients. Postoperatively, WSIB patients had higher pain scores, poorer self-perceived functional outcomes and lower flexion range. WSIB patients required more postoperative clinic visits and were more reluctant to answer questions regarding functional outcome. All differences were statistically significant. The short-term outcomes of primary TKA in patients receiving WSIB benefits are inferior to those obtained by non-WSIB patients.

Retrospective review to evaluate short-term outcomes of primary TKA patients receiving WSIB as compared to non-WSIB patients.

Short-term outcomes of primary TKA in WSIB patients are inferior both subjectively and objectively to non-WSIB patients. WSIB patients are seen more frequently for postoperative follow-up which we would attribute to the persistence of subjective complaints following primary TKA.

Short-term outcomes of primary TKA in WSIB patients are inferior to those obtained by non-WSIB patients. WSIB patients undergoing primary TKA require more postoperative visits with a greater prevalence of subjective postoperative complaints.

Thirty-eight WSIB patients who underwent primary TKA were matched to thirty-eight non-WSIB patients. There were no statistical differences in preoperative Knee Society (KSS) and Oxford Score. Six-week total KSS (p=0.011), pain as measured by KSS (p=0.015), and flexion (p=0.012) were significantly different between the groups. At six-months similar results were noted among KSS function (p=0.027) and pain (p=0.024), Oxford Score (p=0.027), and flexion (p=0.035). One-year Oxford Score (p=.011) and flexion (p=0.013) were statistically significant, as were the McGrory Modified Knee Score (p=0.001), patient expectations (p=0.030), perceived quality of life (p=0.009), and number of postoperative clinic visits (p=0.024).

Retrospective review on successive WSIB patients undergoing primary TKA, at a single arthroplasty centre, matched to a cohort of non-WSIB patients for demographics and preoperative diagnosis. Outcomes included Knee Society, Oxford Knee, and McGrory et al Modified Knee scores, patient satisfaction, and number of postoperative clinic visits. Unpaired t-tests were used to determine differences in outcomes.

There are few reports but many allusions regarding inferior outcomes of TKA in WSIB patients. Our study provides further evidence to support this view. Multiple factors may account for this variance, including psychosocial factors. Further prospective studies are needed to address this burgeoning issue.


C.H. Rorabeck D.D.R. Naudie J. Guerin D.A. Parker R.B. Bourne

This study reports the survivorship free of revision or radiographic loosening of one hundred and eight consecutive cemented Miller-Galante unicompartmental knee arthroplasties at a mean ten-year follow-up.

The purpose of this study was to report our experience with the Miller-Galante (MG) unicompartmental knee arthroplasty (UKA) at a mean ten-year follow-up in order to determine if this procedure can provide durable long-term clinical results.

One hundred and eight cemented MG-UKAs in eighty-two patients performed by two surgeons between 1988 and 1997 were reviewed. There were one hundred and six medial and two lateral MG-UKAs performed. Mean age at surgery was sixty-seven years (range, thirty-nine to eighty-seven). There were forty-four males and thirty-eight females. Mean follow-up was ten years (range, five to thirteen). A Kaplan-Meier survivorship analysis using an end-point of revision surgery or radiographic loosening was employed to determine probability of survival at five and ten years.

Of the eighty-two patients (one hundred and eight knees), nine patients (eleven knees) died and one patient (two knees) was lost to follow-up. Eleven patients (eleven knees) were revised at a mean of four years (range, one to nine), and one patient demonstrated radiographic loosening of the tibial component at seven years. Of the eleven revisions, only two required use of revision components. Mean pre-operative and final follow-up Knee Society clinical and functional scores were forty-seven and fifty-three, and ninety and seventy-nine points, respectively. Kaplan-Meier survivorship analysis revealed a probability of survival free of revision or radiographic loosening of 93% at five years and 88% at ten years.

The results of this study demonstrate that the MG-UKA can provide reliable pain relief and restoration of function in selected patients. Our experience has shown that the survivorship of the MG-UKA approaches that of tricompartmental knee arthroplasty, and suggests that UKA may offer the advantage of ease of revision.


M. Kassab P. Zalzal G.M.S. Azores A. Pressman B. Liberman A.E. Gross

We reviewed and discussed the results of thirteen distal femoral allografts in conjunction with revision total knee arthroplasty for the treatment of periprosthetic femoral supracondylar fractures associated with poor bone stock. The mean follow up time was six years. We looked at graft survivorship, functional outcome, radiographic assessment, and complications. We concluded that this is a viable salvage procedure for this type of injury.

The incidence of periprosthetic supracondylar fractures of the femur is rising due to the aging population, and the increased number of total knee arthroplasties (TKA) being performed. One option for the treatment of severe fractures, associated with poor bone stock, is the use of a distal femoral allograft (DFA) in conjunction with revision TKA. The purpose of this study was to review and discuss the results of thirteen consecutive patients who were treated at our center between 1990 and 2001.

Data was obtained from a prospective database. Ten of the thirteen patients were available for follow up. The average age was sixty-five years (range twenty-four to ninety-three) and the mean length of follow up was six years (range one to twelve). A chart review was performed to identify complications and graft survivorship. Functional assessment was made on the basis of the modified Hospital for Special Surgery knee score (HSS) and the MOS 36-ITEM Short Form Health Survey (SF-36). Patients were evaluated radiographically by two independent observers (kappa = 0.75, P = 0.02) in an attempt to determine union between the graft and host bone, graft resorption, and component loosening. The average postoperative HSS score and SF-36 were seventy-five and eighty-eight respectively. Mean flexion was 100°. One had an amputation due to the recurrence of infection. X-rays showed no migration, no loosening, good interface union in nine cases and mild to moderate resorption in three cases. We concluded that this is a viable salvage procedure for this type of injury.


D. Sahajpal D. Drosdowech J. Macdermid S. Patterson K. Faber

This study prospectively evaluated the functional outcome and strength of patients after rotator cuff surgery. Thirty-three patients were evaluated pre-operatively and post-operatively for one year. Each patient underwent clinical evaluation of shoulder range of motion and machine strength testing. Additionally they completed the SF-36, DASH, Western Ontario Rotator Cuff, and Washington Simple Shoulder Test questionnaires. The study showed that patients with small and large tears showed improvement after surgery. Smaller tears had better outcomes. Workplace Safety and Insurance Board (WSIB) patients had lower functional outcomes despite strength and range of motion showing no difference with non- WSIB patients.

This study prospectively evaluated strength and functional outcome after rotator cuff surgery.

Thirty-three patients, mean age 55.6, were evaluated pre-operatively and post-operatively for one year. Twenty-eight patients were male and five were female. Seventeen patients involved the Workplace Safety and Insurance Board and sixteen patients had non-WSIB related tears. The patients were also divided based on tear size into two groups (< 3cm and > 3.1cm). Allpatients underwent an acromioplasty. Twenty-two also had an open or mini-open repair. Two underwent arthroscopic repair. Five patients had a debridement and four patients had Latissimus Dorsi Transfer. All had an evaluation of range of motion(ROM), machine isometric strength testing, and completion of the SF-36, DASH, Western Ontario Rotator Cuff (WORC) and Washington Simple Shoulder Test (WST) at each visit.

Based on tear size, there was a significant difference in functional outcome on the SF-36 (p< 0.05), DASH (p< 0. 005), WORC (p< 0.001) and WST (p< 0.01). Within each group there was significant improvement in strength (p< 0.01) over time. The smaller tear group showed significantly greater strength. The ROM was improved within each group over time (p< 0.01), though no statistical difference was determined between groups. In comparing the sample based on WSIB status, functional outcomes were better in Non-WSIB patients (p< 0.01). Although no statistical difference in strength and ROM was noted.

Patients with both small and large tears showed improved functional outcome, strength and ROM over time, with the smaller tear group having better outcomes. WSIB patients had lower functional outcomes despite strength and ROM showing no difference between the two groups.


J.C. MacDermid D. Drosdowech K.J. Faber

Forty-nine patients with a repair of their rotator cuff were evaluated at baseline and at six-months after surgery using four self-reports scales (DASH, Western Ontario Rotator Cuff (WORC,) SF-36 and Washington Simple Shoulder (SST) scales. Standardized response means were used to determine responsiveness. The DASH was most responsive (SRM=1.27), the WORC (SRM=1.0) and SST (0.91) were intermediary and the least response was the SF-36 (0.73). These results suggest that the DASH may be preferable to either a disease specific scale or a shoulder scale for detecting clinical progress following cuff repair.

A number of self-report scales exist for shoulder problems, including regional, joint-specific and disease specific scales. Determining the most responsive scale is essential for outcome evaluation and clinical trials.

Forty-nine patients with a repair of their rotator cuff were evaluated at baseline and at six-months after surgery using four self-reports scales (DASH, Western Ontario Rotator Cuff (WORC,) SF-36 and Washington Simple Shoulder (SST) scales. An independent research assistant administered scales. Standardized response means were used to determine responsiveness.

The DASH was most responsive (SRM=1.27), the WORC (SRM=1.0) and SST (0.91) were intermediary and the least response was the SF-36 (0.73). The subscale of the WORC that showed the most change was lifestyle. Physical subscales of the SF-36 showed improvement; whereas, minimal impact on mental health was observed.

The DASH can be used for a variety of upper extremity conditions, whereas the WORC was designed specifically for rotator cuff disease. Unless a disease specific scale is more responsive, there is little reason to adopt a scale than can only be used for one condition. This data supports the ability of the DASH to indicate upper extremity function and the important role of the rotator cuff in function.

The implications of these findings are that the DASH may be preferable to either a disease specific scale for rotator cuff disease or a shoulder scale for detecting clinical progress.


P. Duffy D. P. Petrie R. K. Leighton K. Collier

One hundred and ninety patients requiring total knee arthroplasty were randomized to one of two treatments: retaining or sacrificing the posterior cruciate ligament during surgery. Both groups received a Genesis II implant (Smith and Nephew Richards) appropriate to the treatment. Patients were seen preoperatively, at three months, one year, and two years. The end-of-study date is at five years postoperatively. Outcome measures include range of motion, the KSCRS, SF-12, and WOMAC. At two years both groups have shown improvement in pain, function, and stiffness. There is no apparent difference between groups with regard to any outcome measures or complications.

The purpose of this study was to compare retaining vs. sacrificing the posterior cruciate ligament (PCL) in total knee arthroplasty in the patients who satisfy the criteria for a cruciate retaining knee.

Two years after total knee replacement, both groups have improved knee function, less pain, and less knee stiffness. There is no apparent difference between the groups with regards to range of motion, function, or other outcome measures.

Designs of total knee arthoplasty implants, as well as surgical techniques continue to evolve. The role of the PCL in primary total knee arthroplasty remains controversial. Current prosthetic designs have the flexibility to either substitute for a resected PCL or allow preservation of the ligament.

One hundred and ninety patients requiring total knee arthroplasty upon satisfying the criteria for a cruciate retaing arthroplasty were randomized to receive either a posterior cruciate retaining implant or a posterior cruciate sacrificing implant. Surgery was performed following standard procedure with the only difference between groups being the sacrificing or retaining of the PCL. Patients were followed at three months, one year, and two years postoperatively. Outcome measures included range of motion, the Knee Society Clinical Rating Score (KSCRS), SF-12, and Western Ontario and McMaster Osteoarthritis Index (WOMAC).

Early results indicate that both groups are doing equally well with no statistical difference in outcomes at two years. There is a trend toward increased range of motion at six and twelve months in the PCL sacrificing group. A six- degree gain was noted in the sacrificed group as compared to a two degree gain in the intact group.

Funding: Smith and Nephew


R.T. Bicknell J.C. Harwood L.M. Ferreira G.J.W. King J.A. Johnson K.J. Faber D. Drosdowech

We compared the initial strength of two techniques for repair of rotator cuff tears. Eight paired cadaveric shoulders with a standardized supraspinatus defect were studied. A transosseous suture and anchor repair was conducted on each side. Specimens were tested under cyclic loading, while fixation was monitored with an optical tracking technique. Mode of failure, number of cycles and load to failure were measured for 50% (5 mm) and 100% (10 mm) loss of repair. Anchors provide improved repair strength at 50% repair loss, in comparison to sutures (p< 0.05). Strength was unaffected by bone mineral density, age and gender.

The purpose of this study was to compare the initial strength of two rotator cuff repair techniques.

Repair strength with anchors was superior to sutures. Strength was unaffected by bone quality.

Anchors, enabling a quicker, less invasive arthroscopic repair, offer improved fixation over sutures, which are more time consuming and invasive.

Eight paired shoulders with a standardized supra-spinatus defect were randomized to anchor or suture repair, and subjected to cyclic loading. Repair migration was measured using a digital camera. Failure mode, cycles and load were measured for 50% and 100% loss of repair. Results were correlated with bone mineral density, age and gender.

The anchors failed at the anchor-tendon interface, whereas the sutures failed through the sutures. Mean values for 50% loss of repair were 205.6 ± 87.5 cycles and 43.8 ± 14.8 N for the sutures, and 1192.5 ± 251.7 cycles and 156.3 ± 19.9 N for the anchors (p< 0.05). The corresponding values for 100% loss of repair were 2457.5 ± 378.6 cycles and 293.8 ± 27.4 N for the sutures, and 2291.9 ± 332.9 cycles and 262.5 ± 28.0 N for the anchors (p> 0.05). These results did not correlate with bone quality.

This study has demonstrated that anchors provide improved repair strength, in comparison to sutures. This may be due to the relative less deformability of the anchors. Repair strength did not correlate with bone quality. This may be attributed to each repair failing primarily through the repair construct or at the anchor-tendon interface, and not through bone.


A. Changoor G. Tytherleigh-Strong J. Runciman M.B. Hurtig A. Miniaci

Two fixation devices for rotator cuff repair were compared in a sheep model. Surgical transection of the supra-spinatus tendon insertion was repaired using metallic OBL suture anchors or Suretac II anchors. Twelve weeks postoperatively the repair site was assessed using histology, polarized light microscopy and biomechanical testing. No important differences were found between these two repair methods.

The purpose of this study was to compare traditional rotator cuff fixation devices with bioabsorbable press-fit tacks.

Sixteen sheep were assigned to OBL (n=8) or Suretac (n=8) treatment groups. Four sheep shoulder joints were used as unoperated controls. Treated sheep underwent general anesthesia and a lateral arthrotomy using aseptic technique to allow transection of the supraspinatus tendon insertion. The tendon-bone interface was repaired with two fixation devices according to the manufacturer’s directions. After recovery from anesthesia the sheep were maintained in small pens for twelve weeks. After sacrifice, muscle-tendon-bone blocks were prepared for mechanical testing. The specimen underwent a preload of 25N, followed by cyclic loading (10–50N x10), then loading at 480mm/min until failure. The remaining bone-tendon interface was fixed, embedded in plastic and 100μ undecalcified histological sections were cut, polished and stained.

All tendons had healed to the humerus and the repair site was two to three times larger than unoperated controls. There were no significant differences between the two treatment groups with respect to maximum load, modulus, and energy per unit area. Histological analysis is ongoing.

These data suggest that these two fixation methods are functionally equivalent in this model. Press-fit fixation devices do not knot tying and they can be inserted arthroscopically so they are a convenient fixation method.

This study confirms that press fit anchors and metallic anchors with sutures are equivalent for repair of bone-tendon interfaces.

Funding: Smith & Nephew supplied the fixation devices for this project. Thanks to Deb McWade for technical assistance.


A. Armstrong C. Dunning L. Ferreira K. Faber J. Johnson G. King

The strength of the intact and four reconstruction techniques (figure-eight, docking, single strand utilizing interference screws, and a single strand) of the medial collateral ligament (MCL) of the elbow were compared. Twenty cadaveric specimens were tested with a cyclic valgus loading protocol. The peak loads to failure of the MCL reconstructions were inferior compared to the intact ligament (p< 0.05). The docking and single strand reconstruction utilizing an endobutton for ulnar fixation were equivalent and had greater initial strength than the interference screws or figure-eight technique. It is suggested that improved interference screws are required for this repair.

The purpose of this study was to compare the initial strength of the intact medial collateral ligament (MCL) of the elbow and four reconstruction techniques.

The docking and endobutton reconstructions showed equivalent peak load to failure.

Improved interference screws are required before they are employed clinically.

The average peak load to failure or 5mm of joint gapping was 142.5±39.4N for the intact, 53.0±9.5N for the docking, 52.5±10.4N for the endobutton, 41.0±16.0N for the interference screw, and 33.3±7.1N for the figure-eight reconstructions. The peak load to failure was higher for the intact specimens compared to any of the reconstructions (p< 0.001). The docking reconstruction showed higher peak loads than the figure-eight or interference screw reconstruction, and the endobutton reconstruction showed higher peak loads than the figure-eight reconstruction (p< 0.004). There was no difference in peak loads between the docking and endobutton reconstructions (p> 0.05).

Twenty (ten pairs) unpreserved cadaveric upper extremities were mounted in a custom jig with the elbow at 90°, and a valgus force was applied 12cm from the elbow joint. The specimens were loaded starting at 20N with the load increased in increments of 10N (200 cycles at each load), until either complete ligament failure or a 5mm increase in the distance between the attachment sites of the MCL. The results support that a single strand or multistrand ligament reconstruction can be equivalent with respect to maximal peak loads and cyclic loading. There are concerns with regard to the use of interference screw fixation in the clinical situation.


J.H. Dubberley K.J. Faber J.C. MacDermid S.D. Patterson W. Romano G. Garvin J. Bennett G.J.W. King

The reliability and accuracy of plain radiographs, MRI and CT Arthrography to detect the presence of loose bodies was evaluated in twenty-six patients with mechanical elbow symptoms. The location of loose bodies found by the imaging studies was compared to arthroscopic findings. Overall sensitivity for the detection of loose bodies was 88 – 100% and specificity was 20 – 70%. Plain radiographs had a similar sensitivity and specificity of 84% and 71% respectively. MRI and CT Arthrography were similar to plain radiography, suggesting that routine use of these modalities is not indicated.

The purpose of this study was to determine the clinical utility of MRI and CT Arthrography (CTA) to reliably and accurately predict the presence of loose bodies in the elbow.

Twenty-six patients with mechanical elbow symptoms underwent plain radiography, MRI and CTA, followed by standard elbow arthroscopy. Three musculoskeletal radiologists reviewed the ‘blinded’ plain radiographs with both the MRI and CTA at separate sittings. The location and number of loose bodies on the MRI and CTA were recorded. The preoperative plain radiographs, MRI and CTA were compared to the arthroscopic findings.

Agreement between radiologists was higher for the number of loose bodies identified in the posterior compartment (ICC=0.72 for both MRI and CTA) than in the anterior compartment (ICC=0.41 and 0.52 for MRI and CTA respectively). The correlation between the number of lose bodies observed on MRI and CTA compared to those found arthroscopically was also higher in the posterior compartment (r=0.54–0.85) than in the anterior compartment (r=0.01–0.45). Both MRI and CTA had excellent sensitivity (92–100%) but moderate to low specificity (15–77%) in identifying posteriorly located loose bodies. Neither MRI nor CTA were consistently sensitive (46–91%) or specific (13–73%) in predicting anterior loose bodies. Overall sensitivity for the detection of loose bodies in either compartment was 88–100% and specificity was 20–70%. The preoperative radiographs had a similar sensitivity and specificity of 84% and 71% respectively.

MRI and CTA were similar to plain radiography in the prediction of elbow loose bodies.


N. Mohtadi I. Bitar T. Sasyniuk W. Harper R. Hollinshead

This meta-analysis supports the conclusion that in patients with recurrent traumatic anterior shoulder instability, an open repair has a more favorable outcome with respect to recurrence and return to activity when compared to arthroscopic repair. More evidence from randomized clinical trials is required to either refute or substantiate this conclusion.

The purpose of this study was to evaluate the outcomes between arthroscopic and open repair for recurrent traumatic anterior shoulder instability.

The search involved clinical studies of all languages in the Medline database up to October 31, 2001. The following key words were used:

anterior shoulder instability;

Bankart lesion;

traumatic recurrent anterior shoulder instability; and

arthroscopic and open Bankart repair.

All abstracts were reviewed and articles were included if there was a direct comparison between arthroscopic and open repair for traumatic recurrent anterior shoulder instability. These articles were manually assessed and cross-referenced for additional abstracts. The final group of articles were independently critically appraised and data on recurrent instability and return to activity (RTA) was extracted.

Recurrent instability was defined as patient report of one or more subluxations and/or dislocations. RTA was not consistently defined in these articles and was based upon the available information.

584,

161,

59 and

44.

From these searches, sixteen articles were determined eligible for the meta-analysis including two foreign and two unpublished manuscripts. Ten studies were included in the final analysis: one RCT, two pseudo-experimental designs, four prospective cohorts, and three retrospective studies.

Pooled Mantel-Haenszel Odds Ratio for recurrent instability and RTA were 2.22 (p=0.002, 95%CI 1.36,3.65) and 2.85 (p=0.004, 95%CI 1.40,5.78) respectively, in favor of the open repair.

Based upon this meta-analysis open repair has a more favorable outcome with respect to recurrence and RTA.


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N.A. Manson K.A. McKean W.D. Stanish

Prospective analysis of a homogeneous group of ninety-two well-trained runners quantified injury parameters in relation to objective gait measurements. A negative correlation was found between peak tibial acceleration and magnitude of rearfoot motion for specific injury locations, suggesting that objective biomechanical parameters may be implicated in, or conversely, may be predictive of running injury. Gait as a predictor of specific running injury may hold merit in the prevention of running related injuries and the industry of athletic footwear design.

The purpose of this study was to determine the relationship between rearfoot motion and shock attenuation during running and their link to injury in trained runners.

Rearfoot motion appears to affect shock transmission through the tibia in athletes sustaining specific injuries.

Objective biomechanical parameters may be implicated, or conversely, may be predictive of running injury. This relationship has implications in the industry of shoe design and the prevention of running related injuries.

Injury rate during the one-year study period was 52%. Injury to the lower leg (e.g. shin splints, stress fracture) was the most common, comprising 22.7% of all injuries. A negative correlation was found between peak tibial acceleration and magnitude of rearfoot motion in several injury groups (r2=0.35–0.65), suggesting a biomechanical mechanism influencing impact forces. Such a mechanism was not apparent in athletes not demonstrating injury (r2=0.00).

Ninety-two well-trained, intercollegiate running athletes (forty women, fifty-two men) were prospectively monitored through biomechanical analysis, survey data, daily log and physician assessment. Subjects ran on a treadmill at 3.8m/s in a fatigued state. Rearfoot motion was assessed via coronal plane video (60Hz). Shock transmission at the tibia was measured using uniaxial accelerometers (1000Hz). Athletes reported injury, location and associated factors. A CASM qualified physician corroborated diagnosis. Outcome measures included the occurrence of a running related injury affecting the athlete’s ability to train or compete, frequency of injury location and diagnosis. Peak tibial acceleration and average range of rearfoot motion were quantified for each athlete. Pearson product moment determined correlation between biomechanical variables according to injury location.

Funding: A research grant was provided by the Nike Sport Research Laboratory, Beaverton, Oregon


C. Robertson D. Pichora S. Csongvay

Injection of corticosteroids into the digital flexor tendon sheath is an accepted and effective treatment for stenosing tenosynovitis. However, despite long historical experience with this procedure, there remains no guide in the literature as to the optimal dose of steroid. Furthermore, the accuracy of these injections has not been well established. Using a prospective, randomized, blinded design, this study compares the outcomes of high (20 mg) and low (10 mg) dose depomedrol injection. Furthermore, the accuracy of tendon sheath injections was assessed radiographically. The findings demonstrate increased effectiveness of the higher steroid dose and a significant learning curve associated with intra-thecal injections.

Injection of corticosteroids into the digital flexor tendon sheath is an accepted and effective treatment for stenosing tenosynovitis (trigger finger). However, despite long historical experience with this procedure, there remains no guide in the literature as to the safe and effective dose of steroid to be administered. Furthermore, the accuracy of digital tendon sheath injections has not been well established. One study has suggested that steroid injected outside the tendon sheath was as effective as intra-thecal injection and may result in reduced complications of infection and tendon rupture.

Using a prospective, blinded design, patients were randomized to receive either high (20 mg) or low (10 mg) dose depomedrol injection. The accuracy of the steroid injections was determined radiographically using non-ionic radio-opaque dye. Outcome measures included pain, tenderness, presence of a palpable nodule, triggering, and limitation of activities (work, hobbies, ADLs). Complications such as pain, stiffness, bruising, thinning of the fat or skin, infection and tendon rupture were also recorded.

Higher dose depomedrol (20 mg) was found to be more effective for relieving pain and triggering than lower dose depomedrol (10 mg). No increase in complication rate was encountered. Stenosing tenosynovitis in diabetic patients was markedly less responsive to treatment.

Injection accuracy was found to increase with clinical experience from approximately 50% for beginners to over 90% for experienced hand surgeons. At the time of submission of this abstract, patient numbers (currently forty-one participants) do not allow analysis regarding the effect of injection accuracy on clinical outcome.


G.E. Holt A.M. Griffin J.S. Wunder B. O’Sullivan C. Catton R.S. Bell

As patients live longer following treatment for soft tissue sarcomas, complications from treatment will continue to emerge. Predicting which patients are at risk allows for improved preoperative planning, treatment, and surveillance. The data presented here suggests that females greater than fifty-five years of age treated with high dose, postoperative radiotherapy in combination with limb salvage surgery for soft tissue sarcomas are at an increased risk of post irradiation fractures. Unlike previous reports, a significantly higher rate of fracture occurred in patients who received higher doses (60 or 66Gy) of radiation versus lower doses (50 Gy).

This retrospective study was performed to determine if the timing and dosage of radiotherapy are related to the risk of post radiation pathologic fracture following combined therapy for lower extremity soft tissue sarcomas. Three hundred sixty-four patients with sarcomas treated with external beam radiation therapy and limb salvage surgery were evaluated. High dose radiation was defined as 60 Gy or 66 Gy; low dose as 50Gy. Radiation timing schedules were preoperative, postoperative, or preoperative with a postoperative boost. Univariate and multivariate analysis was used to determine which factors were associated with fracture risk. Twenty- seven pathologic fractures occurred in twenty-three patients. Twenty- four fractures occurred in twenty patients who were treated with high dose radiation. Sixteen of these patients had postoperative radiation (fourteen patients received 66Gy, two received 60Gy), and four had pre-operative radiation with a postoperative boost (total dose = 66Gy). Three fractures occurred in three patients who received low dose preoperative radiation (50Gy). Both high dose radiation (versus low dose) (p=.001) and preoperative radiation (versus postoperative) (p =0.002) were associated with a risk of fracture. Findings in this study were consistent with previous reports in that females over fifty-five years of age who undergo removal of a thigh sarcoma combined with radiation therapy are at a higher risk of a pathologic fracture, and differs in that there was a significantly higher rate of fracture in patients who received higher doses (60 or 66Gy) of radiation versus lower doses (50 Gy), and when radiation therapy was given postoperatively versus preoperatively.


P.C. Ferguson A. Abudu S.R. Carter R.J. Grimer N. Deshmukh R.M. Tillman

The unusual phenomenon of histological grade change in locally recurrent soft tissue sarcomas is examined by retrospective review of a large sarcoma database. Increased histological grade was found to occur in 20% of recurrent tumours. Several possible factors predisposing to grade change were examined, and only the histologic diagnosis of myxoid malignant fibrous histiocytoma was found to be significant. Despite increased histologic grade, these tumours do not appear to have a worse prognosis in terms of developing systemic disease.

Soft tissue sarcomas (STS) have a reported local recurrence rate of between five and thirty percent. Recurrent tumours are often similar histologically to the initial tumour, however they are occasionally of higher histological grade than the original lesion. Factors that predispose to this change in grade are not known.

We sought to identify the frequency at which locally recurrent STS demonstrate a change in histological grade, and to investigate the possible factors leading to this change. We also investigate whether a change in grade is associated with a poorer prognosis.

We identified one hundred and seventy-three patients who developed locally recurrent STS, one hundred and twenty-four of which met inclusion criteria and who will form the basis of this study. Ninety-two patients (74%) had no change in histological grade, twenty-four (19%) demonstrated an increase in histological grade and eight (7%) a decreased histological grade. Univariate analysis of time to local recurrence, histological diagnosis and use of radiotherapy and chemotherapy did not reveal significant differences between the groups who did and did not undergo change in grade. When the diagnosis of myxoid MFH was looked at separately, there was a higher proportion in the group that developed increased histological grade. Development of a change in grade was not associated with a poorer survival rate.

Increase in histological grade occurs in approximately 20% of locally recurrent STS, but this phenomenon is not associated with a poorer prognosis than if the grade remains the same. A histological diagnosis of myxoid MFH predicts for an increase in histological grade.


S. Pirani D. Hodges F. Sekeramayi

This paper outlines a valid and reliable, clinical method of assessing the amount of deformity in the congenital clubfoot. Clinical & MRI clubfoot scoring systems were developed to score the amount of deformity clinically & to image & score osteochondral pathology of the club-foot -MRI Total Score (MTS), MRI Hindfoot Contracture Score (MHCS), & MRI Midfoot Contracture Score (MMCS), Clinical Total Score (CTS), Clinical Hindfoot Contracture Score (CHCS), Clinical Midfoot Contracture Score (CMCS). Three independent observers tested the Clinical scoring systems Inter-observer reliability (Kappa Statistic) over one hundred consecutive clubfeet. Kappa values were CTS-0.92, CMCS-0.91, and CHCS-0.86- (almost perfect inter-observer reliability). Nineteen clubfeet were scored clinically and by thirty-eight MRI evaluations during treatment. Validity was evaluated by correlating the MRI and clinical scores (Pearson Correlation). The Pearson Correlations between clinical & MRI scores were CTS: MTS = 0.786 (P< 0.01), CHCS: MHCS = 0.712 (P< 0.01) & CMCS: MMCS = 0.651 (P< 0.01). All correlations were highly significant confirming validity.

There is neither reliability nor validity in current methods of clubfoot assessment. This paper outlines a method of assessing the amount of deformity in the congenital clubfoot deformity using six well-described simple clinical signs that has been tested & found to be both valid and reliable. A clinical clubfoot scoring system was created- Clinical Total Score (CTS)- comprised of a Clinical Hind-foot Contracture Score (CHCS) & a Clinical Midfoot Contracture Score (CMCS). One hundred consecutive congenital clubfeet were scored for clinical deformity each week during cast treatment by three independent observers. Inter-observer reliability (Kappa Statistic) of this clinical scoring system was evaluated. A clubfoot MRI protocol & scoring system were developed to visualise & score osteochondral pathology of the clubfoot -MRI Total Score (MTS)- comprised of a MRI Hindfoot Contracture Score (MHCS) and a MRI Midfoot Contracture Score (MMCS). Nineteen clubfeet were scored clinically and by thirty-eight MRI evaluations during treatment. All MRI films were scored for amount of osteochondral pathology. Validity of this clinical scoring system was evaluated by correlating the MRI and clinical scores (Pearson Correlation).

The Kappa values for inter-observer reliability were CTS-0.92, CMCS-0.91, and CHCS-0.86. All scores showed almost perfect inter-observer reliability. The Pearson Correlations between clinical & MRI scores were CTS: MTS = 0.786 (P< 0.01), CHCS: MHCS = 0.712 (P< 0.01) & CMCS: MMCS = 0.651 (P< 0.01). All correlations were highly significant confirming validity of the clinical scores.

We have developed a clinical scoring system for club-feet that is reliable and valid.


A. Roposch J.H. Wedge

Severe acetabular dysplasia with established dislocation of the hip represents a common problem in cerebral palsy. Once significant dysplasia is present little remodeling of the acetabulum occurs with femoral osteotomies alone. Pelvic osteotomies should address the problem of acetabular deficiency in order to restore optimal coverage of the femoral head. Standard innominate oste-otomies are not recommended for neuromuscular hip dysplasia. To address the lack of postero-lateral coverage in this population, a modified periacetabular osteotomy was performed.

Between 1991 and 2000 a total of forty-four patients (fifty-two hips) with total body involvement CP underwent this procedure at a mean age of nine, four yrs. The modification includes only one bicortical cut at the posterior corner at the sciatic notch. The cut extends down to the triradiate cartilage, if present, and through the former site of the triradiate cartilage after closure of the acetabular growth plate in adolescence. Additional procedures included: open reduction, femoral varus osteotomy, and soft tissue releases. Follow-up included a subjective and clinical evaluation. Radiographic assessment included measurements of the migration percentage and acetabular index, evidence of AVN, and premature closure of the triradiate cartilage.

The mean follow-up period for these patients was 3.5 years (1.0 to 8,1 yrs) after surgery, and 70% of the patients had reached skeletal maturity at that time. The median acetabular index improved from 30% pre-operatively to 18% at follow-up. The median migration percentage was 71% preoperatively, and zero at follow-up. A re-dislocation occurred in one hip, and a re-subluxation in another. All other hips were stable and well contained at follow-up. There were three hips showing signs of postoperative femoral head defects . Premature closure of the triradiate cartilage was not noted. The care-givers had the impression that the surgery had improved personal care, positioning/transferring, and comfort.

This osteotomy reduces the volume of the elongated acetabulum and provides coverage by articular cartilage. It provides coverage particularly at the posterior part of the acetabulum. Compared to other techniques this modified periacetabular osteotomy has only one posterior cortical cut which extends down to the sciatic notch. Since this cut is cortical, the fragment can be mobilized extensively and it allows placement of a graft and a better posterior coverage.


A. Furey C. Stone R. Martin

Wrong site surgery is a preventable problem. In 1994 the Canadian Orthopaedic Association (COA) began an educational program initiated to prevent such mistakes from occurring. The purpose of this study was to assess the proportion of orthopedic surgeons who mark their sites preoperatively. This study confirms a high proportion (74.9%) of surgeons in Canada follow the COA guidelines at least occasionally with over half (52.1%) consistently “signing their sites.”

Wrong site surgery is often a catastrophic, but preventable problem. Reports of wrong site surgery have been on the rise in the United States every year since 1995. In 1994 the Canadian Orthopaedic Association (COA) began an educational program initiated to prevent such mistakes from occurring. Their recommendations involved marking the incision site preoperatively. Since that time the claims of wrong site orthopedic surgery have diminished. The purpose of this study was to assess the proportion of orthopedic surgeons who mark their sites preoperatively.

Two hundred orthopedic surgeons across Canada were asked to complete a survey concerning preoperative incision site marking.

A response rate of 89.3% was achieved. Eighty seven (52.1%) stated they always marked their incision site, thirty eight (22.8%) stated they occasionally marked their incision site, while forty two (25.1%) claimed to never mark their incision site preoperatively. Surgeons in academic centers were more likely to sign their sites than their community counterparts (p=0.021) and surgeons in practice longer were less likely to comply with the COA recommendation (p=0.023).

The COA and American Academy of Orthopedic Surgeons (AAOS) have recommended marking incision sites preoperatively in an attempt to reduce wrong site surgery. This study confirms a high proportion (74.9%) of surgeons in Canada follow the COA guidelines at least occasionally with over half (52.1%) consistently “signing their sites.”


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L. Klingler R. Trammell D.G. Allan M.G. Butler H.S. Schwartz

To determine whether sacral chordoma is monoclonal or polyclonal in origin, a new assay to study the polymorphic human androgen receptor locus (HUMARA) was applied. The ratio of maternal inactive X-chromosone to the paternal inactive X (Lyon hypothesis) was determined via a methylation-specific polymerase chain reaction (PCR) technique. Seven of seven informative samples showed a polyclonal proliferation pattern. This study suggests that chordomas are more comparable to mesenchymal neoplasms than to monoclonal hematopoeitic neoplasms.

The purpose of this study was to determine whether sacral chordoma is monoclonal or polyclonal in origin via a new molecular genetic assay of the x-chromosome.

A polyclonal proliferation pattern was identified in all informative samples studied.

Characterization of the genetic tumorigenesis of this unpredictable neoplasm may lend insight into its biological behavior and offer novel therapeutic intervention.

Utilizing a new assay to study the polymorphic human androgen receptor locus (HUMARA), the ratio of maternal inactive X-chromosome to the paternal inactive X (Lyon hypothesis) is determined via a methylation-specific polymerase chain reaction (PCR) technique to detect X-chromosome polymorphisms. Eight female chordoma patients had their DNA harvested and their x-chromosome inactivation pattern and polymorphisms determined and compared to control. A polyclonal proliferation pattern was identified in seven of seven informative samples. The eighth sample showed a single x chromosome allele in normal and tumor tissue and was thus viewed as uninformative.


F. Fassier M. Amako R. Hamdy K. Montpetit F. Glorieux

The charts and X-rays of one hundred and fifty-nine consecutive children with Osteogenesis imperfecta (OI) were reviewed to evaluate the functional outcome of OI patients with upper limb deformities.

The patients were classified according to Sillence classification modified by Glorieux (Type I: 51, Type III: 33, Type IV: 54 and Type V: 21).

The functional outcome was measured using Pediatric Evaluation of Disability Inventory (PEDI) based on self care and mobility scores, and results were compared between the patients with upper limb deformities and the ones without upper limb deformities. There was significant negative correlation between the functional outcome and the total deformity angle.

Osteogenesis imperfecta is a genetic disorder of bone fragility. There are also some angular deformities of upper and lower limbs secondary to fracture and abnormal structure of bones in many OI patients depending on the severity of their condition.

Corrective surgeries to the lower extremities are established interventions and used extensively but surgical correction of upper limb deformities is less frequent.

The purpose of this study was to measure the severity of upper limb deformities in children with OI and the child’s functional level in order to answer the question: “Do upper limb deformities significantly affect function and therefore require surgical intervention?”

Upper limb deformities were measured and classified using AP and lateral Xrays of the arms and forearms. The site and direction of deformities were recorded. Total deformity angle was calculated as the sum of right and left arm and forearm deformity angles. Upper limb deformities were classified into four groups according to the severity of deformity angles.

The mean self care scores of PEDI were significantly low only in the group with severe and bilateral deformities but mobility scores were dramatically decreased in both the moderate and severe deformity groups.

Deformities of the upper limbs in OI limit not only mobility but also self care functions. Therefore they require more attention and it may be necessary to broaden the indications for surgery.


M. Talbot R. Turcotte M. Isler J. Doyon L. Desharnais P. Chabot

A prospective evaluation of the functional status and quality of life of patients undergoing surgery for long bone and acetabular metastases was performed. Sixty-nine patients were enrolled in the study. IM nailing and prosthetic replacement were the most common methods of treatment. Results were assessed using the MSTS 1987, MSTS 1993, TESS and SF-36 pre-op and then at six and twelve weeks post-op. There was a significant improvement in all of these parameters. The need for pain medication also decreased significantly. These results show surgical treatment of bone metastases can be benificial to patients with a short life expectancy.

The purpose of this study was to objectively assess the benefits of surgical treatment of bone metastases in the first three months post-operatively.

This is the first prospective study to evaluate the impact of surgery on the quality of life and function of patients burdened by metastases to the appendicular skeleton.

Sixty-nine patients gave their informed consent to be followed prospectively. Patients were administered the SF-36, MSTS 1987, MSTS 1993 and TESS questionnaires pre-op, at six weeks and three months post-op.

Average age was sixty-one years. Average follow-up was six months with 71% of patients deceased at the latest follow-up. Thirty-five patients had a pathological fracture and thirty-four had an impending fracture. IM Nailing was performed in thirty-six patients, prosthetic replacement in twenty and various other methods of stabilization in the thirteen other cases. Complications occurred in 25% of patients. There was a statistically significant improvement in the MSTS 1987 (from 13,6 to 22,8), MSTS 1993 (21,7 to 51,7), TESS (37,7 to 67,7) and pain medication use in the first three months post-op. SF-36 physical component scores improved significantly at six and twelve weeks while mental component scores improved significantly only at twelve weeks post-op.

Our data shows that surgical treatment of metastatic disease to long bones improves functional status and quality of life in a relatively short time frame. This is significant in a group of patients suffering from advanced neoplasia.

This study suggest interesting benefits in the overall well-being of patients treated surgically for bone metastases.

Funding: Funding was received from CHIR and FREOM.


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H. Nguyen M. Isler R.E. Turcotte D. Normandin L. Desharnais J. Doyon

This study was designed to be the first to prospectively evaluate CT-guided radiofrequency ablation for osteoid osteoma in terms of pain control, medication consumption, quality of life and patient function.

Over two years, forty patients with symptoms and radiographic findings classic for osteoid osteoma were offered radioablation. Patients were asked to fill out facial, subjective and visual analog pain scales and to undergo the Musculoskeletal Tumour Society 1987 functional assessment.

Results show immediate and lasting resolution of symptoms, a sharp drop in drug use and a significant improvement in function thus supporting the role of radioablation as first line therapy.

The purpose of this study was to prospectively evaluate the usefulness of radioablation for osteoid osteoma in terms of pain control, analgesic drug consumption, quality of life and patient function.

Radioablation appears to be a safe and effective method of treatment for osteoid osteoma. It offers immediate and lasting resolution of symptoms. Results support its role as first line therapy.

This is the first study to prospectively measure the outcome of patients treated with CT-guided radiofrequency ablation for osteoid osteoma.

The mean follow-up time is 6.93 months (sd: 6.51). All but seven procedures were done under regional anaesthesia. No complications were reported. 50% of core biopsy specimens were diagnostic of osteoid osteoma. The visual analog pain scale showed a value of 2.13(sd: 2.5) pre-op and 0.33(sd: 1.07) at 1 year (p=0.00033). The MSTS score rose from 28.86(sd: 4.68) pre-operatively to 34.06(sd: 1.95) after one year (p=0.000000049). Medication consumption was markedly reduced. All eighteen patients with more than one- year follow-up are drug free.

Over two years, forty patients with symptoms and radiographic findings classic for osteoid osteoma who had already received various treatments were offered radioablation. Written consent was obtained and patients were asked to fill out facial, subjective and visual analog pain scales. The Musculoskeletal Tumour Society 1987 functional assessment was performed. This data was collected two weeks prior to treatment and then at two weeks, three months and one year after treatment. The procedure was performed under CT guidance and on a one-day hospital admission basis.


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P.C. Ferguson J.T.C. Lau J.S. Wunder A.M. Griffin R.S. Bell

In this paper, a retrospective review was undertaken of a large musculoskeletal tumour database to identify patients who presented with tumours of the foot and ankle. Soft tissue tumours occurred more frequently than bone tumours, and were also more frequently malignant than bone tumours. In contrast to the more recent trend towards limb-preserving surgery in other anatomic areas, malignant tumours of the foot and ankle were frequently unresectable and were treated with amputation.

Although the majority of extremity tumours that present to the orthopaedic surgeon are found in the proximal limbs or around the knee, tumours of the ankle and foot are also relatively common. The purpose of this study is to identify the frequency with which benign and malignant bone and soft tissue tumours occur in the foot and ankle and the oncologic and surgical outcomes of these patients.

A retrospective review of a large musculoskeletal tumor database in a tertiary referral center from the years 1986–2002 was undertaken. For oncologic outcomes, a minimum two-year follow up was considered.

A total of one hundred and sixteen bone and one hundred and seventy-one soft tissue tumours were identified. Seventy-seven bone tumours were benign and thirty-nine were malignant. Sixty-six soft tissue tumours were benign and one hundred and five were malignant. The most common benign bone tumour was giant cell tumour and osteosarcoma was the most common malignancy. Malignant fibrous histiocytoma was common in the distal leg but synovial sarcoma and clear cell sarcoma were more common in the foot. Twenty patients with bone malignancies (51%) and twenty-four with soft tissue sarcomas (23%) had amputation as definitive surgical management. Death from metastases occurred in 25% of patients with bone malignancies and 10% of soft tissue sarcomas.

At this center, the majority of bone tumours treated are benign but the majority of soft tissue tumours are malignant. Limb salvage is often not possible and amputation for local tumour control is necessary far more often than in other anatomic sites.


M. Talbot D. Blanchette R. Turcotte M. Isler

A retrospective study was performed to evaluate the results of proximal humeral replacement prosthesis in the oncologic setting. Following tumour resection and implantation of the prosthesis, the soft tissues around the shoulder were either sutured directly to the prosthesis (three cases) or a dacron capsuloplasty was performed (five cases). Emphasis was on assessing shoulder instability. Eight patients were availaible for the study. Three patients needed to be re-operated for instability. Average instability rating on the ASES visual analog scale was 3,2/10. We conclude the prosthetic instability can be a significant problem for these patients.

The purpose of this study was to assess the results of oncologic proximal humeral prosthesis with a focus on shoulder instability.

Following limb-salvage procedures of the shoulder girdle, reconstruction of the soft-tissues to obtain prosthetic stability can be a major challenge.

A retrospective study of patients that underwent oncologic shoulder replacement. Results were evaluated using the SF-36 questionnaire, the MSTS 1987 and 1993 scales as well as the Standardized ASES method for assessement of shoulder function, including the visual analog scale for instability.

Nine patients were still living and eight of them were able to participate in this study. Average follow-up was seventy-three months. In five cases a capsuloplasty was performed using a dacron vascular prosthesis. In the remaining cases the capsule, rotator cuff or deltoid were sutured directly to the prosthesis.

Average instability rating was 3,2/10 using the visual analog scale. Three patients were reoperated for instability. Two had a failed soft tissue repair with inferior dislocation of the prosthesis and one had recurrent anterior dislocation.

Average MSTS 1987 and 1993 scores were 19,9 and 18,9 respectively.

SF-36 scores were significantly lower than Canadian standards in the physical functioning, role physical and mental health domains.

Our data show a significant rate of instability related problems following prosthetic replacement of the proximal humerus in cases of limb salvage. We were unable to indentify specific strategies to prevent this.

Further research is needed to determine optimal soft tissue reconstruction for oncologic procedure about the shoulder.


N. Natalya

The purpose of this study was to elaborate “sparing” surgical treatment of benign tumors and tumorlike lesions of bones in children

Ninety-six experiments on human defrosted tibias and twenty-four operations on chinchilla rabbits showed the effect of co2-laser radiation on osteal structures.the clonation of human bone marrow (one hundred ad nineteen cultures) and seventy-two experiments on chinchilla rabbits revealed the effect of uv-radiation on osteogenesis. The clinical study included five hundred and fifty-seven children with benign tumors and tumorlike lesions of bones.

Experimental and clinical investigation showed that co2-laser scanning of residual bone cavity after economic resections prevented relapses of pathological process in 98% cases.osteoplasty with uv-radiated autologus bone marrow in combination with allo-bone material stimulated osteogenesis and provided restoration of bone structure in nine to twelve months.

c02-laser operations with simultaneous osteoplasty by uv-radiated autogenous bone-marrow is an effective “sparing” method of surgical treatment of benign tumors and tumorlike lesions of bones in children.


A. Pressman J. Wunder R. Bell

The outcome of complex acetabular reconstruction was evaluated in twenty-one patients who were confined to a wheelchair or bed because of pain from acetabular metastases. Reconstruction rings were used where bone loss exceeded 50% of the acetabulum. Six roof reinforcement-rings, eight ilioischial-rings and eight Harrington reconstructions were performed. All but two patients(90%) became ambulatory without pain. Median survival was nine months. Two patients underwent acetabular revision for recurrence. These results support the role of acetabular reconstruction for palliation of pain in appropriate patients with acetabular metastases.

Metastatic disease of the acetabulum is painful and disabling. Operative intervention is indicated in certain patients with pathologic fractures, and non-responders to adjuvant treatment. The functional outcome of hip arthroplasty with reconstruction rings was evaluated in twenty-one patients with acetabular metastases between 1989 and 2001. Preoperatively all patients were confined to a wheelchair or bed and used significant narcotic medications. Preoperative radiotherapy was employed in eighteen cases (90%) and 30% had undergone chemotherapy.

AAOS classification of the acetabular lesion revealed: six-type II, seven-type III and eight-type IV deficiencies. All cases required a reconstruction ring due to bone loss exceeding 50% of the acetabular dome. Six roof reinforcement rings, eight ilioischial rings and eight Harrington reconstructions with rings were performed in this group. Determination of the reconstructive technique was based on preoperative computerized tomography and intraoperative examination of the acetabular deficiency.

All but two patients (90%) became ambulatory without significant pain. Eleven patients used a walker or two canes and nine walked with one or no canes. Median survival was nine months and patients with visceral involvement had a shorter duration. Eight early post-operative complications developed in six patients (29%). In two patients the acetabular construct failed with cup migration due to locally recurrent disease; both were successfully revised.

The results of complex acetabular reconstruction for metastatic disease validate its role for palliation of pain and to improve ambulatory status. Preoperative planning with computerized tomography can assist in classifying acetabular bone loss and determining optimal reconstruction technique.


S. Manwell D. Drosdowech K. Faber J. Johnson L. Fereirra

Twenty fresh-frozen clavicles were fractured and randomized to one of four fixation techniques. Three plates were used: the LCP (locking compression plate), LCDCP (low contact dynamic compression plate) and Recon (pelvic reconstruction plate). One intramedullary device was used (the Rockwood Clavicle Pin). The constructs were tested for stiffness in bending and torque modes and ultimate strength in bending. The three plates were significantly stiffer then the Pin. Of the three plates, the Recon was significantly less stiff and weaker in ultimate strength then the LCP and LCDCP plates.

This study was conducted to compare and evaluate different fixation techniques for clavicle fractures.

Plate fixation with LCP (locking compression plate), LCDCP (low contact dynamic compression plate) and Recon (reconstruction plate) is stiffer then Pin fixation. The Recon plate was weaker and less stiff then the other two plates.

Fractures of the clavicle are common and account for approximately 5–10% of all fractures and represent 35–45% of shoulder girdle fractures. Open reduction, internal fixation is becoming a standard for more clavicle fractures with the recognition of the limitations of non-operative management. There is a great disparity in biomechanical literature on clavicle fixation.

The average bending stiffness compared to the intact clavicles for each construct was: Recon=104%, LCDCP=124%, LCP=122%, and Pin=69%. The average torque stiffness for each construct was: Recon=83%, LCDCP=91%, LCP=99%, and Pin=46%. The three plate constructs provided significantly more rigid fixation in both bending and torque testing then the clavicle pin (p< 0.05). Ultimate bending strength for each construct was: Recon=8.5 Nm, LCDCP=21.3 Nm, LCP=21.8 Nm, and Pin=15.8 Nm. The Recon plate was significantly weaker the three other constructs (p< 0.05).

Twenty fresh frozen cadaver clavicles were randomized to one of the four fixation groups. An Instron materials testing machine was used to compare the fixation constructs. Each clavicle was tested for its bending and torque stiffness. Following construct stiffness testing, all samples were brought to their ultimate failure strength with a superior bending load.

This study has shown that plate fixation of clavicle fractures yields stiffer constructs then pin fixation. However, plate fixation requires extensive dissection and stripping of the periclavicular soft tissue and may result in prominent hardware. In fracture situations with significant comminution, the LCP and LCDCP offer significantly greater fracture fixation then the reconstruction plate.

Funding: No external funding was received from a commercial party. Implants were donated by Synthes Canada and Depuy Canada.


B.J. Harley L.A. Beaupre A. Scharfenberger N. Jomha D. Weber

We compared the radiographs, clinical outcomes, and complications of two techniques used for treatment of unstable distal radius fractures in young adults. Fifty patients were randomized to percutaneous pinning or augmented external fixation. At one year follow-up, the external fixator did not improve the parameters of radial length, radial angulation or volar tilt. Reduction of intra-articular steps was slightly improved. No differences in DASH scores or functional outcomes were observed, but more complications were noted with the fixator. While articular restoration can be slightly improved with use of the external fixator, a higher incidence of complications and patient dissatisfaction was noted.

Two common techniques for treatment of unstable distal radius fractures in young adults include percutaneous pinning combined with plaster cast, and application of an external fixator, frequently with adjunctive pinning.

The objective of this study was to:

1. To compare the short and mid-term radiographic and clinical outcomes of these two common fixation techniques.

2. To compare the complications of the two techniques.

Fifty patients (< 65 yrs) with unstable fractures of the distal radius were recruited. Patients were randomized pre-operatively to percutaneous pinning or external fixation. All surgery was performed by one of three surgeons. Patients were followed for one year with radiographs and an independent clinical exam including DASH questionnaires.

86% of fractures were AO classification C2 or C3, with an equal distribution of all types in both treatment groups. Use of an external fixator did not improve the parameters of radial length, radial angulation or volar tilt. However, reduction of intra-articular steps was slightly improved with its’ use. No differences in mean DASH scores, total ROM or grip strength were observed. More pin complications were noted with the fixator, and all three patients diagnosed with RSD received external fixation.

While external fixation represents a popular first line treatment for unstable distal radius fractures, this study suggests that similar gross radiographic and clinical results can be obtained with percutaneous pinning. While articular restoration can be slightly improved with use of the external fixator in highly comminuted fractures, this must be balanced by a higher incidence of complications and patient dissatisfaction.

Funding: Stryker-Howmedica-Osteonics


N. Singh E. Schemitsch A. McConnell M.D. McKee

Using patient-oriented outcome measures, we examined twenty-six patients following surgical repair of clavicular nonunion. Patient satisfaction was high, and there was only a minor degree of residual disability (mean DASH score 14.5, SF-36 scores within normal range). Time from injury to surgical repair did not influence results.

Using modern, patient-oriented limb-specific outcome measures, we sought to determine the effect of time to repair on patient satisfaction following surgical fixation of nonunion of the clavicular shaft.

As measured by the DASH and SF-36, patient satisfaction was high following clavicular nonunion repair with only minor degrees of residual disability. Time to repair did not have a significant effect on outcome.

Previous reports of clavicular nonunion repair have concentrated on radiographic or surgeon-based criteria. Our study shows that successful clavicular nonunion repair effectively restores upper extremity function and general health status to near-normal levels.

We identified twenty-six patients who had undergone open reduction, internal fixation of a nonunion of the clavicular shaft. There were sixteen men and ten women, with a mean age of forty-four years (range thirty to seventy-one years). The mean duration of nonunion was 1.9 years with a range from four months to thirty-one years. All patients underwent fixation with a plate, and 73% of patients also underwent iliac crest bone grafting. Two nonunions required revision surgery for healing: twenty-four healed after the index procedure. We assessed patient outcome using standard history and physical, radiographs, and the DASH and SF-36 outcome instruments. The mean DASH score (0 = perfect, 100 = complete disability, “normal” = 10) was 14.5 (range 0 to 58), indicating good restoration of upper extremity function with mild residual disability. SF-36 scores were within the normal range. There was no significant difference in DASH or SF-36 scores between those fixed “early” (< six months) and those repaired “late” (> six months), p=0.30, p=0.78, respectively.

Using patient-oriented outcome measures, we examined twenty-six patients following surgical repair of clavicular nonunion. Patient satisfaction was high, and there was only a minor degree of residual disability (mean DASH score 14.5, SF-36 scores within normal range). Time from injury to surgical repair did not influence results.


S. Fallatah G.Y. Dervin J. Brunet A. Conway H. Hrushowy

We reviewed forty-three patients who had humeral head replacement for proximal humeral fractures between 1992–2000, with a minimum of two years of follow-up. The patients were evaluated for range of motion, post-operative pain, and the overall activities using the American Shoulder and Elbow Surgeons Evaluation form (ASESE) and the Western Ontario Rotator Cuff Index (WORC). Patients with delayed surgery had more pain than those with primary hemiarthroplasty, all of which were treated with the Global type prosthesis. Postoperative pain was significantly associated with the presence of intra-operative cuff tear.

The purpose of this study was to evaluate the functional outcome after hemiarthroplasty for proximal humeral fractures and whether the prosthesis type, intra-operative technique, or the presence of previous surgery would affect the outcome.

The Medical records and radiographs of patients who had hemiarthroplasty for proximal humeral fractures between 1992–2000 were reviewed. Forty-three patients were identified, thirty-seven with acute fractures and six with fracture related complications. One surgeon performed fifteen cases (35%), while the rest divided among eleven others. The patients were evaluated for pain, range of motion, strength, stability, and function using the American Shoulder and Elbow Surgeons Evaluation form (ASESE) and Western Ontario Rotator Cuff Index. The radiographs were reviewed by the senior authors.

The mean age of the patients at presentation was sixty-nine year (range forty-six to ninety-five year). The mean duration of follow-up was 4.6 years. The mean active forward elevation was ninety-six, active external rotation twenty-two, and the mean active internal rotation was eight. Fifteen percent of the patients reported severe pain and twenty-five percent were unable to sleep on the affected side. The patients with previous surgeries and those with intra-operative cuff tear were found to have more post-operative pain (p=0.027 and 0.022 respectively). The Global type prosthesis was used in all the cases of secondary hemiarthroplasty (p=0.031) and all the Neer prostheses were cemented (0.001).

We concluded that integrity of rotator cuff and primary surgery were more inclined to better results. There does remain significant stiffness and pain in most patients however.


G.P. Beadel J.C. MacDermid B. Turner D. Sanders J.H. Roth

We retrospectively reviewed thirty-six patients who had undergone dorsal opening wedge osteotomies using cancellous bone graft and plate fixation for symptomatic healed angulated distal radius fractures.

Average improvement of the distal radius dorsal articular tilt was 28° and the ulna variance 2.7mm. The final average range of motion was flexion 46°, extension 62°, pronation 79°and supination 75°. The range of supination and pronation was not significantly different from the unaffected limb (p> 0.115).

For healed angulated distal radius fractures, dorsal opening wedge osteotomy combined with cancellous bone grafting and plate fixation, is a reliable technique allowing significant deformity correction.

We retrospectively reviewed thirty-six patients with symptomatic healed angulated distal radius fractures who had undergone dorsal opening wedge osteotomies using cancellous bone graft and plate fixation by a single surgeon. Twenty-five patients were reviewed both clinically and radiologically with an average follow-up of forty-seven months. The radiographs of a further eleven patients were reviewed.

Average age at surgery was fifty years with an interval from injury of twenty-nine months. All osteotomies united. 20% required plate removal.

Preoperatively the average distal radius articular tilt was 25° dorsal, and ulna variance +4.3mm. Following correction, average articular tilt was 3° volar, and ulna variance +2mm. These changes were highly significant (p< 0.0005). There was no significant loss of correction of the deformity between the immediate postoperative radiographs and those following union (p> 0.33).

The average range of motion was flexion 46°, extension 62°, pronation 79°and supination 75°. The range of pronation and supination was not significantly different from the unaffected limb (p> 0.115).

The average Patient Rated Wrist Evaluation Score was thirty, indicating residual pain and disability greater than that for an age matched cohort of patients with uncomplicated distal radius fractures (PRWE=15), previously reported by our laboratory. Patients reported that they were satisfied with the cosmetic appearance and had regained 73% of wrist use – these values had a significant negative correlation with the final ulna variance (p< 0.05).

For healed angulated distal radius fractures, dorsal opening wedge osteotomy combined with cancellous bone grafting and plate fixation, is a reliable technique allowing significant deformity correction.


C. Cooke P. O’Brien R. Meek P. Blachut H. Broekhuyse

There are a variety of surgical approaches available for open reduction and internal fixation of acetabular fractures. Some centres have avoided the use of the triradiate approach in the belief that it may result in a significantly higher rate of heterotopic ossification. This has not been our experience. In contrast to many centres, acetabular fractures are treated in an emergent manner, with surgery usually undertaken within the first few days post injury. It is the investigators’ belief that this may in part result in a lower rate of heterotopic ossification.

The triradiate approach has fallen out of favour in the treatment of acetabular fractures due to concerns with both wound healing and heterotopic ossification. This approach however has been utilised frequently at the Vancouver General Hospital (VGH) in the treatment of acetabular fractures. The purpose of this study was to review the results and complications of this approach experienced in the large series at VGH.

We concluded that the results of this approach are acceptable with the exposure allowing anatomical fracture reduction in the vast majority of cases. The complication rate was low, as was the rate of heterotopic ossification.

The significance of this study is to highlight that this approach remains extremely useful in the treatment of acetabular fractures, due to its ability to give excellent exposure while still having an acceptably low complication rate. We believe that the ability of our unit to operate on these injuries in an emergent manner may impart the low rate of heterotopic ossification that we have observed.

There were a total of one hundred and sixty-one acetabular fractures that were treated operatively with the triradiate approach over the period 1989 to 2001. Of these, the majority were two column injuries (79 or 49%), T type fractures (34 or 21%) and transverse fractures (17 or 11%). The average age of the patients was thirty-seven years and the average time to surgery was three days. Our early complications included five cases of failure of fixation or loss of reduction of the fracture, two cases of neurovascular injury, two cases of superficial wound infection, one case of deep wound infection and one case of wound breakdown.

The study involved examining patient hospital records and radiographs and included fracture types, patient ages, delay to surgery, post-operative complications and degree of fracture reduction and healing. Grading of heterotopic ossification was performed by reviewing the anteroposterior radiographs and using Gruen’s classification system.


P. Guy M. Al-Otaibi E.J. Harvey R. Reindl

Using finely reconstructed helical pelvis CT scans of ninety-three cases and image analysis software, we define the “Safe Zone” for the extra-articular placement of screws during internal fixation of the acetabulum, using a Stoppa approach. Screws should be at most: 11mm from the top of the Sciatic notch, 23mm from the tip of the Ischial Spine, and at most 5mm posterior to the top of the Obturator canal, along the pelvic brim.

The purpose of this study was to identify a “safe zone” in the inner pelvis, to allow extra-articular screw placement using the Stoppa approach.

Acetabulum internal fixation screws can safely (extra-articular position) be placed through the Stoppa approach using three identifiable landmarks.

Surgeons can use these identifiable anatomic landmarks for the safe placement of screws along the inner aspect of the acetabulum.

Study Population: males:females 47%:53%, mean age: 51,3yrs (18–88). Reference measurements (means): Femoral Head (FH): 45,5mm (36–6), Inter-SI joint:177,9mm (102–34). Safe distance to joint: 1) from Sciatic notch: 11mm; 2) from Ischial Spine: 23mm; 3) from Obturator roof: 5mm. The Ischial Spine Distance (ISD) showed clustering (p< 0.05) into two groups according to Femoral Head diameter: FH< 47mm: Safe ISD=23mm ; FH≥47mm: Safe IS=28mm.

Ninety-three Helical Pelvis CT scans with fine reconstruction were done between July 1, 1999-June 30, 2000. Axial images were analyzed using GE Vox Tool® v.3.0.3 image analysis software. The femoral head diameter and the Inter-SI joint distance were used as reference. The distance between three identifiable bony landmarks and the point which would allow the placement of a 4mm screw outside the hip joint were measured. Inter and Intra-observer reliability study showed a difference < 1mm in > 90% of cases.

Surgical approaches which avoid extensive dissection and manipulation of the gluteal musculature are gaining in popularity. The Stoppa is such an approach which gives access to the medial acetabular wall and to the inner pelvis from the SI joint to the symphysis along the pelvic brim. This blind approach does not allow visualisation of the joint and confirmation of screw placement. The present paper offers surgeons these reference points.


Y.G. Laflamme C.M. Borkhoff D. Cogley D.J.G. Stephen H.J. Kreder

The purpose of this study was to evaluate functional outcome in patients with combined pelvic and acetabular fractures and to identify factors associated with outcome. One hundred and fifteen patients were identified. 63% were male; mean age was thirty-seven years; mean ISS was thirty. Four died from their injuries. Five patients had open injuries. Only 18% were treated with ORIF for both injuries. At a mean follow-up of 3.5 years, patients with combined pelvic and acetabular fractures exhibit profound functional deficits compared to the normal population. Combined pelvic and acetabular injuries are associated with high mortality and functional morbidity irrespective of treatment.

The purpose of this study was to evaluate functional outcome in patients with combined pelvic and acetabular fractures and to identify factors associated with outcome.

Combined pelvic and acetabular injuries are associated with high mortality and functional morbidity irrespective of treatment. Those individuals with an acetabular fracture involving the posterior wall and an associated lower extremity injury have a particularly poor prognosis.

Individuals who have sustained high energy combined injuries exhibit profound functional impairments compared to the general normal population even in the long term.

One hundred and fifteen patients with combined pelvic and acetabular injuries were identified using a trauma database at a level one trauma centre. 63% were male; mean age was thirty-seven years (13–8); mean ISS was thirty (9–5). 16% involved bilateral pelvic fractures; 7% bilateral acetabular fractures; and for 2%, both were bilateral. 64% were Tile B and 34% were Tile C. Most acetabular fractures were anterior column (31%) or both column fractures (26%). Only 18% were treated with ORIF for both injuries. 25% had ORIF of their acetabulum and 14% had ORIF on their pelvis. Sixty-five patients completed functional outcome questionnaires at a mean follow-up of 3.5 years (1–21). Function was significantly compromised with a mean MFA score of 33.8±21.8. Function was worse for all eight SF-36 domains and the two component scores compared to the Canadian normal population (p< 0.001). There was no relationship found between severity of pelvic or acetabular injury and patient function nor between treatment and functional outcome.

Funding: Grant funded from AO/ASIF


J.H. Dubberley K.J. Faber J.C. MacDermid S.D. Patterson G.J.W. King

The functional outcomes of twenty-eight patients with capitellum and trochlea fractures treated with open reduction and internal fixation were evaluated at a mean follow-up of fifty-five ± thirty-three months. Patients were independently evaluated by a series of questionnaires, radiographs, physical examination and strength testing. Patients with simple fractures did better than those with complicated fractures. The average DASH score was 19/100 and the average ROM was 20 – 130°. Two fractures did not unite and required conversion to total elbow arthroplasty.

A classification system is proposed based on fracture patterns, surgical technique and clinical outcomes.

Capitellum and trochlea fractures are uncommon fractures of the distal humerus. There is limited information about the functional outcome of patients managed with open reduction and internal fixation.

The functional outcome of twenty-eight patients (average age: forty-three ± thirteen years [range, twenty – seventy-one]) who were treated with open reduction and internal fixation for capitellum and trochlea fractures was evaluated at a mean follow-up of fifty-five ± thirty-three months (range, fourteen – one hundred and twenty-one). Patient outcomes were assessed by physical examination, radiographs, range of motion measurements, strength testing and self reported questionnaires (DASH, SF-36 ASES and PREE elbow scales).

There were eleven fractures involving the capitellum, four involving the capitellum and trochlea as one piece and thirteen in which the capitellum and trochlea were separate fragments. These fractures were further defined by the presence or absence of posterior comminution. Fourteen had isolated fractures and fourteen were associated with other elbow, forearm or wrist injuries. Patients with complicated fractures required more extensive surgery, had more complications resulting in secondary procedures and had poorer outcomes compared to those with simple fractures. The average DASH score (19/100), quality of life scores (SF-36: Physical=46, Mental=49) and the average ROM (20 – 130°) suggest favorable patient outcomes overall.

Patients with simple fractures had better results than those with more complicated fractures. A fracture classification system based on fracture patterns, surgical technique and clinical outcomes is proposed.


P.E. Beaulé F. Dorey M. LeDuff H.C. Amstutz

Ninety-four hips with a mean patient age 34.2 (range 15– 40) with a metal/metal surface arthroplasty (SA) were reviewed with 71% men and 14% with previous surgery. The Chandler risk index was calculated as well as the SA risk index (SARI). At a mean follow-up three years, three hips were converted at a mean of twenty-seven months (two to fifty), and ten patients had significant radiological changes. Mean SARI for the thirteen problematic hips versus remaining hips was significantly higher, 4.7 and 2.6, respectively (p=0.00). If SARI > 3 the relative risk of early problems is twelve times greater than if SARI ≤3.

The purpose of this study was to evaluate the early outcome of a hybrid metal on metal surface arthroplasty of the hip in patients forty years and younger and identify potential risk factors.

Surface Arthroplasty Risk Index can help identify patients who may be at increased risk of early failure following metal on metal surface arthroplasty.

Proper patient selection and careful surgical technique may minimize early failures with the re-introduction of surface arthroplasty of the hip.

Ninety-four hips mean age 34.2 (range 15– 40) with metal/metal surface arthroplasty (SA) were reviewed with 71% men and 14% with previous surgery. The Chandler risk index was calculated and SA risk index (SARI). Mean follow-up three years (range 2–5), three hips were converted at a mean of twenty-seven months (2–50), and ten patients had significant radiological changes. Mean SARI for these thirteen problematic hips versus remaining hips was significantly higher, 4.7 and 2.6, respectively (p=0.00). The mean angle between the prosthesis stem and femoral shaft in the problematic group was significantly smaller than the remaining hips (p=0.03): 133° and 139°, respectively. If SARI > 3 the relative risk of early problems is twelve times greater than if SARI ≤3.


E.J. Harvey D Steinitz R. Reindl G. Berry P. Guy

This study attempted to ascertain if patients with high superior pubic ramus fractures (HSPR) have worse clinical functional outcomes than patients with low superior pubic ramus fractures (LSPR). A retrospective cohort of patients was examined. A statistically significant difference was found with respect to Harris Hip Score, MFA score, Bother Index, and Functional Index. Patients with LSPR fractures consistently scored better on mobility and activity of daily living functional testing. Patients with HSPR fractures were limited in physical abilities and lifestyle adjustment. This study illustrates a need to re-examine our treatment of high pubic ramus fractures.

The purpose of this study was to ascertain if patients with high superior pubic ramus fractures have worse clinical functional outcomes than patients with low superior pubic ramus fractures.

Patients with Low Superior Pubic Ramus (LSPR) fractures consistently scored better on mobility and activity of daily living functional testing. Patients with High Superior Pubic Ramus (HSPR) fractures were more limited in physical abilities and lifestyle adjustment.

No distinction of level of this common fracture is routinely distinguished with treatment usually independent of level. This study illustrates a need to re-examine our treatment of high pubic ramus fractures.

A statistically significant difference was found when the HSPR fracture group was compared to the LSPR fracture group with respect to Harris Hip Score (P=0.0024), MFA score (P=0.0304), Bother Index (P=0.0338), and Functional Index (P=0.0385), and had hip pain which was a limiting factor (P=0.011).

This is a retrospective cohort study of patients sustaining a superior pubic ramus fracture. The criterion for grouping was fracture proximity to the acetabulum. MFA (Short Form) and Harris Hip Score were performed. A physical exam was performed on all patients. The two groups were compared using the Wilcoxon test for continuous variables and the Chi-square test for contingency tables.

These fractures are commonly felt to be of minimal significance. Common treatment regimes consist of pain control and early mobilization. The etiology of the increased pain and functional disability in patients with HSPR fractures is unclear. Our hypotheses include labral tear and missed true acetabular fractures.


N. Mahomed E. Losina J. Barrett J. Baron J. Katz

Hospital and surgeon volume is inversely associated with perioperative mortality, dislocation and infection rates following total hip replacement (THR). This study evaluated the relationship between hospital/surgeon volume on early failures requiring revision in a sample of 6826 Medicare beneficiaries in 1995–1996. The primary outcome for the analysis was the time between the primary THR and the first revision. After adjustment for sociodemographic/clinical variables, patients of low volume surgeons in centers with a caseload less than one hundred THR/year were twice as likely to be revised compared with patients in high volume centers by high volume surgeons.

The purpose of this study was to determine whether hospital/surgeon volume is associated with early failures requiring revision.

Patients of low volume surgeons have considerably higher rates of early failure, especially within the first year following surgery.

This study highlights the importance of including surgeon volume among factors that influence referrals for elective THR.

We analyzed claims data of 6826 Medicare beneficiaries, who underwent elective primary THR in 1995–1996 in OH, PA and CO. Hospitals were stratified into, low (< 12 THR/year), medium (12–100 THR/year) and high (> 100 THR/year) volume groups. Low volume surgeons performed fewer than twelve primary THR/ yr. Associations between rates of revisions/surgeon volume were determined by risk ratios after adjusting for hospital volume, patient age, poverty status, gender and comorbidities. We examined whether the effect of surgeon volume on revision rates differed across yearly time intervals. Of patients who had primary THR in 1995–96, two hundred and seventy-one (4%) had at least one revision by the end of 1999, one hundred and twenty-six (46%) of those occurring within the first year after the surgery. Cumulative rates of revision ranged from 2.3% for primary THR in high volume centers performed by high volume surgeons to 5.9% for patients who had primary THR performed by low volume surgeons in low volume centers. Further analysis revealed that the effect of surgeon volume was striking in the first year after the surgery (RR: 2.34; 95%CI: 1.47– 3.78) and was not evident in the subsequent years (RR: 1.08; 95%CI: 0.73–1.58).


A. Borden E.H. Schemitsch J.P. Waddell M.D. McKee J. Morton M.T. Nousiainen A. McConnell

We evaluated the clinical, radiographic, and functional outcome of uncemented total hip arthroplasty (THA) following vascularized fibular grafting for avascular necrosis (AVN) of the femoral head. A group of twenty-two patients who had been converted from a vascularized fibular graft to THA was compared to a similar group of twenty-two patients who had received a THA with no prior graft. The graft group was found to have worse outcomes than the control group as measured by SF-36, and WOMAC scores, as well as a hip score.

These results show that vascularized fibular grafting complicates future THA.

The Purpose of this study was to evaluate the clinical, radiographic, and functional outcome of uncemented total hip arthroplasty (THA) following vascularized fibular grafting for avascular necrosis (AVN) of the femoral head. These results indicate that functional and clinical outcome following post-graft THA is worse than outcome following THA performed as a primary intervention.

Judicious use of the vascularized fibular graft procedure is critical in order to minimize the number of graft failures and avoid the negative outcomes associated with THA after failed vascularized fibular grafting.

Twenty-six hips in twenty-two patients who had a THA following a failed vascularized fibular graft were compared to a group of twenty-three hips in twenty-two age and sex-matched patients who had received a THA with no prior graft (combined mean age: 39.0 yrs). Primary outcome measures included the SF-36 (patient-based general health assessment – total score and physical sub-component) and WOMAC (patient-based arthritis specific score) scores at matched follow up times (mean: 6.2years, range: two to fourteen years). An objective hip score was also used, as were several radiographic variables. The post-graft group had lower SF-36 final scores (p< 0.006), lower SF-36: physical function scores (p< 0.001), and lower WOMAC scores (p< 0.045) than the control group. Post-graft THA was complicated by longer operative time (p< 0.025) and greater subsidence of the femoral prosthesis (p< 0.004) compared to controls. Additionally, the post-graft group had worse hip score values (p< 0.05) than controls.

Vascularized fibular grafting is a commonly used procedure to cure or delay progression of AVN in the hip. Currently this procedure is used for young (< 40 years) patients with hip AVN who are in an early, pre-collapse stage of the disease. Although the efficacy of vascularized fibular grafting has been proven, up to 29% of grafts fail at five years and need to be converted to THA (Urbaniak et al., 1995). This study shows that THA after failed vascularized fibular grafting has a worse outcome than THA as a primary intervention. Therefore judicious use of the graft procedure is critical in order to minimize the number of graft failures and avoid the negative outcomes associated with it.


T. Sekundiak D. Hedden

Revision of massive femoral defects in revision hip arthroplasty is extremely difficult. This study assesses defects where bone loss extends to the isthmus of the femur. By using a medial allogeneic femoral graft in a wedge fashion, rotational and axial stability of the femoral implant is augmented, allowing bone ingrowth to occur. The technique is described which is simple, inexpensive and readily available in most institutions.

A medial allogeneic femoral strut graft is assessed in hip arthroplasty revision to improve implant stability and thereby promote bony ingrowth into the implant.

Thirty-three revision arthroplasties were preformed in twenty-nine patients (avg. age 63.7 yrs) using a fully-porous coated implant of eight or ten inch length. All patients had a Paprosky Type III or IV femoral defect. The implants, by definition were press-fit at or past the isthmus. To aid ingrowth and to decrease axial and rotational stresses, a medial femoral strut graft was wedged into the remaining medial host bone and under the collar of the implant. Cabling was utilized to prevent dislodgement of the graft from the implant and host. A radiographic and clinical comparison to a series of similar defects without grafting was performed for a minimum of thirty-five month follow-up.

Twenty-eight of the thirty-three implants had radiographic evidence of ingrowth with migration of only two millimeters (average). Medial femoral strut grafting displayed much better potential for ingrowth and decreased potential for migration. Harris hip scores averaged eighty-one from a preoperative score of thirty-two. Cost of the grafts averaged $2100 cheaper compared to a bulk structural graft which would otherwise have been used in this situation.

Medial femoral strut grafts augment initial implant stability to allow for implant in- growth. The advantages of the medial strut grafts are decreased cost, improved stability, and improved implant in- growth potential.


J. O’Brien R.S. Burnett X. Yuan S.J. MacDonald R.W. McCalden R.B. Bourne C.H. Rorabeck

Isolated liner exchange in revision total hip arthroplasty for the treatment of polyethylene wear is an increasingly common surgical procedure. Twenty-four hips underwent this procedure via the direct lateral approach and were prospectively followed clinically and radiographically. Accessible osteolytic lesions were curetted and bone grafted. At a mean follow-up of forty months, a significant clinical improvement was observed. One cup collapsed into an osteolytic lesion postoperatively; all other lesions regressed. No dislocations have occurred. Isolated liner exchange via the direct lateral approach may reduce dislocation rates while avoiding the morbidity associated with the removal of well-fixed components.

The purpose of this study was to evaluate the clinical and radiographic results of isolated liner exchange in revision total hip arthroplasty (THA) for osteolysis and polyethylene wear via the direct lateral surgical approach.

Retention of well-fixed implants avoids unnecessary bone loss at revision surgery. Previous studies report a significant dislocation rate with isolated liner exchange. Revision via the direct lateral surgical approach may reduce the dislocation rate in surgery for acetabular osteolysis.

Twenty-four hips that underwent an isolated liner exchange revision procedure via the direct lateral approach were prospectively followed. Accessible osteolytic lesions were curetted and bone grafted. Harris Hip Score, WOMAC Index, and radiographic analysis were recorded. The area of osteolytic lesions was calculated using a computer imaging technique.

At mean follow-up of forty months, all except one of the osteolytic lesions had regressed in size. Mean Harris Hip scores improved from sixty-nine to eighty-three and WOMAC indices improved from thirty-seven to twenty-four. No dislocations have occurred. One cup collapsed into an osteolytic lesion postoperatively, requiring an acetabular revision procedure.

Isolated liner exchange is a promising technique that avoids the removal of well-fixed acetabular implants. The increased dislocation rate associated with revision THA may be reduced and osteolytic lesions may be debrided and bone grafted through the direct lateral approach.

Isolated liner exchange via the direct lateral approach reduces the dislocation rate in THA. Retention of wellfixed implants and bone grafting is a procedure that preserves bone stock and addresses osteolytic lesions at revision surgery.


P.E. Beaulé M. LeDuff F. Dorey H.C. Amstutz

Eighty-three patients (ninety hips) with well-fixed cementless socket retained during revision of a femoral component were reviewed. At revision, 33% of patients had acetabular osteolysis and 52% were grafted. At mean follow-up 9.6 years (5.5 – 15.9) after femoral revision and 14.8 years (7.1–20.2) after primary arthroplasty, survivorship was 96.5% (95% CI, 91.5% to 100%) at five years and 81%(95% CI, 61% to 99%) at ten years after femoral revision. Revision of a cementless acetabular component solely on the basis of the duration that it was in vivo or whether a previous revision had been done does not appear to be warranted.

Removal a well fixed cementless acetabular component can result in an increased operative morbidity. Data that can be used to predict the long-term survival of retained well-fixed cementless acetabular components are therefore needed.

Retention of the well-fixed cementless acetabular component during femoral revision is a predictable technique.

Revision of a cementless acetabular component solely on the basis of the duration that it was in vivo or whether a previous revision had been done does not appear to be warranted.

Eighty-three consecutive patients (ninety hips) in whom a well-fixed cementless socket had been retained during revision of a femoral component were reviewed. Mean patient age was fifty-four. At the time of revision, 33% of the patients had acetabular osteolysis of which 52% were grafted. At a mean follow-up 9.6 years (5.5 – 15.9) after femoral revision and 14.8 years (7.1–20.2) after primary arthroplasty, 94.5% of the sockets remained in place. With any revision as end point, survivorship was 96.5%(95% CI, 91.5% to 100%) at five years and 81%(95% CI, 61% to 99%) at ten years after femoral revision. With failure of cementless socket as end point (i.e. loosening, deficient locking mechanism), survivorship was 100% (95% CI, 100%) and 94% (95% CI, 82%–100%) at five and ten years after femoral revision and 100% (95% CI, 100%) and 94% (95% CI, 82%–100%) at ten and fifteen years after primary arthroplasty. No cases showed recurrence or expansion of pelvic osteolysis. The overall incidence of dislocation was 15%.


R.M.D. Meek D.S. Garbuz B.A. Masri N.V. Greidanus C.P. Duncan

A concern with diaphyseal-fitting cementless stems in revision total hip arthroplasty is intra-operative fractures. Two hundred and eleven patients consecutively underwent revision hip arthroplasty using Solution stems (DePuy, Warsaw, IN). Intra-operative fractures or perforations occurred in sixty-four patients (30% prevalence), with diaphyseal splits in thirty-nine patients (18% prevalence). Risk factors were pre-operative osteolysis, cortex to canal ratio, under-reaming the cortex and large diameter stems. The majority of diaphyseal linear cracks occurred at the distal end of extended trochanteric osteotomies during stem insertion. Intra-operative fracture is associated with an average two days longer length of stay (p< 0.05).

The purpose of this study was to determine the identification of the risk factors and outcomes of intra-operative fractures using a diaphyseal fitting revision stem.

There is an association of intra-operative fracture associated using a diaphyseal-fitting stem in revision total hip arthroplasty with a longer length of stay in hospital.

Identifying preoperative risk factors will allow avoidance of such fractures and prolonged hospital stay.

Intra-operative fractures or perforations occurred in sixty-four patients (30% prevalence) and thirty-nine patients (18% prevalence) sustained diaphyseal splits. Risk factors associated with intra-operative fracture were pre-operative osteolysis, a low cortex to canal ratio, under-reaming the cortex and the use of a large diameter stem. Surgical approach was not directly related to fracture occurrence but the majority of diaphyseal undisplaced linear cracks occurred at the distal end of extended trochanteric osteotomies during stem insertion. Cortical perforation occurred most often with cement removal. Duration of stay was on average two days longer (p< 0.05) for patients with an intraoperative fracture.

Two hundred and eleven patients who had undergone revision hip arthroplasty using the Solution stem (DePuy, Warsaw, IN) between December 1998 and March 2002 were identified. Patients who sustained an intra-operative fracture were compared to controls patients who underwent hip revision at the same time frame but with no fracture. Multiple factors were analyzed to see which were risk factors for intra-operative fractures.

There is a surprisingly high incidence of intra-operative fracture associated with using a diaphyseal-fitting stem in revision total hip arthroplasty. This was associated with a longer length of stay


A. Pressman B. Cayen P. Zalzal G.M.S. Azores B. Liberman D. Backstein A.E. Gross

Periprosthetic fracture management after hip arthroplasty is complicated by poor bone stock and loose femoral components. Using a prospective database, thirty-five fractures treated by proximal femoral allograft reconstruction were identified. Patients treated between 1989–2000 with minimum two- year results, were reviewed at a mean of 3.8 years. Twenty-six fractures were acute, and nine had failed previous treatment. Union of the PFA was achieved in all but five cases (83%). In twenty-eight cases (78%) no further surgery was required and patient ambulation was pain free. When conventional treatment is not possible, the use of a PFA provides encouraging results.

Periprosthetic femoral fracture treatment is complicated by comminution, bone loss, and potentially loose femoral components. Treatment can include cast-braces, internal fixation, revision arthroplasty or the use of proximal femoral allograft composites (PFA). This study reports on thirty-five fractures treated with a PFA between 1989–2000. Five patients were lost and twelve patients (33%) were deceased. Follow-up averaged 3.8 years (range 0.1–11.3) with minimum two-year results in surviving patients. Six patients had either Rheumatoid arthritis or DDH with very narrow femoral canals.

There were twenty-three acute fractures, five failures of non-operative management, four failures of ORIF and two fractured femoral stems. Fractures were classified by the Vancouver system with: B1–7%, B2–30%, B3–43% and C-20%. Prefracture functional scores revealed that 30% of patients had significant functional impairment and were awaiting revision arthroplasty. Patients had had an average of two previous surgical procedures (range 1–4).

The mean length of the PFA was 14cm and union between graft and host bone was achieved in all but five cases (83%). Resorption of the graft was seen in eight cases (27%), lucent lines in six cases (20%) and implant migration in four cases (13%). Post revision arthroplasty Harris Hip and SF-36 scores revealed substantial disability in this patient group.

Twenty-eight cases (73%) were deemed successful with patients not requiring further surgery and enjoying pain free ambulation. In fractures with unstable femoral components and inadequate bone stock or very narrow femoral canals few options are available. This technique provides encouraging results and a viable option when conventional treatment is not possible.


T. Sekundiak

Staged revision arthroplasty for the periprosthetic hip infection is the accepted mode of treatment. Unfortunately, the first stage revision compromises the patient’s function secondary to inability to weight-bear. Pros-theses coated with antibiotic-loaded cement have been adapted to improve function but have failed in larger femoral defects. This implant and technique described improves patient mobility and decreases morbidity as compared to conventional techniques.

The purpose of this study was to find an implant to accommodate most femoral defects and to be readily available for managing periprosthetic hip infections

A prospective study was performed comparing the PROSTALAC(DePuy, IN) implant (Group I) to a Solution(DePuy, IN) implant (Group II) covered in antibiotics for management of the first stage. All patients had a confirmed pyogenic gram positive or gram negative infection. Fifty-two patients were compared with each group being matched by their femoral defect type (Paprosky: Type I and II: 24, Type III:20, Type IV: 8). Follow-up was for a minimum of thirty-six months. All patients were encouraged to weight bear as tolerated.

One recurrence of infection occurred after a second stage revision in Group I. Cost of the implant averaged $700 cheaper in Group II. More significant was the fact that the average length of hospital stay was decreased in Group II by seven days and forty-seven days for the Type III and Type IV femurs respectively. All patients in Group I received a second stage revision. Five of the Group II patients refused a second stage revision secondary to their satisfactory function and had better post-op function.

An alternative treatment for staged periprosthetic hip infections is proposed which can decrease hospital stay, improve function, and allow routine implant use for its implementation.


J.C. Cameron

The management of medial osteoarthritis of the knee with underlying anterior cruciate ligament deficiency is challenging. Stabilization of the ligament instability at the time of re-alignment osteotomy addresses both components of the disability.

We are reporting a retrospective study of thirty-two cases of combined osteotomy and ligament repair between 1995 and 2000.

Patients were assessed by questionnaire and clinical examination. Objective measures, using the modified Lystolm score, WOMAC index and SF36 were performed. Radiological examination as well as a survivor-ship analysis were performed.

The average age at operation was thirty-six with an average follow-up of five years. Surgery was performed in patients who had complaints of both pain and instability and also had objective findings of Uni-compartmental osteoarthritis and anterior cruciate deficiency.

Seventy five percent of patients were classed as good to excellent with only five percent of patients classed as poor.

Combined tibial osteotomy and anterior cruciate reconstruction is an effective means to deal with this complex problem.


S. Arneja W. Froese P. MacDonald

Thirty- seven patients were enrolled in a single-blind prospective randomized clinical trial comparing the use of the Endopearl in femoral fixation in otherwise similar anterior cruciate ligament (ACL) reconstructions. Evaluation pre-operatively, three months, six months and eighteen months post-operatively suggested significant difference in the side to side KT-1000 values suggesting improved graft fixation with the EndoPearl by eighteen months post surgery with no differences in the Mohtadi ACL QOL questionnaire. Thus, when bioabsorbable interference screws are used for ACL reconstruction, the use of the EndoPearl improves anterior-posterior stability up to eighteen months post-operatively.

The EndoPearl is an adjunct to bioabsorbable interference screw fixation in the femoral tunnel in ACL reconstruction. The purpose of the study was to assess the clinical effectiveness of the EndoPearl using the KT-1000 Knee Arthrometer and the Mohtadi ACL Quality of Life (ACL-QOL) Questionnaire.

The application of the EndoPearl in hamstring ACL reconstruction has no significant benefit when compared to conventional treatment in KT-1000 and ACL-QOL Questionnaire outcomes.

Prospective Single-blind Randomized Clinical Trial. ACL reconstruction with autogenous semitendino-sus and gracilis tendons was performed on thirty-seven patients. Pre-operatively, three months, six months and a eighteen months post-operatively, patients’ knees were evaluated using the KT-1000 Knee Arthrometer and the ACL-QOL questionnaire.

Statistically significant differences were achieved in terms of KT-1000 side-to-side differences between the study group and the control group at six months and eighteen months post-operatively; the mean-side-to-side differences are significantly less in the study group when compared to the control group. Statistically significant differences could not be detected when comparing the ACL-QOL questionnaire between the two groups.

The application of the EndoPearl in conjunction with a bioscrew in the femoral tunnel in autogenous ACL reconstruction using semitendinosus and gracilis tendon grafts provides a significantly decreased laxity up to eighteen months post-operatively in terms of KT-1000 side-to-side differences.

In an accelerated post-operative rehabilitation program, patients and doctors have increased confidence in terms of graft stability with the application of the Endo-Pearl in hamstring ACL reconstruction.

Please contact author for pictures and/or diagrams.


A. Pressman B. Cayen P. Zalzal G.M.S. Azores B. Liberman D. Backstein A.E. Gross

Periprosthetic fracture management after hip arthroplasty is complicated by poor bone stock and loose femoral components. Using a prospective database, thirty-five fractures treated by proximal femoral allograft reconstruction were identified. Patients treated between 1989–2000 with minimum two- year results, were reviewed at a mean of 3.8 years. Twenty-six fractures were acute, and nine had failed previous treatment. Union of the PFA was achieved in all but five cases (83%). In twenty-eight cases (78%) no further surgery was required and patient ambulation was pain free. When conventional treatment is not possible, the use of a PFA provides encouraging results.

Periprosthetic femoral fracture treatment is complicated by comminution, bone loss, and potentially loose femoral components. Treatment can include cast-braces, internal fixation, revision arthroplasty or the use of proximal femoral allograft composites (PFA). This study reports on thirty-five fractures treated with a PFA between 1989–2000. Five patients were lost and twelve patients (33%) were deceased. Follow-up averaged 3.8 years (range 0.1–11.3) with minimum two-year results in surviving patients. Six patients had either Rheumatoid arthritis or DDH with very narrow femoral canals.

There were twenty-three acute fractures, five failures of non-operative management, four failures of ORIF and two fractured femoral stems. Fractures were classified by the Vancouver system with: B1–7%, B2–30%, B3–43% and C-20%. Prefracture functional scores revealed that 30% of patients had significant functional impairment and were awaiting revision arthroplasty. Patients had had an average of two previous surgical procedures (range 1–4).

The mean length of the PFA was 14cm and union between graft and host bone was achieved in all but five cases (83%). Resorption of the graft was seen in eight cases (27%), lucent lines in six cases (20%) and implant migration in four cases (13%). Post revision arthroplasty Harris Hip and SF-36 scores revealed substantial disability in this patient group.

Twenty-eight cases (73%) were deemed successful with patients not requiring further surgery and enjoying pain free ambulation. In fractures with unstable femoral components and inadequate bone stock or very narrow femoral canals few options are available. This technique provides encouraging results and a viable option when conventional treatment is not possible.


M. Hockings J. Borrill P.J. Rae

The aim of this study was to clinically assess the outcome of arthroscopically assisted inside to outside meniscal repair. Seventy-five meniscal repairs were carried out, the average age was twenty-six year eight months. Average follow up was six years four months, fourteen patients (18.6%) were lost to follow up. The overall success rate was 89.5%, with 78.1% scoring clinically good or excellent on the Lysholm Score. Improved results were shown for patients over thirty years, those with ACL laxity and with longer tears. Delay in repair did not make a difference. Clinically lateral repairs did better. With an overall success rate of 89.5% the authors would recommend this traditional technique.

The purpose of this study was to clinically assess the mid to long-term outcome of arthroscopically assisted inside to outside meniscal repair.

Patients were followed up retrospectively by a combination of clinical review, mail and telephone questionnaires. The Lysholm knee (LS) and the Tegner activity (TA) scores were recorded.

From July 1991 until February 1999 seventy-five meniscal repairs were carried out in seventy patients by a single surgeon (PJR). The average age of the patients was twenty-six year eight months, there were fifty-two male and eighteen female patients. Fourteen patients (18.6%) were lost to formal follow up. Of the seventyfive repairs carried out full data, Lysholm Score (LS) and Tegner Activity (TA) scores were available on fifty-five repairs for analysis. The average follow up was six years four months (range three years four months to ten years nine months), Average scores were LS=87.1, TA before surgery=6.1, TA after surgery=5.5. 9 patients had menisectomy following re-tear due to further injury.

The overall success rate was 89.5%, with 78.1% scoring clinically good or excellent on the Lysholm Score.

In contrast to previous studies improved results were shown for patients over thirty years, those with ACL laxity and those with longer tears. The time interval to repair following injury did not make a difference. In agreement with previous studies, clinically lateral repairs did better.

With an overall success rate of 89.5% the authors would recommend this traditional technique in light of the more recent techniques presently in use.


J.S. Theodoropoulos P. Marks

A generic measure of health related quality of life was used to evaluate outcome following ACL reconstruction. This study quantifies the domains of poorer health-related quality of life and provides pre- and postoperative SF-36 scores for patients with ACL deficient knees. Pre-operative Sf-36 scores in ACL deficient knees were significantly lower than age matched normals in the physical domains of physical functioning, role-physical and bodily pain (p< 0.001). Post-operatively, SF-36 scores were significantly improved (p< 0.001) in all domains except general health and social functioning.

Evaluation of the ACL injured knee and the success of reconstructive surgery has traditionally focused on an assessment of knee function. These have proven to be poor indicators of general functional outcome and health related quality of life. The purpose of this study was to use the SF-36 survey to determine whether health related quality of life in patients with ACL deficient knees differed from that of healthy individuals and whether SF-36 scores improved after undergoing ACL reconstruction.

Sixty patients with ACL deficient knees underwent ACL reconstruction using arthroscopically assisted patellar tendon insertion. Prior to surgery and a minimum of two- years post-operatively, patients completed the SF-36 general Health Survey questionnaire. Pre- and post-operative SF-36 scores were compared to each other and to standard scores obtained from a healthy population of a similar age.

Pre-operative Sf-36 scores in ACL deficient knees were significantly lower than age matched normals in the physical domains of physical functioning, role-physical and bodily pain (p< 0.001). Post-operatively, SF-36 scores were significantly improved (p< 0.001) in all domains except general health and social functioning. Comparison between age matched normals were significantly higher in the domains of role-emotional, vitality, mental health and general health

A generic measure of health related quality of life was used to evaluate outcome following ACL reconstruction. This study quantifies the domains of poorer health-related quality of life and provides pre- and post-operative SF-36 scores for patients with ACL deficient knees.

Our finding indicates that ACL reconstruction using patellar tendon autograft with arthroscopically assisted technique improved ling term health related quality of life.


P. Guy S. Kantor E.J. Harvey R. Reindl

We examined the relationship between waiting times for ACL surgery and the need for meniscal surgery at time of reconstruction. Using the Provincial Billing Database we identified 3812 ACL reconstructions between 1999–2001. Patients waited on average four hundred and twenty-two days from initial medical visit to reconstruction. 1722 patients (45%) required meniscal surgery with the ACL procedure. The delay to surgery was: two hundred and fifty-one days (no meniscal surgery required), four hundred and thirteen days (meniscal repair) and six hundred and seventy-six days (meniscectomies). This difference was significant, p< .01, ANOVA. The rate of meniscal surgery per time period was also significantly different: 17% if < 3months, 57% if > 6months. Our present Health Care policies place patients at risk of requiring avoidable meniscal surgery and developing osteoarthritis.

The purpose of this study was to examine the relationship between waiting times for ACL surgery and outcome.

The outcome measure was the need for meniscal surgery at the time of ACL reconstruction. The Provincial Data Base Billing information was reviewed for ACL reconstruction between 1999–2001. The simultaneous need for a meniscal procedure was noted. Tracking back in time, all demographic, diagnostic and interventional billing data (ICD & Visit billing code) preceding their ACL surgery was recorded.

Between 1999–2001, 3812 ACL reconstructions were identified. Of these, 1722 patients required a meniscal procedure (45%). On average, patients waited over four hundred and twenty-two days from injury to reconstruction. Patients who did not require any meniscal procedure waited on average two hundred and fifty-one days, meniscal repairs waited four hundred and thirteen days, while meniscectomies waited six hundred and seventy-six days. More importantly, the need for a meniscal procedure correlated with the timing of surgery: 17% of those reconstructed < three months from injury had a significant meniscal injury, compared to 57% at > six months. Almost half of which (48%) required a meniscectomy for significant meniscal injury. These differences all attained statistical significance (p< 0.01).

Previous reports suggest that the ACL-deficient knee increases the risk of meniscal injury and meniscal incompetence hastens OA. Our data show a progressive increase in the rate to meniscal surgery, and meniscal injury complexity with time. These delays and rates are higher than the ones proposed in the literature.

It appears that the experience in our Province simply reproduces (rather than improves upon) the natural history of the ACL injury. We postulate restricting access to specialists and to surgery place the patient at risk for requiring avoidable surgery and developing osteoarthritis


N.A. Hill R.A. Fellows H.S. Gill N.J. MacIntyre S.C. Leclaire T.S.Y. Tang M.M. Harrison D.R. Wilson

We evaluated the accuracy of a Magnetic Resonance Imaging (MRI)-based method to measure three-dimensional patellar tracking during loaded knee flexion. This method determines the relative positions of the knee bones by shape matching high-resolution three-dimensional geometric models of these bones to fast low-resolution scans taken during loaded flexion.

The accuracy of the method’s assessment of patellar position and orientation was determined by comparing test measurements in four cadaver specimens to measurements made in the same specimens using Roentgen Stereophotogrammetric Analysis (RSA). This MRI-based method is more accurate than current two-dimensional imaging methods.

The purpose of this study was to determine the accuracy of a MRI-based technique for measuring patellar tracking in loaded flexion.

This novel, noninvasive, MRI-based method measures three-dimensional patellar tracking during loaded knee flexion with sufficient accuracy to detect clinically significant changes.

Although abnormal patellar tracking is widely believed to be associated with pain and cartilage degeneration at the patella, these relationships have not been clearly established because most current methods assess only the two-dimensional alignment of the patella at one position. Measurements possible with this method should be sufficiently accurate to yield new insights into these relationships.

Four cadaver knee specimens were flexed through seventy-five degrees of flexion in an MRI-compatible knee loading rig. A high-resolution image was acquired with each knee in extension and then a series of low-resolution scans (in two slice directions: axial and sagittal) were acquired through a flexion cycle. Segmenting bone outlines from high-resolution scans generated models of the femur, tibia and patella. These models were shape matched to the segmented bone outlines in the low resolution scans. Patellar attitude and position were determined and compared to measurements made using RSA.

The mean measurement error in every kinematic parameter was lower for “fast” sagittal plane slices than for “fast” axial plane slices. In general, the mean measurement error was increased by decreasing the number of low-resolution slices.

This method is more accurate than many two-dimensional methods, exposes participants to no ionizing radiation, and can be used through a large range of loaded knee flexion.

Funding: Supported by an operating grant from the Canadian Institutes for Health Research and a Strategic Grant from the Natural Sciences and Engineering Research Council. NJM is supported by the Arthritis Society/CIHR Partnership Fund.

Please contact author for figures and/or tables.


B. Loitz-Ramage P.S. Schneider J. Ronsky R.F. Zernicke T. Breen

Studies have shown significantly shorter hospital stays and earlier return to mobilization when epidural analgesia was used in lower extremity surgeries. This study quantified the effects of epidural analgesia on lower extremity kinetics and kinematics during gait. There were no significant differences found in hip, knee, or ankle joint moments or angles between baseline (no drug) and epidural trials, using two different drugs. These findings indicate that epidural analgesia does not alter normal gait in healthy subjects, suggesting that patients requiring epidural analgesia following orthopaedic surgery may also be able to participate in rehabilitation without significant epidural-related changes in gait.

Epidural analgesia has been used post-operatively following chest, abdominal and lower extremity surgery, with significantly shorter hospital stay and earlier return to mobilization demonstrated. This study quantified the effects of epidural analgesia on lower extremity kinetics and kinematics during gait.

Ten healthy volunteers were tested on different days with two drugs. With the catheter (L3-L4 intervertebral space) in place but prior to drug administration, gait was assessed. Testing was repeated 30 min after drug administration. Motion and ground reaction force data were recorded during walking with a four-camera video-based system (Motion Analysis Corp) and force platform (Kistler).

No significant differences existed in 3-D hip, knee, or ankle joint moments or angles among baseline (no drug) and drug trials.

These findings indicate that epidural analgesia does not alter normal gait in healthy subjects, suggesting that patients requiring epidural analgesia following orthopaedic surgery may also be able to participate in rehabilitation without significant epidural-related changes in gait.

It is well documented that early mobilization and rehabilitation following orthopaedic surgery improve healing and shorten hospital stay. However, pain often limits full participation. Epidural analgesia appears to be an appropriate mode of pain relief that, despite somatosensory changes, may allow normal gait.

Epidural analgesia in healthy volunteers does not alter lower extremity kinetics or kinematics, suggesting that it may be an effective mode of pain relief that will allow better participation in therapy following orthopaedic surgery.

Funding: McCaig Professorship Program Development Fund, Wood Professorship, The Foothills Hospital Obstetric Anesthesia Research Fund, The National Science and Engineering Research Council of Canada, and The University of Calgary Biomedical Engineering Program.


M. Glazebrook M. Langman J.M. Lee

Tendinosis is a common problem causing wide spread morbidity ranging from mild symptoms of pain and limited mobility to catastrophic end stage rupture. The structural and mechanical properties of the rat Achilles tendon were investigated as groundwork for the development of a rat Achilles tendinosis model. This model will generate tendons afflicted with tendinosis that bear histological features identical to those observed in human tendinosis. Tissues afflicted with tendinosis derived from this model will be used in future studies to gain a better understanding of the biology of tendinosis and to evaluate various therapeutic intervention strategies.

The pathology underlying tendinosis is a continuum, with mild symptoms progressing toward catastrophic rupture; still, the corresponding biochemical and biomechanical progression is poorly understood.

We have developed a rat model for Achilles tendinosis, aiming to: (i) define for the first time the structural/mechanical features of the normal tendon and (ii) examine the histological changes with over-exercise.

Normal rat Achilles tendons were assayed via: hydroxyproline for total collagen, SDS-PAGE electrophoresis for collagen subtypes, thermoelastic testing for immature/mature collagen crosslinking, and tensile mechanical testing. As per Soslowsky in the rat rotator cuff, the over-exercise model used 10° uphill treadmill running over twelve weeks. Light histology under H& E staining and birefringence was assessed using a blinded, semi-quantitative scale.

The normal rat Achilles is 89.6 ± 10.6% (SD) collagen with a mean UTS of 5.29 ± 1.91 MPa (SD). Only type I collagen is evident in SDS-PAGE and immature collagen crosslinking is dominant demonstrated by

NaBH4-reduction required to achieve a 90°C isotherm

in hydrothermal testing. The three, six and twelve-week over-exercise regimes produce increasing cell area density and decreasing collagen organization. Surprisingly, the proliferating cells do not seem to be fibroblast dominant and label with factor III antibody to human endothelial cells.

The normal Achilles tendon in young (eight weeks old) but mature rats is a strong, collagen-rich tissue; however, immature crosslinking suggests remodelling. We suspect that low type III collagen in the normal Achilles may increase significantly with inflammation. However, fibroblast proliferation may not be dominant.

Our rat Achilles tendon over-exercise model has demonstrated histopathology consistent with the human literature. With clear structural/mechanical characterization, future studies will focus on changes in these variables with disease tendons derived from the rat ten-dinosis model.

Funding: Research Grants were received from the following organizations: 1-Canadian Orthopaedics Foundation, 2-American Foot and Ankle Society, 3-Dalhousie University Department of Surgery, 4-Nova Scotia Capitol District Health Authority Research Fund


M. Morelli M.B. Hurtig A. Miniaci J. Nagamori

Osteochondral autogenous transfer is an accepted treatment for the management of osteochondral defects in the knee. Concerns about donor site morbidity and kissing lesions of the patella lead us to assess the efficacy of filling donor sites with bioabsorbable bone cement in a sheep model. Donor sites were assessed two, eight and sixteen weeks postoperatively using macroscopic scoring, histology and creep indentation testing. At eight and sixteen weeks after graft harvest there were fewer patellar kissing lesions in the treatment group. Control defects had more extrinsic repair whereas cartilage flow was the predominate source of repair tissue in the treated group.

The purpose of this study was to determine if Norian SRS® bone cement can mitigate donor site morbidity in a model of osteochondral transplantation in the knee.

Ten sheep were assigned to either a control or experimental group. Under general anesthesia and aseptic technique, four donor site defects were created in standardized non-weightbearing regions of the trochlear ridge. These defects measured 4.5 mm in diameter x 10 mm deep. Norian SRS bone cement was used to fill donor site defects up to the level of the tidemark in five experimental sheep. In the control group (n=5), donor sites were left unfilled. One sheep from each group was sacrificed two weeks postoperatively and two sheep from each group were sacrificed at eight and sixteen weeks. Macroscopic scoring, histology and biomechanical creep indentation were used to assess the knee joints.

At eight weeks, treated defects had more filling by facilitating cartilage flow, yielding fewer kissing lesions on the patella. At sixteen weeks, the treated group had more cartilage flow but little extrinsic repair. The control group defects had a more uniform fill with repair tissue and better biomechanical properties but kissing lesions on the patella remained problem.

Short-term results suggest that unfilled donor sites allow better extrinsic repair at the expense of creating kissing lesions. Norian SRS cement reduced kissing lesions on the patella.

Norian SRS was a barrier to extrinsic repair but supported cartilage flow. Cartilage flow in thicker, human cartilage will be greater. It may be possible to support cartilage flow and still allow extrinsic repair by applying Norian SRS up to but not including the tidemark.

Funding: The authors received funding from Synthes, Canada for this project. Thanks to Deb McWade for technical assistance.


T.S.Y. Tang N.J. MacIntyre H.S. Gill R.A. Fellows N.A. Hill D.R. Wilson R.E. Ellis

Patellofemoral Pain Syndrome is characterized by anterior knee pain during activities such as squatting that is thought to be caused by abnormal patellar motion. However, the causative role has yet to be verified since it is difficult to measure the three-dimensional kinematics of the patellofemoral joint (PFJ) in vivo. We developed a fluoroscopy-based method to measure patellar motion as it moves under load through a cycle of flexion and compared the results with those obtained using Roentgen Stereophotogrammetric Analysis (RSA). Our data suggest that the fluoroscopy-based method has sufficient accuracy to detect clinically significant differences in patterns of patellar motion.

The purpose of our study was to determine how accurately a fluoroscopy-based method measures patellar tracking.

Our method measures three-dimensional PFJ kinematics with sufficient accuracy to be of clinical value in assessing dynamic motion.

Patellar tracking can be assessed during aggravating activities to identify specific tracking abnormalities related to anterior knee pain.

Four cadaver knees were imaged using computed tomography (CT). Surface models were generated and the coordinates of implanted tantalum beads (in the femur, patella, and tibia) were determined. A series of fluoroscopic images were taken with the knees loaded in a rig at various flexion angles. Each calibrated fluoroscopic image was registered to the CT model using a point-based method such that the high-resolution CT model was matched to the position of knee flexion associated with each fluoroscopic image. The patellar orientation and position relative to the femur was then reconstructed and described using a gyroscopic joint coordinate system. Measurements were made under the same test conditions using the established uniplanar RSA technique. Fluoroscopy-based and RSA-based measures of patellar orientation and position were compared.

The mean measurement error (SD) for patellar flexion, spin, and tilt was 1.86 (1.55), 1.16 (1.14), and 1.15 (1.10) degrees, respectively. For proximal, lateral and anterior patellar translation, the mean measurement error (SD) was 2.11 (2.16), 0.59 (0.47), and 1.24 (1.18) mm, respectively.

The accuracy of the fluoroscopy-based method of measuring PFJ kinematics was poorer than the reported accuracy of RSA but appears to be sufficiently low to be of clinical value.

Funding: Supported by an operating grant from the Canadian Institutes for Health Research and a Strategic Grant from the Natural Sciences and Engineering Research Council. NJM is supported by TAS/CIHR Partnership Fund.


T.R. Daniels R. Thomas K. Parker

Ankle arthrodesis for isolated ankle arthritis has a high patient satisfaction level; however, gait analysis and functional outcome measurements demonstrate substantial disability. The high patient satisfaction may reflect the extent of disability present prior to the intervention.

This study demonstrates that the presence of subtalar or talonavicular arthritis and/or limited motion is a negative predictor for a satisfactory outcome. The risk of developing arthritis of these joints increases with time and therefore the patient can expect a deterioration of their initial result. Ankle arthrodesis should be considered a salvage procedure. Viable alternatives that preserve motion should continue to be explored.

The purpose of this study was to utilize gait analysis and validated outcome measures to assess the results of an ankle arthrodesis and compare these results to a healthy age – sex matched control group.

Isolated Ankle arthrodesis has a high patient satisfaction rate; however, gait analysis and functional outcome scores demonstrate a significant difference when compared to controls. The presence of limited subtalar and midfoot motion and/or arthritis correlates with a poor clinical result.

This study will help the clinician predict outcomes and better educate patients as to the expected results following ankle arthrodesis.

Twenty-six patients with an isolated ankle arthrodesis underwent gait analysis and functional outcome assessment using AOFAS ankle-hindfoot scale, MODEMS (includes SF-36) and Ankle Osteoarthritis Scale (AOS). A radiographic analysis was preformed. Mean follow-up was 3.7 years. Results were compared to a group of twenty-six controls.

Seventy-seven percent were satisfied and eighty-eight percent would recommend it to a friend. These perceived outcomes did not correlate well with their average Functional Outcome scores and gait analysis. The AOFAS score rated 46% as excellent or good. The MODEMS identified significant differences in Physical Function, Role-Physical and Physical Composite means when compared to controls. The AOS identified significant differences in Pain and Disability means. Gait analysis demonstrated significant differences in stride length, cadence, hip flexion, hindfoot flexion, hindfoot inversion and midfoot flexion. Decreased hindfoot and midfoot motion correlated with poorer outcome scores. Poor radiographic scores correlated with decreased hindfoot/midfoot motion and poorer clinical outcomes.

Ankle arthrodesis should be considered a salvage procedure. Viable alternatives that preserve ankle motion should continue to be explored.


T.R. Daniels R. Thomas

This study demonstrates that harvesting a vascularized fibular graft has a significant number of minor complications. These complications do not result in significant morbidity but could be avoided by other newer methods of managing bony defects and avascular necrosis such as porous bone substitute rods.

The purpose of this study was to evaluate functional outcomes of the foot and ankle following vascularized fibula graft harvest, using validated outcome measures.

This study agrees with previous reports in that minor complications are commonly associated with free fibula harvest. Functional outcome scores demonstrate significant differences in pain and disability; however, the disability associated with daily activities is small.

This is the first study to assess the outcomes of vascularized fibular grafts with validated outcomes measures. It is one of a few studies to assess the outcomes of vascularized fibular grafts on an otherwise normal lower extremity.

Twenty-two patients were available for study, with ten attending for examination. All had undergone free fibula transfer for mandibular reconstruction. Functional outcome was assessed using MODEMS (includes SF-36) and Foot Function Index (FFI). A radiographic analysis was performed. All patients had a normal contralateral foot and ankle which was used as a control. Mean follow-up is 3.1 years.

Sixty percent of patients were satisfied following surgery. Subjective complaints of weakness, instability and numbness were reported. Minor wound complications were seen in twenty-three percent of patients and clawing of the lesser toes in eighteen percent. No significant difference was seen in the SF-36 categories when compared to population norms. The FFI identified significant differences in Pain and Disability means when compared to the contralateral side. Radiographic analysis failed to demonstrate increased arthritic change or instability. Two patients had undergone further surgery for toe clawing and persistent ankle pain.


J.T.C. Lau E. Stamatis B. Parks L.C. Schon

The Weil osteotomy has gained popularity for surgically treating patients with metatarsalgia, intractable plantar keratosis and/or metatarsophalangeal joint dislocation because of its simplicity and lack of complications. Different geometric configurations of the Weil osteotomy have been proposed to reduce plantar pressure. In a dynamic cadaver model, these different geometric configurations of the Weil osteotomy did not significantly alter plantar pressure. Metatarsal head resection was required to significantly reduce plantar pressure.

The purpose of this study was to evaluate the effect of different geometric configurations of the Weil osteotomy on the plantar pressures in a dynamic cadaver model.

Different geometric configurations of the Weil osteotomy have been proposed to decrease plantar pressure, but in a dynamic cadaver model, these modifications did not significantly alter plantar pressure. Metatarsal head resection was required to significantly reduce plantar pressure.

The plantar translation of the metatarsal head occurring with a more oblique Weil osteotomy compared to a standard Weil osteotomy did not significantly increase plantar pressure in a dynamic cadaver model. The addition of a 4 mm slice resection did not significantly reduce pressure. Metatarsal head resection was required to significantly reduce pressure (p=0.02).

Ten specimens (5 matched pairs of cadaver lower extremities) were tested. Each pair of specimens had an oblique Weil osteotomy performed on one side, and a standard (parallel) Weil osteotomy on the other. Then, a 4 mm slice resection, and metatarsal head resection were performed sequentially. The plantar pressures were measured with an F scan in-shoe sensor while cyclically loaded to 700 N at a frequency of 1 Hz in intact specimens, and after each intervention.

The different geometric configurations of the Weil osteotomy did not significantly alter plantar pressure; metatarsal head resection was required to significantly reduce pressure. The Weil osteotomy reliably reduces dislocated metatarsophalangeal joints. The angle of the osteotomy does not affect plantar pressure. Further study in a dynamic model is required to identify other factors, which affect plantar pressure.


A. Younger P.J. Dryden B.J. Sawatzky

Twenty-one symptomatic flat feet from the surgical wait list were compared with twenty-one matched controls. The radiographs were digitized, blinded and the measurements made two occasions by two observers in different order.

On the lateral radiograph the talar to first metatarsal angle reached greatest significance at p< 0.0001, and had an inter and intra observer reliability of 0.83 and 0.75 respectively (r2 value). Only three other of the twelve measurements made reached statistical significance. Radiographic assessment of reconstructive procedures should show restoration of the arch of the foot: We recommend using the talar neck to first metatarsal angle on the lateral view as the correct indicator of loss or restoration of an arch.

The purpose of this study was to determine the radiographic measures that differentiate the symptomatic adult flat foot from a normal foot, and determine the reliability of the measurements.

Although many radiographic measures of flat foot are described, only four out of twelve measurements studied were significantly different between symptomatic adult flat foot and normal adults.

Radiographic assessment of reconstructive procedures should show restoration of the arch of the foot: We recommend using the talar neck to first metatarsal angle on the lateral view as the correct indicator of loss or restoration of an arch.

Twenty-one symptomatic flat feet from the surgical wait list were compared with twenty-one matched controls. Diagnoses included rheumatoid arthritis and posterior tibial tendonitis. All previously described measures of loss of arch were measured on standing AP and lateral radiographs of the foot taken using the same radiographic technique at a single facility. The radiographs were digitized, blinded and the measurements made two occasions by two observers in different order.

On the lateral radiograph the talar to first metatarsal angle reached greatest significance at p< 0.0001, and had an inter and intra observer reliability of 0.83 and 0.75 respectively (r2 value). The medial cuniform to 5th metatarsal height also reached signficance, but had poor intraobserver reliability (r2 =0.09). On the AP view, only the talar head uncoverage distance reached significance (p< 0..0001) but had poor inter and intraobserver reliability (r2=0.05 and 0.08).


V. Sahajpal C. Fisher M. Dvorak

A prospective cohort outcome evaluation of unstable thoracic spine fractures treated with posterior pedicle screw fixation. The purpose of this study was to determine the accuracy of placement and safety of pedicle screws in open reduction of unstable thoracic spine fractures. The surgeries were performed by one of five fellowship trained spinal surgeons. CT scans were formed on twenty-three patients totaling two hundred screws using 3mm cuts. Three independent reviewers assessed and categorized the screw position as within the pedicle or as a violation of the pedicle wall. 98% of the screws were accurate and we recommend the use of pedicle screws in thoracic fractures .

A prospective cohort outcome evaluation of unstable thoracic spine fractures treated with posterior pedicle screw fixation.

This study is to determine the accuracy of placement, safety of pedicle screws in open reduction of unstable thoracic spine fracture

Surgery was performed by one of five fellowship trained spine surgeons. CT scans were performed on twenty-three patients using 3mm cuts in both sagittal and transverse planes. Pedicle screw position was assessed by three independent reviewers. Screw position was categorized as within the wall of the pedicle or in violation of the wall. Further sub-classification of pedicle wall violation reviewed the direction and distance of perforation. Independent perioperative and postoperative surveillance for complications was done.

Twenty-three unstable thoracic spine fractures treated with two hundred posterior pedicle screws were analyzed. The pedicle screws spanned from T1-T12 with the majority of screws in the mid-thoracic region. Of the two hundred thoracic pedicle screws placed, 70% were fully contained within the pedicle wall. The remaining screws were deemed “out” with cortical perforation (30%). Of these, 20% were lateral perforations, 5% were medial perforations and 5% were anterolateral perforations. No superior, inferior, or anteromedial perforations were found. There was no regional area variation in incidence of perforations. 10% of all perforations were directly related to pedicle diameter to screw diameter mismatch. There were no adverse neurological, vascular, or visceral injuries detected intraoperatively or postoperatively.

Surgical management of unstable thoracic spine fractures with posterior pedicle screw fixation is safe. 98% of screws had satisfactory accuracy. Although very minor misplacement of pedicle screws occurred, there were no complications and we recommend the use of pedicle screws in thoracic fractures.


R. Reindl M. Aebi

Easier patient positioning and less extensive soft tissue dissection have spurred a trend for anterior instrumentation and fusion for C-spine fracture/ dislocations. We present group of forty-six patients treated over an eighteen month period with an anterior approach. There were no permanent approach related complications, infections, hardware failures or graft displacements. One patient had worsened post-operative neurological findings. One patient required additional posterior stabilization for a missed injury. Two patients were not reducible from the front and required posterior reduction and stabilization followed by anterior instrumentation and fusion. All grafts healed within four months of the operation.

The purpose of this study was to assess the efficacy of anterior instrumentation and fusion for Cervical Spine fracture/ dislocations

Over an eighteen month period, forty-six out of fifty-two patients with C-spine injuries requiring surgical treatment were followed prospectively. All patients underwent anterior approaches to stabilize and fuse the unstable segments using tricortical bone grafting and application of an anterior plate (CSLP, Synthes). Thirty-eight patients had single level injuries treated with discectomy and fusion. Two patients had two level discecomies. Six patients underwent corpectomy and fusions for fractures of the vertebral bodies

There were no approach related complications such as recurrent laryngeal nerve injuries, oesophageal perforations, vascular injuries or strokes. One patient deteriorated neurologically. All other patients either improved neurologically or remained with their original findings. Two patients required oral antibiotics for superficial infections at the donor site. There were no spine infections, hardware loosening or graft extrusions. All bone grafts healed within four months both clinically and radiologically. Forty-one patients complained of minor or no pain after four months. Five patients continued to have moderate discomfort. One of these patients had a missed injury above his two-level fusion with gradual progression into kyphosis requiring posterior stabilization.

Halo vest immobilization and posterior stabilization for C-spine fracture /dislocations have been the treatment of choice for many surgeons. The low complication and failure rate has spurred on a gradual change towards anterior instrumentation and fusion. Our study very strongly supports this trend. We see little indication for the more invasive posterior approach given our present results.


Y.R. Rampersaud K. Karkouti L. Evans S. McCluskey

The risk of blood transfusion in spinal fusion surgery is significant and mandates efforts to reduce ABT. This prospective study demonstrated a significant reduction in the rate of allogeneic blood transfusion (ABT) using Cell Saver (CS), Preoperative Autologus Donation (PAD), and Preoperative Erythropoietin Therapy (PET). The ABT was inversely related to the number of modalities used: 74% (n=14/19) with zero modalities; 32% (n=24/74) with one modalities; 17% (n=9/52) with two modalities; and 7% (n=2/28) with three modalities. Due to the potential amount of blood loss during spinal fusions the use of several BC techniques in combination is required to effectively reduce ABT.

The purpose of this prospective study is to assess the efficacy of current blood conservation (BC) techniques in reducing the rate of allogeneic blood transfusion (ABT) in spinal fusions.

All three current blood conservation techniques, particularly in combination, proved to be very effective in reducing the rate of ABT in elective spinal fusions.

Transfusion of allogenic blood despite its improved safety is not without risk.

From June 1999 to September 2001, transfusion and related surgical data has been prospectively collected in one hundred and seventy-three patients undergoing elective spinal fusions. The following three BC techniques were utilized: Cell Saver (CS), Preoperative Auto-logus Donation (PAD), and Preoperative Erythropoietin Therapy (PET).

The average number of fusion levels was 2.3 (range 1–5). The average estimated blood loss was 1725 milliliters (range 250–10700). Decompression was also preformed in 75% of cases. The overall ABT rate was 28% (n=49/173). The ABT was inversely related to the number of modalities used: 74% (n=14/19) with zero modalities; 32%* (n=24/74) with one modalities; 17%* (n=9/52) with two modalities; and 7%*† (n=2/28) with three modalities respectively (*statistically significant compared to zero modality group; † statistically significant compared to one modality group). The patient demographics and surgical variables were similar between the four groups. The use of CS, PAD, and PET was independently related to ABT.

The risk of blood transfusion in spinal fusion surgery is significant and mandates efforts to reduce ABT. Due to the amount of blood loss the use of several BC techniques in combination is required to effectively reduce ABT.


A.S.E. Younger T.P. Kalla J.P. Veri G. de Vries

This study is a retrospective review of transmetatarsal amputation (TMA) outcomes in patients with diabetes and non-healing ulcers of the forefoot. All were treated by single stage TMA and insertion of antibiotic beads in the surgical wound. Healing time was approximately eighteen weeks with a failure rate (subsequent BKA) of 25%. This is in contrast to literature values of healing times (not isolated to diabetics) of twenty-eight weeks and BKA rates of 34–40%. The decreased morbidity associated with our surgical procedure may address the costly management of diabetic foot ulcers (presently estimated to be $600 million per year).

The purpose of this study was to review the outcome of transmetatarsal amputation (TMA) in diabetic patients as a single stage procedure using antibiotic pellets in the wound.

We report faster healing times and a decreased rate of subsequent below-knee amputation (BKA) when compared with related studies in the literature.

1) Our procedure may decrease morbidity in a problem (diabetic foot ulcer management) costing approximately $600 million per year. 2) This study uniquely addresses TMA in diabetics.

Mean healing time was eighteen weeks (range six to forty weeks). Patients with intact foot pulses or reconstructed vasculature had a mean recovery time of 12.5 weeks. Healing times for unreconstructable vasculature or documented deep infection were thirty weeks and twenty weeks respectively. The overall failure rate (BKA) was 25%. Neither vascular status nor the presence of deep infection predicted subsequent BKA.

Retrospective review of patient charts. Forty consecutive diabetic patients (mean age 58.3 yrs, range 40–77) with foot ulcers of > twelve weeks duration had TMA performed at a tertiary care center by one of three surgeons. Data tabulated included demographics, diabetes profiling, vascular interventions and follow-up parameters.

Diabetic foot ulcer morbidity is a significant cost burden to health care; despite this, salvage procedures for this problem are not well studied. Previous papers (not isolated to diabetics) report TMA healing times of twenty-eight weeks and subsequent BKA rates of 34–40%. Refinements of the TMA technique in diabetics may decrease early and late morbidity and thus address this costly problem.


N.C. Stone D. Young J. Molgaard D. Durford

Our cadaveric biomechanical study has demonstrated evidence to suggest that commercially available removable cast boots do provide the same reduction of force on a first MTP joint arthrodesis site, during the early post operative period, as a traditional fiberglass cast.

This study compares the effectiveness of three common models of walking boots to a fiberglass cast in protecting an arthrodesis of the first metatarsophalangeal (MTP) joint in the early post-operative period.

First MTP joint arthrodesis is commonly performed for various clinical problems. Weight bearing is encouraged post operatively, however the arthrodesis site must be protected from excessive forces until bony union is achieved.

Two cadaveric models of a 1st MTP joint arthrodesis were prepared with a strain gauge placed at the joint, which provided a measure of the bending moment across the fusion site. Walking was simulated by applying a force to the sole of the cadaver foot at multiple positions, from the heel to the toe, representing the stages of gait from heel strike to toe off. Loading trials were performed using each of the walking boots and a fiberglass cast, with the moments across the joint compared.

For both specimens, the “Walkabout” by Smith & Nephew had the lowest mean moment. Specimen one showed that the “Walkabout” and “Sampson Walker” were both better than the “Equalizer” and fiberglass cast (p< 0.05). Specimen two showed that the “Walk-about” was better than all others (P< 0.05). Also, for both specimens, the “Walkabout” by Smith & Nephew had the smallest absolute maximum moment (P< 0.05). Our study has shown that removable cast boots do provide the same, if not more, reduction of force on a first MTP joint arthrodesis site as a traditional cast.


D.A. Bednar H. Abdelbary M. Dekker

Confirmation of cervical stability in multiple trauma patients is often difficult. Prolonged collar immobilization of these patients is often required. Missed injuries can be catastrophic. Since January 2000, the senior author has regularly applied a modification of the classical White & Panjabi stretch test in the operating room as a method of assessing cervical stability in qualifying trauma patients. Review of the first thirty cases finds two cases of stable ligamentous injury identified which would have otherwise been missed, a mean of almost two weeks’ collar immobilization eliminated and no missed instabilities, with no complications or assessment failures to date.

The purpose of this study was to present the protocol and preliminary results of a modified White & Panjabi cervical stretch test in the assessment of cervical instability in multiple trauma patients.

Multiple trauma patients having no radiographic evidence of cervical instability on static imaging are routinely protected in hard collars until able to cooperate with clinical assessment and/or undergo flexion/extension radiographs for concern to possible discoligame-nous instability in the neck. Beginning in January 2000, such patients who were going to the operating room were routinely assessed with a stress test incorporating fluoroscopically-controlled axial distraction to tensile limit of the neck followed by maximum passive flexion and extension stressing. In the absence of intersegmental hypermobility, cervical precautions and immobilization were considered unnecessary and discarded. Chart documentation was reviewed for outcome and complications after discharge from the hospital.

To date thirty-two tests have been performed and twenty-six cases had complete chart documentation available for review. No complications of the procedure and no missed instabilities have been identified. An average of thirteen days’ collar immobilization were eliminated by this protocol. Two cases of ligamentous hypermobility without instability were identified, one at O/C1 and the other at C5/6; both patients were treated observationally and have done well. One case of an undisplaced C2 pedicle fracture in a massively traumatized geriatric case was confirmed as stable on the day of injury, eliminating the need for collar support until the patient died of multiple organ failure twenty-one days later. Two patients went on to have neck pain complaints on regaining consciousness, but could be reassured that there was no instability.

The operating-room cervical stress test is a practical and safe maneuver that can eliminate the requirement for collar immobilization in obtunded trauma patients, safely identify subtle ligamentous injuries without frank instability, and confirm stability in cases of undisplaced fracture.

The operating-room cervical stress test is an effective tool in screening trauma patients for such injuries. It does not require access to MRI technology and can be used in any hospital with an operating room.

Prolonged cervical collar immobilization and missed discoligamentous injuries of the neck in multiple trauma patients can be eliminated with the application of this test.


K.P. Droll P. Perna A. McConnell D. Beaton M.D. McKee E. Schemitsch

The purpose of this study was to investigate patient-based functional outcome and objectively measure strength following plate fixation of fractures of both bones of the forearm. Twenty-five subjects were clinically and radiographically reviewed. Strength of elbow flexion, extension, supination, pronation, wrist flex-ion, extension and grip were significantly reduced in the injured arm. (p< 0.01, range 62%–84% of normal). Mean (+/− SE) DASH score was 19.5 +/− 4.0 and eighty-eight percent (22/25) scored good to excellent on the Gartland-Werley scale (mean 4.04 +/− 0.91). No statistical difference in mean maximal radial bow (MRB) or location of MRB between injured and non-injured arm was found.

The purpose of this study was to investigate functional outcome and objectively measure strength following plate fixation of fractures of both bones of the forearm (BBOF).

Anatomic reduction was associated with good to excellent functional outcome. However strength of the elbow, forearm, wrist and grip were significantly reduced in the injured arm.

Despite good to excellent functional outcome following this injury, significant reduction in strength of the upper extremity should be expected, and thus is an area for potential improvement in post-operative care.

Twenty-five subjects (M/F 19/6, mean age 47.6 (range 20–71)) treated with plate fixation for fractures of BBOF were clinically and radiographically reviewed. Mean duration of follow-up was 5.7 years (range 2–13.4 y). Post-operative protocol included short-term immobilization followed by active-assisted ROM and strengthening starting between four and six weeks. Isometric muscle strength was objectively measured with the Baltimore Therapeutic Equipment work simulator (model WS-20). Strength of elbow flexion (72% of non-injured arm, p< 0.0001), elbow extension (84%, p=0.0004), forearm supination (75%, p=0.005), forearm pronation (69%, p< 0.0001), wrist flexion (81%, p=0.009), wrist extension (62%, p< 0.0001) and grip (70%, p< 0.0001) were all significantly reduced in the injured arm. Mean (+/− SE) DASH and Gartland-Werley scores were 19.5 +/− 4.0 (range 0–61) and 4.04 +/− 0.91 (range 0–15) respectively. Eighty-eight percent (22/25) scored good to excellent on the Gartland-Werley scale. No statistical difference in mean maximal radial bow (MRB) between injured and non-injured arm was found (mean +/− SE, 1.42 +/− 0.07 vs 1.58 +/− 0.05 respectively) or in location of MRB (61% vs 59%).


E.H. Schemitsch D. Togawa J. Reid T.W. Bauer H. Sakai M. Hawkins F. Dimaano

The purpose of this study was to evaluate trabecular bone response to four different synthetic graft materials (CaSO4 and CaSO4 – HA/TCP composites) as compared to autograft in a canine defect model. The group with the highest HA/TCP proportion (and the lowest CaSO4 proportion) had the greatest amount of residual graft material and total mineralized material (p< 0.05). Increasing the proportion of HA/TCP reduces the rate of dissolution, and appears to have little effect on bone formation. This study suggests that a range of composites could be created to match the spectrum of resorption rates demanded by clinical applications.

Calcium sulfates and phosphates have become popular clinically for use as bone graft substitutes, however, their in-vivo performance has not been well characterized. The purpose of this study was to evaluate trabecular bone response to four synthetic graft materials (CaSO4 and CaSO4 – HA/TCP composites) as compared to autograft in a canine defect model.

Both 100% CaSO4 and the 3 CaSO4– HA/TCP formulations showed good bone formation. The group with the highest proportion of HA/TCP lasted longer than the other formulations, suggesting increased HA/TCP proportions reduce the rates of dissolution, without compromising bone formation in the current model.

Results suggests that a range of composites could be created to match the spectrum of resorption rates demanded by clinical applications.

In this REB-approved RCT, bilateral humeral and femoral cylindrical defects were filled with one of four types of pellets with varying proportions of CaSO4 – HA/TCP, autograft bone, or left unfilled. After sacrifice at six or twelve weeks, defect sites were evaluated histologically for tissue and inflammatory response, area fractions of residual graft material, and bone ingrowth in the defects.

The area of the defect occupied by residual graft material in the group with the highest percentage of HA/TCP was greater than in other composite groups (p< 0.0006). At twelve weeks, this group contained more total mineralized material (graft material + bone) (p< 0.005). The extent of new bone formation was not different among the composite groups at either time-point, but all showed more bone formation than the empty defect.

Funding: This study was funded by a research grant from Stryker Howmedica, Matwah, NJ.


M. Blankstein K. Syed M. Nakane A. Bang J. Freedman R. Richards E. Schemitsch

The purpose of this study was to determine the effect of positioning (lateral vs. supine) on pulmonary patho-physiology following pulmonary contusion and fat embolism in a canine model of polytrauma. Platelet and neutrophil activation were assessed using flow-cytometry. There were no significant differences between groups in CD62P and CD11/18 MCF (markers of platelet and neutrophil activation, respectively) following fat embolism. However, only animals in the lateral position displayed significant increases in both measures as compared to baseline values. Lateral positioning may exert an early effect on proinflammatory and coagulation activation, and may play a role in the development of acute lung injury.

It has previously been suggested that acute lung injury can be influenced by patient positioning, be it lateral or supine. The purpose of this study was to determine the effect of positioning on pulmonary pathophysiology associated with concomitant pulmonary contusion and fat embolism in a canine model of polytrauma.

Twelve dogs were randomly assigned to one of two surgical positioning groups, lateral and supine. The dogs were subjected to pulmonary contusion by application of force between 200–250 N/m2 for thirty seconds in three areas of one lung. Two hours later, fat embolism was induced via reaming of the ipsilateral femur and tibia and cemented nailing. Two hours later, the dogs were sacrificed. For flow-cytometric evaluation of platelet and neutrophil activation, venous blood samples were stained with fluorescence-conjugated antibodies against CD62P and CD11/18, respectively. There were no significant differences between the groups in CD62P and CD11/18 mean channel fluorescence (MCF) following pulmonary contusion and fat embolism. However, only animals in the lateral positioning group displayed significant increases in CD62P and CD11/18 MCF at two hours following fat embolism as compared to baseline values.

Our findings suggest that lateral positioning, autoregulation and preferential blood flow to the contused non-dependent lung may render lung tissue more susceptible to congestion and lead to activation of both platelets and neutrophils. Lateral positioning may have an early effect on activation of the inflammatory and coagulation cascades and may be significant in the development of posttraumatic acute lung injury.


K. Mohanty J.N. Powell D. Musso M. Traboulsi I. Belankie B. Mullen J.V. Tyberg

Using an established canine model of fat embolization, the effect of temporary mechanical blockade of embolic load during medullary canal pressurization was studied. Haemodynamic measurements, echocardiography and postmortem histomorphometry were used as outcome measures. There was statistically significant difference between the filter and the control groups, when the pulmonary vascular resistance, the percentage area of lungs occupied by fat and the percentage of pulmonary vasculature occupied by fat were compared. We have shown that mechanical blockade by a filter does stop the adverse effect on the lungs during canal pressurization.

Acute intramedullary stabilization of femoral fractures in multiply injured patients still remains controversial. Intravasation of medullary fat has been suspected to trigger ARDS. This study investigates the effect of a filter placed into the ipsilateral common iliac vein during medullary canal pressurization.

Using an established canine model, twelve mongrel dogs were randomized into two groups. A special filter was inserted percutaneously into the left common iliac vein in half the dogs where as the other half served as controls. In all dogs, the left femora and tibiae were pressurized by injection of bone cement and insertion of intramedullary rods. Hemodynamic measurements and echocardiography images were recorded continuously. After sacrifice, the lungs were harvested for analysis.

The mean pulmonary artery pressure at three minutes of pressurization was 12 mm of Hg in the filter group and 28mm of Hg in the control group. The pulmonary vascular resistance in the control group was increased from the 3rd minute of pressurization throughout the experiment. This was statistically significant when compared with the baseline. There was no such change seen in the filter group. Transesophageal echocardiography showed less embolic shower in the filter group and histomorphometry demonstrated statistically signifant difference, when the percentage area of lungs and the percentage of pulmonary vasculature occupied by fat in the filter group as compared to the control group.

This canine study has demonstrated that mechanical blockade by a venous filters can significantly reduce the embolic load on the lungs during canal pressurization.


M. Blankstein M. Nakane R. Byrick R. Richards K. Osamu E. Schemitsch

This study was undertaken to assess the contribution of fat embolism (FE) to the development of acute lung injury in the presence of resuscitated hemorrhagic shock. Twenty-seven NZW rabbits were randomly assigned into four groups: resuscitated hemorrhagic shock and FE (HR/FE), resuscitated hemorrhagic shock, FE, and control. FE was induced via intramedullary femoral canal pressurization using a 1–1.5 ml bone cement injection. Only HR/FE animals displayed significant proinflammatory cytokine release as compared to controls. These findings suggest that the combination of resuscitated shock with FE initiates an inflammatory response, which may lead to the development of fat embolism syndrome.

The objective of this study was to assess the contribution of fat embolism caused by intramedullary femoral canal pressurization to the development of acute lung injury in the presence of resuscitated hemorrhagic shock.

Only the animals that underwent resuscitated shock and fat embolism displayed amplified BALF proinflammatory cytokine expression.

These findings suggest that the combination of resuscitated shock with fat embolism initiates an inflammatory response, which may play a role in the development of fat embolism syndrome.

Only HR/FE BALF IL-8 and MCP-1 levels were significantly higher than controls (0.72 ng/ml vs. 0.26ng/ ml, p=0.03; 18.3 ng/ml vs. 2.0 ng/ml, p=0.01, respectively).

Twenty-seven NZW rabbits were randomly assigned into four groups: resuscitated hemorrhagic shock + fat embolism (HR/FE), resuscitated hemorrhagic shock (HR), fat embolism (FE), and control. Shock was induced via carotid bleeding for one-hour prior to resuscitation. For FE induction, the intramedullary cavity was drilled, reamed and pressurized with a 1–1.5 ml bone cement injection. Four hours later, postmortem bronchoalveolar lavage was performed through the right mainstem bronchus. Analyses of bronchoalveolar lavage fluid (BALF) of interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) were carried out in triplicate and blinded fashion using the ELISA technique.

Our findings suggest that FE by itself does not initiate inflammatory lung injury, as there were no apparent differences between the control and FE cytokine levels. Only the HR/FE animals revealed elevated levels of pro-inflammatory cytokines in BALF. These findings are in agreement with our previous results, which displayed neutrophil activation only in the HR/FE group.


L. Luo A. Petit D.J. Zukor O.L. Huk J. Antoniou F. Mwale

The in situ increased production of matrix metalloproteinases (MMPs) has been associated with the development of periprosthetic osteolysis. The aim of the study was to compare the effect of Co2+ and Cr3+ ions on macrophages matrix metalloproteinase-1 (MMP-1) and tissue inhibitor of MMP (TIMP-1) expression. Using reverse transcription-polymerase chain reaction (RT-PCR), we showed that both Co2+ and Cr3+ ions induce the expression of MMP-1 and TIMP-1 in a dose-dependent manner. Since MMP-1 and TIMP-1 participate in the extracellular matrix degradation and tissue remodeling, our results suggest that the modulation of MMP-1 and TIMP-1 may contribute to the development of periprosthetic osteolysis.

The in situ increased production of matrix metalloproteinases (MMPs) has been associated with the development of periprosthetic osteolysis. Aseptic loosening due to periprosthetic osteolysis is the major cause of total hip arthroplasty failure. Because of their potential for improved wear performance, there has been a revived interest in metal-metal bearings, made of cobalt-chromium-molybdenum alloys. However, metal particle and ion toxicity remains a major cause for concern.

The aim of the study was to determine the effects of Co2+ and Cr3+ ions on the expression of matrix metalloproteinase-1 (MMP-1) and tissue inhibitor of metalloproteinase-1 (TIMP-1), two proteins participating in the extracellular matrix degradation and tissue remodeling.

Human U937 macrophages were incubated with Co2+ and Cr3+ ions. The expression of MMP-1 and TIMP-1 mRNAs was measured by reverse transcription-polymerase chain reaction (RT-PCR) and calculated as the ratio of the house keeping gene GAPDH expression.

Results show that both Co2+ and Cr3+ ions induced in a dose-dependent manner the expression of PCR products (mRNAs) of MMP-1 (135 bp) and TIMP-1 (328 bp). Co2+ ions were more effective in inducing MMP-1 and TIMP-1 expression than Cr3+ ions. The induction of MMP-1 and TIMP-1 paralleled the induction of TNF-α mRNA expression.

Our results demonstrate that the expression of MMP-1 and TIMP-1 were up regulated by incubating macrophages with Co2+ and Cr3+ ions, suggesting that metal ions contribute to tissue damage in the periprosthetic environment and that variations in MMP-1 and TIMP-1 expression may contribute to periprosthetic osteolysis.


D.M. Kennedy J. Gollish P.W. Stratford J. Wessel S.E. Hanna

This study explored differences in the early pattern of recovery for self-report (pain and physical function subscales of the Western Ontario and McMaster Universities Osteoarthritis Index) and physical performance measures (six minute walk and timed up and go test) in patients following arthroplasty. Using hierarchical linear modeling, different patterns of recovery and predictors of change were observed. The physical function subscale did not detect the early deterioration in physical function that was detected by the performance measures. Different important clinical information can be learned from performance measures, supporting the use of both types of measures when monitoring decline and recovery.

To explore differences in the pattern of recovery for self-report and physical performance measures in patients following total hip (THA) and knee (TKA) arthroplasty.

Different patterns of recovery and predictors of change were observed for the pain and physical function subscales of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and the performance measures. The physical function subscale did not detect the early deterioration in physical function demonstrated by the six minute walk (6MWT) and timed up and go (TUG) tests.

WOMAC scores are commonly used to monitor changes in pain and physical function both pre and post-operatively. Failure of the physical function sub-scale to detect decline in physical function experienced post-operatively suggests that the WOMAC may not always accurately reflect physical function.

The postoperative predicted scores for the WOMAC either exceeded or met the preoperative scores within one to two weeks compared to seven to eight weeks with the performance measures. The performance measure models contained a greater number of predictors than the WOMAC subscale models.

One hundred and fifty-two patients (mean age 63.8 ± 10.2 years) who underwent THA and TKA were assessed at several points over the first four postoperative months. Average growth curves for the WOMAC, 6MWT and TUG were characterized using hierarchical linear modeling. Predictors of recovery were sequentially modeled after validation of the basic developmental models.

Differences in models and the time point at which preoperative scores are met suggest that different information is being learned from self-report and physical performance measures.

Funding: This research was not supported by funding from a commercial party. It was supported by a grant from the Orthopaedic & Arthritic Foundation.


H. Frei J. O’Connell B.A. Masri C.P. Duncan T.R. Oxland

In impaction allografting, the host bone interface consists of morsellized allograft alone or as a composite with bone cement. The objective of this study was to investigate the host bone temporal changes in the interface for these two materials in a rat bone chamber model. The composite-host bone interface strength was significantly higher at three weeks and was higher than the allograft construct. Limited allograft, but extensive periosteal remodelling, was observed at three weeks. At six weeks a new medullary canal was formed and the endosteal cortex was partially absorbed. Endosteal absorption resulting in medullary canal widening may be responsible for clinically unstable stems after impaction allografting.

The host bone interface after impaction allografting consists of morsellized allograft alone or as a composite with cement and it may be important for the clinical success of this procedure. The purpose of this study was to investigate the temporal changes of these interfaces in a rat bone chamber model.

Bone chambers were inserted in both tibiae of thirty-three rats and tightened to the endosteal surface to create a microenvironment. One chamber was filled with allograft bone and the other with an allograft/ cement composite. After zero, three, and six weeks, the rats were euthanized, the interfaces mechanically tested and processed for histomorphometric analysis.

The composite-host bone interface strength was significantly higher at three weeks and was higher than the allograft construct. Extensive periosteal remodelling was observed at three weeks. At six weeks a new medullary canal was formed and the endosteal cortex was partially absorbed.

The increased interface strength of the composite-host bone interface was due to fibrous tissue attachment rather than direct bonding of the bone particles. Cortical porosity and cancellisation is known to be caused by a damaged endosteal circulation resulting in medullary canal widening and may cause clinically unstable implants.

Interface strength of the composite-host bone interface was increased at three weeks through fibrous tissue attachment. A damaged endosteal circulation caused cortical porosis and cancellisation.

With this rat bone chamber model a potential cause of stem subsidence after impacting allografting was identified.

Funding: The George W. Bagby Research Fund.

The Canadian Institutse of Health Research.

The Maurice E. Müller Foundation.

The Swiss Academy of Engineering Science.

The Robert Mathys Foundation.


P.A. Cripton G.A. Dumas L.P. Nolte

Information regarding the axes of motion or centers of rotation of the normal cervical spine are necessary to evaluate the similarity of the motion allowed by cervical total disc replacement designs to the natural cervical spine. However, little data has been presented previously regarding the three-dimensional axes of motion of the cervical spine for the three primary motions of flexion/extension, lateral bending and axial rotation. The objective of this study was to measure the three-dimensional axes of motion (Helical axis of Motion) in the natural sub-axial cervical spine using ex-vivo human cadaveric cervical spines.

To measure the Helical Axes of Motion (HAM) for the sub-axial cervical spine under flexion/extension, lateral bending and axial torsion moments and evaluate the effect of a physiologic axial preload on the axes locations and orientations.

This study demonstrated the feasibility of calculating the HAM in the cervical spine using an ex-vivo experimental protocol.

The HAM is a three-dimensional analogue to the two-dimensional center of rotation. The data presented here can be used to evaluate the similarity of the motion allowed by total disc replacement designs to the natural cervical spine. They can also be applied for the characterization of spinal trauma, pathology, instability or surgical devices.

The orientation and locations of the HAMs for axial torsion loading are presented in Figure 1. In flexion/extension the HAM penetrated the sagittal plane near the posterior aspect of the vertebral body and near the cranial endplate. The lateral bending results were similar to the axial torsion results. The addition of axial preload had little effect on the position and orientation of the HAM.

Sub-axial (level C2-C7) cadaveric cervical spine functional spinal units (n=7) were subjected to pure moments of 1 Nm. Specimens were tested with and without axial preloads of 200 N. Vertebral kinematics were measured using an optoelectronic motion analysis system. These data are particularly applicable to the evaluation and design of “motion-retaining” devices such as total disc replacements, facet joint replacement systems or flexible stabilization systems.

Please contact author for figures and diagrams.


C. Bellabarba T.A Schildhauer S.K. Mirza S.E. Nork M.L. Chip Routt J.R. Chapman

Retrospective review of eighteen patients with sacral fracture dislocations and cauda equina deficits treated with posterior sacral decompression and lumbopelvic fixation. At mean nineteen-month follow-up, all fractures healed without loss of alignment despite immediate full weight-bearing. Fifteen patients (83%) improved neurologically, and ten patients (56%) had full bowel/ bladder recovery. Complications consisted mainly of infection (17%) and asymptomatic rod breakage (33%). This series demonstrates the clinical effectiveness of lumbopelvic fixation, allowing the application to sacral injuries of decompression and fixation principles commonly used in fractures with neurologic deficits that occur in more rostral areas of the spine.

To evaluate the results of sacral decompression and lumbopelvic fixation for sacral fracture-dislocations with neurologic deficits.

Lumbopelvic fixation provided the stability necessary for full weight-bearing without loss of fracture reduction despite extensive sacral decompression. The functional neurologic improvement in most patients and complete neurologic recovery in all but one patient with intact lumbosacral roots are encouraging. The effectiveness of lumbopelvic fixation facilitates the application of principles of early decompression and stabilization to sacral fracture-dislocations.

Sacral fractures healed in all eighteen patients without loss of reduction. Average sacral kyphosis improved from forty-one to twenty-four degrees. Fifteen patients (83%) had normalization or improvement of bowel and bladder deficits, although only ten patients (56%) had improved Gibbons scores. Average Gibbons type improved from four to 2.8 at nineteen-month average follow-up. Rod breakage (33%) and infection (17%) were the most common complications. Recovery of bowel and bladder function was less likely in patients with disruption of any lumbosacral root (36% vs. 86%, p=.066) and complete deficits (47% vs. 100%, p=.241) although the small cohort size precluded statistical significance.

Retrospective review of medical records, radiographs, and prospectively collected data of eighteen consecutive patients with sacral fracture-dislocations and cauda equina deficits identified between 1997 and 2002 through institutional databases. Treatment consisted of open reduction, sacral decompression and lumbopelvic fixation. Radiographic and clinical results of treatment were evaluated. Neurologic outcome was measured by Gibbons’ criteria.

Please contact author for figures and diagrams.


C. Niosi Q. Zhu D. Wilson O. Keynan D. Wilson T. Oxland

The Dynesys is a flexible posterior stabilization system that is designed to preserve intersegmental kinematics and reduce loading at the facet joints. The purpose of this study was to determine if the length of the Dynesys spacer has an effect on range of motion (ROM) at the implanted level. Spacer length was found to significantly affect ROM in all three loading directions with and without a follower preload. The longer spacer increased ROM and the shorter spacer decreased ROM, largely due to differences in segmental compression between the two.

The Dynesys, a flexible posterior stabilization system that provides an alternative to fusion, is designed to preserve intersegmental kinematics and alleviate loading at the facet joints. Recent biomechanical evidence suggests that motion with Dynesys is less than the intact spine (Schmoelz, 2003). The purpose of this investigation was to determine if the length of the Dynesys spacer contributes to differences in range of motion (ROM) at the implanted level.

Ten cadaveric lumbar spine segments (L2-L5) were tested by applying a pure moment of ±7.5Nm in three directions of loading with and without a follower preload of 600N. Test conditions included: intact, injury at L3-L4, Dynesys at L3-L4 (standard spacer), long spacer (+2mm), and short spacer (−2mm). Intervertebral rotations were measured using an optoelectronic camera. Pressure sensors placed inside the joint capsules measured facet loads. Statistical significance was determined using repeated measures ANOVA.

Spacer length had a significant effect on ROM in all three loading directions with and without a follower preload. Initial contact loads within the facet joints were 150% and 64% that of the standard spacer for the short and long spacer, respectively.

The magnitude of distraction of the segment affects ROM. Shorter spacers increased segmental compression of the intervertebral disc and facet joints and therefore reduced ROM. With a follower preload, the segment is further compressed and ROM is further reduced.

The results contribute to an understanding of the design of such implants and could help guide future research.

Funding: Synos Foundation, Switzerland, National Science and Engineering Research Council of Canada (NSERC)

Please contact author for table or diagram.


E.D. Simmons C.B. Huckell Y. Zheng

Fifty-two patients older than sixty years had undergone multilevel lumbar decompression and fusion with instrumentation and reached a minimum two-year follow up. The relationship between abnormal sagittal plane configuration of the proximal segments and the number of lumbar fusion segments was radiographically analyzed. Group A (L1-L5 or S1) patients had two (20%) proximal vertebral compression fractures and four (40%) focal kyphosis. Group B (L2-L5 or S1) patients had one (6%) proximal vertebral compression fractures, five (33%) retrolisthesis and two (13%) focal kyphosis. Group C (L3-S1) had seven (39%) retrolisthesis. Group D had only one retrolisthesis and two disc height loss.

Radiographically analyze the relationship between abnormal sagittal plane configuration of the proximal segments and the number of lumbar fusion segments in patients older than sixty years old.

It appears that lumbar fusion up to L1 causes more kyphotic changes and topping off syndrome in the elderly. Fusion L2-L5 or S1 seems having less severe adjacent level degeneration. Retrolisthesis is a significant problem in fusion from L3-L5 or S1. The least adjacent level degenerative changes were seen in L4-S1 fusion.

Selected limited instrumentation avoiding kyphotic segments or extending the fusion above the thoracolumbar junction may be the needed.

Solid fusion was seen in 46 (88%) patients. There were ten patients in group A, and two (20%) had vertebral compression fractures in the most cranial vertebrae and four (40%) focal kyphosis. Of fifteen patients in group B, one (6%) had compression fracture, five (33%) retrolisthesis, and two (13%) focal kyphosis. Of eighteen patients in group C, retrolisthesis was seen in seven (39%) patients. Group D had nine patients with only one patient having retrolisthesis and two having disc height loss.

Since January 1997, there were fifty-two consecutive patients with an average age of seventy years who have undergone multilevel lumbar decompression and posterolateral fusion with pedicle screw-rod instrumentation, and have reached a minimum two-year follow up. Postoperative radiographs of lumbar fusion were classified into group A (L1-L5 or S1), group B (L2-L5 or S1), group C (L3-L5 or S1) and group D (L4-S1).


H. Ahn Y.R. Rampersaud

Spinal procedures relying on percutaneous pedicle cannulation (PPC) are becoming increasingly common. The accuracy of PPC using currently available two-dimensional intraoperative imaging such as conventional C-arm fluoroscopy (CF) or computer-assisted fluoroscopy (2D_Nav) has not been evaluated. Following PPC of cadaveric spines (T4-S1) using CF and 2D_Nav, by a novice and clinical expert, the number and degree of pedicle breaches was assessed by CT. Accuracy using CF or 2D_Nav was equivalent and comparable to published reports for open pedicle cannulation. However, clinical expertise was the significant determinant of improved accuracy rather than technological factors.

To assess the accuracy of percutaneous pedicle cannulation(PPC) using currently available two-dimensional intraoperative imaging (C-arm fluoroscopy (CF) or computer-assisted fluoroscopy (2D_Nav)) for two levels of clinical expertise.

Accuracy using CF or 2D_Nav was equivalent and comparable to published reports for open pedicle cannulation. Main determinant of PPC accuracy is clinical experience, rather than technological factors.

Current technology cannot replace the need for rigorous training required to gain skill in percutaneous pedicle procedures.

Using an eleven-gauge bone biopsy needle, sixty randomized pedicles(two cadavers, T4–S1) were cannulated using CF or 2D-Nav by a staff spine surgeon or a third year orthopaedic resident. Pedicles for each vertebra were paired as internal controls for technique. After insertion of the biopsy needle, a 1.5mm aluminum tube was inserted through the needle as a marker. Using fine cut CT scans the position of each tube was assessed using a predefined grading system based on tube location relative to pedicle, direction of breech, trajectory, and position in vertebral body. Minimum score was three(ideal) and maximum was fourteen(gross misplacement). There were significantly (p< 0.05) more pedicle breaches for the resident (four CF, four 2D-Nav) compared to staff (one 2D-Nav). All breaches were thoracic with no statistical difference between number of breaches using CF and 2D-Nav for either skill group. Grade of breaches for CF (8.8) and 2D-Nav (9.4) were statistically similar. Main sources of error included poor image quality, image misinterpretation and biopsy needle flexibility causing navigational maltracking.


J.S. Tan C.S. Bailey M.F. Dvorak C.G. Fisher T.R. Oxland

A biomechanical study assessing compressive failure load, strength and stiffness with three different interbody device shapes was performed in human cadaveric vertebrae. The custom-made interbody devices had similar cross-sectional areas and specimens were tested with 20% or 40% coverage of indentor to endplate area. Axial compressive load was applied at 0.2mm/s to a depth equivalent to 20% of the vertebral height. The clover-leaf shaped device resulted in significantly higher failure load, strength and stiffness over the elliptical and the kidney shaped devices for both areas of coverage. The clover-leaf shaped devices extended over stronger periphery regions of the endplates and resulted in stronger interface properties.

To determine if two novel interbody cage shapes, the kidney and the clover-leaf, are biomechanically superior to a standard elliptical shape of similar cross sectional area.

Uniaxial compression tests with unrestricted rotations were carried out on the superior endplates of forty-eight thoracolumbar (T9-L2) vertebrae with one of three shaped indentors covering 20% or 40% of the endplate area. Compressive load was applied using a servohydraulic testing machine at 0.2mm/s, to depth equivalent to 20% of the vertebral height. Failure load, strength and stiffness were compared.

The clover-leaf shaped indentors resulted in higher failure load (53% average increase), higher strength (67% average increase) and higher construct stiffness (43% average increase), and these results were significant (p< 0.05). Larger indentor coverage area of 40% also resulted in significantly higher failure loads over 20% coverage (75% average increase).

Current elliptical interbody devices are placed over the central region of the endplate, which is also the weakest. A clover-leaf shaped device extended over the stronger peripheral regions of the endplates and resulted in improved bone-implant interface properties. This implant if implemented in vivo could potentially reduce implant subsidence and lead to better long-term outcomes in osteoporotic patients.

The novel clover-leaf shaped indentor displayed superior bone-implant interface properties. Larger interbody devices should be used when possible to improve interface properties.

Implant subsidence in osteoporotic patients could be significantly reduced with a clover-leaf shaped device, leading to better long-term outcomes.

Funding: Funding from the Canadian Institutes for Health Research.


P.R. Kim T.Y. Getahun A. Conway H. Hrushowy

The purpose of the present study is to report the failure rate after total knee replacements performed with poly-ethylene inserts that had been sterilized with gamma irradiation in air and implanted after a prolonged shelf life. 395 PFC total knees were performed using polyethylene that had been sterilized by gamma irradiation in air. Shelf life of all polyethylene inserts was determined from manufacturer data. A Chi-square test revealed that the proportion of implants that required a revision for polyethylene failure was related to the number of years that the implant had been stored on the shelf.

Report failure rate of PFC total knee replacements performed with polyethylene sterilized by gamma irradiation in air and implanted after a prolonged shelf life.

There was an increased revision rate in total knees with polyethylene sterilized by gamma irradiation in air and implanted after a shelf life greater than two years.

Polyethylene sterilized by gamma irradiation in air should not be implanted after a shelf life of greater than two years.

Ten of twelve revisions had polyethylene inserts with a shelf life greater than two years. A Chi-square test revealed that the proportion of implants that required a revision was related to the number of years that the implant had been on the shelf, particularly if greater than two years χ2 (1)=7.427, p=.006

395 PFC total knees were performed using polyethylene sterilized by gamma irradiation in air. Shelf life of all polyethylene inserts was determined from manufacturer data. A retrospective review was undertaken to determine which patients underwent revision surgery as a result of aseptic loosening secondary to polyethylene failure. The data was then used to determine the relationship between shelf life and revision status.

The mechanical toughness of polyethylene that has been sterilized by gamma irradiation in air decreases with a prolonged shelf life. This results in an unacceptably high revision rate. We therefore recommend against the use of polyethylene that has been gamma irradiated in air and stored for greater than two years on the shelf.

Funding: This study has been sponsored in part by Johnson& Johnson/Depuy Orthopedics.


K. Gordon A. Kedgley L. Ferreira G. King J. Johnson

Quantitative measurements of load transfer through the distal radioulnar joint (DRUJ) are limited. An instrumented ulnar head prosthesis was developed to measure bending and torsion moments about the three anatomic axes of the ulna. This device has shown repeatable loading data following insertion in a cadaveric specimen during active forearm rotation trials conducted in an in-vitro upper extremity joint simulator. The data acquired from this device will have important implications for upper extremity modeling, implant fixation and design, and optimizing surgical procedures related to DRUJ arthroplasty.

To develop a system to quantify in-vitro load transfer through the distal radioulnar joint (DRUJ) following ulnar head arthroplasty during simulated active forearm rotation. Also, the effect of an eccentric ulnar head implant design was investigated.

A load-measuring system was developed that was easily surgically inserted, and produced repeatable loading data.

The instrumented implant developed in this study will contribute to the optimization of surgical procedures and implant design parameters related to distal ulnar arthroplasty.

Four pairs of strain gauges were applied to the stem of an ulnar head prosthesis to measure bending and torsion moments about the three anatomic axes of the ulna. Three ulnar heads were machined with varying eccentricities (axisymmetric, 1.5 mm offset and 3.0 mm offset). The implant was inserted in one unpreserved cadaveric upper extremity and active forearm rotation induced using a computer controlled joint simulator. Repeatability (assessed using the maximum standard deviation over 5 trials of pronation and supination) was less than 9% of the output range for all loads. Bending and torsion moments between −0.4 and 0.5 Nm, correlating to joint loads between 0 and 50 N, were measured. The measured loads followed a consistent pattern with forearm position. Higher loads were noted for the eccentric implant heads compared to the axisymmetric head, especially at the extreme ranges of rotation. Clinical interpretation of these findings is difficult since the optimal loading scenario for distal ulnar implant longevity remains unknown.

Please contact author for diagrams and graphs.


N.N. Mahomed J. Wright G. Hawker A. Davis E. Badley

Home- based rehab is increasingly utilized to save costs but concerns have been raised about early hospital discharge and adverse clinical outcomes. This study compares the efficacy and patient satisfaction of home- based verses inpatient rehabilitation following total joint arthroplasty (TJA). Despite concerns about early hospital discharge there was no difference in functional outcomes and in patient satisfaction with procedure at the primary endpoints, between the groups receiving home based verses inpatient rehabilitation.

This study compares the efficacy and patient satisfaction of home- based verses inpatient rehabilitation following total joint arthroplasty (TJA).

Given that home- based rehab is less expensive, we would recommend the use of home based rehab protocols following elective primary TJA.

Home- based rehab is increasingly utilized to save costs but concerns have been raised about early hospital discharge and adverse clinical outcomes.

The groups were similar at baseline for patient demographics and WOMAC scores. At the six weeks, twelve weeks and one- year follow-up post TJA there was no statistically significant difference in WOMAC pain, physical function, stiffness and overall WOMAC scores. Both groups showed a trend of decrease in pain, stiffness, restriction in physical function over the follow-up period. Similarly, patient satisfaction scores at six, twelve weeks and one year did not show a statistically significant difference between the home versus inpatient group (P> 0.05)

Two hundred and thirty-four patients were randomized to either home based or inpatient rehabilitation following TJA, using block randomization techniques. Standardized care pathways were followed for both procedures. All patients were evaluated at baseline (two weeks prior to surgery), six weeks, twelve weeks and one- year post surgery using standardized questionnaires. Primary outcomes were the self-reported WOMAC pain and function score and satisfaction in terms of improvement in pain and function.

Despite concerns about early hospital discharge there was no difference in functional outcomes and in patient satisfaction with procedure at the primary endpoints, between the groups receiving home based verses inpatient rehabilitation.

Funding: PSI


A.M. Davis H.J. Kreder J. Parsons N.N. Mahomed J. Gollish E.H. Schemitsch A.E. Gross

1069 primary hip arthroplasty (THA) (416 males) and 1846 revision (798 males) patients were matched for sex, age and date of primary THA. Data were collected via retrospective chart review. Time to revision averaged 9.5 years. Revision THA patients were younger at primary THA (55 vs. 64 years), had a higher body mass index (27 vs. 30) and more frequently had a cemented acetabulum (p< 0.0001). After controlling for institution, earlier time to revision was predicted by younger age at primary THA, secondary OA or dysplasia, increased BMI, posterior surgical approach, cemented acetabulum, and small femoral head size (28 mm) (p< 0.05).

To determine whether patient (age, gender, underlying disease, body mass index), surgical (surgical approach), and prosthetic (cemented vs. uncemented acetabular or femoral component, femoral head size) factors predict time to revision arthroplasty of primary total hip arthroplasty (THA).

Patients who are younger when undergoing primary THA, have secondary osteoarthritis (OA) or dysplasia, are obese, and have a cemented acetabulum with a small femoral head by a posterior approach are at increased risk for revision THA.

This study identified important, potentially modifiable patient, surgical and prosthetic factors that are adverse predictors of outcome.

For the period 1980 to 2000, 1069 primary hip arthroplasty patients (416 males) and 1846 revision arthroplasty (798 males) patients were matched for sex, age and date of primary THA within two years. Revision THAs for infection were excluded. Data were collected via retrospective chart review. Time to revision THA averaged 9.5 years. In univariate analysis, patients who had revision THA were younger at primary THA (55 vs. 64 years, p< 0.0001), had a higher body mass index (BMI) (27 vs. 30, p< 0.0001), and more frequently had a cemented acetabulum (p< 0.0001). After primary THA, fewer patients who went on to revision arthroplasty had orthopaedic complications (6.5 vs. 16.5%). After controlling for institution, earlier time to revision was predicted by younger age at primary THA, underlying joint disease of secondary OA or dysplasia, increased BMI, posterior surgical approach, cemented acetabulum, and small femoral head size (28 mm) (multivariate Cox model, p< 0.05).

Funding: This work was supported in part by a grant from the Canadian Orthopaedic Foundation and The Arthritis Society


R. Trammell D.G. Allan E.J. Moticka

SEREX was used to identify candidate tumor antigens in the nonimmunogenic fibrosarcoma (NFSA) tumor model. One of the six clones identified was of particular interest. NFSA-5 was identified as the receptor for hylaronan-acid-mediated motility (RHAMM), which is involved in cell growth and metastasis. RHAMM is expressed in a variety of human tumors. RHAMM is differentially expressed, with significant levels not found in normal tissues other than testis, placenta, and thymus. Therefore, RHAMM may be an appealing target for human tumor vaccines. The identification of murine homologs to human tumor antigens may aid in the preclinical development of human tumor vaccines.

The goal of our studies was to use serological analysis of antigens by recombinant expression cloning (SEREX) to identify candidate tumor antigens in a nonimmunogenic murine fibrosarcoma model.

SEREX provides a rapid means of identifying candidate tumor antigens in murine cancer models.

The identification of murine homologs to human tumor antigens may aid in the preclinical development of human tumor vaccines.

The SEREX approach included construction of a cDNA expression library from NFSA tumors followed by immunoscreening of the library with sera from C3H mice growing NFSA tumors. The nucleotide sequence of insert cDNA was determined for positive clones. Sequence alignments were performed with BLAST software on GenBank database.

Six positive clones were identified. Two clones coded for proteins with known expression in normal tissues. Two clones represented heat-shock proteins, known to be upregulated in human and murine tumors. Two of the clones were of particular interest. Clone NFSA-1 was the homolog to NY-REN-58, an antigen previously identified by SEREX analysis of renal cell carcinoma patients. NFSA-5 was identified as the receptor for the hylaronan-acid-mediated motility (RHAMM), which is involved in cell growth and metastasis. RHAMM was recently identified as a leukemia-associated antigen and is expressed in a variety of human solid tumors including renal cell carcinoma, breast carcinoma, and ovarian carcinoma. RHAMM is differentially expressed, with significant levels not found in normal tissues other than testis, placenta, and thymus. Therefore, RHAMM may be an appealing target for human tumor vaccines.

Funding: This study was supported by a grant received from the William E. McElroy Charitable Foundation.


J.C. Cameron

One hundred and forty eight meniscus allografts transplanted in one hundred and forty patients between 1988 and 2000 were reviewed. The indication for surgery included disabling knee pain, refractory to conservative treatment, objective symptoms of compartmental crepitus, pain on valgus/varus stress and osteoarthritis documented on arthroscopy following prior total meniscectomy. Knee mal-alignment and instability were also documented. Patients with varus alignment and medial OA, as well as valgus alignment with lateral OA, underwent re-alignment to unload the compartment for allograft transplantation. Patients with anterior cruciate deficiency, underwent ACL reconstruction at the time of allograft transplantation.

The purpose of this paper is to show the benefit of meniscus transplantation in osteoarthritis of the knee.

At a mean follow-up of six years (range two to fourteen), one hundred and twenty-five out of one hundred and forty-eight knees received good to excellent results.

Meniscus allograft transplantation can restore function in patients with arthritis secondary to prior total meniscectomy. The transplantation of a biological load-bearing structure has given reliable long term results, when used in well selected cases.

Forty six patients received an isolated meniscus allograft with forty-one receiving good to excellent results. Eleven received a medial or lateral meniscus allograft with an ACL reconstruction and nine obtained good to excellent results. Seventy five knees received a meniscal allograft in combination with an osteotomy to correct for pre-operative deformity, with sixty-four attaining good to excellent results. The remaining twenty-two knees underwent valgus high tibial osteotomy, meniscus allograft and ACL repair, with nineteen achieving good to excellent results.

Outcome was assessed subjectively and functionally using a modified Lysholm socre and objectively by clinical examination. The Tegner activity scale was used to compare pre and post- operative function. Second look arthroscopy was performed on the first ten transplanted meniscus to assess healing and graft integrity.


C. Bellabarba S.K. Mirza G.A. West F.A. Mann D.W. Newell J.R. Chapman

Retrospective review of seventeen consecutive survivors of craniocervical dissociation (CCD). Thirteen patients had delay in diagnosis, with associated neurologic deterioration in five. Diagnosis of CCD was entertained after lateral C-spine x-ray in only two patients, and after screening C-spine CT in two others. At fifteen-month average follow-up, mean ASIA motor score improved from fifty preoperatively to seventy-nine postoperatively. One patient had temporary postoperative neurologic decline. There were no pseudarthroses. The diagnosis of CCD is often missed, with potentially severe neurologic consequences. Early diagnosis and stabilization are neuroprotective. A classification that identifies minimally displaced yet unstable injuries may improve diagnostic accuracy.

To identify the timing and method of diagnosis, diagnostic reliability of screening lateral radiographs, effect of delayed diagnosis, complications of treatment, and neurologic outcome of this life-threatening condition.

Diagnosis of craniocervical dissociation (CCD) was frequently delayed, increasing the risk of neurologic decline. Early diagnosis and stabilization protected against worsening spinal cord injury.

This study highlights the importance of disciplined evaluation of the lateral cervical spine radiograph of poly-traumatized patients. Head-injured patients with cranio-facial trauma and asymmetric high cervical spinal cord injuries should heighten clinicians’ suspicion of CCD.

CCD was identified or suspected on two of seventeen (12%) initial lateral cervical spine radiographs, and on screening CT scan in only two additional patients (12%), despite an abnormal dens-basion relationship in 16/17 (94%) patients. Of the thirteen patients with (two-day average) delay in diagnosis, 5/13 (38%) had profound neurologic deterioration. One patient worsened temporarily after fixation. There were no pseudarthroses at fifteen-month average follow-up. Mean ASIA motor score of fifty improved to seventy-nine, and the number of patients with useful motor function (ASIA D or E) increased from seven (41%) preoperatively to thirteen (76%) postoperatively.

Four patients with severe craniocervical instability had < 3 mm displacement. We therefore adopted a classification based on provocative traction testing of minimally displaced injuries.(Table).

Retrospective review of seventeen consecutive CCD survivors identified between 1994–2002 through institutional databases. Radiographic and clinical results were evaluated, emphasizing timing of diagnosis, effect of delayed diagnosis, clinical or radiographic warning signs, and response to treatment.

Please contact author for tables and /or diagrams.


A.J.M. Yee N. Adjei M. Vidmar M. Ford M. Al-Gahtany J. Finkelstein

There is increasing knowledge regarding the functional outcome of patients following posterior lumbar spinal surgery for degenerative conditions of the spine. There is less known regarding the expectations patients have for spinal surgery and how that may relate to commonly reported surgical outcome measures. It was the purpose of this study to evaluate the results of elective lumbar spinal surgery as it relates to patient expectations for outcome. and outcome as quantified by both physician reported outcome and patient derived generic and disease-specific measures.

Patient expectations for surgery were evaluated in one hundred and fifty-five consecutive patients undergoing posterior lumbar surgery for degenerative conditions (single institution, two surgeons).

SF-36+Oswestry disability was quantified preoperatively, and serially postoperatively. Preoperative expectations (pain relief, sleep, recreational, ADL, work return) were documented and postoperative expectations quantified at time of anticipated maximal medical improvement (6mos decompressions,1yr with fusions). Mean preoperative SF-36 MCS and PCS scores were 3.4 and 1.2 S.D. below age/gender matched Canadian norms. Although patients reported improvements in SF-36+Oswestry scores following surgery, mean SF-36 MCS and PCS scores were still 2 and 1.5 S.D. below norms. Mean Oswestry disability improved from 48.7%±1.7% to 23.1±1.9%.

Expectations for surgery were met in 81%(responders:143/155). Of 19%(27/143) where expectations were not met, 6/27 have either nonunion, technical, or medical factors. There was no difference in mean age, gender, comorbidity, procedure type and follow-up comparing patients where expectations were met to those that were not. Patients where expectations were not met reported lower preoperative SF-36 (GH and VT) domain scores (p=0.02 and 0.04, respectively), however, preoperative Oswestry, SF-36 MCS and PCS scores were not significantly different. Patients were less satisfied if they had prior lumbar surgery (p=0.02) or involved in WCB/litigation (p< 0.001).

We note 15%(21/143) where expectations were not met and there were no apparent surgical or medical confounds to account. There are likely other factors that may influence patient perception and expectation for treatment which requires further study.


S. Burch A.J.M. Yee S. Bisland B. Wilson A. Boogards J. Finkelstein C. Whyne

Photodynamic therapy is a promising cancer treatment that employs wavelength-specific light in combination with a photosensitizing agent to induce local tumor destruction by photochemical generation of cytotoxic singlet oxygen. Clinical PDT has been evaluated for a variety of primary tumors, however, its use in spinal metastases to our knowledge has not been previously evaluated. A practical consideration is the ability to deliver light to bone. The investigators are evaluating a novel method of applying light to targeted spinal lesions using a minimally invasive technique similar to percutaneous vertebroplasty. This preliminary preclinical study evaluates the feasibility and efficacy of spinal PDT.

To evaluate the feasibility and efficacy of spinal meta-static photodynamic therapy (PDT) using a percutaneous minimally invasive surgical approach similar to that of vertebroplasty in a preclinical model of bone metastases.

A bioluminescent metastatic model was developed (intracardiac injection 2x106 MT-1Luc human breast cancer cells; rnu/rnu rats). In forty-three tumor bearing rats, a PDT light dose escalation trial (photosensitizer BPD-MA;2mg/Kg IV) was conducted to assess safety and efficacy of tumor ablation in a single treatment via an implanted optical fibre held adjacent to targeted spinal lesions. Pre and forty-eight hours post bioluminescent imaging was performed to gauge PDT related effects followed by post-sacrifice microCT and histology.

Spinal PDT caused a reduction in bioluminescence of targeted lesions (66% to 87% in three hour drug-light group using light fluence rates of 25J and 150J, respectively; p< 0.05). The most selective drug-light interval was twenty-four hours where PDT induced tumor cell apoptosis/necrosis occurred, however, no spinal cord injury was observed. The greatest anti-tumor effect was observed at the three hour drug-light interval but observations of neurologic sequalae (9/22 animals) highlight the importance of ongoing study to closely define the therapeutic window of PDT.

Drug dosimetry and the drug-light interval are critical in establishing an efficacious and safe treatment range for spinal PDT. Bioluminescent reporter imaging provides an in vivo longitudinal assessment of tumor growth kinetics. The feasibility of the minimally invasive approach for spinal PDT in this model has been established.

Funding: this study was support, in part, by a CBCRA (formerly CBCRI) Idea’s grant


P.A. Vendittoli S. Jean D. Major A. Simpson K.S. Davison J.P. Brown

A descriptive study of osteoporotic fractures and the evaluation of the relative risk of hip fracture following a minor fracture were done on 2.5 million individuals from 1980 to 1997. People aged forty-five years old and older have a risk for hip fracture after a minor fracture of 2.3–17.3 time the risk of people without previous fracture. Given the availability of pharmaceuticals that decrease the fracture risk dramatically within the first 18 months of therapy, the average four to six years time between minor and hip fracture represents a perfect window of opportunity for preventive treatment.

Osteoporotic fractures, especially hip fractures, represent a major health problem in terms of morbidity, mortality and cost. Since the availability of new treatments for osteoporosis, a better understanding of the disease is needed to define the indications for treatment.

A descriptive study of osteoporotic fractures and the evaluation of the relative risk of hip fracture following a minor fracture were done on a population aged fortyfive years old and older from 1980 to 1997 (2.5 million individuals).

During the follow-up period, 220,120 fractures (hip, wrist, proximal humerus and ankle) were recorded. Wrist fractures were the most frequent (42.2%) followed by hip fractures (32.5%). Although the proportions of fracture sites were similar for both sexes, 75% of the fractures occurred in females. The mortality rate 1 year after a hip fracture is increased by 14–27% for men and 9–13% for women. Men and women aged fortyfive years old and older have a risk for hip fracture after a humerus or a wrist fracture of 2.3–17.3 time the risk of people without previous fracture. The average time between a wrist or humerus fracture and a hip fracture was four to six years.

Wrist and humerus fractures represent a major risk for future hip fracture. Given the availability of pharmaceuticals that decrease the risk of hip fracture dramatically within the first eighteen months of therapy, the interval between minor and hip fracture represents a perfect window of opportunity for preventive treatment to decrease the risk of future hip fracture.


P. Zalzal G. Cheung M. Bhandari J.K. Spelt M. Papini

Femoral nails are thought to be load sharing devices. However, the specific load sharing characteristics and associated stress concentrations have not yet been reported in the literature. The purpose of this study was to use a validated, three dimensional finite element model of a nailed femur subjected to gait loads in order to determine the resulting stresses in the femur and the nail. The results showed that load was shared between the nail and the bone throughout the gait cycle. In addition, high stress concentrations were noted in the bone around the screw holes, and dynamization was of minimal benefit.

To determine the stresses in the bone and nail in a femur with a locked, retrograde, intramedullary nail.

The retrograde femoral nail is a load sharing device. High stress concentrations occur in the bone around locking screw holes. When only one locking screw is used proximally and distally, stresses in the implant are excessive and may lead to failure. Dynamization was of minimal benefit.

This is the first study to use a validated three dimensional finite element model to provide a detailed biomechanical analysis of stress patterns in a retrograde nailed femur under gait loads. The results can help resolve issues of stress shielding, implant removal, number of locking screws and dynamization.

In the fully locked condition, loads in the femur were significantly higher than those in the nail for most of the gait cycle. Removal of locking screws to obtain dynamization only increased axial load in the femur by 17 %. However, stresses in the locking screws increased by as much as 250% when fewer than 4 screws were used. Maximum stresses in the bone were found around screw holes.

A three dimensional finite element model of the femur and nail was developed. The model was validated by comparing results to a physical saw bone model instrumented with strain gages and subjected to a simple a compressive load. Once good correlation with simple loading patterns was demonstrated, gait loading patterns obtained from literature were incorporated and simulations were run for various conditions.


C.N. Demers J. Antoniou A. Petit O.L. Huk D.J. Zukor F. Mwale

Recent evidence indicates that link N can stimulate synthesis of proteoglycans and collagen by adult (2–4 years old) bovine disc tails. Here we sought to determine the effect of link N on the accumulation of disc matrix proteins from young (eight to twenty month old) bovine tails. We show that degradation products of link protein generated by matrix metalloproteinases cannot “feed-back” and stimulate matrix assembly of the disc matrix from young bovine tails but may have a regulatory role in cell proliferation. Link N may have value only in stimulating the growth and regeneration of the old damaged intervertebral disc.

To date, there have been no reports on the effect of the amino terminal peptide of link protein (DHLSD-NYTLDHDRAIH) (link N) on disc cells from young (eight to twenty month old) bovine coccygeal discs. Link N is produced when removed by proteolysis from the N-terminus of the link protein of cartilage proteoglycan aggregates. We recently showed that link N can act directly on disc cells from adult (two to four years old) bovine discs to stimulate matrix production (J Cell Biochem, 2003; 88:1202–13).

To examine whether link N can play a role in maintaining the matrix integrity of young bovine disc cells.

Nucleus pulposus (NP) and annulus fibrosus (AF) cells were isolated from fresh grade I discs from young steers, and cultured in pellets at 1 million cell per tube in 1 ml of DMEM-high glucose supplemented with 1% 100X Pen-Strep, 1% ITS, 1 mg/ml BSA, and 50 μg/ml ascorbic acid. Cell pellets were digested and then analysed for sulfated glycosaminoglycan, type II collagen, percent denatured type II collagen, type IX collagen, and DNA content, using specific assays.

A concentration of 100 ng/ml link N significantly increased the DNA content of AF cells. However, link N had no significant effect on proteoglycan, type II and type IX collagen accumulation.

This study demonstrates that link N at a concentration of 10 ng/ml and 100 ng/ml cannot stimulate matrix production but may increase cell division in young bovine disc tails.


D. Oliphant G. Kawchuk R. Frayne L. Lauzon R. Fauvel

Because internal disc derangement is a significant factor in low back pain, it is important to devise a method of inducing internal disc injuries so that these conditions can be investigated experimentally. We have devised a method of creating internal disc disruption that can create minor or severe internal disc damage as required.

The purpose of this study is to develop a method of creating internal disc derangements, which mimic those seen physiologically.

Discogram provocation studies have shown that internal disc derangement may be associated with up to forty percent of chronic low back pain. Given that these derangements produce significant changes in disc biomechanics, lamellar thickening and vertebral body bone, creation of an injury model which mimics these derangements, would be of importance toward understanding mechanisms of back pain.

Four porcine lumbar spines were each placed in an MRI-compatible support and a plastic needle was inserted along the lateral annulus fibrosis from anterior to posterior. Compressed nitrogen was introduced at 50 PSI, 100 PSI and 150 PSI for one minute each. Axial T2 MR images were obtained after each injection. Edge detection analysis was used to determine alterations in disc morphology.

Internal disc derangement was not visualized following injection of 50 PSI, although at 100 PSI annular tears and nuclear displacement away from the injection site were visualized. These derangements increased in magnitude with 150 PSI injection.

This study demonstrates that internal disc derangements can be created by injecting air into the disc. In addition, the magnitude of derangement is a function of the magnitude of air pressure applied, as evidenced by MR images.

This technique is able to create a spectrum of derangements that has not been achieved by other disc injury models.

Funding: Support from the University of Calgary


H. Ahn P. Mousavi L. Chin S. Roth J. Finkelstein A. Vitkin C. Whyne

Vertebroplasty (VP) is currently used to improve spinal stability in patients with vertebral metastases. This study assessed the effects of Laser Induced Thermo Therapy (LITT), a minimally invasive technique used to ablate tumor tissue prior to vertebroplasty. Load-induced canal narrowing (LICN) was measured pre and post-vertebroplasty in twelve paired spinal motion segments with simulated lytic metastases. LICN improved post-vertebroplasty for all specimens treated with LITT. In all specimens, cement location was an important factor in post-vertebroplasty stability. Reduction of the tumor volume pre-vertebroplasty resulted in more reliable defect filling.

To investigate the effect of tumor ablation using Laser Induced Thermo Therapy (LITT) prior to vertebroplasty (VP) on cement distribution and vertebral stability.

Tumor volume reduction using LITT prior to cement injection improves defect filling and consistently reduces Load Induced Canal Narrowing (LICN).

A simple, minimally invasive procedure providing accurate tissue destruction pre-vertebroplasty may result in more reliable cement fill, reduce cement extravasation and improve post-vertebroplasty stability.

Following verebroplasty, LICN improved in all specimens treated with LITT and in those VP alone specimens with cement located posterior to the tumor tissue (33%). LITT treated vertebrae exhibited a trend toward reduced posterior wall motion post-vertebroplasty (LICN=29.7±27.1%) versus specimens treated with VP alone (LICN=248.7±253%). In the LITT+VP group, cement was fully contained within the vertebral body while cement extravasation into the canal was noted in 33% of the specimens treated without LITT.

Twelve paired cadaveric thoracolumbar spinal motion segments with simulated lytic metastases were randomized for treatment with VP alone or LITT+VP. In the LITT+VP group, a laser fibre inserted through a transpedicular approach was used to ablate the tumor tissue prior to cement injection. The specimens were axially loaded to 800N pre and post-treatment. LICN was used as a measure of vertebral stability. Cement location was assessed post-testing through axial sectioning. Location of cement is an important factor in determining post-VP stability. Vertebroplasty is effective in decreasing LICN if the tumor is ablated or surrounded posteriorly with cement.

Funding: USAMRMC DAMD 17–00–1–0693


P. Morin R. Reindl T. Steffen J. Ouellet V. Arlet M. Aebi

“Delta fixation” was developed to treat low-grade L5 isthmic spondylolisthesis. It involves placement of pedicle screws into L5 and from S1 through the L5/S1 disc into L5 (Fig.1). A biomechanical comparison to standard Posterior Lumbar Interbody Fusion (PLIF) with two anterior cages and pedicle screws in L5 and S1 was made. Eight fresh frozen human specimens were instrumented with both fixations and tested. Delta fixation was significantly more stable in resisting rotation. It requires less manipulation of the nerve roots and spares the cost of the fusion cages.

Our objective is to compare the stability of Delta versus PLIF fixation in the treatment of low grade isthmic spondylolisthesis

Delta fixation provides superior initial stability, and therefore is an acceptable alternative to PLIF for the treatment of low grade isthmic spondylolisthesis of L5-S1.

Symptomatic low-grade isthmic spondylolisthesis of L5 is often managed with PLIF. This procedure requires extensive manipulation of the cauda equine, posterior resection of the disc and the placement of two inter-body cages as spacers in addition to pedicle screws in L5 and S1.

Delta Fixation has been developed to provide stable fixation with less nerve root manipulation and without the use of inter-body cages. It is therefore a safer alternative method of fixation that spares the additional cost of the fusion cages.

When comparing Delta fixation to PLIF fixation the only statistically significant difference was found in axial rotation. Delta fixation had 2.05 degrees less ROM and 0.90 degrees less NZ compared to PLIF fixation with P values of 0.0052 and 0.0104 respectively. This demonstrates that the delta fixation is more stable than PLIF fixation.

Eight fresh frozen human spines were used. Matched pairs were created and block randomization used to create two groups: PLIF fixation and Delta fixation groups. The specimens were instrumented with a grade II spondylolisthesis of L5-S1, tested, and then re-instrumented with the alternative fixation and tested again. Vertical displacement, axial rotation, flexion– extension and side bending were tested using an MTS machine.

Please contact author for tables and/or diagrams.


D. Garneau J. Lamontagne D. Rancourt

Four matched pairs of fresh frozen human femora were used to compare the biomechanical properties in axial and torsional loading of a Locking Condylar Plate and a retrograde intramedullary nail. One-centimeter gap osteotomy was created in the supracondylar region to simulate an AO/OTA 33-A3 fracture. The instrumented specimens were then mechanically tested under physiologic conditions in axial and torsional loading to determine the stability of the constructs. This laboratory study enhances the biomechanical advantages of the Locking Condylar Plate when fixation stiffness is essential. Devices with head locking screws provide angular rigidity and maximize fixation stability in osteopenic bone.

To compare the biomechanical properties in axial and torsional loading of a Locking Condylar Plate and a retrograde intramedullary nail. To determine the modes of failure of these two devices under axial loading.

Four matched pairs of fresh frozen human femora were used. Plain film radiographs and Dexa scanning were performed to evaluate bone quality and to screen for pathologic lesions. For each pair, one femur was stabilized with the Locking Condylar Plate and the other with a retrograde nail.

One-centimeter gap osteotomy was created in the supracondylar region to simulate an AO/OTA 33-A3 fracture. Radiographs were obtained to exclude iatro-genic fractures before mechanical testing. The instrumented specimens were then mechanically tested under physiologic conditions in axial and torsional loading to determine the stability of the constructs. Three-dimensional displacement across the fracture site was recorded. Finally, all femurs were loaded to fracture under axial loading. The modes of failure were determined by assessing final radiographs.

The Locking Condylar Plate provided statistically significant greater rigidity both in axial (p = 0.048) and torsional loading (p = 0.031) compared to the retrograde nail. The axial mode of failure occurred proximally for the plate and mainly at the distal fixation for the nail.

This laboratory study enhances the biomechanical advantages of the Locking Condylar Plate when fixation stiffness is essential. Devices with head locking screws provide angular rigidity and maximize fixation stability in osteopenic bone.


C. Gallimore H. Koo A. McConnell E.H. Schemitsch

The purpose of this study was to determine the effect of cement mixing time on fixation augmentation in both healthy and simulated osteoporotic canine bone. In a canine diaphyseal model, screw insertion into liquid cement achieves greater bending stiffness and resists a greater load to failure than cement inserted as a paste. Bone cement in its liquid state may provide increased structural support in the setting of an osteoporotic fracture, possibly due to increased interdigitation of the cement with the screw threads and bone.

An inconsistency exists among orthopaedic surgeons with regards to the appropriate mixing time for bone cement to achieve optimal results. The purpose of this study was to determine the effect of cement mixing time on fixation augmentation in both healthy and simulated osteoporotic canine bone.

In a canine diaphyseal fracture model, screw insertion into liquid cement achieves greater bending stiffness and resists a greater load to failure than insertion into cement with the consistency of a paste.

Bone cement in its liquid state may provide increased structural support in the setting of an osteoporotic fracture, possibly due to increased interdigitation of the cement with the screw threads and bone.

Baseline stiffness for fourteen pairs of cadaveric canine femora was determined. A transverse diaphyseal osteotomy was created and fixed using an eight-hole DC plate and 3.5 mm screws. A 1cm gap was created at the osteotomy site simulating loss of bone. In the left femora, cement was mixed for one minute (liquid) prior to injection into pre-drilled holes; in the right femora, cement was mixed for five minutes prior to injection (thick paste). In each mixing time group, seven specimens were treated with a plate and properly sized pre-drilled and tapped holes (2.5mm), and seven received over-drilled holes (3.2 mm) to simulate osteoporotic bone. Four-point bending stiffness was determined for each plated construct, and normalized to baseline stiffness. Specimens were then loaded to failure.

Within the properly sized holes, there were no statistically significant differences (SSD) in bending stiffness with or without a gap. The liquid cement had a force to failure 77% greater than that of cement as a paste (p< 0.05). Within the over-sized holes, there was no SSD between liquid and paste without a gap. With a gap, liquid cement demonstrated an increased bending stiffness of 24 % (p< 0.05) and force to failure was 92% higher (p< 0.05).


M. Blankstein K. Syed M. Nakane A. Bang J. Freedman R. Richards E. Schemitsch

The purpose of this study was to determine the effect of positioning (lateral vs. supine) on pulmonary pathophysiology following pulmonary contusion and fat embolism in a canine model of polytrauma. Platelet and neutrophil activation were assessed using flow-cytometry. There were no significant differences between groups in CD62P and CD11/18 MCF (markers of platelet and neutrophil activation, respectively) following fat embolism. However, only animals in the lateral position displayed significant increases in both measures as compared to baseline values. Lateral positioning may exert an early effect on proinflammatory and coagulation activation, and may play a role in the development of acute lung injury.

It has previously been suggested that acute lung injury can be influenced by patient positioning, be it lateral or supine. The purpose of this study was to determine the effect of positioning on pulmonary pathophysiology associated with concomitant pulmonary contusion and fat embolism in a canine model of polytrauma.

Twelve dogs were randomly assigned to one of two surgical positioning groups, lateral and supine. The dogs were subjected to pulmonary contusion by application of force between 200–250 N/m2 for thirty seconds in three areas of one lung. Two hours later, fat embolism was induced via reaming of the ipsilateral femur and tibia and cemented nailing. Two hours later, the dogs were sacrificed. For flow-cytometric evaluation of platelet and neutrophil activation, venous blood samples were stained with fluorescence-conjugated antibodies against CD62P and CD11/18, respectively.

There were no significant differences between the groups in CD62P and CD11/18 mean channel fluorescence (MCF) following pulmonary contusion and fat embolism. However, only animals in the lateral positioning group displayed significant increases in CD62P and CD11/18 MCF at two hours following fat embolism as compared to baseline values.

Our findings suggest that lateral positioning, autoregulation and preferential blood flow to the contused non-dependent lung may render lung tissue more susceptible to congestion and lead to activation of both platelets and neutrophils. Lateral positioning may have an early effect on activation of the inflammatory and coagulation cascades and may be significant in the development of posttraumatic acute lung injury.


Y.G. Laflamme C.M. Borkhoff V.K.R. Bodavula D. Cogley D.J.G. Stephen M.D. McKee E.H. Schemitsch H.J. Kreder

The purpose of this study was to evaluate functional outcome in patients with combined pelvic and acetabular fractures and to identify factors associated with outcome. One hundred and fifteen patients were identified. 63% were male; mean age was thirty-seven years; mean ISS was thirty. Three patients died from their injuries. At a mean follow-up of 3.5 years, patients exhibited profound functional deficits compared to the normal population. Those with an acetabular fracture involving the posterior wall or an associated lower extremity injury have a particularly poor prognosis. Combined pelvic and acetabular injuries are associated with high mortality and functional morbidity irrespective of treatment.

To evaluate functional outcome in patients with combined pelvic and acetabular fractures and to identify factors associated with outcome.

Combined pelvic and acetabular injuries are associated with high mortality and functional morbidity irrespective of treatment.

These results will allow us to further investigate which injury is dictating prognosis in the combined injury – the pelvic or the acetabular fracture.

One-hundred and fifteen patients with combined pelvic and acetabular injuries were identified at a level One trauma centre. 63% were male; mean age was thirty-seven years (13–88); mean ISS was thirty (16–75). Three patients died from their injuries. 16% involved bilateral pelvic fractures; 7% bilateral acetabular fractures; and for 2%, both were bilateral. 64% were Tile B and 34% were Tile C. Most acetabular fractures involved the anterior column or both column. Only 18% were treated with ORIF for both injuries. 25% had ORIF of their acetabulum and 14% had ORIF on their pelvis. Sixty-five patients completed validated functional outcome questionnaires at a mean follow-up of 3.5 (one to eleven) years. Patient function was significantly compromised with a mean MFA score of 33.8 (SD 21.8). Function was worse for all 8 SF-36 domains and the two component scores compared to the health status of the Canadian normal population (p< 0.001). Those individuals with an acetabular fracture involving the posterior wall or an associated lower extremity injury have a particularly poor prognosis. There was no relationship found between treatment or the pre-defined stability groups and functional outcome.

Funding: Grant funded from AO/ASIF


H.J. Kreder I. Weller E. Wai

The purpose of this study was to evaluate mortality following delay to surgery in hip fractures in the province of Ontario. All patients undergoing a surgical procedure for a hip fracture between 1993 and 1999 were identified using administrative databases. For every day that surgery was delayed, the adjusted odds of in-hospital mortality increased by a factor of 1.12 times (95%CI), with similar results at three months and one year. A significant relationship exists between delay to surgery and mortality in elderly hip fracture patients. Every effort should be made to avoid non-medical delays in providing operative treatment for hip fractures.

To evaluate mortality following delay to surgery in hip fractures in the province of Ontario.

A significant relationship exists between delay to surgery and mortality in elderly hip fracture patients. Every effort should be made to avoid non-medical delays in providing operative treatment for patients with fractured hips.

This finding will have far reaching implications for the allocation of health resources in the future.

All patients undergoing a surgical procedure for a hip fracture between 1993 and 1999 in the Province of Ontario were identified using administrative databases and the provincial mortality database. Multivariable logistic regression models were used to adjust for age, gender, medical comorbidity, type of hip fracture, and teaching status of the treating hospital.

For every day that surgery was delayed, the adjusted odds of in-hospital mortality increased by a factor of 1.12 times (95% CI). The adjusted odds of in-hospital mortality increased as the delay to surgery lengthened from a factor of 1.2 [95% CI] with a one day delay to a factor of 1.5 [95% CI] for a delay over two days as compared with patients operated within twenty-four hours. Similar relationships were observed at three months and one year. Even when considering only healthy patients, < seventy years old with no comorbid conditions, the relationship between mortality and surgical delay remained significant (p < 0.0001), suggesting that surgical delay was unlikely to be caused by patient factors alone.


I. Weller H. Kreder E. Wai S. Jaglal J. Schatzker

We compared the mortality of hip fracture patients treated in teaching versus community hospitals in Ontario. Hip fracture patients ≥ 50 yrs were identified from the Canadian Institute for Health Information Hospital Discharge Abstracts Database and linked to the Registered Persons Database for death information. Logistic regression analyses were done to assess the relation between hospital type and both mortality and complications after surgery. Covariates examined include sex, age, Charlson-Deyo index, time to surgery and their interactions. Although patients treated in teaching hospitals have more comorbidities and complications they have lower mortality than those treated in community hospitals.

To compare the mortality of hip fracture patients treated in teaching versus urban and rural community hospitals in Ontario. Although patients treated in teaching hospitals have more comorbidities and complications they have lower mortality than those treated in community hospitals. This finding will have far-reaching implications for health policy in this province. Hip fracture (ICD-9 code 820) patients ≥ 50 yrs treated in Ontario between 1993 and 1999 were identified from the Canadian Institute for Health Information Hospital Discharge Abstracts Database. These were linked to the Registered Persons Database for death information. Logistic regression analyses were done to assess the relation between hospital type and both mortality and complications after surgery. Covariates examined include sex, age, Charlson-Deyo index, time to surgery and their interactions.

Patients treated in teaching hospitals and rural community hospitals were more likely to have a major complication than those in urban community hospitals, adjusted OR (95% CI) 1.37 (1.29–1.45); 1.28 (1.06–1.55) respectively. Patients in teaching hospitals had more comordities than those in community urban or rural hospitals. Nevertheless, patients treated in teaching hospitals have lower mortality (in hospital, and at three, six and twelve months post-surgery) than those in urban community hospitals, adjusted OR (95% CI) 0.76 (0.60–0.96), 0.90 (0.85–0.96), 0.91 (0.86–0.96), 0.92 (0.88–0.96) respectively. The difference between rural and urban community hospitals was not statistically significant, however there was a trend to higher mortality in rural institutions, adjusted OR (95% CI) 0.79 (0.63–1.00), 1.13 (0.95–1.36), 1.16 (0.98–1.36), 1.13 (0.97–1.32) respectively.


D.W. Sanders M.D. MacLeod T. Charyk-Stewart J. Lydestad A.D. Domonkos J. Poon

Recovery after femur fractures is slow, despite rapid bone union. Causes of disability require investigation. Forty patients with isolated, diaphyseal femur fractures treated with antegrade locked intramedullary nailing were prospectively studied. Functional outcome was measured using the Western Ontario – McMaster University Osteoarthritis Index (WOMAC) and Short Musculoskeletal Functional Assessment (SMFA). Pain scores from the groin, buttock, thigh, and knee six months following the injury were correlated with functional outcome. Severity of pain was highest at the knee. Both knee and thigh pain had strong correlations with functional outcome measures following diaphyseal femur fractures. Further investigation into post-traumatic pain is warranted.

This study was performed to compare pain at the knee, thigh, buttock and groin with functional outcome scores 6 months following femur fractures.

Pain at the knee and thigh correlated with functional outcome measures.

Many patients with femoral fractures have prolonged disability. Knee pain is common, severe, and correlates with functional outcome.

Forty skeletally-mature patients with diaphyseal femoral fractures treated with locked antegrade intramedullary nails were prospectively enrolled. Exclusion criteria included polytrauma, ipsilateral injuries, metaphyseal extension, and pathologic fractures. Functional outcomes were assessed using the Western Ontario-McMaster University Osteoarthritis Index (WOMAC) and the Short Musculoskeletal Function Assessment (SMFA). Patients were instructed to record pain in the groin, buttock, thigh or knee of the fractured extremity on a 10-point visual analog scale.

Patients reported more pain at the knee (3.7 ± 3.1), compared to the thigh (2.5 ± 2.7), buttock (1.7 ± 2.7), and groin (1.0 ± 1.7) (p=0.003). Pain and functional outcomes were plotted on scatter graphs and correlations performed using the Spearman rank test. Strongest correlations were noted between knee pain and WOMAC pain (ρ=0.748, p< 0.001), function (ρ=0.701, p< 0.001), and SMFA (ρ=0.733, p< 0.001); and between thigh pain and WOMAC pain (ρ=0.705, p< 0.001), stiffness (ρ=0.707, p< 0.001), function (ρ=0.731, p< 0.001), and SMFA (ρ=0.723, p< 0.001). Weaker correlations were noted between groin and buttock pain and functional outcomes.

Knee pain is common and severe after femur fractures. Knee and thigh pain correlate with functional outcomes. Further investigation should be directed to this common problem.

Funding: Funding from Synthes Canada, Smith and Nephew Richards Canada, and the Lawson Health Research Institute was received in support of this study.


P. O’Brien V. Jando T. Lu H. Chan F. Timms

Antegrade intramedullary nailing via a piriformis fossa start point is the treatment of choice for most femoral shaft fractures in adults. Recently alternate approaches for intramedullary nailing of the femur have been advocated, including retrograde nailing and trochanteric start point antegrade nailing. Reasons cited for considering altenative starting points to the piriformis fossa include a concern about the damage to the hip abductor muscles that may occur during access to the piriformis fossa. There is very little literature about long- term muscle function after standard antegrade intramedullary nailing and the conclusions of the available studies are conflicting.

The purpose of this study was to document the hip abductor muscle strength following standard antegrade intramedullary nailing utilizing two different objective measures (KinCom and gait analysis).

Objective evidence of hip abductor muscle strength will assist in planning new nailing techniques.

Twenty-two patients with isolated femoral shaft fractures who were treated with standard antegrade reamed interlocking intramedullary nailing and who had a minimum one year follow-up were identified. The patients were examined for muscle strength, range of motion and limb length. All of the patients answered a questionnaire and completed the SF-36 and Musculoskeletal Functional Assessment outcome measures. All patients had isokinetic muscle testing of their hip abductors, hip extensors and knee extensors using the KinCom muscle testing machine. Ten of the patients also underwent formal gait lab analysis.

Isokinetic muscle testing showed no significant difference from the uninjured contralateral side in hip abduction, hip extension or knee extension. The gait lab analysis failed to show any important changes in gait pattern. SF-36 scores were comparable to norms. MFA scores did not indicate any significant long term disability.

Antegrade reamed interlocking intramedullary nailing of femoral shaft fractures utilizing a standard piri-formis fossa starting point is not associated with any significant long term hip abductor muscle strength deficit. Gait pattern returns to normal following femoral shaft fracture treated with this technique and functional outcomes are good.


R. Leighton T.A. Russell R. Bucholz P. Tornetta C.N. Cornell J. Goulet M. Vrahas P. O’Brien T. Varecka R. Ostrum W. Jackson A. Jones

This prospective randomized multicenter study compares two methods of bone defect treatment in tibial plateau fractures: a bioresorbable calcium phosphate paste (Alpha-BSM) that hardens at body temperature to give structural support versus Autogenous iliac bone graft (AIBG).

One hundred and eighteen patients were enrolled with a 2:1 randomization, Alpha-BSM to AIBG. There was a significant increased rate of non-graft related adverse affects and a higher rate of late articular subsidence (three to nine month period) in the AIBG group.

A bioresorbable calcium phosphate material is recommended in preference to the gold standard of AIBG for bone defects in tibial plateau fractures.

This prospective randomized multicenter study was undertaken to compare two methods of bone defect treatment: a bioresorbable calcium phosphate paste (Alpha-BSM –DePuy, Warsaw, IN) that hardens at body temperature to give structural support and is gradually resorbed by a cell-mediated bone regenerating mechanism versus Autogenous iliac bone graft (AIBG).

One hundred and eighteen adult acute closed tibial plateau fractures, Schatzker grade two to six were enrolled prospectively from thirteen study sites in North America from 1999 to 2002. Randomization occurred at surgery with a FDA recommendation of a 2–1 ratio, Alpha BSM (seventy-eight fractures) to AIBG (forty fractures). Only internal fixation with standard plate and screw constructs was permitted. Follow-up included standard radiographs and functional studies at one year, with a radiologist providing independent radiographic review.

The two groups exhibited no significant differences in randomization as to age, sex, race, fracture patterns or fracture healing. There was however, a significant increased rate of non-graft related adverse affects in the AIBG group. There was an unexpected significant finding of a higher rate of late articular subsidence in the three to nine month period in the AIBG group.

Recommendations for the use of AIBG for bone defects in tibial plateau fractures should be discouraged in favor of bioresorbable calcium phosphate material with the properties of Alpha BSM. We believe further randomized studies using AIBG as a control group for bone defect support of articular fractures are unjustified.

A bioresorbable calcium phosphate material is recommended in preference to the gold standard of AIBG for bone defects in tibial plateau fractures.

Funding: DePuy, Warsaw, IN.


J. Mountney M. Paice N.V. Greidanus D.A. Wilson B.A. Masri

We have evaluated the function of a trabecular metal augmentation patella to restore knee kinetics and kinematics after revision total knee arthroplasty. An “Oxford type” rig was used with fresh frozen cadaveric knees, for an active model that maximally retained the soft tissue envelope.

Investigating the force through the extensor mechanism, we found a statistically significant difference between the TKA before and after patelloplasty, which was abolished by the insertion of the augmentation patella.

Investigation patella tracking, we found a statistically significant difference between the TKA before and after patelloplasty, that was rectified by the insertion of the augmentation patella.

The purpose of this study is to evaluate the kinetic and kinematic function of a new trabecular metal augmentation patella.

Investigating the force through the extensor mechanism, we found a statistically significant difference between the TKA before and after patelloplasty, which was abolished by the insertion of the augmentation patella.

Investigation patella tracking, we found a statistically significant difference between the TKA before and after patelloplasty, that was rectified by the insertion of the augmentation patella.

This study demonstrates that the augmentation patella restorers the abnormal tracking and higher extensor mechanism forces seen after patelloplasty in revision TKA to those normal after a TKA.

The mean, maximum extensor mechanism force in extension for the TKA group as compared to the patelloplasty group (p=0.0000032), reduced to near normal with the augmentation patella (p=0.198).

The mean, maximum patella maltracking in extension for the TKA group as compared to the patelloplasty group (p=0.025), reduced to near normal with the augmentation patella (p=0.301).

Eight frozen human cadaveric knees (mean age sixty-eight years) were prepared for an “Oxford type” knee rig. Alignment ands offset were addressed and the soft tissue envelope kept as intact as possible. A load cell was introduced into the extensor mechanism. Femoral, patella and tibial motion were assessed using the Optotrak system.

Patella bone loss at revision TKA remains an unsolved problem, with the patella often too thin to accept a new prosthesis. Leaving the patella shell to articulate against the femoral component can lead to disappointing results.

Funding - Zimmer


A.S. Comley S. J. MacDonald R. W. McCalden C.H. Rorabeck R.B. Bourne

In recent years articulating cement spacers have been used to treat infected knee arthroplasty. The aim has been to better maintain tissue planes and joint mobility thereby improving second stage re-implantation surgery. Two groups of patients treated for infected knee arthroplasty were reviewed. Twenty-six patients with articulating and forty patients with static antibiotic-impregnated methyl-methacrylate spacers were compared. The articulating spacers demonstrated easier surgical exposure at second stage and improved range of knee motion after re-implantation. There was no compromise in the rate of infection eradication with articulating spacers. Bone loss at revision was independent of spacer type.

To compare the results of patients treated with articulating versus static antibiotic-impregnated spacers for infected knee arthroplasty.

Articulating cement spacers facilitate re-implantation surgery by maintaining tissue planes and joint mobility without compromising joint stability or eradication rate of infection. Patients demonstrate better range of motion and less complications related to the extensor mechanism with the articulated spacer.

Antibiotic impregnated methyl-methacrylate spacers have become a mainstay in two-stage revision arthroplasty for sepsis. It is thought that articulating cement spacers facilitate prosthesis re-insertion by better maintaining tissue planes and joint mobility between stages.

In the articulating group fewer extensile exposure methods were required at second stage prosthesis reimplantation (19% vs 36 %). No tibial tuberosity osteotomies have been required since using the articulating spacer. The articulating group demonstrated a significantly improved range of flexion compared to the static group(106 vs 97 degrees- p=0.045) and had fewer patients with significant loss of extension or quadriceps lag. Eradication of infection was improved in the articulating group (92% vs 82%) but at shorter average follow-up. The need for augments and stabilized prostheses at revision surgery as a measure of bone loss was no different between the groups but was related to the number of prior surgical procedures.

Twenty-six patients treated with articulating spacers were compared to a matched consecutive group of forty patients treated with static spacers. Minimum follow-up was twelve months from second stage re-implantation (average twenty-two months articulating, forty months static)

Funding: No direct funding from any commercial source has been received for this study. The primary author’s fellowship position is partially funded by Smith and Nephew Richards Inc.


S.J. MacDonald J.T. Marr R. Bourne R. McCalden C. Rorabeck

Fixed bearing and mobile bearing knee designs are both currently used in clinical practice with little evidence- based research available to determine superiority of one system. We performed a prospective, randomized, blinded clinical trial to compare a mobile bearing to two standard fixed bearing implants. A single observer was used to measure all range of motion scores. We evaluated the short and long- term outcomes of the SAL® (mobile bearing) versus the AMK® and Genesis II® (fixed bearings) total knee joint replacements. Minimum two- year follow-up revealed no differences in the outcome measures (WOMAC, SF-12, Knee Society Clinical Rating System).

The purpose of this study was to compare the results between a cruciate retaining mobile bearing total knee (SAL®, Sulzer) and two cruciate retaining fixed bearing total knee prostheses (AMK®, Depuy and Genesis II®, Smith and Nephew).

Ninety patients were randomized to receive a SAL, AMK, or GenesisII prostheses. Patients were evaluated pre-operatively, at three, twelve months and annually thereafter. Patient demographics, radiographs, and multiple outcome measures (WOMAC, SF-12 and the Knee Society Clinical Rating System) were evaluated.

No patients were lost to follow-up. One patient was withdrawn due to dementia before three months, one patient died prior to the two year follow up, and one patient was revised for infection at 6 months leaving eighty-seven patients at an average follow-up of 3.37 years (range 2.91 – 4.44 years). There were no significant differences in any outcome measures or radiographic findings. There were no differences in KSCRS at two years (SAL - 167, AMK – 158, GenesisII – 166). There were no differences in knee flexion at two years (SAL – 117°, AMK – 115°, GenesisII – 118°).

No differences in multiple outcome measures were seen between a cruciate retaining mobile bearing and two cruciate retaining fixed bearing total knee prostheses.

In this prospective randomized clinical trial no differences could be seen between a mobile bearing and two fixed bearing designs at a minimum of two years follow-up. Long-term evaluation will be required to comment on differences in polyethylene wear and implant longevity.

Funding: London Health Sciences Centre Internal Research Fund


P. Zalzal M. Papini D. Backstein A.E. Gross

Notching of the anterior femoral cortex during total knee arthroplasty is thought to be a possible risk factor for subsequent periprosthetic femoral fracture. Understanding the stress pattern caused by notching may help the orthopedic surgeon reduce the risk of fracture. A validated, three dimensional, finite element model of the femur using gait loads has been used to analyze the stress concentrations caused by anterior femoral cortex notching. Three factors that increase these stresses were identified. The notch depth, radius of curvature, and its proximity to the end of the femoral prosthesis influence the state of stress in the surrounding bone.

The purpose of this study was to characterize the stress concentration caused by anterior femoral notching during total knee replacement (TKR) in order to determine when a patient is at risk for a periprosthetic fracture of the femur.

We concluded that notches greater than 3 mm with sharp corners located directly at the proximal end of the femoral implant produced the highest stress concentrations and may lead to a significant risk of periprosthetic femur fracture.

One complication that can occur during TKR is notching of the anterior femoral cortex which results in a stress concentration. It is important to characterize this stress riser in order to determine when a stemmed femoral component should be used to minimize the risk of fracture.

Three factors that affected the stress concentration were identified. First, increasing the notch depth lead to significant increased stress concentrations. When the depth was greater than 3 mm, local stresses increased markedly. Second, the radius of curvature was found to be inversely related to stress concentration. As the radius decreased, the local stress increased. Third, the proximity of the notch to the prostheses affected the stress concentration. Notches that were 1 mm proximal to the implant resulted in much larger stresses than those that were 10 mm away.

A validated, three dimensional finite element model of a femur subjected to a gait loading pattern was used to characterize the stress concentration caused by anterior femoral notching. The results compared well to previous work reported in the literature.


J. Rudan D. Mayman D. Pichora W. Long T. Vasarhelyi R. Ellis

Two computer assisted techniques (CT and a fluoro-guide based system) were used to insert the femoral component of the Oxford Unicompartmental Knee arthroplasty. The accuracy and variability of component positioning were compared. Clinical data was collected pre-operatively and is being collected post-operatively. Standing AP and lateral knee X-rays as well as skyline X-rays were collected pre-operatively and post-operative full length AP and lateral femur X-rays were completed in order to measure alignment of the femoral component. Results are showing accurate insertions of the Oxford knee femoral component using both systems.

To review two computer-assisted techniques for inserting Oxford Unicompartmental Knee arthroplasties. CT based and fluro based techniques were compared with regards to accuracy and variability of component positioning.

Currently we are able to use either a CT based system or a fluro based system to accurately insert the femoral component of the Oxford Unicompartmental Knee arthroplasty.

Computer assist techniques are allowing us to perform minimally invasive arthroplasty procedures with great accuracy.

Patients were all seen in a pre-admission clinic where pre-operative clinical survey data were collected. All patients had standing AP and lateral knee X-rays as well as skyline X-rays pre-operatively. Post-perative full length AP and lateral femur X-rays were completed in order to measure alignment of the femoral component. Patients are being followed post-operatively with SF-36, WOMAC, Knee Society Scores, and X-rays. Patients being operated on with the CT based system had pre operative CT scans. Intra-operatively a DRB was fixed to the patient’s femur and the chosen computer assisted technique was used to direct the rotation of the tibial cut as well as the alignment of the femoral cutting jig. To date we have completed seventeen computer assisted Oxford Unicompartmental Knee Arthroplasties. The average error in the AP plane using CT based system was 3.2 degrees and 2.1 degrees for the lateral plane. The average error in the AP plane using the fluro-based system was 2.2 degrees and 1.3 degree for the lateral plane.

Funding: NSERC, IRIS, ORDCF


Turgeon R.D. Coutts R.M. Healey M. Elington

Allogenic blood transfusions are frequent sequellae of hip and knee arthroplasty with potentially deleterious consequences. A prospective collection of a comprehensive data set of 1,185 knee and 1,064 hip arthroplasty patients including primary and revision surgeries was completed with analysis of allogenic and predonated blood usage, blood salvage systems and costs. The most effective strategy in reducing allogenic blood transfusion is the use of a blood salvage system. The most expensive strategy is the use of blood salvage systems with predonation. The least expensive and least effective strategy is no predonation of blood and no blood salvaging system.

The purpose of this study is to evaluate the usage, effectiveness and cost of blood salvage technologies in total hip and knee arthroplasty.

The most effective strategy in reducing allogenic blood transfusion is the use of a blood salvage system. The most expensive strategy is the use of blood salvage systems with predonation. The least expensive and least effective strategy is no predonation of blood and no blood salvaging system. More than half of the predonated blood collected was never used.

Blood loss in total hip and knee arthroplasty can have significant deleterious physiologic effects on patients. There are potential health risks with allogenic blood transfusion as well as patient anxiety toward allogenic transfusion. Recent advances in blood management provide additional options that need further evaluation.

The lowest cost strategy was no predonation and no blood salvage system at an average of $30 per patient, but with a 14% incidence of allogenic transfusion. Pre-donation alone had a cost of $330 with a 12% transfusion rate. Predonated blood was wasted in 60% of knee arthroplasties and 48% of hip arthroplasties. The Consta Vac and OrthoPAT blood salvage systems had a cost of $110 and $365 with 5% and 7% transfusion rate, respectively.

A prospective collection of a two-year comprehensive data set of 1,185 knee and 1,064 hip arthroplasty patients including both primary and revision surgeries was completed. Analysis of blood counts, allogenic and predonated blood usage, blood salvage systems, length of stay, demographics and costs were performed.


K. Lai E.R. Bohm C. Burnell D. Hedden

A retrospective case-control study was performed to examine modifiable medical co-morbidities in patients who develop deep infection after primary total hip or knee replacement. To reduce bias, matching was undertaken using age, gender, and procedure. Co-morbidities were classified by system: cardiovascular, respiratory, gastrointestinal, genitourinary, metabolic, haematological and neurological. Initial analyses demonstrate that patients with infected primary hip or knee replacements are more likely to suffer from medical conditions than patients who did not develop infections. Since many of these co-morbidities are preventable or treatable, early screening and intervention may play a role in reducing prosthetic joint infection.

Deep infection of total hip (THA) and knee replacements (TKA) causes significant patient morbidity and requires considerable health care resources to treat. In order to identify preventable or modifiable medical conditions associated with prosthetic joint infection, a retrospective case-control study was undertaken.

Fifty patients who developed a culture proven deep infection after primary THA or TKA were studied. To reduce bias, a control group of arthroplasty patients was selected using one to one matching based on age, gender, and procedure. Co-morbidities in each group were recorded, and classified by system.

Analysis revealed that patients with joint infections are more likely to suffer from an increased number of co-morbidities than the matched control group. The odds ratios and 95% confidence intervals were determined as: cardiovascular 2.3 (1.0–5.0), respiratory 2.3 (0.8–6.7), gastrointestinal 0.8 (0.4–1.9), genitourinary 3.1 (1.1–8.9), metabolic 1.8 (0.7–4.9), haematological 2.9 (1.1–7.8), neurological 2.9 (0.8–9.9) and diabetes 4.0 (1.2–13.4). The case group had a higher mean BMI than the control group: 33.7 versus 30.9, p=0.00.

Since many of the co-morbidities associated with infection are preventable or readily treatable, early screening and intervention may play a role in reducing the burden of prosthetic joint infection.


M. Fouse F. Al-Jassir M.L. Burman E. Lenzcner

Closing wedge tibial osteotomy has been the gold standard in proximal osteotomy procedures to correct uni-compartmental osteoarthritis. Opening wedge tibial osteotomies are achieving similar long-term results while avoiding some of the pitfalls of the closing wedge procedure. Opening wedge osteotomies maintain patellar length, tibial inclination, and proximal tibia bone stock. This allows for a technically easier conversion to a total knee arthroplasty in the future.

The purpose of this study was to assess the functional outcomes as well as the anatomical changes caused by opening wedge high tibial osteotomy

Opening and closing wedge osteotomies have been shown to have near equivolent long-term results. Using functional outcome studies (SF-36 and WOMAC ) and radiographic review we have shown good outcomes while maintaining the original anatomy of the knee.

Opening wedge tibial osteotomy will allow for a less complicated conversion to a total knee arthroplasty than the closing wedge tibial osteotomy

The patients attained a significant valgus correction that was maintained postoperatively (pre-op 6.12 varus to 5.5 valgus )

Clinical status of the patient was improved significantly in the functional outcomes testing using the WOMAC knee score( pre-op value 29.75 to 19.5; p = 0.0318 ) and the SF-36 ( pre-op value 64.4 to 81.7; p = 0.0035 ).

Patellar height (Pre-op Insall-Salvati ratio 1.15 to 1.09; p = 0.2339 ) and tibial inclination( pre-op 7.3 degrees to 6.85 degrees; p = 0.6743 ) were maintained.

This study retrospectively examined twenty-two patients with medial joint uni-compartmental osteoarthritis. Radiographic review of the pre-operative and post-operative films assessed the valgus correction, patellar height, and tibial inclination. The patients were seen in follow-up to assess the clinical exam and functional outcomes were measured using the SF-36 and WOMAC knee scores.

Opening wedge HTO is able to achieve acceptable correction of deformity while maintaining the normal anatomy of the knee.


K. Himori H.K. Uhthoff G. Trudel P. Poitras F. Matsumoto H. Sano

The purpose of this study was to clarify the effect of delay of the reattachment of the supraspinatus tendon into a bony trough to the strength of the repaired tendon-bone complex. The supraspinatus tendon of rabbits were transected and reattached into bony troughs at the greater tuberosity immediately and six weeks after transection. The tensile strength of the tendon-bone complex, harvested twelve weeks after reattachment, were measured.

The tensile strength showed no difference between immediate and delayed reattached shoulders. Six weeks delay of supraspinatus tendon repair seems not to weaken the tensile strength of repaired tendon-bone complex.

The purpose of this study was to clarify the effect of timing of surgery on the strength of the supraspinatus tendon-bone complex after the reimplantation of the tendon into a bony trough.

In eight rabbits, the supraspinatus tendon was transected and reinserted into a bony trough at the greater tuberosity (early reattachment group). In seven rabbits, the supraspinatus tendon was reinserted six weeks after transection (delayed reattachment group). In both groups, the rabbits were sacrificed twelve weeks after reattachment, and the tensile strength of the tendon-bone complex was measured. The contralateral shoulders served as controls.

None of the operated tendons failed at the site of reimplantation. The ratio of tensile strength of the operated tendon-bone complex to the controls showed no difference between two groups (Immediate reattachment group: 79.9± 1 S.E. 16.5%, delayed reattachment group: 80.4± 12.6%, P> 0.05).

This is the first experimental study to compare the tensile strength of supraspinatus tendon-bone complex repaired after different time intervals.

Stress-shielded tendon & bone tend to decrease their tensile strength. Given the six weeks duration of detachment, a weaker tensile strength of delayed reattachment group was expected than of the early reattachment group. The fact that both groups did not show a difference might be due to the recovery of tensile strength of tendon & bone in twelve weeks after reattachment.

Six weeks delay of repair of supraspinatus tendon does not weaken the tensile strength of repaired tendon-bone complex.

Fundings This study has been supported in part by a grant from the American Shoulder and Elbow Surgeons.


R. Bray C. Huculak C. Leonard P. Salo R. Bray

Joint instability was induced by posterior cruciate ligament (PCL) transection. This resulted in significant changes in medial collateral ligament (MCL) gene expression as early as three days after injury that persisted as long as 6 weeks. We noted substantial changes in expression of matrix-metalloproteinases (MMPs) −1, −3 and -13, with reciprocal effects on their specific inhibitors TIMP-1 and −3. Sustained changes in expression of these angiogenesis-associated matrix-degrading enzymes likely account for the observed degradation of the mechanical properties of secondary stabilizers in chronically unstable joints.

To determine changes in gene-expression induced by traumatic instability.

Instability activates aberrant expression of angiogenesis-associated matrix metalloproteinases.

PCL transection induces a significant increase in the expression of MMP-3 and decrease in its specific inhibitor TIMP-3 with opposite effects on MMP-1 and TIMP-1 as early as three days after injury.

Understanding the changes in gene expression induced by instability may lead to specific treatments that could prevent the “collateral damage” to secondary stabilizing structures.

Under anaesthesia, four cohorts of six adult rabbits underwent surgical transection of the PCL. Three days, and two, six and sixteen weeks later, the MCL was harvested and the relative expression of TGF-β, MMP-1, -3, and −13, and their tissues inhibitors, and urokinase-type plasminogen activator (uPA) was measured using semi-quantitative RT-PCR.

Previous work revealed increased in blood flow by two weeks and increased vascular volume by six weeks in the MCL of PCL-deficient joints. These changes are preceded by substantial changes in expression of mRNA for matrix degradation enzymes involved in the early stages of angiogenesis. This aberrant expression of matrix metalloproteinases likely accounts for the progressive degradation of the mechanical properties of secondary stabilizing structures seen in chronic instability.

Funding: This work was supported by funding from the CIHR and the Alberta Heritage Foundation for Medical Research.

Please contact author for figures and/or graphs.


R.S.J. Burnett C.M. Haydon C.H. Rorabeck R.B. Bourne

The results of a randomized controlled clinical trial of ninety patients comparing resurfacing to non-resurfacing of the patella in total knee arthroplasty (TKA) are reported with a minimum of ten-years of follow-up. Using a cruciate retaining hybrid TKA, the outcome measures included Knee Society Clinical Rating scores, functional testing (stair climb and flexion extension torques), patient satisfaction, anterior knee pain, and a patellofemoral specific questionnaire. The results indicated no difference between the groups in all categories. Results at two and ten years postoperatively are compared. This study represents the longest follow-up to date comparing resurfacing to nonresurfacing of the patella.

Patellar resurfacing in TKA remains controversial.

Purpose: To evaluate the results of resurfacing/non-resurfacing of the patella in a randomized controlled clinical trial at a minimum of ten-years of follow-up.

One hundred knees (ninety patients) with osteoarthritis were enrolled in a prospective randomized controlled double-blinded trial using the same posterior cruciate retaining total knee replacement. Patients were randomized to resurfacing or nonresurfacing of the patella. Evaluations were performed preoperatively and yearly to a minimum ten years (range, 10.1–11.5 years) postoperatively. Disease specific (Knee Society Clinical Rating System), functional (stair climbing, knee flex-ion/extension torques, patellar examination) outcomes were measured. Patient satisfaction, anterior knee pain, and patellofemoral questionnaires were completed. Intraoperative grading of the articular cartilage was performed.

No patients were lost to follow-up; forty-six knees remained alive. Nine revisions (9/90-ten percent) were performed – 7/48 (fifteen percent) in the nonresurfaced and 2/42 (five percent) in the resurfaced group. Three knees in the nonresurfaced group were revised to a resurfaced patella for anterior knee pain. One resurfaced patella was complicated by AVN and fracture, requiring revision. No significant difference was found between the groups regarding revision rates, KSCR score, functional, satisfaction, anterior knee pain, patellofemoral, and radiographic outcomes. Intraoperative cartilage quality was not a predictor of outcome.

This study represents the longest follow up to date of a randomized controlled clinical trial to examine patellar resurfacing in TKA. The results showed no significant difference between the groups for all outcome measures at a minimum of ten-years.


D. Miller K. Forrester C. Leonard P. Salo R. Bray

We examined the vasoconstrictive actions of neuropeptide Y (NPY) in the intact medial collateral ligament (MCL) of normal and anterior cruciate ligament (ACL) -deficient rabbit knees. Blood flow to the surgically exposed MCL was measured using high-resolution laser speckle imaging (LSI) before and after topical administration of NPY and the α1-adrenoreceptor agonist phenylephrine. In control rabbit knees, dose-dependent vasopressor responses were significantly greater than those in ACL-deficient knees, where there was little or no vasoconstrictor response. We conclude that chronic ACL deficiency markedly changes the vascular physiology and pharmacology of the surrounding articular tissues.

To determine the effect of chronic ACL-deficiency on the physiologic responses to the potent sympathetic vasoconstrictor NPY.

Abrogation of the vasoconstrictor response to both NPY and phenylephrine indicates that chronic ACL deficiency induces major changes in the vascular physiology of associated articular tissues.

This study is the first to examine the vasoregulatory role of NPY in the MCL of unstable knee joints using LSI.

In control rabbits, topical administration of NPY produced dose-dependent vasopressor responses (maximal effect at 10−10mol NPY). In ACL-transected knees there was little or no response to NPY (Figure 1). BIBP 3226 (selective NPY-Y1 receptor antagonist) did not affect the constrictor response to NPY in normal tissue, indicating that a receptor other than Y-1 mediates the response.

Many neuropeptides participate in the post-traumatic inflammatory response. The sympathetic-derived NPY helps regulate inflammatory responses, is a vasoconstrictor and stimulates angiogenesis. Rupture of the ACL induces inflammation, hyperaemia and angiogenesis in the MCL. These changes in vascular physiology induced us to study the effect of ACL-deficiency on the actions of NPY in the MCL.

Unoperated control (n=6) and 6-week ACL-transected (n=5) adult rabbits were used. Under anaesthesia, the MCL was surgically exposed and tissue blood flow was measured in real time using LSI as various doses and combinations of NPY, phenylephrine, and BIBP 3226 were administered topically.

Possible causes of the reduced vasoconstrictive response to both NPY and phenylephrine in the MCL after 6wk of ACL-deficiency include change in the distribution or functionality of their specific receptors or inactivation of the associated down stream signalling pathways.

Funding: This work was supported by funding from the CIHR and the Alberta Heritage Foundation for Medical Research.

Please contact author for tables and/or graphs.


M.L. Zec C.B. Frank N.G. Shrive

The aim of this study was to characterize the effect of ligament water content on the accumulation of damage in vitro. MCLs of the rabbit knee were subjected to a constant cyclic stress for twenty-four hours (isotonic or hypotonic solution) and then failed. Ligaments cycled in hypotonic solution at 0.1 Hz demonstrated significantly more cyclic strain during loading and had significant reductions in both failure stress and failure strain. This study has demonstrated that elevated tissue water content influences the accumulation of damage in ligaments subjected to repetitive loading in vitro, leading to reductions in both strength and failure strain.

Ligament water content may be altered in vivo during activity, following injury or during surgical intervention; tissue hydration can also be manipulated during in vitro testing. Currently, the effect of ligament water content on the accumulation of damage with loading is unknown. The aim of this study was to characterize the effect of ligament water content on the accumulation of damage during in vitro mechanical testing. We hypothesized that Medial Collateral Ligaments (MCL) subjected to repetitive stress under hypotonic conditions would accumulate more damage than ligaments loaded in an isotonic environment.

MCLs of the rabbit knee were subjected to a constant cyclic stress (28 MPa) in this ex vivo model of loading. Tissues were bathed in either an isotonic or hypotonic solution (10% or 0.1% Sucrose) and were cycled at one of two frequencies (1 Hz or 0.1 Hz) for 24 hours followed by failure testing.

After twenty-four hours of loading, ligaments cycled in hypotonic solution at 0.1 Hz had statistically significant reductions in both failure stress and failure strain. This group also demonstrated significantly more cyclic strain during loading than MCLs cycled in isotonic solution. Surprisingly, a significant difference in cyclic modulus was not detected between groups.

This study has demonstrated that elevated tissue water content influences the accumulation of damage in ligaments subjected to repetitive loading in vitro, leading to reductions in both strength and failure strain. The interaction between tissue water content, cyclic strain and tissue damage will be the focus of further study.


J.M. LaMothe R.F. Zernicke

Bones can adapt in response to mechanical stimuli; higher rates of loading have been associated with greater bone formation rates. This study determined where bone accretion was localized in response to high loading rates. Non-invasive loads were applied to mice tibiae at one of three rates for four week. It was found, via calcein labels, that adaptation on the periosteal, but not endosteal, surface exhibited a dose-response relation with loading rate; periosteal and endosteal adaptation was localized to regions of high strain gradients. Understanding the stimuli bone responds to may underpin the development of non-pharmacological treatments to enhance bone mass.

Bones can adapt to mechanical stimuli; higher rates of loading have been linked with greater bone formation rates (BFR).

The purpose of this research was to determine if bone accretion associated with higher loading rates occurs in regions of high strain gradients or strain rates and if adaptation is similar on periosteal and endosteal surfaces.

Periosteal but not endosteal surfaces displayed a dose-response relation with loading rate. Adaptation on both periosteal and endosteal surfaces was localized to sectors with high strain gradients.

Understanding the precise stimuli by which bone responds may underpin the development of non-pharmacological treatments to enhance bone mass.

Tibia loaded at the high rate had significantly greater periosteal BFR, relative to tibiae loaded at medium (> 48 %) and low (> 104 %) rates; adaptation was localized to posterior sectors (high strain gradients). Endosteally, adaptation was localized to regions of high strain gradients (anterior sectors), but did not display a dose-response relation with loading rate.

Forty-three skeletally mature C57BL/6 mice were randomly assigned to one of three groups, based on loading rate; low (0.004 ε/s; n = 14), medium (0.020 ε/s; n = 15), and high (0.100 ε/s; n = 14). Loads were applied so that tibiae experienced non-invasive medio-lateral cantilever bending (peak strain = 1000 με) at 1 Hz, 60 s, 5 d/w, for 4 wk. Calcein bone labels were administered on d one and eighteen. A standardized sector of the tibial middiaphyeal shaft was digitally divided into 45° radial sectors, and prepared for histomorphometry.

Funding: Funded in part by NSERC, and CIHR


S.G. Haslam S.D. Miller M.R. Doschak R.F. Zernicke R.C. Bray

Ten New Zealand White rabbits underwent anterior cruciate ligament transection (ACLX), then reconstruction using a mersiline tape graft and mitek mini anchors. Animals were divided into two groups and sacrificed at six and fourteen week after surgery. Medial collateral ligament (MCL)-complexes were evaluated for joint laxity, and periarticular tissues evaluated for changes in vascular volume. Both reconstructed groups showed significantly reduced MCL-complex laxity and inflammatory angiogenesis compared to ACLX controls. This reconstructive method (using an artificial graft) provided transient restabilization out to 6 and 14 wk after ACLX in the rabbit, with a high 80% success rate of intact grafts.

To refine a method of ACL reconstruction in the New Zealand White (NZW) rabbit to study angiogenic adaptations in a restabilized knee joint.

The artificial graft approach provided transient restabilization out to six and fourteen week post ACLX with an 80% success rate, and reduced MCL-complex laxity and inflammatory angiogenesis.

Addressing joint instability after ACLX reduces inflammatory angiogenesis and mechanical deterioration in peri-articular tissues, and delays the progression of OA.

Compared to normal control tissues, loss of the ACL resulted in marked joint instability, and significantly increased vascular volumes in all periarticular tissues examined six and fourteen week post-ACLX. However, following transient restabilization using reconstructive surgery, MCL-complex laxity and periarticular tissue vascular volume were significantly reduced at both the six and fourteen week intervals compared to ACLX controls.

ACL reconstructive surgery was performed on the right knee of ten skeletally mature NZW rabbits using a mersiline tape graft and mitek mini anchors, immediately after the ACL had been transected. MCL-complex laxity was measured in all joints using established biomechanical procedures. To assess the effect of joint restabilization six and fourteen week after ACL reconstruction, limbs were infused with a 5% carmine red dye/5% gelatin solution, and the vascular volume of periarticular tissues was detemined.

The artificial graft approach to rabbit ACL reconstruction resulted in a high success rate of intact grafts 6 and 14 wk post-ACLX. The transient restabilization of an ACLX knee joint results in less inflammatory angio-genesis in periarticular tissues.

Funding: CIHR


M. Glazebrook M. Langman W. Stanish J.M. Lee

Tendon disease causes widespread morbidity ranging from mild pain to catastrophic end-stage rupture. The pathophysiology of tendon disease is not certain. An overuse exercise model was developed using rats with the aim of developing tissue with histological, biochemical and biomechanical features similar to those in human tendinosis. Results indicate that the biological response to over-exercise of the rat Achilles tendon is similar to the literature description of pathological specimens of human with disease. Biochemical and histological analysis of the rat Achilles tendons suggest that the patho-physiology is more consistent with a repair response than with a classical inflammatory response.

Tendon disease causes widespread morbidity ranging from mild pain to catastrophic end-stage rupture and the pathophysiology of tendon disease is not certain.

To develop an overuse exercise animal model to study the pathophysiology of Achilles tendon disease.

Experimental rats were subjected to an over-exercise running regime, while control rats were maintained under normal cage activity. Achilles tendons were analyzed for histological features, glycosaminoglycan content, collagen content, collagen subtype, collagen crosslinking (hydrothermal isometric tension testing), and mechanical properties.

Experimental rat Achilles tendons demonstrated: increased nuclear numbers per high-power field (527 vs. 392, p < 0.05), decreased semi-quantitative grade for collagen organization (2.9 vs. 3.7, p < 0.05) and decreased semi-quantitative grade for collagen staining (1.9 vs 3.5, p < 0.05). The total collagen content remained unchanged (84.3 vs. 89.0% p=0.38), while the glycosaminoglycan content was increased (17.5 vs. 9.0% p=0.02). Increased levels of collagen type III were not demonstrated, however. Experimental tendons were determined to have distinct differences in the collagen crosslinking patterns, with reduced total cross links and a greater population of immature, hydrolytically unstable cross links. These differences did not, however, translate into a decrease in ultimate tensile failure during mechanical testing (UTS of 77.8 vs. 88.8 N, p=0.26).

The histology and biochemistry observed in the experimental rat Achilles tendons were similar to those described in the literature on human Achilles tendon disease.

The rat Achilles tendon over-exercise model has demonstrated histopathology that was different from a control group and was consistent with the human literature for Achilles tendon disease.

Research Grants were received from the following organizations:

Canadian Orthopaedics Foundation

American Foot and Ankle Society

Dalhousie University Department of Surgery

Nova Scotia Capitol District Health Authority Research Fund


R.C. Hamdy M. Mandu M. Kawaguchi D. Lauzier F. Rauch

The different pathways by which bone morphogenetic protein 7 (BMP-7) could exert its osteogenic function in distraction osteogenesis (DO) were investigated. Using immunohistochemistry, the temporal and spatial expression of markers for angiogenesis, cell proliferation, Indian hedgehog pathway, osteogenic growth factors and their receptors were investigated in a rabbit model of DO. Our results showed that local injection of BMP-7 at the lengthened site caused up-regulation of expression of growth factors and their receptors, cell proliferation and vascular markers and Indian hedgehog gene in a temporal fashion. By knowing these pathways, manipulation of DO by pharmaceutical agents may be possible.

Based on preliminary data, BMP-7 can accelerate the consolidation of newly formed bone if locally injected early in the distraction phase; however, the exact mechanism remains unknown.

The purpose of this study was to investigate the different pathways through which BMP-7 exerts its effects in DO.

The right tibia of twenty-four rabbits was lengthened 2.0 cms. The rabbits were divided into three groups : control, placebo and treated groups. The rabbits received no injection (control), buffer (placebo) and 75 micro grams BMP7 (treated) in the distracted zone one week after the start of distraction. The rabbits were sacrificed ten minutes, one day, two days and two weeks following the injections. Using immunohistochemistry, the different pathways of bone formation were assessed by analysing the expression of markers for angiogenesis (VGEF, Vascular Endothelial Growth Factor and PECAM , platelet endothelial cell adhesion molecule) , cell proliferation markers (PCNA, proliferation cell nuclear antigen), osteogenic growth factors (TGFβ, IGF, FGF and their receptors) and Indian hedgehog gene as part of the parathyroid hormone related peptide pathway.

BMP-7 may stimulate bone formation through several pathways in a temporal fashion early after local injection, by up-regulating the expression of numerous osteogenic growth factors and their receptors and Indian hedgehog, and late two weeks after the injection, by up-regulating cell proliferation and vascular markers.

Our results showed the possible mechanisms of action of BMP-7 in DO and more importantly the various pathways through which pharmacological agents could be used in the manipulation of DO.


P. Zalzal M. Papini D. Backstein A.E. Gross

Notching of the anterior femoral cortex during total knee arthroplasty is thought to be a possible risk factor for subsequent periprosthetic femoral fracture. Understanding the stress pattern caused by notching may help the orthopedic surgeon reduce the risk of fracture. A validated, three dimensional, finite element model of the femur using gait loads has been used to analyze the stress concentrations caused by anterior femoral cortex notching. Three factors that increase these stresses were identified. The notch depth, radius of curvature, and its proximity to the end of the femoral prosthesis influence the state of stress in the surrounding bone.

The purpose of this study was to characterize the stress concentration caused by anterior femoral notching during total knee replacement (TKR) in order to determine when a patient is at risk for a periprosthetic fracture of the femur.

We concluded that notches greater than 3 mm with sharp corners located directly at the proximal end of the femoral implant produced the highest stress concentrations and may lead to a significant risk of periprosthetic femur fracture.

One complication that can occur during TKR is notching of the anterior femoral cortex which results in a stress concentration. It is important to characterize this stress riser in order to determine when a stemmed femoral component should be used to minimize the risk of fracture.

Three factors that affected the stress concentration were identified. First, increasing the notch depth lead to significant increased stress concentrations. When the depth was greater than 3 mm, local stresses increased markedly. Second, the radius of curvature was found to be inversely related to stress concentration. As the radius decreased, the local stress increased. Third, the proximity of the notch to the prostheses affected the stress concentration. Notches that were 1 mm proximal to the implant resulted in much larger stresses than those that were 10 mm away.

A validated, three dimensional finite element model of a femur subjected to a gait loading pattern was used to characterize the stress concentration caused by anterior femoral notching. The results compared well to previous work reported in the literature.


A.S. Comley S. J. MacDonald R. W. McCalden C.H. Rorabeck R.B. Bourne

In recent years articulating cement spacers have been used to treat infected knee arthroplasty. The aim has been to better maintain tissue planes and joint mobility thereby improving second stage re-implantation surgery. Two groups of patients treated for infected knee arthroplasty were reviewed. Twenty-six patients with articulating and forty patients with static antibiotic-impregnated methyl-methacrylate spacers were compared. The articulating spacers demonstrated easier surgical exposure at second stage and improved range of knee motion after re-implantation. There was no compromise in the rate of infection eradication with articulating spacers. Bone loss at revision was independent of spacer type.

To compare the results of patients treated with articulating versus static antibiotic-impregnated spacers for infected knee arthroplasty.

Articulating cement spacers facilitate re-implantation surgery by maintaining tissue planes and joint mobility without compromising joint stability or eradication rate of infection. Patients demonstrate better range of motion and less complications related to the extensor mechanism with the articulated spacer.

Antibiotic impregnated methyl-methacrylate spacers have become a mainstay in two-stage revision arthroplasty for sepsis. It is thought that articulating cement spacers facilitate prosthesis re-insertion by better maintaining tissue planes and joint mobility between stages.

In the articulating group fewer extensile exposure methods were required at second stage prosthesis reimplantation (19% vs 36 %). No tibial tuberosity osteotomies have been required since using the articulating spacer. The articulating group demonstrated a significantly improved range of flexion compared to the static group(106 vs 97 degrees- p=0.045) and had fewer patients with significant loss of extension or quadriceps lag. Eradication of infection was improved in the articulating group (92% vs 82%) but at shorter average follow-up. The need for augments and stabilized prostheses at revision surgery as a measure of bone loss was no different between the groups but was related to the number of prior surgical procedures.

Twenty-six patients treated with articulating spacers were compared to a matched consecutive group of forty patients treated with static spacers. Minimum follow-up was twelve months from second stage re-implantation (average twenty-two months articulating, forty months static)

Funding: No direct funding from any commercial source has been received for this study. The primary author’s fellowship position is partially funded by Smith and Nephew Richards Inc.


J. Mountney M. Paice N.V. Greidanus D.A. Wilson B.A. Masri

We have evaluated the function of a trabecular metal augmentation patella to restore knee kinetics and kinematics after revision total knee arthroplasty. An “Oxford type” rig was used with fresh frozen cadaveric knees, for an active model that maximally retained the soft tissue envelope.

Investigating the force through the extensor mechanism, we found a statistically significant difference between the TKA before and after patelloplasty, which was abolished by the insertion of the augmentation patella.

Investigation patella tracking, we found a statistically significant difference between the TKA before and after patelloplasty, that was rectified by the insertion of the augmentation patella.

The purpose of this study is to evaluate the kinetic and kinematic function of a new trabecular metal augmentation patella.

Investigating the force through the extensor mechanism, we found a statistically significant difference between the TKA before and after patelloplasty, which was abolished by the insertion of the augmentation patella.

Investigation patella tracking, we found a statistically significant difference between the TKA before and after patelloplasty, that was rectified by the insertion of the augmentation patella.

This study demonstrates that the augmentation patella restorers the abnormal tracking and higher extensor mechanism forces seen after patelloplasty in revision TKA to those normal after a TKA.

The mean, maximum extensor mechanism force in extension for the TKA group as compared to the patelloplasty group (p=0.0000032), reduced to near normal with the augmentation patella (p=0.198).

The mean, maximum patella maltracking in extension for the TKA group as compared to the patelloplasty group (p=0.025), reduced to near normal with the augmentation patella (p=0.301).

Eight frozen human cadaveric knees (mean age sixty-eight years) were prepared for an “Oxford type” knee rig. Alignment ands offset were addressed and the soft tissue envelope kept as intact as possible. A load cell was introduced into the extensor mechanism. Femoral, patella and tibial motion were assessed using the Optotrak system.

Patella bone loss at revision TKA remains an unsolved problem, with the patella often too thin to accept a new prosthesis. Leaving the patella shell to articulate against the femoral component can lead to disappointing results.

Funding - Zimmer


S.J. MacDonald J.T. Marr R. Bourne R. McCalden C. Rorabeck

Fixed bearing and mobile bearing knee designs are both currently used in clinical practice with little evidence- based research available to determine superiority of one system. We performed a prospective, randomized, blinded clinical trial to compare a mobile bearing to two standard fixed bearing implants. A single observer was used to measure all range of motion scores. We evaluated the short and long- term outcomes of the SAL® (mobile bearing) versus the AMK® and Genesis II® (fixed bearings) total knee joint replacements. Minimum two- year follow-up revealed no differences in the outcome measures (WOMAC, SF-12, Knee Society Clinical Rating System).

The purpose of this study was to compare the results between a cruciate retaining mobile bearing total knee (SAL®, Sulzer) and two cruciate retaining fixed bearing total knee prostheses (AMK®, Depuy and Genesis II®, Smith and Nephew).

Ninety patients were randomized to receive a SAL, AMK, or GenesisII prostheses. Patients were evaluated pre-operatively, at three, twelve months and annually thereafter. Patient demographics, radiographs, and multiple outcome measures (WOMAC, SF-12 and the Knee Society Clinical Rating System) were evaluated.

No patients were lost to follow-up. One patient was withdrawn due to dementia before three months, one patient died prior to the two year follow up, and one patient was revised for infection at 6 months leaving eighty-seven patients at an average follow-up of 3.37 years (range 2.91 – 4.44 years). There were no significant differences in any outcome measures or radiographic findings. There were no differences in KSCRS at two years (SAL - 167, AMK – 158, GenesisII – 166). There were no differences in knee flexion at two years (SAL – 117°, AMK – 115°, GenesisII – 118°).

No differences in multiple outcome measures were seen between a cruciate retaining mobile bearing and two cruciate retaining fixed bearing total knee prostheses.

In this prospective randomized clinical trial no differences could be seen between a mobile bearing and two fixed bearing designs at a minimum of two years follow-up. Long-term evaluation will be required to comment on differences in polyethylene wear and implant longevity.

Funding: London Health Sciences Centre Internal Research Fund


J. Rudan D. Mayman D. Pichora W. Long T. Vasarhelyi R. Ellis

Two computer assisted techniques (CT and a fluoro-guide based system) were used to insert the femoral component of the Oxford Unicompartmental Knee arthroplasty. The accuracy and variability of component positioning were compared. Clinical data was collected pre-operatively and is being collected post-operatively. Standing AP and lateral knee X-rays as well as skyline X-rays were collected pre-operatively and post-operative full length AP and lateral femur X-rays were completed in order to measure alignment of the femoral component. Results are showing accurate insertions of the Oxford knee femoral component using both systems.

To review two computer-assisted techniques for inserting Oxford Unicompartmental Knee arthroplasties. CT based and fluro based techniques were compared with regards to accuracy and variability of component positioning.

Currently we are able to use either a CT based system or a fluro based system to accurately insert the femoral component of the Oxford Unicompartmental Knee arthroplasty.

Computer assist techniques are allowing us to perform minimally invasive arthroplasty procedures with great accuracy.

Patients were all seen in a pre-admission clinic where pre-operative clinical survey data were collected. All patients had standing AP and lateral knee X-rays as well as skyline X-rays pre-operatively. Post-perative full length AP and lateral femur X-rays were completed in order to measure alignment of the femoral component. Patients are being followed post-operatively with SF-36, WOMAC, Knee Society Scores, and X-rays. Patients being operated on with the CT based system had pre operative CT scans. Intra-operatively a DRB was fixed to the patient’s femur and the chosen computer assisted technique was used to direct the rotation of the tibial cut as well as the alignment of the femoral cutting jig. To date we have completed seventeen computer assisted Oxford Unicompartmental Knee Arthroplasties. The average error in the AP plane using CT based system was 3.2 degrees and 2.1 degrees for the lateral plane. The average error in the AP plane using the fluro-based system was 2.2 degrees and 1.3 degree for the lateral plane.

Funding: NSERC, IRIS, ORDCF


M. Fouse F. Al-Jassir M.L. Burman E. Lenzcner

Closing wedge tibial osteotomy has been the gold standard in proximal osteotomy procedures to correct uni-compartmental osteoarthritis. Opening wedge tibial osteotomies are achieving similar long-term results while avoiding some of the pitfalls of the closing wedge procedure. Opening wedge osteotomies maintain patellar length, tibial inclination, and proximal tibia bone stock. This allows for a technically easier conversion to a total knee arthroplasty in the future.

The purpose of this study was to assess the functional outcomes as well as the anatomical changes caused by opening wedge high tibial osteotomy

Opening and closing wedge osteotomies have been shown to have near equivolent long-term results. Using functional outcome studies (SF-36 and WOMAC ) and radiographic review we have shown good outcomes while maintaining the original anatomy of the knee.

Opening wedge tibial osteotomy will allow for a less complicated conversion to a total knee arthroplasty than the closing wedge tibial osteotomy

The patients attained a significant valgus correction that was maintained postoperatively (pre-op 6.12 varus to 5.5 valgus)

Clinical status of the patient was improved significantly in the functional outcomes testing using the WOMAC knee score( pre-op value 29.75 to 19.5; p = 0.0318 ) and the SF-36 ( pre-op value 64.4 to 81.7; p = 0.0035 ).

Patellar height (Pre-op Insall-Salvati ratio 1.15 to 1.09; p = 0.2339 ) and tibial inclination( pre-op 7.3 degrees to 6.85 degrees; p = 0.6743 ) were maintained.

This study retrospectively examined twenty-two patients with medial joint uni-compartmental osteoarthritis. Radiographic review of the pre-operative and post-operative films assessed the valgus correction, patellar height, and tibial inclination. The patients were seen in follow-up to assess the clinical exam and functional outcomes were measured using the SF-36 and WOMAC knee scores.

Opening wedge HTO is able to achieve acceptable correction of deformity while maintaining the normal anatomy of the knee.


K. Lai E.R. Bohm C. Burnell D. Hedden

A retrospective case-control study was performed to examine modifiable medical co-morbidities in patients who develop deep infection after primary total hip or knee replacement. To reduce bias, matching was undertaken using age, gender, and procedure. Co-morbidities were classified by system: cardiovascular, respiratory, gastrointestinal, genitourinary, metabolic, haematological and neurological. Initial analyses demonstrate that patients with infected primary hip or knee replacements are more likely to suffer from medical conditions than patients who did not develop infections. Since many of these co-morbidities are preventable or treatable, early screening and intervention may play a role in reducing prosthetic joint infection.

Deep infection of total hip (THA) and knee replacements (TKA) causes significant patient morbidity and requires considerable health care resources to treat. In order to identify preventable or modifiable medical conditions associated with prosthetic joint infection, a retrospective case-control study was undertaken.

Fifty patients who developed a culture proven deep infection after primary THA or TKA were studied. To reduce bias, a control group of arthroplasty patients was selected using one to one matching based on age, gender, and procedure. Co-morbidities in each group were recorded, and classified by system.

Analysis revealed that patients with joint infections are more likely to suffer from an increased number of co-morbidities than the matched control group. The odds ratios and 95% confidence intervals were determined as: cardiovascular 2.3 (1.0 – 5.0), respiratory 2.3 (0.8 – 6.7), gastrointestinal 0.8 (0.4–1.9), genitourinary 3.1 (1.1–8.9), metabolic 1.8 (0.7 – 4.9), haematological 2.9 (1.1–7.8), neurological 2.9 (0.8–9.9) and diabetes 4.0 (1.2–13.4). The case group had a higher mean BMI than the control group: 33.7 versus 30.9, p=0.00.

Since many of the co-morbidities associated with infection are preventable or readily treatable, early screening and intervention may play a role in reducing the burden of prosthetic joint infection.


Turgeon R.D. Coutts R.M. Healey M. Elington

Allogenic blood transfusions are frequent sequellae of hip and knee arthroplasty with potentially deleterious consequences. A prospective collection of a comprehensive data set of 1,185 knee and 1,064 hip arthroplasty patients including primary and revision surgeries was completed with analysis of allogenic and predonated blood usage, blood salvage systems and costs. The most effective strategy in reducing allogenic blood transfusion is the use of a blood salvage system. The most expensive strategy is the use of blood salvage systems with predonation. The least expensive and least effective strategy is no predonation of blood and no blood salvaging system.

The purpose of this study is to evaluate the usage, effectiveness and cost of blood salvage technologies in total hip and knee arthroplasty.

The most effective strategy in reducing allogenic blood transfusion is the use of a blood salvage system. The most expensive strategy is the use of blood salvage systems with predonation. The least expensive and least effective strategy is no predonation of blood and no blood salvaging system. More than half of the predo-nated blood collected was never used.

Blood loss in total hip and knee arthroplasty can have significant deleterious physiologic effects on patients. There are potential health risks with allogenic blood transfusion as well as patient anxiety toward allogenic transfusion. Recent advances in blood management provide additional options that need further evaluation.

The lowest cost strategy was no predonation and no blood salvage system at an average of $30 per patient, but with a 14% incidence of allogenic transfusion. Pre-donation alone had a cost of $330 with a 12% transfusion rate. Predonated blood was wasted in 60% of knee arthroplasties and 48% of hip arthroplasties. The Consta Vac and OrthoPAT blood salvage systems had a cost of $110 and $365 with 5% and 7% transfusion rate, respectively.

A prospective collection of a two-year comprehensive data set of 1,185 knee and 1,064 hip arthroplasty patients including both primary and revision surgeries was completed. Analysis of blood counts, allogenic and predonated blood usage, blood salvage systems, length of stay, demographics and costs were performed.


R.S.J. Burnett C.M. Haydon C.H. Rorabeck R.B. Bourne

The results of a randomized controlled clinical trial of ninety patients comparing resurfacing to non-resurfacing of the patella in total knee arthroplasty (TKA) are reported with a minimum of ten-years of follow-up. Using a cruciate retaining hybrid TKA, the outcome measures included Knee Society Clinical Rating scores, functional testing (stair climb and flexion extension torques), patient satisfaction, anterior knee pain, and a patellofemoral specific questionnaire. The results indicated no difference between the groups in all categories. Results at two and ten years postoperatively are compared. This study represents the longest follow-up to date comparing resurfacing to nonresurfacing of the patella.

Patellar resurfacing in TKA remains controversial. Purpose: To evaluate the results of resurfacing/non-resurfacing of the patella in a randomized controlled clinical trial at a minimum of ten-years of follow-up.

One hundred knees (ninety patients) with osteoarthritis were enrolled in a prospective randomized controlled double-blinded trial using the same posterior cruciate retaining total knee replacement. Patients were randomized to resurfacing or nonresurfacing of the patella. Evaluations were performed preoperatively and yearly to a minimum ten years (range, 10.1–11.5 years) postoperatively. Disease specific (Knee Society Clinical Rating System), functional (stair climbing, knee flexion/extension torques, patellar examination) outcomes were measured. Patient satisfaction, anterior knee pain, and patellofemoral questionnaires were completed. Intraoperative grading of the articular cartilage was performed.

No patients were lost to follow-up; forty-six knees remained alive. Nine revisions (9/90-ten percent) were performed – 7/48 (fifteen percent) in the nonresurfaced and 2/42 (five percent) in the resurfaced group. Three knees in the nonresurfaced group were revised to a resurfaced patella for anterior knee pain. One resurfaced patella was complicated by AVN and fracture, requiring revision. No significant difference was found between the groups regarding revision rates, KSCR score, functional, satisfaction, anterior knee pain, patellofemoral, and radiographic outcomes. Intraoperative cartilage quality was not a predictor of outcome.

This study represents the longest follow up to date of a randomized controlled clinical trial to examine patellar resurfacing in TKA. The results showed no significant difference between the groups for all outcome measures at a minimum of ten-years.


E.R. Bohm V. Bubbar K. Yong-Hing A. Dzus

We undertook a prospective, single blinded, randomized, controlled trial of one hundred children treated with either an above or below elbow cast for treatment of closed, distal third forearm fractures requiring reduction. The re-manipulation rate in the below elbow group was 2% (95%CI: 0–11%) compared to 6% (95%CI: 2–15%) in the above elbow group, p=0.62. Above elbow casts do not appear to improve fracture immobilization nor reduce the requirement for re-manipulation in pediatric distal third forearm fractures.

Debate exists regarding the benefits of using below elbow casts instead of above elbow casts for maintaining reduction in pediatric distal third forearm fractures. The literature indicates a loss of reduction rate of 14.6% of children treated in an above elbow cast and 2.5% in those treated with a below elbow cast.

We undertook a prospective, single blinded, randomized, controlled trial of one hundred children treated with either an above or below elbow cast for treatment of closed, distal third forearm fractures requiring reduction. Outcome measures included re-manipulation rate, fracture displacement during cast wear, and cast complications. One hundred patients were suitably enrolled; fifty-four received an above elbow cast, forty-six received a below elbow cast. The two groups were similar in terms of age and gender. The above elbow group contained a higher proportion of both bone fractures (41/54) than the below elbow group (27/46).

There were no significant differences between the two cast groups in initial, post-reduction or cast-off fracture angulation; nor any difference in the amount of fracture displacement during cast wear. The number of cast complications was similar between the two groups. The re-manipulation rate in the below elbow group was 2% (95%CI: 0–11%) compared to 6% (95%CI: 2–15%) in the above elbow group, p=0.62.

Above elbow casts do not appear to improve fracture immobilization nor reduce the requirement for re-manipulation in pediatric distal third forearm fractures.

Funding Hip Hip Hooray, Saskatoon


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M. Aarabi F. Rauch R.C. Hamdy F. Fassier

In osteogenesis imperfecta (OI) because of bone fragility, deformities in load bearing regions of the body such as femoral neck and proximal femur are expected. The purpose of this study was to determine the prevalence and clinical presentation of coxa vara in two hundred and ninety-two patients with different types of OI. More than half of the patients were OI type III (55%) and the highest prevalence of coxa vara was seen in OI type VI (44,5%). The children suffering from coxa vara had also a significant limitation of range of motion in their hips.

The charts and x-rays of one hundred and fifty-four girls and one hundred and thirty-eight boys with OI were reviewed. The patients were classified according to the Sillence classification modified by Glorieux: eighty-seven Type I, sixty-nine Type IV, sixty-two Type III, eighteen Type V, nine type VI, four types VII, and forty-three unclassified. The mean age was nine, four years (0, 3–23, 3).

Twenty-nine patients (9, 9%) had coxa vara (twenty-three left, twenty right). 55% of them were type III, 17% type IV, 13, 8% type VI and three, 4% each of types I, V, VII and unclassified OI. The prevalence of coxa vara was 1% in type I, 5,5% in type V, 7 % in type IV, 25% in type VII , 26% in type III and 44,5% in type VI (p< 0,001 for difference between types I, III and IV). Coxa vara was less frequent in patients with blue sclera (p=0,007). The mean neck-shaft angle was 99° (80°–110°) and the mean Hilgenreiner-epiphyseal angle was 68° (40°–90°). Twenty-five of coxa vara patients (thirty-six hips) had femoral rodding before diagnosis and six hips (all type III) had no history of rodding; however, 26 % of five hundred and thirty-one hips without coxa vara, had previous history of femoral rodding (p=0,004).

Abduction, extension and internal rotation were restricted in the hips with deformity. The abductors and extensors of the hips were weak in some that resulted in limping and Trendelenburg gait.

Special attention including clinical and radiological follow-up should be given to type III and VI patients particularly in the presence of previous femoral rodding.


F.D. Lalonde D.R. Wenger A. Aminian

Over the last several years, triple pelvic osteotomy has become our preferred method for surgical containment in Perthes disease. Since 1995, seventeen patients with Perthes disease have been treated with triple pelvic oste-otomy at our institution. Fourteen of seventeen patients (82%) had a good or excellent clinical result at latest follow-up. According to Sundt’s criteria, radiographic outcome was rated as good in fourteen patients (82%), fair in one patient and poor in two patients. Experience with the technical aspects of the procedure is necessary to avoid pseudarthrosis and iatrogenic external rotation of the acetabular fragment.

To evaluate the efficacy of triple pelvic osteotomy as a method of surgical containment in Perthes disease.

Recent trends point to surgery as the method of choice for containment in older children with Perthes disease. Over the last several years, triple pelvic osteotomy has become our preferred method for surgical containment in Perthes disease.

Since 1995, seventeen patients (seventeen hips) with Perthes disease classified as either lateral pillar B or C have been treated with triple pelvic osteotomy at our institution. The average age at surgery was 8.5 years with an average follow-up of 4.3 years. Outcome was assessed using clinical as well as multiple radiographic criteria.

Fourteen of seventeen patients (82%) had a good or excellent clinical result at latest follow-up. No patients had a residual limp or limb length inequality. Two patients had a minor postoperative complication (transient peroneal nerve palsy, meralgia paresthetica). According to Sundt’s criteria, radiographic outcome was rated as good in fourteen patients (82%), fair in one patient and poor in two patients.

Triple pelvic osteotomy minimizes potential complications associated with other surgical methods such as Trendelenberg gait and shortening with proximal femoral osteotomy or hinge abduction following a Salter innominate osteotomy. Experience with the technical aspects of the procedure is necessary to avoid pseudarthrosis and iatrogenic external rotation of the acetabular fragment.

Triple pelvic osteotomy is now our procedure of choice for containment in the older child with Perthes disease.


U.G. Narayanan J.G. Wright D.M. Hedden B. Alman A. Howard M. Slater S. Donaldson

Little is known about the priorities of patients undergoing surgery for idiopathic scoliosis. This study explores the priorities of adolescents and contrasts them from their parents and their surgeons. Fifty-five pairs of children and parents underwent structured interviews separately, to explore their concerns, desires and expectations both about scoliosis and surgery. Surgeons of these patients and from across Canada completed a similar questionnaire. We found a significant mismatch between child, parent and surgeon priorities. This mismatch has implications on matters relating to decision making, informed consent, understanding of patient satisfaction, and measuring outcomes that are meaningful to patients.

To define the concerns, desires (goals) and expectations of adolescents undergoing surgery for idiopathic scoliosis and to contrast them from their parents and surgeons.

We conducted structured interviews of fifty-five pairs of adolescents and parents separately. The questionnaire had sections on concerns, desires and expectations regarding both scoliosis and surgery, with items pertaining to present and future effects on appearance, pain, physical and psychosocial function and health. Parents also reported what their child’s responses might be. Their surgeons (four) and paediatric spine surgeons (twenty-four) across Canada completed the same questionnaire. Analysis involved repeated measures ANOVA, intra-class correlation coefficients and kappa statistics.

Parents were more concerned than their children about present and future consequences of scoliosis. Surgeons were least concerned. Children, parents and surgeons agreed that improving physical appearance was the primary goal of surgery. Surgeons agreed very little about the natural history of scoliosis, other goals of surgery and the likelihood of specific outcomes. Parents wanted more from surgery than their children. Parents and patients had greater expectations of surgery than surgeons. Adolescents had different priorities from their parents, but parents were aware of this difference and knew what their child’s priorities were.

Adolescents with idiopathic scoliosis, their parents and surgeons have different priorities. This mismatch might stem from uncertainty about the natural history of idiopathic scoliosis for individual patients.

Knowledge of patient priorities is vital for shared decision making, informed consent, understanding patient satisfaction, and for measuring outcomes that matter most to patients.

Funding:

Orthopaedic Research & Education Foundation: (Unni. G. Narayanan: AAOS/OREF Health Services research Fellowship award)

Canadian Institutes of Health Research: (James G. Wright, Douglas M. Hedden, Benjamin Alman, Andrew Howard, Sandra Donaldson)

DePuyAcroMed-Johnson & Johnson Medical Products (James G. Wright, Douglas M. Hedden, Benjamin Alman, Andrew Howard, Sandra Donaldson)

Synthes, Canada (James G. Wright, Douglas M. Hedden, Benjamin Alman, Andrew Howard, Sandra Donaldson)


A. Rabinovich J. Mah A. Adili R. Gandhi

Recent concerns regarding the prospective growth disruption of the olecranon apophysis in skeletally immature patients with intramedullary nail fixation for ulnar fractures has been documented. This retrospective review investigated the long-term functional and radiological outcomes of intramedullary nail fixation through the olecranon apophysis in skeletally immature patients.

Intramedullary nail fixation through the olecranon apophysis in skeletally immature patients is an effective, efficient procedure with excellent functional outcomes and without radiographic evidence of growth disruption at maturity.

To investigate the long-term radiological and functional outcomes on the olecranon apophysis after intra-medullary nail fixation in skeletally immature ulnar fractures.

Retrospective review of patients who where skeletally immature at the time of intramedullary nail fixation through the olecranon apophysis. Patients were excluded if they had previous forearms fractures or fracture of the contralateral forearm. Functional measures included the “Activities Scale for Kids (ASK)”, “Disabilities of the Arm, Shoulder and Hand (DASH)” and “Elbow Assessment Form (EAF)” questionnaires. Radiological outcomes where independently evaluated for ulnar, olecranon, coronoid and trochlear notch proportions at follow-up and initial post-op radiographic data. All patients had a clinical exam and the injured forearm outcomes were compared to the contralateral forearm.

Nineteen patients were assessed. The average age at surgical intervention was 10.8 years (range, 1.6–15.9) with a mean follow up time of 3.4 years (range, 1.2–7.2). We outlined the demographics, clinical outcomes and functional questionnaire outcomes for the study cohort. Detailed radiographic measurements for ulnar, olecranon, coronoid and trochlear notch proportions are outlined also.

Intramedullary nail fixation through the olecranon apophysis in skeletally immature patients is an effective, efficient procedure with excellent functional outcomes and without radiographic evidence of growth disruption at maturity. When skeletally immature ulnar fractures require an intramedullary nail fixation, disrupting the olecranon apophysis has not been shown to affect the long-term functional and radiological outcomes.

Please contact author for tables and/or diagrams.


S. Donaldson D. Hedden D. Stephens B. Alman A. Howard J. Wright

Five surgeons independently rated clinical photographs of forty patients with AIS. Ratings of shoulder blades, shoulder symmetry, and waist symmetry were related to “overall appearance”, and were also correlated with rib prominence and Cobb angle. Because the components of surgeons’ ratings of appearance differed, this may lead to inconsistent recommendations regarding surgery.

To identify patient characteristics associated with surgeons’ ratings of patient physical deformity in Adolescent Idiopathic Scoliosis (AIS).

Five surgeons independently rated clinical photographs of forty patients with AIS. Surgeons separately rated the appearance of patients’ shoulder blades, shoulder symmetry, waist symmetry and also rated their “overall appearance [in five categories from zero (best) to five (worst)]. The following clinical and radiographic data was also collected: rib prominence, vertebral rotation, shoulder height, spinal imbalance, Cobb angle, age, sex, and body mass index.

Surgeons’ mean rating for “overall appearance” was moderately correlated with rib prominence (r = 0.48), vertebral rotation (r = 0.44) and Cobb angle (r = 0.53). Surgeons’ rating of patients’ “overall appearance” was affected by each of: shoulder blades (p = 0.001), shoulder symmetry (p = 0.01) and waist symmetry (p = 0.001). However, each surgeon weighted components of patients’ appearance differently to arrive at their overall rating of appearance (p< 0.006).

Because patients’ physical appearance is an important element of surgical decision making, differences among surgeons could be contributing to inconsistent recommendations.

Surgeons’ ratings of physical appearance are based on surgeons’ ratings of patients’ shoulder blades, waist symmetry and shoulder symmetry but surgeons weight those elements differently.

Surgeon decision making is complicated. It is based on radiographs and subjective assessment. Patients’ appearance undoubtedly influences surgeon recommendation for surgery. We need to clarify surgeons’ ratings and improve the criteria for surgeon decision making.

Funding: This trial was funded by (in alphabetical order) The Canadian Institutes of Health Research, DePuyAcroMed-Johnson & Johnson Medical Products, and Synthes, Canada.


J.A. Ouellet V. Arlet L. Chung

Classic management of large and stiff thoracic scoliotic curves in the adolescent comprise of anterior release followed by posterior instrumentation. However third generation segmental spinal instrumentations have shown increased correction of thoracic curves. Therefore, the indication for an anterior release may no longer be required. We reviewed our database for cases with thoracic curves with Cobb angle between 70 and 90° that we had only done posterior surgery. We found that with adequate posterior release, and the use of third generation segmental instrumentation there is no need for anterior release even for curves in the 70–90° range.

Large and stiff thoracic scoliotic curves in the adolescent represent a classic indication of anterior release before posterior spinal instrumentation.

To assess if third generation segmental posterior instrumentation can omit the need of anterior surgery in large and stiff thoracic curves.

An independent observer, reviewed in a retrospective fashion our electronic database of adolescent scoliosis surgery (Scolisoft) with the following query: Thoracic curves, Cobb angle between 70 and 90° degrees and posterior surgery only. There was nineteen patients who fit the criteria. Out of these, four were judged to flexible (bends < than 45°) and were not included. Fifteen patients (mean age 13.6) with thoracic scoliosis with average Cobb 78.5° with a flexibility index of 32.5% were analyzed. (mean f/u: twenty-eight months)

Postoperatively the thoracic Cobb angle measured on average 34.8° (25° −45°), which represents a correction rate of 54 % (range, 40.0–67.1%) and remained unchanged at the last follow-up (35°). Sagittal alignment improved from an average 11° to 18°. There were two complications (one excessive bleeding and one infection). Coronal balance was improved, as was shoulder balance. All patients reported satisfactory results except the patient with an adding-on phenomena

In the literature most of the results of anterior thora-coscopic release and posterior surgery give a percentage of Cobb angle correction similar or inferior (averaging 50%) to our series for an average initial Cobb angle of less magnitude. With adequate posterior release, and the use of third generation segmental instrumentation there is no need for anterior release even for curves in the 70–90° range.


P.J. Moroz P. B. Benoit J.B. Emans T. Hresko J.R. Kasser

Operative treatment of flexion-distraction fractures of the thoraco-lumbar spine in children and adolescents may be the preferred approach to the management of this fracture.

In this retrospective review of thoraco-lumbar flexion-distraction spine fractures at a paediatric level One trauma center we compared outcomes (fusion and loss of reduction) of operatively and non-operatively managed patients. Twenty cases of thoraco-lumbar and lumbar region flexion-distraction fractures were identified. Patients were grouped by non-operative versus operative and three Cobb angles were recorded from radiographs of each patient: one taken at the time of fracture, one at initiation of treatment, and the last at final follow-up. Union rate and changes in angular deformity was analysed using Chi square analysis and Fischer’s exact test.

Patients included eleven males and nine females with an average age of 13.9 (range 6 – 17). Average length of follow-up was 5.4 years. Eighty-five percent of cases involved motor-vehicle crashes with seventy percent wearing some form of seatbelt. Twenty percent had a neurological injury, all having surgery as initial management. All (100.0%) patients initially treated surgically healed with an average loss of lordosis of 7.5°. Five of the seven (71.4%) in the non-operative group developed non-union with instability and an average loss of 33.2° of reduction. All five non-unions went on to successful surgical fusion. Flexion-distraction fractures were 29.9 times more likely to heal successfully if having initial surgery (Odds ratio = 29.9, 95% C.I. 2.1 to 410.9).

Non-operative management leads to an unacceptably high rate of non-union and we recommend primary surgical management of all paediatric thoraco-lumbar flexion-distraction injuries.


T.P. Carey G.K. Chan C.A. Black R. El-Hawary K.K. Leitch

Scaphoid fractures are rare injuries in the pediatric population. A clinical and radiographic review over a six-year period at our institution revealed ninety-nine suspected scaphoid fractures. All of these patients presented with post-traumatic tenderness in the anatomic snuffbox and were treated with thumb spica cast immobilization. Only 9% of these patients demonstrated radiographic evidence of scaphoid fracture on initial presentation. At subsequent follow-up, six additional patients revealed radiographic evidence of scaphoid fracture. Positive predictive value of snuffbox tenderness for scaphoid fracture was 6% for patients with initially normal radiographs.

To review the clinical and radiographic results of suspected pediatric scaphoid fractures, as well as to determine the predictive value of anatomic snuffbox tenderness for occult fracture.

Pediatric scaphoid fractures are rare injuries that were found to be non-displaced and to involve the waist and distal scaphoid in most cases. Snuffbox tenderness had a positive predictive value of 6% in the identification of occult fracture.

In cases of suspected scaphoid fracture and normal radiographs, reliance on anatomic snuffbox tenderness alone will result in unnecessary immobilization in the majority of children.

Ninety-nine potential injuries were identified. Average age was 13.9 years. Although all patients in this group had tenderness in the snuffbox, only nine of the original x-rays revealed a true scaphoid fracture. The ninety “clinical scaphoid fractures” were immobilized for twenty-three days on average. Of these, only six demonstrated future radiographic evidence of fracture. No injuries required surgery for non-union.

All pediatric scaphoid fractures that were diagnosed clinically or radiographically at our institution between 1998 and 2003 were reviewed. Initial and follow-up radiographs were examined for evidence of fracture.

Given the sequelae of untreated scaphoid fractures in adults, tenderness in the snuffbox has been used to diagnose “clinical scaphoid fractures”. Although never validated in children, this test continues to be used in this population. As the natural history of scaphoid fracture in children is more favorable than in adults, reliance on snuffbox tenderness alone has resulted in the over-treatment of this injury.


A.S. Comley R.W. McCalden C.H. Rorabeck S.J. MacDonald R.B. Bourne

Constrained acetabular components are a useful adjunct for the potentially unstable hip arthroplasty. There have been concerns over implant failure and early acetabular component loosening secondary to the increased implant constraint. We report the results of a constrained ace-tabular component used as treatment for dislocating hips and as prophylaxis against dislocation in high risk primary and revision hip arthroplasty. At average 3.1 years follow-up only one insert of eighty-nine inserted had failed. No cups have demonstrated radiographic or clinical evidence of loosening. We conclude this implant is safe and effective for both the prevention and treatment of hip instability.

To review the effectiveness and durability of a constrained acetabular component used to treat and prevent recurrent dislocation after total hip arthroplasty

Constrained acetabular components of this type provide both an excellent treatment and preventative option in total hip arthroplasty. There is no evidence of accelerated cup loosening and the implant failure rate remains acceptable despite the increased constraint.

Constrained acetabular components have been mainly used as a salvage option for dislocating hip arthroplasty. There have been concerns over implant failure and early acetabular component loosening secondary to the increased implant constraint. Use of this implant can prevent dislocation in high risk patient groups (eg: revision surgery) without compromising implant longevity. This significantly reduces the potential morbidity associated with hip instability.

Eighty-nine patients received the tripolar constrained acetabular component. Fifteen were inserted for recurrent dislocation whilst seventy-two were inserted in patients felt to be at high risk of dislocation (forty-nine for intra-operative instability at revision surgery, twenty-five for primary THA in patients with poor compliance, neurological conditions or deficient abductor mechanism). One implant failed by component dissociation at eighteen months. All other recurrent dislocators remained stable. There was no evidence of accelerated component loosening at medium term review (range twelve – eighty three months, average thirty-seven months)

Radiographic and clinical data was prospectively collected on eighty-nine patients who had the constrained acetabular component inserted.

Funding: The primary author’s fellowship position is partially funded by Smith and Nephew Richards Inc.


P.E. Beaulé M. LeDuff F. Dorey H.C. Amstutz

Fifty-six hips, mean age 40.4 underwent surface arthroplasty (SA) and twenty-eight hips, mean age 37.2 underwent hemiresurfacing (HSR). Diagnosis was osteo-necrosis in all. UCLA hip function and activity score, SF-12 physical, and Harris Hip score were significantly (p< 0.05) better for SA versus HSR. However, 2 SA were revised to THR, and 5 had evidence of femoral loosening. There was no evidence of femoral loosenings in the hemiresurfacing group. The median femoral component size was significantly larger in HSR than SA. Although the functional results are inferior with HSR, patients are at greater risk of femoral loosening with the full surface arthroplasty.

To determine if differences in outcome exist between HSR and MMSA at five years of follow-up in a group of patients with Ficat Stage III and IV osteonecrosis.

Treatment of osteonecrosis of the hip in the young adult still remains a challenge. The continued use of conservative prosthetic solutions should help minimize the morbidity of revision hip surgery.

Although the functional clinical outcome of MMSA is superior to HSR, patients are at greater risk of femoral loosening. Use of a larger femoral component in MMSA may decrease the risk of femoral loosening.

Eighty-four hips with osteonecrosis were treated with a resurfacing implant: fifty-six with a metal-metal SA, mean age 40.4 and twenty-eight, mean age 37.2 with a hemiresurfacing when the acetabular cartilage was minimally damaged. Male/female ratio was 73%/27% for HSR and 87%/13% for MMSA. Mean follow-up of 4.5 years, UCLA hip scores were significantly (p< 0.05) better for MMSA versus HSR for function (9.3 vs. 7.9) and activity (6.8 vs. 5.5) but not for pain (9.3 vs.8.6) and walking (9.5 vs. 9.0). SF-12 scores were comparable for the mental component but significantly better in the MMSA group (48.4 vs. 38.1, p= 0.001) for the physical component. Harris Hip Score was significantly better for MMSA (92.3 vs. 83.3, p=0.001). 2 MMSA were revised to THR, and five presented with evidence of femoral loosening. There was no evidence of femoral loosenings in HSR. Median femoral component size was significantly larger for HSR (50.0 vs. 46.0, p= 0.001).


P.A. Vendittoli N. Duval P. Lavoie

One hundred and forty eight hybrid total hip arthroplasties in patients less than seventy years old were randomised to metal on polyethylene or alumina on alumina bearing surfaces. At two to seven years of follow-up, no significant difference was found on hip scores or survivorship of the implants. No specific complication associated to alumina components like fracture or malpositionning of the acetabular insert were observed. Alumina on alumina bearing surfaces give early clinical and radiological results similar to metal on polyethylene, suggesting that they have a potential to become good bearing surfaces in hip arthroplasty for young patients.

The excellent results obtained with metal-polyethylene (M-P) bearing surfaces in total hip arthroplasty (THA) are still limited by the production of polyethylene wear debris, osteolysis and aseptic loosening. Because of it superior tribologic properties and bioinert composition, alumina-alumina (AL-AL) bearing surfaces are proposed to improve survival of THA but previously reported early complications prevented widespread use of alumina ceramic. This study compares early results and complication with Ceraver M-P and AL-AL THA.

One hundred forty-eight Ceraver hybrid THA in patients less than seventy years old were randomised to M-P or AL-AL bearing surfaces. We present the clinical and radiological results for patients two to seven years after their surgery.

No significant difference was found on W.O.M.A.C. and Merle D’Aubigné Postel scores. No specific complication associated with alumina components like fracture or malpositionning of the acetabular insert were observed in this study. Documented complications were: infection 4 AL-AL/2 M-P; dislocation 1 AL-AL/4 M-P; and heterotopic ossification 47% AL-AL/24% M-P. No aseptic loosening was observed.

Ceraver AL-AL bearing surfaces give early clinical and radiological results similar to M-P. Our results are in accordance with studies suggesting that AL-AL have a potential to become good bearing surfaces in THA in the young patients.

Funding: funding was obtained from Ceraver, Paris to perform this study.


K.P. Droll V. Prasad A. Ciorau B. Gray M.D. McKee

The purpose of this study was to investigate the use of early post-operative bone scintigraphy to predict surgical outcome following vascularized fibular grafting (VFG) for osteonecrosis of the hip. Bone scans from one hundred and four hips (Steinberg stage I–IV) treated with VFG between 1994 and 2000 were retrospectively reviewed. Bone scan scores were significantly lower in the failed group (n=31) compared to the successful group (n=73), p=0.03. Logistic regression demonstrated that a higher bone scan score was associated with success, p=0.028, with an odds ratio of 3.08 (1.13–8.40).

The purpose of this study was to investigate the use of bone scintigraphy to predict surgical outcome following vascularized fibular grafting (VFG) for osteonecrosis of the hip.

Subjects with a higher bone scan score post-operatively had a three-fold higher chance of success than subjects with the lowest score.

These results suggest that having a well perfused and viable graft in the early post-operative period improves the chances of a successful result.

Single Photon Emission Computed Tomography images from one hundred and four hips (Steinberg I–IV) treated with VFG between 1994 and 2000 were retrospectively reviewed. Each scan was divided into three regions, the greater trochanter, neck, and head. The intensity at the graft in each region (axially and coronally) was compared to the intensity at the ipsilateral proximal femoral diaph-ysis and assigned a score: less than diaphysis (one), equal to (two), and greater than (three). Cumulative scores were obtained for each subject. Intraobserver variability was 0.93. Surgical failure was defined as conversion to or on the waiting list for total hip arthroplasty.

Thirty percent of hips failed treatment (n=31, mean survival 34.9 months, range 5–98), while 70% were successful (n=73, mean follow-up 56.6 months, range 22–100). Bone scan scores were significantly lower in the failed group (mean 7.1, range 6–12) compared to the successful group (mean 8.5, range 6–18), p=0.03. Positive skewness (+1.7) was demonstrated as 64% of hips had a score of six while 36% had a score > 6 (range 8–18). Logistic regression demonstrated that a bone scan score > 6 was associated with success, p=0.028, with an odds ratio of 3.08 (1.13–8.40).


D. Knowles T. Khan

We examined the position of the superior gluteal nerve in forty-four cadaveric hips in relation to the greater trochanter and the acetabulum . We found that the nerve lay a mean of 4.8 centimetres from the greater trochanter with a range of two to nine centimetres and a mean of 3.2 centimetres from the acetabulum. The nerve was visibly damaged in three out of forty-four hips following direct lateral approach. Our study does not support the “safe zone” proximal to the greater trochanter and suggests the proximity of the nerve to the acetabulum as a potential cause of nerve injury.

Abductor weakness following the direct lateral approach to the hip is well described and is associated with damage to the superior gluteal nerve on neurophysiological testing in from 23–26 %. A “safe zone” has been described of up to five centimeters proximal to the greater trochanter.

We examined forty-four cadaveric hips exposed by the direct lateral approach by surgeons not directly involved with the study. We measured the position of the superior gluteal nerve in relation to the greater trochanter, the acetabulum and the margin of the skin incision. We examined the nerve for visible signs of damage.

We found the position of the superior gluteal nerve to be a mean of 4.8 centimeters from the greater trochanter (range two to nine), 3.2 centimeters from the superior margin of the acetabulum (range one to eight), and 4.1 centimeters from the margin of the skin incision. There was visible damage to the nerve in three of forty-four cases.

Neurophysiological studies show subclinical damage to the superior gluteal nerve in up to 77% of cases following direct lateral approach to the hip and in association with abductor weakness in 23–26%. Our study does not support the notion of a “safe zone” of five centimetres proximal to the greater trochanter, and with a mean of 4.8 centimetres the zone is unsafe more often than it is safe. The proximity of the superior gluteal nerve to the superior margin of the acetabulum suggests that it may be damaged by retractor placement at this site.


P. Gamble J. deBeer M. Winemaker F. Farrokhyar D. Petruccelli S. Kaspar

Failed open reduction internal fixation (ORIF) of the proximal femur can render patients severely disabled. This study analyzed the short-term functional results and complications of total hip arthroplasty (THA) for complications of ORIF of the proximal femur. Using the Hamilton Arthroplasty Database, thirty-six patients treated with a THA for complications of ORIF of the proximal femur were compared to a matched cohort. Analysis showed that THA for complications of ORIF of the proximal femur is a successful procedure despite increased intraoperative difficulty that results in comparatively lower short-term Harris Hip Scores. No statistically significant differences in intraoperative or postoperative complications were noted.

Open reduction internal fixation (ORIF) of the proximal femur is a common, successful orthopedic procedure. However, failed ORIF of the proximal femur can render patients severely disabled. The purpose of this study is to analyze and compare the short-term functional results and complications of total hip arthroplasty (THA) for complications of ORIF of the proximal femur.

After ethics approval, the Hamilton Arthroplasty Registry, a prospective database, was used to identify thirty-seven patients treated with THA for complications of ORIF of the proximal femur. From September 1998 to the present a group consisting of sixteen males and twenty females, with a mean age of sixty-seven, were matched to a cohort of patients treated with a primary THA. Using Wilcoxon Test and Chi-Square Tests, the two groups were compared (p< 0.05).

Initially, ORIF was used to treat thirty-six patients for proximal femur fracture. The mean follow-up was 13.5 months. The experimental group had a significantly lower (p=0.035) Harris Hip Score at the one year follow-up, however both groups showed a significant improvement from preoperative scores (p=0.0001). A significant difference was noted between the two groups in estimated blood loss (p=0.01) and operative time (p=0.01). There was no significant difference in complication rate.

THA for complications of ORIF of the proximal femur is a successful procedure improving patient’s pain and functional status. This is a more complicated procedure than primary THA, at times requiring the use of a revision stem, which results in significantly lower Harris Hip Scores. Nonetheless, there appears to be no comparative increase in short-term complications.


O. Safir M. Flint P. Zalzal G. Morag A. Gross

We reviewed and discussed the results of one hundred and fifty-five proximal femoral allografts for revision total hip replacement at an average of eleven years (range , five to twenty years).We looked at graft survivorship, functional results, radiographic assessment and complications. We concluded that this is an excellent technique for restoration of bone stock in the multiplied revised hip.

To review the results of revision hip replacement with use of a proximal femoral allograft (PFA) to restore femoral bone stock.

Between 1983 and 1998 a PFA – prosthetic composite was used to revise two hundred and twenty-seven hips in two hundred and ten patients. Of these two hundred and ten revisions involved an allograft longer than 8 cm. The average age of the patients at the time of revision was sixty-six years. The average number of previous total hip replacements was 2.2. Each patient was assigned a SF-12 score and a Short WOMAC Score. Radiographic assessment for trochanteric union, allograft-host union, component stability, graft fracture and resorption was performed.

At an average of 11.2 years ( range, five to twenty years) after the revision, one hundred and eighty-five patients were alive, twenty-five patients had died and thirty were unavailable for follow-up. SF-12 and short WOMAC scores are still being calculated at the time of abstract submission. 4.4% of hips failed due to infection with 50% being successfully revised. Aseptic loosening of the construct occurred in 3.9% and 78% of these were revised at the time of follow-up. Nonunion of the allograft-host junction occurred in 4.8% and dislocation in 8.4%. Success was defined as a stable implant and no need for additional surgery at the time of follow-up. Success was noted in 84% of available cases.

At an average of eleven years revision hip arthroplasties with a PFA are performing very well. This technique remains an excellent alternative when confronted with femoral bone loss in the revision hip setting.


G. Morag B. Liberman P. Zalzal O. Safir M. Flint A.E. Gross

This is a retrospective study of fifty nine hips in fourty nine patients with a previous total hip replacement for developmental dysplasia of the hip who underwent a revision arthroplasty of the hip. Fifty three patients were available for follow up. Radiographs and charts were reviewed and functional outcome scores were obtained in order to determine if a correlation existed between cup position and functional outcome and survivorship. Cup height was found to be a statistically significant predictor for functional outcome and cup survivorship.

To determine if cup height, lateralization or angle are correlated with functional outcome or survivorship in revision total hip replacement (THR) in patients with a previous THR for developmental dysplasia of the hip (DDH).

There is a paucity of literature correlating functional outcome with cup position in revision THR.

Cup height was found to have a statistically significant (p< 0.05) correlation with Harris Hip, SF36, and WOMAC functional scores. High hip centers correlated with worse scores. In addition, patients with hip centers less than 3.5 cm above the radiographic tear drop had a statistically significant improvement in cup survivorship compared to those with higher hip centers.

A retrospective investigation of forty-nine sequential patients (fifty-nine hips) previously diagnosed with DDH who underwent revision THR at our center between 1984 and 2000 was performed. Forty-three patients (fifty-three hips) were available for survivorship analysis and thirty-five patients (forty-five hips) were available for functional analysis. The mean follow up was one hundred and eighteen months (range 36–230). Three independent variables identified apriori as possible correlates were cup height, lateralization and angle as measured on the AP radiographs. Functional outcome measurement consisted of the Harris Hip, SF36 and WOMAC questionnaires. Linear regression analysis and Kaplan-Meier curves were used to determine if any of the variables correlated with functional outcome or survivorship.

Restoration of hip center height to as close to the radiographic tear drop as possible improves functional outcome. Placement of the cup to within 3.5 cm of the tear drop improves cup survivorship.


N.G.H. Mohtadi R.M. Hollinshead T.M. Sasyniuk

This investigation was performed to determine whether MRI would provide any additional diagnostic information to the clinical evaluation and diagnostic arthroscopy of the shoulder. The study was performed in patients with shoulder impingement syndrome booked for an arthroscopic subacromial decompression. Although there was significant discordance between the MRI and arthroscopic findings, the MRI did not change the diagnosis or treatment plan in a clinically important way.

To determine whether the radiologist’s MRI report provided to an arthroscopist upon completion of a standard diagnostic shoulder arthroscopy would result in changes to the initial arthroscopic findings.

Despite high percentage of discordance between MRI and arthroscopy, the MRI information modified the initial arthroscopic diagnosis in a much smaller percentage of cases. In only one patient, did the change in diagnostic information have an impact on the planned treatment.

MRI adds minimal clinically important information to diagnostic shoulder athroscopy in patients with impingement syndrome.

The percentage discordance between MRI and arthroscopy for each structure of interest was calculated along with the percentage change in diagnosis based upon the arthroscopic re-evaluation and the consequence of the change.

Supraspinatus 55.2% discordance(n=32/58), 18.8% change in diagnosis(n=6/32), in 1 patient a change in the planned operation occurred from subacromial decompression to mini-open rotator cuff repair. Infra-spinatus 44.8% discordance(n=26/58), 3.8% change in diagnosis(n=1/26), and no consequence to planned treatment. Subscapularis 37.9% discordance(n=22/58), no change in diagnosis. Biceps tendon 62.3% discordance(n=33/53; five patients not adequately visualized on MRI), no change in diagnosis.

Fifty-eight patients presenting with shoulder impingement syndrome underwent a standardized MRI prior to planned arthroscopic subacromial decompression. A standard diagnostic arthroscopy was performed. The anatomic and pathologic findings were documented intra-operatively by an independent observer. The arthroscopist was initially blinded to the MRI information. MRI results were then revealed to the surgeon. An arthroscopic re-evaluation was performed to resolve discrepancies between MRI and arthroscopy.


M. Volesky M. Burman E. Lenczner F. Al-Jassir

The purpose of the present study is to determine a correlation between articular cartilage changes and underlying bone contusions in ACL-deficient knees. Analysis of surgical and MRI findings in thirty-seven knees shows that medial femoral condyle and medial tibial plateau bone contusions, present in 30% of ACL injuries, correlate strongly with articular cartilage damage, irrespective of meniscal status. Although lateral compartment bone contusions are more commonly seen following injury, we have not found this to be associated with the status of the overlying cartilage. Degenerative changes in the ACL-deficient knee are multifactorial, but medial compartment bone contusions may be an important contributor that warrants further investigation.

Despite successful reconstruction of the anterior cruciate ligament, many patients eventually develop osteoarthritis, suggesting that something in addition to mechanical instability may contribute. The purpose of the present study is to determine a correlation between articular cartilage changes and underlying bone contusions in ACL-deficient knees.

Between January 2002 and March 2003, sixty-eight knees consecutively underwent ACL reconstruction at our institution. Presence and location of bone contusions on MRI were noted, and correlated to presence of articular cartilage changes and meniscal pathology witnessed during surgery.

Of the sixty-eight knees operated, thirty-one were excluded because of either: pre-existing arthritis, previous surgery, presence of multiple ligament injury, or absence of bone contusions on MRI. In the analysis of the thirty-seven remaining knees, bone contusions were present on the medial tibial plateau and medial femoral condyle in 30%, on the lateral tibial plateau in 84%, and on the lateral femoral condyle in 73%. Articular cartilage damage is most commonly seen on the medial femoral condyle, irrespective of meniscal status. Analysis using Fisher’s Exact test shows that medial femoral condyle (p=0.026) and medial tibial plateau articular cartilage damage (p= 0.011) is strongly correlated with presence of underlying bone contusions. No association was found between lateral compartment articular cartilage status and presence of bone contusions.

Although lateral compartment bone contusions are common following ACL injuries, we have not found an association with cartilage damage. Degenerative changes in the ACL-deficient knee are multifactorial, but medial compartment bone contusions may be an important contributor.


D. Nguyen J. MacDermid G.J.W. King K.J. Faber

The purpose of this study was to determine if arthroscopic release is safe and effective in the management of elbow contracture. Twenty patients (mean age of forty-two), undergoing arthroscopic contracture release were retrospectively reviewed at a minimum follow-up of one year (mean twenty-five months). Most patients had combined extrinsic & intrinsic causes for contractures. Mean flexion improved from 122 to 137°. Mean extension improved from 38° to 18°. The mean arc improvement was 35° (p < 0.001). None of the patients had instability and there were no major neuro-vascular complications. All patients had decreased pain and improved elbow function.

To determine if arthroscopic release is safe and effective in the management of elbow contracture.

Twenty patients (mean age of forty-two), undergoing arthroscopic contracture release were retrospectively reviewed at a minimum follow-up of one year (mean twenty-five months). Most patients had combined extrinsic & intrinsic causes for contractures. Motion and strength were measured with standard goniometry and the LIDO isokinetic system by independent evaluators.

Mean flexion improved from 122 ± 16° to 137 ± 12°. Mean extension improved from 38 ± 18° to 18 ± 14°. The mean arc improvement was 35 ± 21° (p < 0.001). Arthroscopic release did not affect forearm rotation or strength. One patient developed a permanent medial antebrachial cutaneous neuroma. One patient required a repeat surgery to remove a loose body. There were no instability and no major neurovascular complications. All patients had improved elbow function with a mean ASES score of thirty-one out of thirty-six. Most patients were satisfied with their surgery, had minimal pain, considered themselves in good physical health on the SF-36, and had minimal impairment on the DASH.

Arthroscopic release is safe and effective in experienced hands.

Results are comparable to traditional open techniques. The theoretical advantages of arthroscopy include improved joint visualization, decreased morbidity and earlier rehabilitation.

Disadvantages include the potential for serious neurovascular complications, and the inability to deal with ulnar nerve pathology or heterotopic ossification. Indications for conversion to open release include excessive swelling, and failure to maintain adequate view.


N. Noiseux M. Tanzer

Labral tears are increasingly recognized as a source of hip pain. These rarely occur in normal hips, but in individuals with subtle femoral deformities. Anterior impingement of the femoral neck on the acetabulum due to loss of anterior offset results in a labral tear in active individuals. Future surgeries should be directed at this anterior offset deficiency in order to completely alleviate pain and prevent further recurrences.

To determine the incidence of anterior hip impingement and femoral pathology in patients undergoing hip arthroscopy for labral tear.

Anterior labral tears occur in the presence of abnormal femoral anatomy, which results in anterior hip impingement.

Future treatment of labral tears should include addressing the hip impingement.

Labral tears of the hip are increasingly being recognized as a source of hip pain in young, active individuals. Athroscopic labral debridement is commonly associated with poor results. As a result, it is likely that other hip pathology is present at the time of labral tear. The purpose of this study was to determine the incidence of anterior hip impingement secondary to a pistol grip deformity in patients undergoing hip arthroscopy for labral tears.

The charts and radiographs of forty consecutive patients who underwent hip arthroscopy were evaluated. X-rays were evaluated for presence of acetabular or femoral pathology. Femoral pathology was then graded based on degree of slip and posterior slip angle.

All patients who underwent hip arthroscopy for labral tears had abnormal femoral or acetabular anatomy. In those patients without acetabular dysplasia, a pistol grip deformity of the femoral head was present in all cases. Evidence of anterior hip impingement with osteophyte formation was present in ninety-two percent. In these patients, hip arthroscopy results in complete resolution of mechanical symptoms, but hip pain was still present.

Labral tears of the hip appear to be secondary to anterior femoral impingement. This is analogous to a rotator cuff tear in the presence of shoulder impingement. Anterior impingement of the femoral neck on the acatabulum due to an anterior femoral offset deformity results in both pain and labral tears. Future surgeries should be directed at this anterior offset deficiency in order to prevent recurrent injuries or residual pain.


R. McCormack F. Sekeramayi

Range of motion, degree of hemarthrosis and leg circumference was prospectively recorded in one hundred and eighteen consecutive isolated ACL reconstructions. A higher grade of hemarthrosis at one week was associated with a flexion deficit at eight weeks (P=0.002, relative risk 1.93). Increased leg circumference at one week was also associated with a flexion deficit at eight weeks (P=0.007, relative risk 1.37). An extension deficit was not associated with a hemarthrosis (P=0.47) or increased circumference (P=0.07). This prospective review identifies a risk factor for clinicians to be aware of after ACL Reconstruction. These patients merit closer observation and possibly a modified rehabilitation protocol.

To determine if increased swelling in the early post operative period is predictive of difficulty in regaining full range of motion after ACL reconstruction.

Increased swelling, at one-week post op (presence of a large hemarthrosis or a measured circumference greater than 1.5cm more than the control limb) is associated with flexion loss at eight weeks post surgery. These patients merit closer observation and possibly a modified rehabilitation protocol.

Patients with a higher grade of hemarthrosis at one week were more likely to have a flexion deficit at eight weeks (P=0.002, relative risk 1.93). Increased circumference was also associated with a flexion deficit at eight weeks (P=0.007, relative risk 1.37). The presence of a large hemarthrosis was not associated with an extension deficit at (P=0.47) although there was a trend for increased circumference to be associated with extension deficit (P=0.07).

One hundred and eighteen consecutive patients were prospectively assessed post ACL reconstruction. Range of motion was measured by goniometer at week one, four and eight. A deficit greater than 10° of flexion or 5° of extension (compared to normal leg) at the eight-week mark was defined as significant. The grade of hemarthrosis and circumference of the leg at the level of the patella were recorded at the same intervals. All patients underwent endoscopic, primary, ACL reconstruction with a standardized post op physio protocol. Exclusion criteria included previous surgery on either knee, significant effusion at the time of surgery or associated ligament injuries.


A. Miniaci G. Berlet C. Hand A. Lin

Although soft tissue capsulolabral repairs are the mainstay of treatment for recurrent anterior shoulder instability, bone defects are becoming more commonly recognized as additional problems for these patients. Humeral Head defects have been commonly ignored, however, there are a group of patients with failed procedures who have this as their main pathology.

The purpose of this paper is to present a review of patients with large Humeral Head impression defects with a large structural irradiated Allograft.

From April 1995 to January 2001, eighteen patients with recurrent anterior shoulder instability with Large Humeral Head Defects (> 25%) were treated with irradiated humeral allografts. Patients underwent physical and radiographic examination, subjective assessments including VAS scores for pain, instability, and satisfaction and completed a Constant and WOSI scores to determine clinical result. Radiograhic evaluation included standard radiographs and either MR or CT assessment.

Eighteen Patients with an average age of 31.5 (18–52) were reviewed at an average time of fifty months (24–96) following their surgical procedure. There were fourteen male and four female patients each having had an average of 2.1 (1–8) prior operative procedures. All patients had resolution of their instability with no documented recurrences. All patients had severe apprehension preop and this resolved completely in fifteen. Average loss of external rotation was forty degrees preop and improved to ten degrees postop. Two patients had partial collapse of the graft with symptoms of pain in External Rotation requiring screw removal. There were no other complications. Patients improved on WOSI from 1882 to 381 and had an avearage Constant score of eighty-seven postop. Subjectively all patients would have the procedure again and pain improved from 72.5 to 22.5.

There are certain situations where large humeral head defects contribute to the failure of instability repairs and ongoing instability. Allograft reconstruction with matched irradiated grafts is an excellent alternative for eliminating instability.

Funding: Smith and Nephew


J.C. Cameron

Fifty-five patients were assessed with a minimum of five- year follow up. Patients in this study underwent initial conservative treatment consisting of twelve months of physio. Those patients who continued to have recurrent instability underwent surgery. Only patients without rotational abnormalities of the femur were included. Tibial rotational was assessed geriometrically, with the degree of external rotation corrected to 20 – 23°. Those patients with associated patella alta underwent a distal transfer of the patella tendon also. Assessment included range of motion, thigh girth, quads strength, effusion and a modified Lystrom knee score assessed function and pre and post-op radiographic assessment.

The purpose of this paper is to report on the results of rotational osteotomy of the proximal tibia to treat patella instability.

At a mean follow-up of seven years (range 5 – 8.2) 76% of knees treated for congenital dislocation of the patella with external tibial torsion, achieved good to excellent results.

External tibial torsion associated with an increased “Q” angle is an important factor in recurrent dislocation of the patella. It is surgically correctable with a rotational osteotomy of the proximal tibia above the patella tendon insertion. This technique “normalizes” the extensor mechanics and produces better results than patella tendon transfer.

Ninety percent of the patients were female with an average age of thirty (range fourteen to forty-five years). Prior unsuccessful surgical procedures included lateral release (sixteen) Maquet procedure (ten) Hauser (sixteen) medialization of the patella tendon (ten) semitendinosis tenodesis and patellectomy (two). Pre-operative external tibial torsion averaged 45° (range 40° – 65°) with an average rotational correction of 25°. The average pre-op “Q” angle was 27° and post-op 14°. Outcome assessment of the fifty-five knees showed twenty-six excellent, sixteen good and thirteen poor. Overall 76% were good to excellent.

Outcome assessment was performed using a modified Lysholm score and the Tegner activity scale. The average pre-op score was forty and post-op seventy. Patients with less painful symptoms pre-op had significantly better outcomes. Knees that had undergone multiple unsuccessful surgical procedures had poorer outcomes.


D.A. LeGay E. Burns M. Forbes

Eighteen Arthroscopic and nine mini-open Rotator Cuff repairs were evaluated at an average of 31.5 months post-operatively. The tears were classified as small, moderate and massive with all the massive tears in the mini-open group. The arthroscopic group showed 94% patient satisfaction with the Western Ontario Rotator Cuff Index scale (WORC) of 89.6% and the University of California at Los Angeles (UCLA) score of 32.4/35. The mini-open technique showed 100% patient satisfaction, 83.7% with the WORC and 27.7/35 with the UCLA. This study showed both procedures were effective. It is one of the first to report on the use of the WORC index for evaluation.

The purpose of this study was to evaluate the mid term results of arthroscopic and mini-open (arthroscopic assisted) rotator cuff repairs using the Western Ontario Rotator Cuff Index (WORC) and the University of California at Los Angeles (UCLA) validated assessment systems.

Patients with classic rotator cuff tears were identified retrospectively and then seen for a one-time evaluation and scoring, using the WORC and UCLA index. The tears were classified as small- < 2 cm, moderate 2– 5 cm, and massive > 5cm.

27/33 (82%) responded, eighteen arthroscopic, nine mini-open with all the massive tears falling into the mini-open category. The average time frame from operation was 31.5 months, average age, 57.7 years. Overall results for the arthroscopic technique were, 94% (17/18) patient satisfaction, WORC 89.6%, UCLA 32.4/35. Overall result for the mini-open technique was 100% patient satisfaction, WORC 83.7%, UCLA 27.7/35. The size of the tear was found to be statistically significant only with respect to the degree of external rotation achieved at the final evaluation. WCB patients (three) showed a discrepancy between subjective and objective outcomes.

Arthroscopic and mini-open Rotator Cuff repairs are associated with a very high level of patient satisfaction, and high scores when evaluated by the WORC and UCLA indexes.

This study shows that arthroscopic, and mini-open repairs (for the massive tears), are very effective procedures. It is one of the first to utilize the WORC index for evaluation along with the UCLA which has been more commonly used.


A.D. Armstrong C. Lashgari J. Menendez S. Teefey L. Galatz K. Yamaguchi

Healing of the subscapularis, documented by ultrasound, following total shoulder arthroplasty was examined in thirty shoulders. All had marked improvement in pain, SST, and ASES scores. Four subscapularis tears were identified but only one patient had a positive abdominal compression test, 7/26 patients had a positive compression test despite an intact cuff, and 4/7 patients had a significant internal rotation contracture. The abdominal compression test was not accurate in detecting sub-scapularis tears. There was a significant false positive rate, which may be related to a lack of internal rotation. Overall, the outcome was excellent and not related to the status of the subscapularis.

Very little information is available on healing of the subscapularis after shoulder arthroplasty. The purpose of this study was to document the subscapularis healing rate and relate it to post-operative function and the abdominal compression test.

Thirty consecutive shoulders (twenty-three patients) s/p total shoulder replacement had standardized pre- and post-operative examinations including quantitative strength assessment and specific subscapularis testing. Ultrasound (validated for postop accuracy) was performed to document tendon healing.

All thirty shoulders had marked improvements in pain, SST, and ASES scores. Four subscapularis tears were identified but only one patient had a positive abdominal compression test. Seven out of twenty-six patients had a positive compression test despite an intact cuff. Four of seven patients had a significant internal rotation contracture. Neither the status of the subscapularis nor a positive compression test appeared to affect outcome.

Although specific subscapularis tests are often positive, only a small percentage of subscapularis tendons appear to retear after shoulder arthroplasty. The abdominal compression test is not accurate in detecting subscapularis tears post arthroplasty. There is a significant false positive rate, which may be related to a lack of internal rotation. However, overall outcome of shoulder arthroplasty was excellent and did not appear to be dependant on the status of the subscapularis.


C. Brauer B. Manns M. Ko R. Buckley

To evaluate the cost-effectiveness of operative versus non-operative management of displaced intra-articular calcaneal fractures (DIACFS), a model was constructed based on a randomized clinical trial. Model outputs were costs and quality-adjusted life years (QALYs). When a societal perspective was taken (i.e. productivity losses were included), operative management was less costly and more effective than non-operative care. Sensitivity analysis revealed that cost-effectiveness was highly dependent on the estimates of productivity losses. When productivity losses were excluded, the increase in cost of operative treatment was $2,700 for an incremental gain of .06 QALYs, giving an incremental cost-utility (CU) ratio of $44,000 per QALY gained.

To evaluate the cost-effectiveness of operative versus non-operative management of displaced intra-articular calcaneal fractures (DIACFs).

A decision tree was constructed to model the effect on costs and quality-adjusted life years (QALYs) of operative versus non-operative management for DIACFs. Complication rate, fusion rate, patient survival and utilities, and productivity losses were estimated from a recent prospective randomized control trial. Four-year costs were estimated from the center treating 73% of the patients in the trial. A societal perspective was used. Future costs and benefits were discounted at 5% and reported in 2002 Canadian Dollars. One-way and multi-way sensitivity analysis was performed on all variables using plausible ranges.

When productivity losses were included, operative management was less costly ($13,000 saving) and had a gain of .06 QALYs (based on improvements in health related quality of life), making it the dominant strategy compared to non-operative treatment. The cost-effectiveness was most sensitive to the return to work estimates. When productivity losses were excluded, the increase in cost of operative treatment was $2,700 for a .06 QALY gain, giving an incremental cost-utility (CU) ratio of $44,000 per QALY gained.

The treatment of the DIACF has long a source of uncertainty in orthopedic surgery. A recent prospective, randomized, trial concluded that operative management provided no improvement over non-operative care. The cost-effectiveness of operative management indicates that it is a moderately economically attractive treatment (a CU ratio of < $50,000). Further exploration of the impact of productivity losses is required.

Funding: Dr. Brauer is supported by a grant from Alberta Heritage Foundation


A.M. Griffin C. McLaughlin P.C. Ferguson R.S. Bell J.S. Wunder

Two hundred and forty-one patients with extremity osteosarcoma presented to our institution between 1989 and August 2002, thirty-six of whom had a pathologic fracture. There were twenty-five limb salvage surgeries and ten primary amputations, with three limb salvage surgeries requiring secondary amputations. One patient had an unresectable tumor and was treated palliatively. At mean follow-up of 96.9 months there was one local recurrence and eighteen patients were alive without disease in the pathologic fracture group. There was no survival difference between the pathologic fracture group with no metastases at presentation and the non-pathologic fracture group with no metastases (119.4 months vs 134.3 months, log rank 0.83, p=0.36).

To examine the outcome of osteosarcoma patients that present with a pathologic fracture as compared to those patients without a pathologic fracture.

There was no significant difference in the rate of amputation vs limb salvage surgery in osteosarcoma patients that presented with a pathologic fracture as compared to those without. There was no difference in the two groups’ disease-free and overall survival, for those patients that presented without metastatic disease.

Presentation with a pathologic fracture in osteosarcoma does not preclude limb salvage surgery and is not a prognostic indicator for decreased survival.

Retrospective review of all patients presenting to our institution with extremity osteosarcoma between 1989 and August 2002.

There were two hundred and forty-one patients with extremity osteosarcoma, thirty-six of whom presented with a pathologic fracture. In the pathologic fracture group, there were nineteen males and seventeen females. Twenty-five were treated with limb salvage surgery, ten required a primary amputation and one was unre-sectable. Three limb salvage surgery patients required a secondary amputation. Sevenpatients presented with metastatic disease. Twenty-eight of the thirty-six patients received (neo) adjuvant chemotherapy. At last follow-up, eighteen patients were alive no evidence of disease (51.4%), three were alive with disease, eleven were dead of disease and three were deceased from other causes. There was one local recurrence (2.8%). Mean overall survival was 119.4 months (0–147.1) for patients with a pathologic fracture and no metastasis at presentation and 134.3 months (0–172.5) for patients with no pathologic fracture and no metastasis (log rank 0.83, p=0.36).


B. Liberman S. Riad A.M. Griffin B. O’Sullivan C.N. Catton M.E. Blackstein P.C. Ferguson R.S. Bell

Lymph node metastasis in soft tissue sarcoma is considered to be a rare event (1.6–8.2%), From 1986 to 2001 1066 patients with extremity soft tissue sarcoma were treated surgically (+/− adjuvant therapy) at our institution.

Thirty-nine patients (3.6%) were identified with lymph node metastasis, most common histological subtypes were: Epitheliod sarcoma (3/15), rhabdomyosarcoma (4/21), clear cell sarcoma (2/18), and angiosarcoma (2/18).

Comparing expected five- year survivorship, we found that surprisingly in this study, extremity soft tissue sarcoma patients initially presenting with lymph node metastases had survival comparable to patients with high grade soft tissue sarcoma and no metastases.

To determine the outcome in patients with soft tissue sarcoma (STS) of the limbs that presented with lymph node metastasis (LNM) at diagnosis or developed them after it, comparing to all STS of limbs population that was treated at our center.

LNM in soft tissue sarcoma is considered to be a rare event (1.6–8.2%) with a devastating effect on the outcome,our study represent one of the largest reported cohorts, and suggest that agressive approach to LNM might contribute to survivorship.

Thirty-nine patients (3.6%) were identified with LNM along their course of disease

Thirteen patients presented with both lymphatic and systemic disease while twenty-six had isolated LNM at time of diagnosis. The mean follow-up from diagnosis of the primary tumor was 46.3 months (range zero to one hundred and forty-eight), and from diagnosis of lymph node involvement was 29.9 months (range zero to one hundred and twenty).

Expected five year survival in patients initially presenting with LNM was comparable to patients with high grade soft tissue sarcoma and no metastases.

From Jan’ 1986 to Dec’ 2001 1066 patients with extremity STS were treated at our institution.

Fifteen patients presented with LNM at time of first diagnosis, and twenty-four subsequently developed LNM after it.

Linear regression analysis and Kaplan-meier curves were used to compare expected survivorship in all patients with STS of limbs.

Comparing expected five- year survivorship, we found that Surprisingly in this study, extremity STS patients initially presenting with LNM had survival comparable to patients with high grade soft tissue sarcoma and no metastases.


D.P. Barei C. Bellabarba S.E. Nork B.J. Sangeorzan

Pilon injuries without fibula fractures may be associated with increased tibial plafond fracture severity. To evaluate this, we used the rank order technique, with traumatologists blinded to the fibular injury, who ranked the radiographic severity of forty pilon injuries with and without fibula fractures.

Pilon injuries with fibular fractures were ranked as more severe than those without. C-type injuries were ranked as more severe than B-type. Fibular fracture was more frequently associated with C-type injury than B-type. The presence of an intact fibula is not predictive of a more severe injury to the tibial pilon.

To determine if the absence of a fibular fracture is predictive of tibial pilon fracture severity.

Fibular status is not predictive of a more severe injury to the tibial pilon, and is more commonly associated with the less severe B-type injuries.

Absence of an ipsilateral fibular fracture in patients with tibial pilon injuries may predict a more severe tibial plafond injury pattern. Presumably, the energy is completely absorbed by the tibia resulting in more severe epimetaphyseal injury. The reverse relationship, however, was identified. This fact may aid in prognosis and treatment strategies.

Twenty consecutive pilon injuries without associated fibular fractures were matched 1:1 to an age/gender-matched cohort of pilon injuries with fibular fractures. Initial radiographs were digitized, the fibular image concealed, and then independently ranked (One, least severe; forty, most severe) by three orthopaedic traumatologists according to tibial plafond fracture severity. Injuries were classified using AO/OTA guidelines.

Inter-observer agreement was moderate (κ =0.6). Mean rank for pilon injuries with fibula fractures was 24.4 versus 16.7 for those without (t = 0.02). C-type injuries demonstrated a mean of 10.3 for those with fibular fractures versus 8.7 for those without (t = 0.5). Mean rank for B-type injuries was 11.1 versus 24.5 for C-type injuries (t = 0.001).

Overall, tibial pilon injuries with fibular fractures are more severe than those without. C-type injuries with or without fibular fractures are equally severe. C-type injuries were ranked significantly more severe than B-type. Fibular fracture was more frequently associated with C-type injury than B-type.


G. Beadel A. Griffin C. Ogilvie J.S Wunder R.S. Bell

A retrospective review of our prospectively collected database was undertaken to determine the functional and oncologic outcome following combined pelvic allograft and total hip arthroplasty (THA) reconstruction of large pelvic bone defects following tumour resection. There were twenty-four patients with a minimum followup of fifteen months. The complication rate following hemipel-vic allograft and THA reconstruction of resection Types I+II and I+II+III was high, but when successful this reconstruction resulted in reasonable functional outcome. In comparison, the functional outcome after allograft and THA reconstruction of isolated Type II acetabular resections was better and more predictable.

Resection of large pelvic bone tumours often results in segmental defects with pelvic discontinuity and loss of the acetabulum. We reviewed the functional and oncologic outcomes following pelvic allograft and total hip arthroplasty (THA) reconstruction.

Reconstruction of large pelvic defects including the acetabulum using hemipelvic allograft and THA is associated with high complication rates, however when successful provides reasonable function. In comparison, the outcomes of allograft and THA for acetabular defects alone are better and more predictable.

A retrospective review of our prospectively collected database was undertaken. Minimum followup was fifteen months (15–167). Nineteen patients were hemipel-vic resections (twelve Type I+II and seven Type I+II+III, eleven cases including partial sacral resection) reconstructed by hemipelvic allograft and THA. Five patients had Type II acetabular resections, reconstructed with structural allograft, roof ring and THA.

Osteosarcoma and chondrosarcoma were the most frequent tumours. All patients required walking aids. In the hemipelvic group there were two early deaths (peri-operative haemorrhage and aplastic anaemia). In seven patients (37%) the allograft remained intact without infection but three required revision THA for loosening. For these seven patients the functional outcome scores were TESS 64%, MSTS87 17/35 and MSTS93 of 45% (mean fifty-two months.). There were nine cases of deep infection (47%) with three patients maintaining a functional implant. The nineteenth patient was revised following allograft fracture.

In the Type II acetabular group, three patients had no complications, and two patients dislocated. The average scores were TESS 78%, MSTS87 21/35 and MSTS93 64% (mean fifty-five months).


A.S.E. Younger T.P. Kalla G. DeVries M.A. Awwad C.D. Meakin

The cost effective management of diabetic foot infections is a challenge to the Canadian health system. The objective of this study was to predict preoperatively diabetic foot patients who will fail a transmetatarsal amputation (TMA) and end in a costly and disabling below knee amputation (BKA) and hence perform a primary BKA in select patients.

Twenty-one patients failing TMA and revised to BKA within the first year were compared with a matched cohort of twenty-one successful TMA’s. The factors that were selected for comparison were: age at amputation, sex, smoking, type of DM, use of osetoset, presence of charcot fractures, previous contralateral surgery, previous debridement before TMA, debridement after TMA, dialysis, duration of ulcer prior to TMA, hemoglobin level at time of TMA, HbA1C, presence of heel ulcer, prior ipsilateral toe amputation, pulse status prior to TMA, vascular reconstruction and presence of unre-constructable vascular problem. Chi-square was done for group data, and ANOVA for numeric data.

Long-term control of blood glucose level (HbA1C) was found to be significant in predicting the success of TMA. Need of debridement after TMA was found to be a significant predictor of failure of TMA. There was a trend towards duration of ulcer prior to TMA and smoking being significant. All other variables, including vascular status or renal failure were not significantly different between the two groups.

As we have previously achieved a 75% success rate with TMAs in diabetics, we recommend a TMA as the first procedure in all diabetics with major forefoot infection or ulceration instead of a BKA. Obtaining good diabetic control in patients at risk for or requiring amputation for foot infection may prevent the TMA from failing and the subsequent need for BKA.


D.T. Rajan G. Bhattee S. Hussain

Some patients following operation for Hallux Valgus deformity develop Transfer Metatarsalgia. Many believe that a long oblique osteotomy of the second metatarsal as part of surgical correction of Hallux Valgus deformity reduces the risk of developing transfer metatarsalgia.

Metatarsal Break Angle (MBA) is the angle subtended by one line from the centre of the head of First Metatarsal to the centre of the head of the Second Metatarsal and another from the centre of the head of the Second Metatarsal to the centre of the head of Fifth Metatarsal. The MBA changes following osteotomy of the Second metatarsal.

Is the Metatarsal Break Angle(MBA) altered in patients who undergo long oblique osteotomy of the second metatarsal?. Literature does not mention anything to this effect. We prospectively studied the course of this angle in patients who underwent osteotomy of the second metatarsal at the same time as they had surgical correction of their painful Hallux Valgus deformity.

Twenty-four consecutive patients (thirty-one feet), nineteen Female and five Male, in the age range of eighteen to seventy-one years successfully fulfilled the inclusion criteria. The inclusion criteria being - Hallux Valgus deformity with a dorsally subluxed second Meta-tarsaophalangeal joint(MTPJ) and presence of tenderness/hyperkeratotic plantar patch at the second MTPJ.

The postoperative range of increase in the angle was two to sixteen degrees in all except one patient (decreased by one degree). Median change was eight degree increase. This study concludes that the MBA is altered in patients who undergo long oblique osteotomy of the second metatarsal. This type of osteotomy done so as to provide the head of the second metatarsal a fresh plantar fat pad to rest upon does help to remove the tenderness over the second MTPJ.

To the best of our knowledge this change in MBA has not been mentioned in the medical literature and we believe that our study highlights this important geometrical change in the architecture of post-operative forefoot.


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D. Younge S. Rabbani I. Ilyas

Twenty cases of malignant sarcomas of the foot and ankle included: four osteosarcomas, three Ewing’s sarcomas, three chondrosarcomas, three fibrosarcomas, five synovial cell sarcomas, one clear cell sarcoma and one malignant schwannoma.

Five-year survival was: three of the nine who had B-K amputation, five of the nine who had more distal amputation or local resection, for a total of eight of eighteen.

More distal amputation than B-K or local resection was offered if plantar sensation and stability of the foot could be retained, and was accepted by half of the patients. There were no local recurrences of eighteen operated.

Twenty cases of malignant sarcomas of the foot and ankle seen over a ten-year period from 1985 to 1995 were reviewed retrospectively.

Eleven tumors arose from bone and nine from soft tissue. The bone tumors were: four osteosarcomas, three Ewing’s sarcomas, three chondrosarcomas, and one fibrosarcoma. The soft tissue sarcomas were: five synovial cell sarcomas, two fibrosarcomas, one clear cell sarcoma and one malignant schwannoma. The average age for all patients was twenty-four years.

Two patients presented with chest metastases, both had palliative radiation and one had palliative B-K amputation.

The surgical treatment given for the eighteen non-metastatic cases was: B-K amputation nine, Symes, Chopart, or ray amputation six, and wide excision of the tumor three patients.

Five-year survival was eight of eighteen: three of the nine who had B-K amputation, four of the six who had more distal amputation, and one of the three who had local resection. There were no local recurrences, all deaths were from distant metastases.

Although B-K amputation is often recommended, in our series more distal amputation or local resection was offered for the non-metastatic patient if plantar sensation and stability of the foot could be retained. This gave good function in nine of eighteen patients, with no local recurrences.

A long duration of symptoms before presentation or referral influenced the outcome of the disease.

In selected patients, amputation more distal than B-K level or wide local resection can give good function without compromising the prognosis.


A. Scharfenberger D. Pearce T. Daniels

CT scans of thirty pes planus and eighteen normal feet were obtained in a simulated weight-bearing mode at 50% of body weight. The navicular skin distance was 22% less (1.9vs2.5cm) in the pes planus feet and forefoot supination was only 50% of normal (8.9vs18.6 degrees). Subtalar subluxation was observed in only the most severe pes planus feet. Navicular skin distance relates to medial arch collapse; loss of forefoot supination reflects the rigidity of the forefoot compensation to hindfoot valgus. Severe pes planus results in subtalar subluxation. The radiological indices described have not previously been reported in the literature.

To compare the inter-tarsal relationships of the pes planus foot to the normal foot in the weight-bearing state.

Weight-bearing CT scan of the feet is a practical examination with rapid set-up and minimal patient discomfort. Preliminary results demonstrate differences in the inter-tarsal relationships of pes planus feet compared to normal feet. Better understanding of pes planus deformity will advance clinical evaluation and treatment strategies.

Radiological indices described have not previously been reported in the literature.

Thirty pes planus and eighteen normal feet were imaged. All patients were able to tolerate the six- minute exam at 50% of body weight. Total study time averaged fifteen minutes. The navicular skin distance was 22% less (1.9vs2.5 cm) in pes planus feet compared to normal feet. Pes planus feet had only 50% of the normal forefoot supination (8.9vs18.6 degrees). Lastly, subtalar joint subluxation was observed in only the most severe pes planus feet. Values ranged from 0.2 to 1.1cm.

Axial CT images of 1mm thickness with 0.5mm overlap were obtained at a weight-bearing load of 50% of body weight using the weight-bearing CT device. Coronal and Sagital images were then reconstructed.

Radiological indices obtained can be related to the clinical picture of the pes planus foot. The navicular skin distance reflects medial arch collapse, where as the lack of forefoot supination reflects the rigidity of the forefoot compensation to hindfoot valgus. Severe hindfoot valgus in pes planus results in subtalar sub-luxation.


J. de Beer S. McKenzie M. Hubmann D. Petruccelli M. Winemaker

Historically, cemented THA femoral stems inserted in varus have yielded poor clinical results. Very few studies to date have addressed the question of the effects of varus alignment on uncemented stems. We have conducted a retrospective review of one hundred and twenty-five uncemented THA femoral stems implanted by a single surgeon from 1994 to 1999. Within this single surgeon group we were able to identify sixteen stems implanted in varus and thus proceeded to analyze the effect of varus alignment on functional outcome.

To assess functional and radiographic outcome of uncemented primary THA femoral stems implanted in varus.

After four-years of follow-up, there have been no radiographic or clinical problems associated with implanting uncemented femoral stems in varus.

Although it is not recommended to implant stems in varus, radiographic and clinical problems associated with implanting uncemented femoral stems in varus appear to be non-consequential.

Of the study sample, one hundred and sixteen hips were in neutral alignment as compared to sixteen varus hips. We could not show any significant difference in Harris Hip scores between the varus and non-varus hips (p> 0.5). No cases showed evidence of radiographic loosening, or subsidence (p=0.3) at four-year follow-up.

Retrospective radiographic review of one hundred and twenty-five uncemented primary THA femoral stems implanted by a single surgeon (now retired) from 1994 to 1999, using the Watson-Jones approach, identified sixteen femoral stems implanted in varus. These sixteen stems were matched 1:1 for demographics and preoperative diagnosis to a cohort of sixteen non-varus uncemented stems implanted by the same surgeon over the same study period. Functional outcome included Harris Hip score and range of motion at four-years postoperative. Radiographic signs of loosening and subsidence, defined as > 2mm, were measured. Varus alignment was defined as ≥ 5°. Paired t-tests were conducted on all outcome variables, p< 0.05 was considered statistically significant.

Study results suggest there to be no consequence of varus femoral alignment in uncemented stems. Patients will need to be followed for a longer duration to further examine the effects of varus implantation of unce-mented femoral stems.


J.P. Waddell J. Morton K.A. Griffith E.H. Schemitsch K. White

Revision hip arthroplasty does not bring to the patient the same degree of benefit as the primary operation. We compared two hundred and thirteen patients undergoing revision arthroplasty with five hundred and forty-seven patients undergoing primary total hip replacement. The complication rate in the revision arthroplasty group was approximately twice as high in the primary group (p< .05) primarily as a result of postoperative dislocation. Both groups of patients had a statistically significant improvement between their pre- and postoperative WOMAC and SF-36 physical scores; however, there was also a statistically significant difference in outcome when the two groups were compared, with primary patients having significantly improved WOMAC and SF-36 physical scores.

To compare the outcomes between primary and revision total hip arthroplasty patients at one institution with regard to demographics, complication rates and functional outcome.

Revision hip arthroplasty does not bring to the patient the same degree of benefit as does the primary operation. The reason for this is multi-factorial and includes a higher complication rate and lower functional outcome.

Further study of the problems associated with revision total hip replacement especially focused on complication rates would appear to be warranted.

All patients were entered prospectively in a database and were assessed by means of physical examination, radiographs, SF-36 and WOMAC questionnaires. Patients were followed for a minimum of two years with a range of two to five years. Patients were seen on an annual basis.

Five hundred and forty-seven patients underwent primary total hip replacement and two hundred and thirteen patients underwent revision total hip replacement. 53.4% of patients undergoing primary and 52% of patients undergoing revision arthroplasty were female. Mean age at primary hip replacement 61.8 years, revision hip replacement 67.1 years. Post-operative complication rate was 7.6% in primary patients and 14.7% in revision patients (p< .05); there was no statistically significant difference between the two groups with regard to intra-operative fracture, implant loosening or postoperative infection; there was a statistically significant difference in terms of dislocation with 0.8% of primary arthroplasties and 5.6% of revision patients sustaining at least one dislocation following their surgery (p< .01). Both groups of patients had a statistically significant improvement between their pre- and post-operative WOMAC and SF-36 physical scores (p< .0001); however, there was also a statistically significant difference in outcome when the two groups were compared with primary patients having significantly improved WOMAC scores (p< .0001) and significantly improved SF-36 physical scores (p< .0001).


A.M. Davis J. Gollish E. H. Schemitsch J.R. Davey J.P. Waddell J.P. Szalai H.J. Kreder A. Gafni E. Badley N.N. Mahomed K.J. Saleh Z. Agnidis A.E. Gross

This study (n=126, mean age=68.8 years, males=62) evaluated pre-operative WOMAC pain and physical function, age, gender, general health status, revision severity classification, number of revisions, comorbidity and unilateral vs. bilateral surgery as predictors of WOMAC pain and physical function at twenty-four months post revision hip arthroplasty. Pain improved from 9.3 to 3.6 and physical function improved from 35.4 to 17.1. No factors were predictive of patient function. Decreased pain was predicted by less pain pre surgery (p=0.01) and being male (p=0.04).

To determine if pre-operative WOMAC pain and physical function, age, gender, general health status (SF-36), revision severity classification, number of revisions, comorbidity and unilateral vs. bilateral surgery are predictive of WOMAC pain and physical function at twenty-four months post revision hip arthroplasty.

Physical function at twenty-four months is not independently predicted by the pre-treatment factors evaluated in this study. Male patients with less pain pre surgery and little comorbidity have less pain post surgery.

With the exception of pre-treatment pain, the pre-treatment factors tested in this study provide minimal guidance in identifying factors that might be modified to enhance patient outcome.

This prospective cohort study included one hundred and twenty-six patients (mean age=68.8 years, males: females=62:64) who had revision for other than infection or peri-prosthetic fracture. On average from pre-surgery to twenty-four months post-surgery, WOMAC pain improved 9.3 to 3.6 and physical function improved from 35.4 to 17.1. In univariate analysis (t-test, p< 0.05), males tended to have better function (19.6 vs. 14.7) and reported less pain (4.4 vs. 2.8). No other factors were significant in univariate analysis. None of the a priori factors noted above were independently predictive of patient function at twenty-four months in the multivariate model (F=2.06, p=0.04, R2=0.16). Decreased pain with activity at twenty-four months independently was predicted by having less pain pre surgery (p=0.01), being male (p=0.04) and having fewer comorbidities (p=0.07) in the multi-variate model (F=2.9. p=0.004, R2=0.21).

Funding: This work was supported by a grant from The Arthritis Society


G. Beadel A. Griffin F. Aljassir D. Iannuzzi R. Turcotte M.H Isler R.S Bell J.S Wunder

A retrospective review of our prospectively collected database was undertaken and the functional and oncologic outcomes after Type One pelvic resections for bone tumours of the ilium and sacrum were analyzed. Seventeen patients were identified with a minimum followup after resection of twelve months. In seven patients the bone defect was reconstructed, with no reconstruction in the remaining ten patients. The functional/oncologic outcomes of the two groups are similar, however patients without reconstruction had fewer complications and less dependence on walking aids suggesting that reconstruction may not be justified.

Management of defects created by Type One pelvic resections of large iliac bone tumours remains controversial. We reviewed the functional/oncologic outcome following resection with and without reconstruction.

Similar functional/oncologic outcome was achieved in both groups suggesting that reconstruction is not justified.

A retrospective review of our prospectively collected database was undertaken analyzing functional/oncological outcome of seventeen patients with Type One pelvic resection. Minimum follow up was twelve months (12–96). Outcome data was available on 8/10 patients managed without reconstruction (WOR), with residual ilium collapsing back onto sacrum, and on 5/7 patients with bone graft reconstruction (WR).

Average age thirty-three years (WOR) and 48yrs (WR), (p=0.04), with average maximal tumour dimensions of 12cm and 9cm (p=0.1). The most frequent diagnosis was chondrosarcoma. The WOR group average TESS, MSTS 87 and MSTS 93 scores were respectively 73%, 18/35 and 58% at an average of 50 months (24–96) compared to 69%, 21/35 and 51% at an average of 37 months (12–60) for the WR group. 33% of WOR and 20% of WR patients did not require walking aids. Infection or wound necrosis occurred in 40% of WOR patients and 57% of WR patients. No local recurrences.

The perceived advantages of no reconstruction are shorter operating times, reduced incidence of complications and improved functional outcome due to medialization of the weightbearing axis in the absence of hip abductors. The oncologic/functional outcomes of both groups were similar but in those not reconstructed there was a lower incidence of complications and walking aids.


R. B. Bourne C. H. Rorabeck S. J. MacDonald R. W. McCalden D. Kelman

Femoral stem fracture occurred in five (2%) of 283 revision hip arthroplasties when extensively coated, distal fixation femoral implants were used. Common features were complex revisions, high body mass index, poor proximal support, smaller stems (< 13.5 mm) and use of an extended trochanteric osteotomy. Use of strut allografts can reduce femoral stem stresses.

The purpose of this study was to analyze the surgical factors associated with fracture of cementless distal fixation revision femoral stems and supplement this analysis with a finite element analysis.

Data from our institutional joint replacement database identified five (2%) fractured femoral stems (three Solution, two Echelon) in a cohort of two hundred and eighty-three cementless distal fixation femoral stems (one hundred and eighty-two Solution, one hundred and one Echelon) followed over two years. Patient, surgical and implant factors were compared between the fractured and not fractured stems. Finite element analysis was performed on two fractured stem cases to better understand the fracture mechanism.

Common clinical features of the five fractured stems were complex revisions, high patient body mass index, poor proximal bone support, smaller stems (< 13.5 mm) and use of an extended trochanteric osteotomy (ETO) (3/5). Fatigue failure was the mode failure in all cases.

Finite element analysis confirmed that the location of highest stem stress was near the location of the stem fracture and that use of a strut graft over an extended trochanteric osteotomy in patients lacking proximal femoral cortical support decreased the stem stresses by 48%.

Use of cementless distal fixation revision femoral stems is accompanied by a 2% risk of stem fracture in the face of proximal femoral support of the stem and/or use of a stem with a diameter less than 13.5 mm. When an extended trochanteric osteotomy is used, the stem fracture rate increased to 4%. Use of a strut allograft in conjunction with the ETO can reduce stem stresses by 48% and the risk of stem fracture.

Funding: Research support from J& J DePuy and Smith & Nephew


T.R. Turgeon M.J. Lavigne A.A. Sanchez R.D. Coutts

Surgical treatment of recurrent dislocation after total hip arthroplasty (THA) is challenging with often disappointing results. The influence of the posterior hip capsule is important, and restoration of its function is a major goal of treatment. We describe our experience using an Achilles tendon allograft as a checkrein to limit hip internal rotation and to prevent posterior instability. Twenty unstable THAs were treated using this technique, eliminating instability in fifteen. At an average follow-up of 3.6 years, Achilles tendon allograft augmentation has proven a useful adjunct for the treatment of recurrent posterior dislocation after THA in selected patients.

The purpose of this study is to review our results with a novel treatment for recurrent dislocation after total hip arthroplasty (THA) using an Achilles tendon allograft as a checkrein to prevent instability.

Achilles tendon allograft augmentation has proved to be a useful adjunct for the treatment of recurrent posterior dislocation after THA in selected patients.

Surgical treatment of recurrent dislocation after total hip arthroplasty (THA) is challenging with often disappointing results. Among possible causes of dislocation, the influence of the static soft tissue restraint provided by the hip capsule is important, and restoration of its integrity and function is a major goal of treatment. We describe a new technique in which an Achilles tendon allograft is employed as a checkrein to limit hip internal rotation and to prevent posterior instability.

Twenty unstable THAs with recurrent instability were treated using this technique, eliminating instability in fifteen at an average follow-up of 3.6 (0.5 to 6.6) years.

Prospective data was collected and reviewed on the first twenty patients with recurrent THA instability stabilized with an Achilles tendon allograft. Head and liner exchanges accompanied the allograft. Use of a constrained cup was considered a failure.

Instability was successfully controlled in 75% of patients with use of the Achilles allograft. The technique is an important addition to the treatment arsenal of this difficult problem.


R. Mehin X. Yuan C. Haydon C.H. Rorabeck R.B. Bourne R.W. McCalden S.J. MacDonald

The timing of liner exchange for retroacetabular oste-olysis in THA remains uncertain. Liner exchange should be done before the shell becomes loose. The purpose of this study was to determine the radiographic quantity of osteolysis that will predict impending loosening of the cementless shell. Osteolytic lesions were quantified radiographically using three different measures. Implant stability was confirmed intraoperatively. Percent of shell circumference with surrounding osteolysis appears to be more predictive of cementless shell loosening than the area of osteolysis. When greater than fifty percent of the shell circumference has osteolysis on AP or lateral films, liner exchange is necessary.

The timing of liner exchange for retroacetabular osteolysis in cementless THA remains uncertain. Liner exchange should be done before the shell becomes loose.

To determine the radiographic quantity of osteolysis that will predict impending loosening of the cementless shell.

Osteolytic areas differ between loose and stable shells.

Between 1992 to 2002, seventy-one cementless shells of the same design were revised at our institution; forty-six were for aseptic retroacetabular osteolysis. Radiographs and a computer-assisted technique were used to quantify osteolytic areas and percent of shell circumference associated with lesions. Implant stability was confirmed intraoperatively.

Of twenty-six stable and twenty loose shells, the average area of osteolysis on AP radiographs showed no significant difference (Stable 591mm2, Loose 630 mm2, p greater than 0.05); whereas, lateral radiographs demonstrated a significant difference (Stable 546 mm2, Loose 837 mm2, p 0.05). The percentage of shell circumference with associated osteolysis on AP and lateral films demonstrated a significant difference (AP: Stable 60, Loose 75, p 0.042; LATERAL: Stable 49, Loose73, p 0.016). Diagnostic criteria of fifty percent shell circumference associated with osteolysis on AP films has sensitivity 1, specificity 0.27 while the same criteria on lateral films has sensitivity 0.84, specificity 0.54 for shell loosening.

Percent of shell circumference with surrounding oste-olysis appears to be more predictive of cementless shell loosening than the area of osteolysis. When greater than fifty percent of the shell circumference has osteolysis on AP or lateral films, liner exchange is necessary.


P.R. Kim B.M. Deheshi

The purpose of the study was to evaluate the outcome of curettage and grafting with calcium sulfate pellets for progressive retroacetabular osteolysis with retention of the acetabular component. Seven patients who underwent the procedure were evaluated clinically and radiographically at an average follow-up time of fifteen months. There was no progression of osteolysis following curettage and grafting with good to excellent osseo-integration. All patients had a good functional outcome with no pain during follow-up. Curettage and synthetic grafting of retroacetabular cysts with calcium sulfate pellets is a viable option in halting the progression of retroacetabular lysis and promoting osseous recovery.

The purpose of this study was to evaluate outcome of curettage and grafting of progressive retroacetabular osteolysis with calcium sulfate pellets and retention of components.

Restoration of retroacetabular bone stock by curettage and grafting with synthetics would obviate the need for autogenous bone graft and its associated risks. Retention of well-fixed acetabular components also aids in prevention of further bone loss associated with component extraction.

We conducted a clinical and radiographic review of seven patients who presented to the senior author with radiographic findings of progressive retroacetabular osteolysis. All patients were treated with curettage and filling of the defects with calcium sulfate.

Mean follow-up time is fifteen (five to twenty-seven) months. Polyethylene wear was noted in all cases. The size of the lesions ranged from 3.1 x 2.0 to 9.0 x 5.3 cm. On follow-up evaluation, there was no recurrence or progression of the lesions. Osseo-integration was excellent in four cases and good in three cases. All patients had returned to normal level of function with no pain.

Patients with retroacetabular osteolysis are often asymptomatic until catastrophic failure occurs as a result of extensive bone loss. Treatment of retroacetabular osteolysis in the setting of well-fixed components is controversial. Retention of the components, curettage and synthetic grafting with calcium sulfate is a viable option to prevent progression of lysis and stimulate bone formation.

Curettage and grafting of progressive retroacetabular osteolysis with calcium sulfate and retention of components results in good osseo-integration of the graft and halts the progression of lysis.


N. Greidanus D. Garbuz B. Masri C. Duncan

The two most common surgical approaches used in primary hip arthroplasty are the anterolateral and posterolateral approach. While both approaches have potential advantages and disadvantages in comparison to the other, there are no reports with sufficient power to compare their effect on post-operative function and quality of life. This prospective cohort study evaluates and compares the independent effect of surgical approach on function and quality of life among patients who have received their total hip arthroplasty through one of these techniques. Results suggest that there is no significant difference in function or quality of life among these respective cohorts.

The purpose of this study was to evaluate and compare the effect of anterolateral versus posterolateral approach on function and quality of life following primary total hip arthroplasty.

There is no significant difference in outcome as a result of surgical approach. Significance: This is the first report with sufficient power to evaluate and compare outcomes of these two approaches among high volume hip surgeons. This study suggests that surgeons need not worry that the anterolateral or posterolateral approach may compromise patient function or generic quality of life more-so than the alternative approach.

Univariate and regression analyses demonstrate similar outcomes on WOMAC, Oxford-12, SF-12 and satisfaction among cohorts of patients receiving the anterolateral or posterolateral approach for primary total hip arthroplasty.

A prospective evaluation of function and quality of life outcomes was performed on patients receiving the anterolateral or posterolateral approach for primary hip arthroplasty. All participating surgeons were considered to be high volume arthroplasty surgeons. One hundred and sixty procedures were followed and provided complete outcomes data including WOMAC, Oxford, SF-12, and satisfaction scores. Univariate analyses demonstrated no differences among the two cohorts with regards to baseline variables. Regression analyses were performed for the outcome measures with surgical approach treated as an independent covariate while controlling for other potential confounders. The results suggest that there is no independent effect of surgical approach on patient reported outcomes. This suggests that the surgeon should continue to employ the approach which is the most familiar and most likely to result in consistent results in their clinical environment.


S. Walsh R. Reindl E. Harvey G. Berry L. Beckman T. Steffen

Many two-part fractures of the proximal humerus are treated conservatively due to the frequent failure of internal fixation. The current investigation examines the biomechanical properties of a unique plate versus a standard plate for internal fixation of proximal humerus fractures. The unique plate employs screws that thread into the plate, creating a multi-planer, fixed angle device. A cadaveric model was developed that relied on the rotator cuff musculature as the primary deforming force. The locking plate displayed significantly greater holding power on the humeral head (p=0.007). This may lead to more consistent results in two-part fractures treated with internal fixation.

The current investigation evaluates a unique plate designed to treat fractures of the proximal humerus. The plate employs screws that thread into the plate creating a fixed angle device. This plate was tested versus a standard cloverleaf plate.

The locking plate displayed greater holding power on the humeral head in the model tested. This may lead to decreased failure rates in two-part fractures treated with internal fixation.

Many two-part fractures of the proximal humerus are treated conservatively due to the frequent failure of common internal fixation modalities. This is done with the acceptance of possible non-union and loss of function. A more reliable method for stable internal fixation is therefore desirable.

A significant difference was found (p=0.007) with the locking plate displaying greater holding capability on the humeral head.

Eight pairs of preserved, cadaveric humeri were dissected and plated with either the locking plate or standard cloverleaf plate followed by an osteotomy at the surgical neck. A servo-hydraulic testing machine was then used to pull on the rotator cuff musculature until failure was achieved. Failure of the plate-head interface was reached in five of the eight pairs. Previous biomechanical studies have not taken into account the clinical mode of failure when testing internal fixation modalities for proximal humerus fractures. The current study has reproduced failure into varus by relying on the rotator cuff musculature as the primary deforming force.

Funding: All implants donated by Synthes, Canada


P. Guy J. Stone R.G. McCormack P.J. O’Brien

We reviewed the results of sixteen patients with three and four part proximal humerus fractures treated with the Locking Proximal Humerus Plate (LPHP) in two trauma centres. All fractures were radiographically healed by six weeks. We found a high rate of fixation failure 4/16 cases within two weeks of surgery and range of motion results similar to previously reported techniques. This device has not demonstrated its clear superiority when used in trauma centres which commonly treat proximal humerus fractures. A randomised control trial comparing it to classical techniques and using outcome-based measures would seem appropriate.

Proximal humerus fractures with poor functional outcomes are expected to increase in frequency owing to an active ageing population. New angle stable devices have been developed to address the frequently associated osteoporosis and loss of fixation.

This study reviews the early experience of fixation with an angle stable device, the LPHP (Synthes Canada).

Three and four part fractures treated with the LPHP were identified from the database of two trauma centres. Demographics, patient activity level, mechanism of injury, fracture type were collected. Early complications, maintenance of reduction, and ROM were reviewed.

Sixteen fractures treated with the LPHP. Male to female ratio was 1.3:1. Mean age was 51.5 (29–77) Activity: 12/16 sedentary, 4/16 manual labourers. Mechanism: four Low and twelve High-energy injuries. Fracture classification: Five three part, and Eleven four part fractures.

Early complications: one wound haematoma,one re-operation for intra-articular hardware, and four of sixteen pts pulled off the greater tuberosity fixation within two weeks of surgery. Union was achieved in all sixteen by six weeks. The mean forward elevation was 60° at six weeks and 80° at three months.

This review of the early experience with the LPHP shows a significant rate of fixation failure (4/16 cases) and functional ROM results similar to other previously described techniques. Although a “learning curve effect” is possible, this device has not demonstrated clear superiority with surgeons who commonly treat proximal humerus fractures. A randomised control trial comparing it to classical techniques would seem appropriate.


D. Beaton A. Orner S. Dyer E. Schemitsch M. Gignac A. Davis H. Kreder R.L. Franche C. Bombardier R. Reardon G. Devins

Clinicians ask patients “How are you now?” to ascertain treatment outcomes and to set a plan for subsequent care. However, sometimes patient views do not agree with those of the clinicians. This study compared patient and clinician views of outcome one to two years after an operatively managed extremity fracture and described any discordance. There were significant differences between groups, especially in areas such as pain and disruption of their personal and work lives. A discordance was observed between patient and physician views of recovery after fracture, likely associated with disruptions to personal life, unaccounted for in a clinician’s view of outcome.

Clinicians ask patients “How are you now?” to ascertain treatment outcomes and to set a plan for subsequent care. However, sometimes patient views differ from those of clinicians’.

The purpose of this study is to compare patient and clinician views of outcome one to two years after an extremity fracture and to describe any discordance.

Cross-sectional survey of patients one to two years after an operatively managed upper or lower extremity fracture. Patients were recruited from two tertiary care centres and completed a mailback questionnaire that included measures of health (DASH, SMFA), self-rated recovery, burden of illness (Illness Intrusiveness, Loss of self), symptoms, and work status. These were linked with clinical records of radiologic and clinical recovery.

Two hundred and fifty-five patients returned usable questionnaires. Mean age was forty-two years and 42% were female. Sixty-seven patients said that they were completely better (CB), one hundred and thirty-four almost better (AB) and fifty-four not completely better (NCB). Significant differences were found between groups. In four variables, NCB was distinct from AB/CB, while in all other variables, such as pain, disability and disruption of their personal and work lives, all three groups were unique (Duncan’s post hoc). However, of the patients who said they were not better, the radiologist and clinician reports stated that thirty (68%) and twenty-eight (64%) were healed, respectively.

A discordance was observed between patient and physician views of recovery after fracture. It appeared associated with disruptions to personal life that may not be accounted for in a clinician’s view of outcome.

Funding: Canadian Institutes of Health Research (CIHR)


D. Sahajpal J. Gambrel D. Pichora

This study asseses the biomechanical properties of the Locking Volar T-Plate. It compares the axial load to failure to more traditional plating methods including the T-Plate and Pi-Plate. All three plates were tested for axial load to failure in both a dorsally comminuted model and a highly comminuted model with disruption of both the volar and dorsal cortices. The data in this study indicates may support volar plating for dorsally comminuted distal radius fractures.

The pirpose of this study was to compare the biomechanical properties of three distal radius plates.

The Locking Volar T-Plate performs equally as well regardless of the presence of volar comminution while the other systems do not. It also outperforms both other systems when volar comminution is present.

This study provides biomechanical data of the Volar Locking T-Plate.

Three distal radius plating systems were used on left radii after having either a segmental or dorsal wedge osteotomy performed to simulate severely comminuted and dorsally comminuted distal radius fractures respectively. Group One was plated with an AO stainless steel Pi plate, Group Two with a stainless steel T-plate volarly and Group Three with a stainless steel Locking Volar T-Plate. Specimens in all six of these groups (three groups with each type of osteotomy) were tested in axial loading to determine their load to failure.

The load to failure was significantly higher with the Locking Volar T-Plate than the T-plate (p = 0.001) and Pi plate (p < 0.001) in the severely comminuted model. There was no significant difference between the groups in the dorsally comminuted model. There was no significant difference in the load to failure of the Locking Volar T-Plate between both models and between it’s the load to failure in the severely comminuted model and that of the Pi plate in the dorsally comminuted model.

There has been limited data to date on the Locking Volar T-Plate. Studies, such as this one will provide biomechanical evidence supporting its use.


J.C. MacDermid J.H. Roth R.S. Richards

This study investigated the time lost from work following a distal radius fracture and its predictors. A cohort of one hundred and sixty-eight workers who experienced a distal radius fracture were followed at two, three, six, and twelve months to determine their work status. The average number of weeks lost from work was 9.5 weeks. Significant correlates with lost-time from work were: energy of injury, occupational demand, workers compensation, initial radial inclination on x-ray, baseline PRWE and DASH scores and Mental Component-SF-36). Without self-report, 45% of the variation in lost-time was explained by workers compensation status, radial inclination, occupational demand, energy of injury, sex and age.

This study investigated the time lost from work following a distal radius fracture and its predictors.

Time lost from work after a distal radius fracture is highly variable. Patients who have higher job demands (hand use), are on workers compensation, report higher initial pain/disability and who present with more severe displacement have the highest lost-time.

This data defines average expectations of return to work and the extent to which injury, job and personal characteristics influence it.

The average number of weeks lost from work was 9.5 weeks ( median= 6; 75th percentile=12 SD=9.6; range = 0–44). Significant correlates with lost-time from work were: energy of injury, occupational demand, workers compensation, initial radial inclination on x-ray, baseline PRWE and DASH scores and Mental Component-SF-36). A stepwise multiple linear regression found that 50% of the variation in lost-time could be explained on the basis of the initial PRWE, occupational demand and radial inclination. Without self-report, 45% of the variation in lost-time was explained by workers compensation status, radial inclination, occupational demand, energy of injury, sex and age.

A cohort of one hundred and sixty-eight workers who experienced a distal radius fracture were enrolled. Age, sex, education level, smoking status, alcohol consumption, injury compensation status, occupational use of hand, energy of injury and radiographic injury severity (pre-reduction radial shortening, radial inclination, dorsal angulation) were recorded. Patients were followed at two, three, six, and twelve months to determine their work status. Multiple linear regression identified predictors of time lost from work.


M. Ashe K. Khan P. Guy P. Janssen H. McKay

Osteoporosis investigation following a low-trauma fracture is often missed. The aim of this study was to (i) measure the current rate of osteoporosis investigation and (ii) to test a simple intervention that seeks to increase patient awareness and physician alerting following these sentinel events. Our study showed that 92% of the intervention group was investigated compared to 18% of the control group. This study suggests that a simple inexpensive intervention can increase the rate of osteoporosis investigation in an at risk population.

National guidelines (1–3) emphasize that low-trauma fractures should prompt to investigate for osteoporosis but more than 80% of “at risk” people are not investigated.

To measure the rate of diagnosis of osteoporosis when patients with low-trauma wrist fractures obtain usual care compared to a patient education and physician alerting intervention.

This is a prospective, controlled trial of patient education and physician alert following a distal radius fracture. Participants in the intervention group received four-parts: (i) an information sheet, (ii) a letter from the treating orthopedic surgeon to the patient’s family physician signaling the recent low-trauma fracture (iii) a follow-up reminder call to return to the family doctor for assessment and (iv) a fax to the family physician suggesting assessment and management of osteoporosis. The control group received usual care of the fracture and no specific information about osteoporosis. All participants were telephoned at 6 months to assess investigation status.

Fifty-one participants > 50 yrs. with a fragility wrist fracture were enrolled: 92% of the Intervention participants were investigated for osteoporosis by the family physician compared to 18% of the Control group. This is a significant difference (p ≤ 0.01).

This study suggests that a simple inexpensive intervention by the surgeon can increase the rate of osteoporosis investigation in an at risk population.

Orthopedic surgeons can contribute to the care of osteoporosis by readily adopting simple clinical actions which will make patients more likely to be investigated for osteoporosis.


E.K. Wai L. Vexler R. D. Fraser

Independent reviewers performed systematic reviews of the abstracts presented at the annual meeting of the ISSLS and the CSS. Papers employing blinded or independent review of outcome were the strongest predictor of publication and papers employing this had an adjusted odds ratio of 4.7 for being published compared to those papers that did not. Other significant factors include use of an experimental design, statistically positive result, and basic science research.

To identify factors associated with eventual peer-reviewed publication in spinal research presented at national and international meetings.

This review has highlighted factors that are associated with eventual peer-reviewed publication. It will also present comparisons between the International Society for Study of the Lumbar Spine (ISSLS) and the Canadian Spine Society (CSS).

Independent reviewers performed systematic reviews of the abstracts presented at the annual meeting of the ISSLS and the CSS. All abstracts reviewed were categorized into type of research and aspects of research quality were identified. A medline database, blinded to the results of the review, was performed to identify abstracts that went onto peer-reviewed publication.

Univariate and multivariate analyses reviewed that blinding, use of an experimental design, basic science or biomechanical research, and a statistically significant positive result were significant predictors of eventual publication. Papers employing blinded or independent review of outcome were the strongest predictor of publication and papers employing this had an adjusted odds ratio of 4.7 for being published compared to those papers that did not. Other significant factors include use of an experimental design, statistically positive result, and basic science research. Overall, 23% of ISSLS’ abstracts were published within one year and 67% within two years. In contrast, 6% and 13% of CSS abstracts were published within one and two years respectively.


M.I. Boyer R.H. Gelberman F. Raaii

Surgical results following proximal row carpectomy modified with proximal capitate resection and dorsal capsule interposition are presented. A consecutive cohort of thirteen patients was operated upon, and outcomes measured by radiograph, physical examination and DASH questionnaire. AROM values of 50° to 105° for the flexion/extension arc, restoration of grip strength to 72% of the contralateral extremity, and an improved functional outcome can be expected; and patients’ perceptions of functional outcome, as measured by the DASH, are significantly improved as early as six weeks. The results of PRC with interposition for stages II and III SLAC wrist were uniformly favorable.

Eaton has described two modifications to the proximal row carpectomy (PRC) procedure: partial capitate resection and dorsal capsular interpositional arthroplasty. The objective is to enlarge the radiocarpal interface to form a broad mobile pseudoarthrosis that would disperse compressive forces across the wrist more effectively. We present the first consecutive cohort of patients (n=13) who have undergone this procedure,

We extend the indications for PRC in this series to include those wrists with stage III SLAC deformity; approximately 67% of wrists had capitolunate arthritis.

AROM values of 50° to 105° for the flexion/extension arc, restoration of grip strength to 72% of the contralateral extremity, and an improved functional outcome can be expected from PRC with dorsal capsular interpositional arthroplasty.

Patients’ perceptions of functional outcome, as measured by the DASH, are significantly improved as early as six weeks following the procedure.

Mean flexion/extension arc achieved was 86° (range, 50° to 105°). Radial deviation averaged 13° (range, 10° to 20°), and ulnar deviation averaged 21° (range, 15° to 25°). Grip strength averaged 72% of the contralateral extremity. The mean decline in the revised carpal height ratio was 24%. The mean DASH score was 20.8 (range, 10 to 29). Visual analog pain improved from 9.25 to 2.67 on average, with one patient reporting no pain with heavy exertion.

Patients were evaluated by active range of motion ; grip and pinch strength; radiographs; subjective analog pain; and DASH questionnaire.


A. Van Houwelingen K. Panagiotopoulos E. Schemitsch R. Richards M. McKee

Thirty-eight patients with nonunion of the humeral shaft underwent a comprehensive assessment including completion of three patient-based functional outcome surveys as well as the determination of the Constant shoulder and Mayo elbow scores. Treatment consisted of compression plating with or without bone grafting. Smokers were found to have significantly longer time to union as compared to nonsmokers (25.1 weeks vs. 16.2 weeks, p< 0.001). Our results also demonstrated that increased time to union had a significant negative effect on the patient-reported functional outcome scores.

To evaluate the functional outcome and identify prognostic factors that influence the healing time of surgically treated humeral shaft nonunions.

Time to consolidation of operatively treated humeral shaft nonunions was significantly longer in smokers versus non-smokers. Time to union was negatively associated with the patient-reported functional outcome scores.

The long-term functional outcome following surgical treatment of humeral shaft nonunions is dependent upon the time to consolidation. Smoking is a significant remediable risk factor for delayed union following surgical repair of humeral shaft nonunion.

We identified thirty-eight patients (mean age fifty-five years) treated surgically for nonunion of the humeral shaft at a mean follow-up of sixty months. All patients underwent a comprehensive assessment including the completion of the SF-36, the DASH, the SMFA and the determination of the Constant shoulder and Mayo elbow scores. Seventeen (44.7%) patients were classified as ‘smokers’ and twenty-one (55.3%) were ‘non-smokers’. All nonunions united with a mean time of 16.2 weeks for non-smokers and 25.1 weeks for smokers (p< 0.001). Time to union was negatively associated with the Physical Function portion of the SF-36 (p=0.01), the DASH (p=0.01), and the Arm and Hand Function part of the SMFA (p=0.005). The only other factor that had a significant negative effect on the functional outcome scores was the presence of one or more comorbid factors (SF-36, p< 0.001; DASH, p< 0.001; SMFA, p< 0.001). Patient-oriented and surgeon based scores were found to correlate well (range r=0.545 to r=0.916, p< 0.001 for all combinations).


M. Blankstein K. Syed M. Nakane A. Bang J. Freedman R. Richards E. Schemitsch

The purpose of this study was to determine the effect of positioning (lateral vs. supine) on pulmonary pathophysiology following pulmonary contusion and fat embolism in a canine model of polytrauma. Platelet and neutrophil activation were assessed using flow-cytometry. There were no significant differences between groups in CD62P and CD11/18 MCF (markers of platelet and neutrophil activation, respectively) following fat embolism. However, only animals in the lateral position displayed significant increases in both measures as compared to baseline values. Lateral positioning may exert an early effect on proinflammatory and coagulation activation, and may play a role in the development of acute lung injury.

It has previously been suggested that acute lung injury can be influenced by patient positioning, be it lateral or supine. The purpose of this study was to determine the effect of positioning on pulmonary pathophysiology associated with concomitant pulmonary contusion and fat embolism in a canine model of polytrauma.

Twelve dogs were randomly assigned to one of two surgical positioning groups, lateral and supine. The dogs were subjected to pulmonary contusion by application of force between 200–250 N/m2 for thirty seconds in three areas of one lung. Two hours later, fat embolism was induced via reaming of the ipsilateral femur and tibia and cemented nailing. Two hours later, the dogs were sacrificed. For flow-cytometric evaluation of platelet and neutrophil activation, venous blood samples were stained with fluorescence-conjugated antibodies against CD62P and CD11/18, respectively.

There were no significant differences between the groups in CD62P and CD11/18 mean channel fluorescence (MCF) following pulmonary contusion and fat embolism. However, only animals in the lateral positioning group displayed significant increases in CD62P and CD11/18 MCF at two hours following fat embolism as compared to baseline values.

Our findings suggest that lateral positioning, autoregulation and preferential blood flow to the contused non-dependent lung may render lung tissue more susceptible to congestion and lead to activation of both platelets and neutrophils. Lateral positioning may have an early effect on activation of the inflammatory and coagulation cascades and may be significant in the development of posttraumatic acute lung injury.


A.E. Kedgley G.A. Mackenzie L.M. Ferreira D.S. Drosdowech G. J.W. King K.J. Faber J.A. Johnson

This in-vitro study was conducted to determine the effect of rotator cuff tears on joint kinematics. A shoulder simulator produced unconstrained active abduction of the humerus. Three sequential 1cm lesions were created, the first two in the supraspinatus tendon and the third in the subscapularis tendon. The plane of abduction moved posteriorly and became more abnormal throughout abduction as the size of the tear increased. It is concluded that in order to generate the same motions achieved by the intact joint other muscle groups must be employed, inevitably resulting in altered joint loading.

This in-vitro study was conducted to determine the effect of simulated progressive tears of the rotator cuff on active glenohumeral joint kinematics.

Five cadaveric shoulders were tested using a shoulder simulator designed to produce unconstrained active motion of the humerus. Forces were applied to simulate loading of the supraspinatus, subscapularis, infraspinatus/teres minor, anterior, middle, and posterior deltoid muscles based upon variable ratios of electromyographic data and average physiological cross-sectional area of the muscles. Three sequential 1cm lesions were created, the first two in the supraspinatus tendon and the third in the subscapularis tendon. Simulated active glenohumeral abduction was performed following the creation of each lesion. Five successive tests were performed to quantify repeatability.

The plane of abduction moved posteriorly and became more abnormal throughout abduction as the size of the lesion increased (p=0.01) (Figure 1).

In order to generate the same motions achieved with an intact rotator cuff other muscle groups must be employed, inevitably resulting in altered joint loading.

A better understanding of the effects that rotator cuff tears have on the kinematics of the glenohumeral joint may result in the development of innovative rehabilitation strategies to compensate for this change in muscle balance and improve the clinical outcomes.

Please contact author for diagram and/or graph.


B. Benoit Y. Laflamme F. Zhim

We compared internal fixation augmented with a trabecular metal implant to internal fixation augmented with morcellized bone grafting for depressed lateral tibial plateau fractures. Six cadaveric tibia pairs were prepared and tested on a MTS machine for both cyclic loading and static load to failure. Results showed greater resistance in cyclic loading and load to failure in the trabecular metal group. We found half the loss of reduction of the tibial articular surface compared after cyclic loading over 10 000 cycles. These surprising results show the biomechanical superiority of our trabecular metal construct over the current standard of care.

Restoration and maintenance of the plateau surface are the key points in the treatment of tibial plateau fractures. Any deformity of the articular surface jeopardises the future of the knee by causing osteoarthritis and axis deviation. The purpose of this study is to develop a more solid way to fix the Shatzker III fracture and to test a trabecular metal implant in the trauma setting for the first time.

Six matched pairs of fresh frozen human cadaveric tibias were fractured and randomly assigned to be treated with either the standard of care (two 4,5mm cortical raft screws augmented with morcellized bone graft) or the new method (the same screws supporting a 2 cm diameter trabecular metal disc placed under the comminuted articular surface). The specimens were tested in cyclic loading and put at load to failure.

The trabecular metal construct showed 40% less caudad displacement of the articular surface (1,43 mm vs 0,81 mm) in cyclic loading (p< 0.05). Its mechanical failure occurred at a mean of 3275 N compared to 2650 N for the standard of care construct (p< 0,05).

The current study shows the biomechanical superiority of our trabecular metal construct compared to the current standard of treatment with regards to both its resistance to caudad displacement of the articular surface in cyclic loading and its strength at load to failure. Trabecular metal is a good metaphyseal void filler in the studied fracture.


F. Moola D. Jacks R. Reindl G. Berry E. J. Harvey

To determine if immediate closure of open wounds is safe, we examined our results over a five year period. Of the two hundred and ninety-seven open fractures, two hundred and fifty-five (86 %) were closed immediately. Grade III open fractures accounted for 24.2% of cases. The superficial infection rate was 10.9%. The combined deep infection and osteomyelitis rate was 4.7%. Neither region of injury, Gustilo grade, velocity of trauma, nor time to primary closure had a significant influence on the incidence of infection. Primary closure may be a safe practice and could be accepted as a viable treatment plan in the care of most open fractures.

The purpose of this study was to determine if immediate primary closure of open fracture wounds is a safe practice without increased deep infections and delayed/ nonunions?

There was neither an increase in deep infection nor delayed union/non-union. Benefits include a decreased requirement for repeat debridements and soft tissue procedures, minimized surgical morbidity, hospital stay, and cost of treatment. Primary closure may be a safe practice in the care of most open fractures.

The standard of care has been to leave traumatic wounds open after initial emergent surgical debridement. Due to orthopedic advancements and current resource limitations, treatment at our institution has evolved to immediate closure of all open wounds after adequate irrigation and debridement.

Of the two hundred and ninety-seven open fractures, two hundred and fifty-five (86 %) were closed immediately after irrigation and debridement. Grades 3a, 3b and 3c open fractures accounted for 24.2% of cases. The superficial infection rate of primary closure was 10.9 %. All cases resolved with oral antibiotics. The combined deep infection and osteomyelitis rate was 4.7%. Neither region of injury, Gustilo grade, velocity of trauma, nor time to primary closure had a significant influence on the incidence of infection.

The study reviewed all open fractures presenting to a Level One Trauma center over a five-year study period. Patients were followed until fracture union or complication resolution. Multiple variables were examined including patient demographics, injury mechanism, fracture location, Gustilo classification, time to antibiotic administration, surgical debridement and wound closure, and method of wound closure. Outcome measurement included infection or union problems.


E.H. Schemitsch D. Togawa J. Reid T. W. Bauer H. Sakai M. Hawkins F. Dimaano

The purpose of this study was to evaluate trabecular bone response, at fifty-two week follow-up, to four different synthetic graft materials (CaSO4 and CaSO4 – HA/TCP composites) as compared to autograft in a canine defect model. The group with the highest HA/ TCP proportion had the greatest amount of residual graft material and total mineralized material. Increasing the proportion of HA/TCP reduces the rate of dissolution, and appears to have little effect on bone formation at long term follow-up. This study further suggests that a range of composites could be created to match the spectrum of resorption rates demanded by clinical applications.

The purpose of this study was to evaluate trabecular bone response to four synthetic graft materials (CaSO4 and CaSO4 – HA/TCP composites) as compared to autograft in a canine defect model, at long term follow-up.

Both 85% CaSO4 – 15% HA/TCP and 65% CaSO4 – 15% HA/TCP showed bone formation similar to autograft. The group with the highest proportion of HA/TCP lasted longer than the other formulations. The results suggest that increased HA/TCP proportions reduce the rates of dissolution, without compromising bone formation in the current model.

Results suggests that a range of composites could be created to match the spectrum of resorption rates demanded by clinical applications.

In this REB-approved RCT, bilateral humeral and femoral cylindrical defects were filled with one of four types of pellets with varying proportions of CaSO4 – HA/TCP, autograft bone, or left unfilled. After sacrifice at six, twelve, twenty-six or fifty-two weeks, defect sites were evaluated histologically for tissue and inflammatory response, area fractions of residual graft material, and bone ingrowth in the defects.

The area of the defect occupied by residual graft material in the group with the highest percentage of HA/TCP was greater than in other composite groups (p< 0.0001). This group contained the greatest amount of total mineralized material (graft material + bone) (p< 0.03. The extent of new bone formation increased from twelve to twenty-six weeks (p< 0.0001). Both 85% CaSO4 – 15% HA/TCP and 65% CaSO4 – 15% HA/TCP showed bone formation similar to autograft.

Funding: Research grant from Stryker Howmedica, Matwah, NJ.


M.T. Nousiainen E.H. Schemitsch J.P. Waddell M.D. McKee A. Roposch

This study investigated the effect presence, method, and timing of fixation of femoral shaft fractures have on the morbidity and mortality of patients with pulmonary contusion.

In the multiply-injured patient with femoral shaft fractures, early (< 24 hours) fracture stabilization with closed, reamed, statically-locked intramedullary nailing has been shown to decrease morbidity and mortality. Controversy exists as to whether such treatment compromises the outcome in patients that have significant co-existing pulmonary injury. This study is the first to specifically investigate the sub-group of patients that have pulmonary contusion.

A retrospective review of patients presenting to a Level One trauma center from 1990 to 2002 with pulmonary contusion identified three hundred and twenty-two cases. Patient characteristics of age, sex, GCS, ISS, AIS, presence of femoral shaft fracture, method and timing of treatment of femoral shaft fracture, and presence of other pulmonary injuries were recorded, as were the outcomes of pulmonary complications (acute lung injury (ALI), ARDS, fat embolism syndrome, pulmonary embolism, and pneumonia), days on ventilatory support, days in the intensive care unit and ward, and death.

There were no significant differences in the patient characteristics between groups with and without femoral shaft fracture. Except for an increased likelihood of the femoral shaft fracture group having ALI (RR 1.11), there were no significant differences in outcomes between the femur fracture/non-femur fracture groups. As well, there were no significant differences in outcomes between the groups that had fracture fixation before or after twenty-four hours or had the fracture fixed with or without intramedullary nailing.

The presence, method, and timing of treatment of femoral shaft fractures do not increase the morbidity or mortality of trauma patients that have pulmonary contusion.


C. Ninh M.H. Hatahet R. Vaidya S. Bartol M. Morandi

Dislocation after hemiarthroplasty for femoral neck fracture is a rare event. Two hundred nineteen patients underwent hemiarthroplasty for femoral neck fracture all with a modern stem and modular unipolar prosthesis at our institution over a three year period. Eleven patients (4.1%) suffered a dislocation. Epidemiologic, technical and anatomic-radiographic factors were reviewed to assess risk factors for dislocation. Our findings indicate that. Mental disease was a significant risk factor. Femoral neck offset and center edge angle of the acetabulum were also contributing factors for dislocation.

To determine the risk factors for dislocation after hemiarthroplasty with a modern stem and modular unipolar prosthesis for femoral neck fracture.

A retrospective review was undertaken at our institution from January 2000 to December 2003. We reviewed factors including gender, age, time of dislocation, medical comorbidities, side of operation, surgical approaches and radiographical data including femoral neck offset, contra lateral femoral neck offset, center edge angle, residual femoral neck, prosthesis femoral neck shaft angle and acetabular index.

Hemiarthroplasty for femoral neck fracture was pre-formed on two hundred and nineteen patients all with a modular unipolar prosthesis. Eleven patients (4.1%) had at least one dislocation during a one year follow-up. The average time of dislocation following surgery was 19.3 days (std 12.7days). There were no significant difference for gender, age, surgical approach, residual femoral neck, and prosthesis femoral neck shaft angle. There was a statistical significance of mental disease in 55% of dislocated hemiarthroplasty compared to 21% of nondislocated hemiarthroplasty but other comorbidities were not a factor. Median femoral neck offset of nondislocated hemiarthroplasty measured 51mm versus dislocated hemiarthroplasty value of 47mm, a difference of 4 mm (P=0.043). Center edge angle of nondisplaced hemiarthroplasty measured median thirty-six degrees versus a median of thirty-two degrees for dislocated hemiarthroplasty, a difference of four degrees (P=0.006).

The factors predicting dislocation are likely multifactorial. Our findings indicate that Mental disease was a significant risk factor. Femoral neck offset and center edge angle of the acetabulum are contributing factors for dislocation.


A. Scharfenberger T. Weber

This study documents the use of bone graft harvested by the RIA system and used in treating segmental bone loss in the femur and tibia following trauma.

Eight patients with segmental defects of the tibia or femur were enrolled in the study. The segmental defects were optimized for bone grafting by repeated debridements and muscle flap coverage as required. Graft was harvested from the ipsilateral femur via a percutaneous technique. Volumes of bone graft were recorded and then placed to the defect site during the same surgical procedure.

The average age of the patients was twenty-nine years (sixteen to forty-one years). In the five tibiae and three femora there were four grade IIIA, three grade IIIB and One grade IIIC injuries. Muscle flap coverage was required in four patients. The average size of defect was 7 cm (1–14.5 cm). The RIA grafting was performed at an average of three months (2.5 – 5 months) post injury. The average bone graft volume obtained was 73cc(45–90 cc). The average hemoglobin drop was 4.4g/dl(2.3 – 8.0 g/dl) and the average hematocrit drop was 12.3%(6–21%). One patient required transfusion. Donor site complications were limited to one post-operative bleed. Defect site complications included one wound dehiscence and two infections. Radiographic union of the defects was achieved at an average time of four months (two to twelve months).

Grafting of large segmental defects using RIA bone graft has resulted in union at an average of four months. This technique represents an alternative to bone transport for treatment of segmental defects.

Reamed Irrigation Aspirator (RIA) allows access to large volumes of bone graft from the femur through percutaneous technique. The grafting technique was utilized to obtain graft for eight segmental defects in the tibia and femur. These healed at an average of four months.


C. Tang D. Liu S. Kontulainen P. Guy T. Oxland H. McKay

This study identified imaging parameter(s) which best predict the mechanical properties of distal tibia. Seventeen human cadaver tibiae were assessed by PQCT at four, eight and ten percent site from distal and tested in compression at the twenty-five percent distal portion. Ultimate compressive loads were recorded with a mean of 8276 ± 2915 N. Spearson rank correlation and stepwise regression analysis revealed that CoA, total BMC, SSI and SSI4-TrA4-CoD4 combination had statistically significant correlations with the failure loads. Among all imaging parameters, SSI had the highest relevance due to its account for geometry, density and material distribution, important factors for structural properties.

Musculoskeletal diseases, especially hip fractures, have huge and growing impact on Canadian society. To develop techniques for identification of high risk population, we needed a link between clinical evaluations and laboratory measures of bone health. This study identified imaging parameter(s) which best predict the mechanical properties of distal tibia.

Seventeen human cadaver tibiae were considered in this study (mean age seventy-four, SD six years). PQCT was used to assess the four, eight and ten percent site. It measured the cross-sectional area, bone mineral content and bone mineral density of the cortical bone, trabecular bone and combined. Strength Strain Index (SSI) was calculated from these measurements. Each tibia was cut at twenty-five percent distal. Compressive force was applied uniaxially through a custom-made PMMA indentor onto the distal plateau along the longitudinal axis of the tibia at a rate of 10mm/s. Load and displacement data were recorded. Spearson rank correlation and stepwise regression analysis were used to identify individual and combination of imaging variables that were related to ultimate failure load.

Ultimate failure loads were recorded with a mean of 8276 ± 2915 N. Cortical area (R_0.72), total BMC (R_0.72) and SSI (R_0.86) had statistically significant correlations with the failure load. Stepwise regression revealed that the combination of SSI, TrA, CoD at 4% site explained the greatest amount of variance (R2 = 0.868) and SSI was the major contributor. SSI takes the polar moment of inertia (geometry), density and distribution of material into account. This explains its relevance towards predicting the ultimate failure load.

Please contact author for referenced images


S.J. MacDonald C.H. Roabeck R.B. Bourne R.W. McCalden D.M. Cleland

Controversy continues to exist regarding the choice of a cementless femoral component in a primary total hip arthroplasty. Both proximally coated tapered stems and fully coated cylindrical stems have excellent clinical results. The incidence of both thigh pain and proximal femoral stress shielding and multiple validated outcome measures were evaluated in a prospective randomized clinical trial with a minimum of two year follow-up comparing a proximally coated tapered femoral stem to a fully coated cylindrical femoral stem.

A prospective randomized clinical trial (RCT) was performed comparing a cylindrical cobalt chrome fully coated femoral stem (Prodigy, Depuy, Warsaw, IN) to a tapered, titanium, proximally porous coated stem (Synergy, Smith & Nephew,

Memphis, TN) with respect to thigh pain, femoral stress shielding and multiple outcome measures.

One hundred and ninety-four patients were enrolled and evaluations were performed pre-operatively, three months, six months and annually. Multiple outcome measures (Harris Hip Score, SF12, WOMAC, Patient Satisfaction Questionnaire, Thigh Pain Questionnaire) were obtained. Sixty-one of these patients were randomized to receive a bone density scan pre-operatively, two weeks post-operatively, six months and annually.

Twelve patients were unavailable for two-year follow-up, leaving one hundred and eighty-two patients evaluated. No significant differences were demonstrated in thigh pain incidence or the multiple outcome measures. Bone density scans demonstrated significantly greater bone density (p< 0.005) in the tapered stem versus the cylindrical stem patients at two-week evaluations from distal femoral reaming. Both stem designs demonstrated statistically significant bone loss in Gruen zones one, six, seven between the two-week and one and two-year evaluations. There were no differences between stem designs although the Prodigy stem demonstrated trends towards greater bone loss in Gruen zones six and seven.

This prospective RCT demonstrated no difference in thigh pain incidence and multiple outcome measures between patients receiving a proximally coated tapered versus a fully coated cylindrical femoral component. Both stem designs demonstrated statistically significant proximal femoral bone loss between the post-operative and two-year evaluations; however, there were no differences between stem designs.


S. Xing E. Boynton

The blocking effects of anti-inflammatory cytokines and osteoprotergerin (OPG) on tartrate resistant acid phosphatase (TRAP) synthesis by monocyte-macrophages (MDMs) were investigated. Human Monocytes were cultured on PE/collagen coverslips supplemented with 50 mL of conditioned media from implant revision membranes, and anti-IL-6, anti-TNF- or OPG was added. Cultured media were collected and the cells were lysed. Both the cell releasates and lysates were analyzed for TRAP activity. Statistical analysis showed significantly inhibition of TRAP with addition of anti-IL-6 or anti-TNF-, but no inhibition was seen with addition of OPG. Blocking of TRAP with anti-inflammatory cytokines could provide a potential therapeutic method of preventing TRAP-associated peri-prosthesis osteolysis.

To investigate the blocking effects of anti-inflammatory cytokines and osteoprotergerin (OPG) on monocyte-macrophage tartrate resistant acid phosphatase (TRAP) syhthesis.

Either anti-IL-6 or anti-TNF- significantly inhibits monocyte-macrophage TRAP synthesis in vitro.

Since TRAP has been related to bone resorption, blocking monocyte-macrophage TRAP synthesis would be beneficial for preventing peri-prosthesis osteolysis.

Monocyte isolations were performed using blood from healthy donors. The isolated monocytes were cultured in triplicate on PE/collagen coverslips supplemented with 50 uls of fresh culture media or conditioned media from implant revision membrane. Anti-IL-6, anti-TNF-, or OPG at a concentration of 2 μg/mL was added at time zero, day two and four. The culture media were completely replaced with no addition at twenty-four hours prior to termination at day seven. On the terminating day, conditioned media were collected and the cells were lysed. Both the cell lysates and releasates were analyzed for TRAP activity, and the cell lysates were also assayed for DNA contents. The TRAP activity measured was normalized to the DNA contents. Statistical analysis showed significantly inhibition of TRAP with addition of anti-IL-6 (p< 0.01, n=3) or anti-TNF- (p< 0.01, n=3), but no inhibition was seen with addition of OPG. TRAP is believed to be mainly secreted by monocyte-macrophages and osteoclasts and associated with bone resorption. Therefore, these results suggest that the peri-prosthesis osteolysis be unlikely via the OPG-OPGL osteoclast activation axis, but possibly through the inflammatory cytokine pathway. Blocking of TRAP with anti-inflammatory cytokines could provide a potential therapeutic method of preventing peri-prosthesis osteolysis.

Funding from the Arthritis Society.


P.R. Kim M. Dunbar Y. Laflamme A. Conway H. Hrushowy

This study evaluates metal ion levels in patients enrolled in a prospective evaluation of hip resurfacing arthroplasty utilizing the Conserve Plus implant (Wright Medical Technology). Serum, urine and erythrocyte metal ion levels were assessed preoperatively and postoperatively. Average levels at three months were 24 nmol/l for cobalt and 40 nmol/l for chromium. These increased to 40 nmol/l for cobalt and 80 nmol/l for chromium at the six-month mark. The clinical significance of increased metal ion levels is yet to be determined.

To evaluate the clinical, functional and radiographic outcome of hip resurfacing arthroplasty utilizing the Conserve Plus implant (Wright Medical Technology). Serum, urine and erythrocyte metal ion levels were evaluated both pre and postoperatively.

Ion levels for both cobalt and chromium increased from the three-month to the six-month mark postoperatively and were significantly elevated relative to preoperative values.

This study helps to establish a baseline for metal ion levels following hip resurfacing arthroplasty.

Serum, urine and erythrocyte metal ion levels were assessed preoperatively and postoperatively. All levels were within normal range preoperatively. Average serum levels at three months were 24 nmol/l for cobalt and 40 nmol/l for chromium. These increased to 40 nmol/l for cobalt and 80 nmol/l for chromium at the six-month mark. Average erythrocyte metal ion levels at three months were 0.92 ug/l for cobalt and 1.8 ug/l for chromium. The average erythrocyte levels at six months were 1.3 ug/l for cobalt and 2.0 ug/l for chromium.

A prospective multi-center study to evaluate the outcome of hip resurfacing arthroplasty was initiated in July 2003. Each patient was evaluated preoperatively and postoperatively with outcome scores, radiographs as well as serum, urine and erythrocyte metal ion levels.

The results of this prospective evaluation show a rise in ion levels from three to six months postoperatively. Further follow-up is necessary to assess future trends with respect to the ion levels as well as the clinical significance.

Funding: This study has been sponsored in part by Wright Medical Technology.


F. Aljassir T. Vail D. Fisher M. Tanzer D. Goetz C. Mohler J. Callaghan

Patient postoperative outcome can be accurately predicted by the patient’s preoperative HHS or WOMAC score. Prospective, cohort studies of one hundred and seventy-five THAs. SF-36, WOMAC and Harris Hip Score (HHS)questionnaires were used to determine pre-operative and two year final outcome. Student’s t-test, 95% confidence intervals, receiver operator characteristic curves, simple regression analysis and probability were measured. Patients with a HHS = sixty-five pre-operatively had a 100% probability of having an excellent result postoperatively. A preoperative HHS value of thirty-four, and preoperative WOMAC (physical function) value of fifty were the best cutoff points to attain a significantly better postoperative functional outcome.

Total hip arthroplasty (THA) has been well documented to enhance patient function, but patient outcome is dependant on preoperative statuts. The exact timing of surgery to optimize patient outcome after THA remains unknown. This study determines the ideal timing for surgery to obtain the best possible functional outcome.

Prospective, multicenter, cohort studies of one hundred and seventy-five identical, cemented THAs. General health (SF-36) and disease specific (WOMAC and Harris Hip Score(HHS)) questionnaires were used to determine preoperative and two year final outcome. Student’s t-test, 95% confidence intervals, receiver operator characteristic curves, simple regression analysis and probabilty were measured.

All functional scores were improved significantly postoperatively (p< 0.001). Patients with a HHS = sixtyfive preoperatively had a 100% probability of having an excellent result postoperatively. A preoperative HHS value of thirty-four, and preoperative WOMAC (physical function) value of fifty were the best cutoff points to attain a significantly better postoperative functional outcome.

Patient postoperative outcome can be accurately predicted by the patient’s preoperative HHS or WOMAC score. Optimization of surgical timing, by prioritizing wait lists or deciding to treat the arthritis operatively, based on these preoperative score guidelines will help ensure an excellent outcome post THA.


J. K. Bow K. Pittoors M. Hunt I. Jones J.T. Marr R.B. Bourne

This randomized clinical trial compares fixed- and mobile-bearing total knee prostheses in terms of the patients’ clinical outcome parameters (Knee Society Clinical Rating, WOMAC, SF-12), range of motion and performance during gait analysis for level-ground walking. Our results show no significant differences in the clinical outcomes and gait performance of the fixed- and mobile-bearing total knee arthroplasties.

The purpose of this study was to compare the clinical outcomes and gait parameters of patients with a fixed-bearing or mobile-bearing total knee arthroplasty (TKA).

Fifty-five patients were entered into a prospective, randomized clinical trial comparing fixed- versus mobile-bearing TKAs (Genesis II, Smith & Nephew, Memphis, TN). From this patient population, fifteen fixed-bearing and fifteen mobile-bearing TKA patients were matched based on age, sex and BMI to undergo gait analysis. Patients performed trials of level-ground walking at a self-selected velocity while three-dimensional kinetic and kinematic data were collected.

The fixed-bearing and mobile-bearing TKA patient groups were comparable regarding Knee Society Clinical Rating (181 ± 22 versus 171 ± 28), WOMAC scores (7 ± 5 versus 9 ± 12), SF-12 and range of motion (121° ± 11° versus 125° ± 6°).

Patients with fixed- and mobile-bearing TKAs performed similarly in the gait analysis in terms of their velocity, percent weight acceptance in the operated versus the non-operated limb, peak flexion in stance and swing phases, the support moments and extension moments at the ankle, knee and hip. Decreased peak extension in the mid-stance and swing phases was observed in the operative limb versus the non-operative limb for both fixed- and mobile-bearing TKAs (P=0.02 and 0.04). Decreased peak extension was also observed during mid-stance and swing phases in the mobile-bearing TKAs versus the fixed-bearing TKAs (P=0.064 and 0.052).

Fixed-bearing and mobile-bearing TKAs perform similarly in terms of their clinical outcome measures and the kinetics and kinematics of level-ground walking.

Funding for this project obtained from Smith & Nephew, Memphis, TN.


P.E. Beaulé Z. Lu J.V. Luck P. Campbell

3-D finite element model of a resurfaced femoral head was composed. Five configurations of cement layer were analyzed and the transient heat transfer analysis during cement polymerization was performed. Peak temperature at the bone-cement interface temperature was lower than 40 oC when there was no or 1.5 mm cement penetration but reached 54 oC and 74 oC with 6 mm penetration and 6 mm penetration plus a cement –filled cyst of 1 cm3, respectively. With deep cement penetration, and a large cement-filled cyst, the peak temperatures exceeded bone thermal osteonecrosis at 55 oC.

To evaluate using a finite element analysis model, the possibility of bone thermal necrosis secondary to cement in resurfacing arthroplasty of the hip.

With deep cement penetration, and the presence of a large cement-filled cyst, the peak temperatures were in the range of bone thermal osteonecrosis 55 oC.

Cementing technique in resurfacing arthroplasty should strive to strike a balance between fixation and avoiding bone thermal necrosis by excessive cement penetration. This information could explain why femoral head cysts > 1cm are a risk factor for femoral loosening after resurfacing arthroplasty and excessive cement penetration could lead to femoral neck fracture.

3-D finite element model of a hemispherical resurfaced femoral head was composed of a metal shell with a diameter of 46 mm. Five configurations of cement layer were analyzed a) no penetration into the bone, b) 1.5 mm penetration, c) 6 mm penetration, d) 6 mm penetration and a 1 cm3 cement filled cyst, and e) 6 mm penetration and 2 cm3 cement-filled cyst. The transient heat transfer analysis during cement polymerization was performed in a series of time steps. The temperature within the bone and cement was lower than 40 oC when there was no or 1.5 mm cement penetration into the femoral head. In contrast, the peak temperature at the bone-cement interface reached 54 oC and 74 oC and 63 oC with 6 mm penetration and 6 mm penetration plus a cement –filled cyst of 1 cm3, respectively.


E.C.S. Chen J. L. Lanovaz R. R. Ellis

A near real-time, image-free, contact-determination algorithm is developed for the use of analyzing in vivo kinematics of an artificial knee joint. Using a three-dimensional motion tracker and the knowledge of the precise geometries of the contacting surfaces, the contact regions between two articular surfaces can be determined within seconds. The results are validated with the use of Fuji films, which show high degree of accordance in the contact regions determined. Applications include knee kinematics validation, TKA wear-pattern analysis, and intro-operative surgical assessment.

To determine the in vivo contact locations between total knee prosthetic components without the use of any imaging modality.

Validated with the Fuji film contact study, this computer algorithm provides an image-free, and accurate way of finding contact regions between prosthetic components.

An image-free, near real-time, algorithm is developed to study the in vivo contact condition between prosthetic components.

A Dynamic Reference Body (DRB) is attached to each of the Total Knee Arthroplasty component and their motions, while in contact with each other, are tracked with an optical spatial sensor. The geometries of the articular surfaces, represented in point-clouds with point-normal, were obtained from a laser-scanner at 0.4mm resolution. For each recorded pose, the contact between articular surfaces were determined by first matching point normal and then performing a nearest-point search, both facilitated by the use of a generalized binary-search-tree (kd-tree).

A size-3 Sigma Knee (Johnson& Johnson), represented by approximately 31,000/19,000 points for each of the femoral/tibial component, respectively, is used for this study. For each pose, the contact between components can be determined under one second on a 2GHz PC, rendering it applicable for intra-operative use. The contacts between prosthetic components are visualized using standard computer graphics techniques and contrasted with the contact obtained by Fuji film of the same pose. Depicted below, the contact regions determined by these two methods show high degree of accordance with each other. This allows for, in particular, an image-free TKA wear-pattern analysis.

Please contact Author for diagrams.


P.E. Beaulé P. Campbell R. Hoke

Fourteen hips with osteoarthritis had femoral head blood flow measured with laser Doppler flowmeter while undergoing during total hip replacement through a modified lateral approach. Mean age sixty-five years (48–77); eight males & six females. Two measurements were taken within the femoral head one after anterior hip dislocation and one after simulated notching of the femoral neck. All hips had a significant decrease in blood flow with a median percentage decrease of 76% (range 4.4–90.4). During surface arthroplasty of the hip, notching of the femoral neck may not only mechanically weaken the bone but also put the femoral head at risk of osteonecrosis.

To evaluate femoral head blood supply in patients with osteoarthrtis of the hip undergoing simulated notching of the femoral neck during total hip replacement and its potential implications in hip resurfacing.

During surface arthroplasty of the hip, notching of the femoral neck may not only mechanically weaken the femoral neck but also put the femoral head at risk of osteonecrosis and subsequent femoral loosening.

It would appear that the retinacular vessels (extraosseous blood supply) are as important in the arthritic femoral head as they are in the nonarthritic state, contradicting the notion that arthritic femoral heads in humans rely mainly on an intraosseous blood supply.

Fourteen hips with a diagnosis of degenerative arthritis had femoral head blood flow measured with laser Doppler flowmeter while undergoing during total hip replacement through a modified lateral approach. With the femoral head exposed and leg in neutral position, a 3.5mm drill hole was made into the anterior lateral quadrant and the fiber optic probe of the laser Doppler flowmeter (Moor Instruments, Wilmington Delaware, 20mW laser, wavelength 780nm) was inserted. Mean age was sixty-five years (48–77). Eight males and six females. Two measurements were taken one after anterior hip dislocation and one after simulated notching of the femoral neck. All but four hips had a significant decrease of more than 50% in blood flow after neck notching with a median percentage change of 76% (range 4.4–90.4), p< 0.001.


J.P. Waddell F. Lui J. Morton E. H. Schemitsch

Thirty total hip replacements in twenty-eight patients in which a Zirconia/Polyethylene articulation was utilized were compared to a control group undergoing total hip replacement utilizing Cobalt-Chrome/Polyethylene articulation. These patients were matched for gender, BMI and pre-operative diagnosis.

At nine years after implantation there was no difference in the functional outcome between the two groups and no difference in liner wear rate on x-ray (Livermore technique). There was a 27% revision rate in the Zirconia group compared to the 11.5% revision rate in the Cobalt-Chrome group.

Bearing surfaces require long- term clinical follow-up to validate in vitro performance.

To determine the benefit of Zirconia on polyethylene versus cobalt-chrome on polyethylene in total hip articulation.

Zirconia offers no advantage over a cobalt-chrome head in decreasing in vivo polyethylene wear at ten- year follow-up.

Newer bearing surfaces require long- term clinical follow-up to validate in vitro laboratory performance.

All primary total hip replacements at this institution are entered prospectively in a database and are assessed on an annual basis. All patients in this study were followed for a mean of nine years with a range of six to thirteen years.

Thirty cementless total hip arthroplasties were performed in twenty-eight patients utilizing a Zirconia head coupled with a polyethylene acetabular component. Twenty-six hips have been followed for a mean of nine years. These were matched to a control group of twenty-six hips in twenty-six patients utilizing a cobalt-chrome head coupled with an identical polyethylene liner followed for a mean of ten years (range five to fourteen years). There was no functional difference in outcome at nine years between the two groups utilizing the Livermore technique there was no difference in the liner wear rate between the two patient groups. However, seven hips (27%) of the Zirconia group required revision due to loosening and/or extensive osteolysis around the cup and only three hips (11.5%) required revision in the cobalt-chrome group. Our study demonstrates that although changes in component designs and materials may offer theoretical advantages over current components their effect in vivo remains questionable.


M. Dunbar L. Molloy A. Hennigar M. Davies

A centralized wait list management system (WLMS) for TKR, THR and knee arthroscopy was developed to collect accurate data on parameters of patients’ wait for surgery. A priority metric rating patient priority was implemented. Data from hospital enterprise systems related to aspects of patients’ wait for surgery was collected and imported. Patients’ functional status was significantly worse than population norms, they were adversely affected while waiting and are unsatisfied with their access to surgery. Traffic ratios (ratio of booked to completed surgeries) exceed the maximum value for a stable wait list and the waits for surgery exceed national and international recommendations for maximum wait-times.

To develop and implement a WLMS for TKR, THR and knee arthroscopy to enable the accurate and efficient collection of data on size of list, rate of list growth, rate surgeries are performed, health and functional status of patients, and surgeon rated priority.

Patients are adversely affected while waiting and are unsatisfied with the length of their wait. Traffic ratios exceed the maximum value for a stable waitlist. The priority metric has face validity for rating patient acuity.

SF36 and WOMAC scores were three to four standard deviations worse than the population norm, over 50% of patients felt wait time would negatively affect outcome, 80% felt waits should be twelve months or less, and over 50% were unsatisfied with access to surgery. VAS scores were normally distributed with good face validity. Wait times are one hundred and thirty to three hundred days for arthroplasty and ninety to four hundred days for arthroscopy. Traffic ratios are 0.9 for arthroplasty and 1.5 for arthroscopy.

Prospective outcomes with respect to the wait list will allow determination of minimum acceptable wait times from administrative, surgeon and patient perspectives. Accurate and reliable collection of wait list data provides a sound basis for future decision-making.

Surgery bookings were centralized. A priority metric based on a visual analog scale (VAS) with a single question asking the surgeon to rate the patient priority was implemented. A cross-sectional postal survey was conducted. Data from hospital enterprise systems related to aspects of patients’ wait for surgery was collected and imported into the WLMS.


C.E. Dunham S.E. Takaki J.A. Johnson C.E. Dunning

Three 3mm transverse slices were sectioned from the distal cancellous region of seven fresh-frozen cadaveric humerii. Each slice was marked with a 3x3mm grid, and subjected to compressive testing using a flat cylindrical indenter (1.6mm diameter). Indentation modulus and strength were calculated for each site, and pooled into nine anatomically-defined regions. The most distal slice had higher moduli values (p< 0.05), and the posterior capitellar region had lower moduli values (p< 0.05). There were no slice or regional differences in strength. This suggests that surgical procedures requiring cancellous fixation utilize the most distal aspect of the humerus while avoiding the posterior capitellum.

To quantify the indentation strength and modulus of distal humeral cancellous bone, and identify any regional variations.

Cancellous bone modulus in the distal humerus decreases from distal to proximal. The posterior capitellum has a lower modulus than the other regions of the distal humerus.

The influence of slice depth emphasizes the importance of minimizing the amount of bone removed during prosthetic replacement. Regional variations in modulus suggest that the posterior capitellum should be avoided during fixation of implants or placement of screws.

Three 3mm transverse cancellous bone slices obtained from the distal end of each of seven fresh-frozen cadaveric specimens were subjected to compressive testing using a materials testing machine with a 1.6mm flat cylindrical indenter. Testing was performed in a 3x3mm grid. The indentation modulus and local strength were calculated for each test site, and then averaged into nine regions defined by the capitellum, medial and lateral trochlea, and anterior, central and posterior sections for each slice. Mean modulus was found to be 309.8±242.0 MPa (range: 2.9–1041.7 MPa). Yield strength averaged 4.4±2.5 MPa (range: 0.6–16.3 MPa). The highest modulus was found in the distal-most slice (p< 0.05). The lowest modulus region was the posterior capitellum (p< 0.05). There were no differences in strength between slices or across the nine regions. A comparison with proximal tibial cancellous bone properties suggests the distal humerus may carry loads approaching 30% of those at the knee, assuming that bone adapts to stress magnitudes.

Funding: Natural Sciences and Engineering Research Council; University of Western Ontario


J. Pichora K. Furukawa L. Ferreira S. Steinmann K. Faber J. Johnson G. King

Single-strand medial collateral elbow ligament (MCL) reconstruction strength was evaluated using double docking (DD) and interference screw (IS) methods with either palmaris longus (PL) or Graft Jacket_ (GJ) as the reconstruction material. Thirteen upper-extremities were mounted in 90° valgus orientations, and subjected to increasing cyclic valgus loading until failure. DD reconstructions outperformed IS reconstructions (P< 0.05), while PL and GJ performed comparably (P> 0.05). The initial Graft Jacket strength makes it a potential alternative to palmaris longus tendons; Laboratory evaluation of graft strength during healing is required. For its simplicity and strength, the DD technique should be considered, clinically.

Single-strand medial collateral elbow ligament (MCL) reconstruction strength was evaluated using double docking (DD) and interference screw (IS) methods with either palmaris longus (PL) or Graft Jacket_ (GJ) as the reconstruction material.

Thirteen, fresh-frozen upper-extremities (66 ±5 years) were cleaned of all soft tissues except the medial and lateral collateral ligaments, flexed to 90° and mounted in a rigid, valgus testing system. DD or IS reconstructions were performed using either PL or GJ. A cyclic (0.5Hz) load was applied 12cm distal to the medial epicondyle. After 500 cycles, the load was increased by 10N until catastrophic failure or a length increase of 10mm.

The mean maximum load for the DD with GJ was 65 ±12N; for the IS with GJ: 45 ±5N; for the DD with PL: 59 ±11N; and for the IS with PL: 56 ±14N. The mean maximum number of cycles endured by the DD with GJ was 1292 ±562; for the IS with GJ: 356 ±292; for the DD with PL: 1104 ±479; and for the IS with PL: 924 ±690. For both the maximum load and number of cycles, the DD outperformed the IS (P< 0.05) and the GJ and PL performed comparably (P> 0.05).

Single-strand reconstructions using the double dock method outperform the interference screw technique. For its simplicity and strength, the DD technique should be considered, clinically. The initial Graft Jacket strength makes it a potential alternative to palmaris longus tendons; laboratory evaluation of graft strength during healing is required.

Funding: This study was partially funded by Wright Medical Technology (Arlington, TN) and the Canadian Institute for Health Research.

Please contact author for graphs and/or diagrams.


J.A. Beye R.C. Bray R.A. Seeratan C. Leonard D.A. Hart P.T. Salo

Our aim was to determine the effect of denervation on repair-associated mRNA levels in the MCL after partial tear.

Cohorts of rabbits underwent partial MCL tear with or without concomitant femoral nerve transection. Ligaments were harvested, RNA extracted and RT-PCR was performed using rabbit-specific primers for repair-associated molecules at three days, two wks, six wks and sixteen wks post-injury.

Angiogenesis genes MMP3, MMP13, matrix components Collagen I and III and growth factors TGF-ß and NGF mRNA levels were increased in the denervated group at two-weeks post-injury (p< 0.05).

Denervation significantly alters mRNA levels during the early stages of rabbit MCL healing.

To determine the effect of denervation on repair-associated mRNA levels in the injured medial collateral ligament (MCL). Previous experiments revealed that denervation impairs healing of the MCL. We hypothesized that denervation would decrease repair-associated mRNA levels in the injured MCL when compared with normally innervated injured MCL.

Adult, skeletally mature female rabbits were assigned to one of four groups: unoperated control, femoral nerve transection alone (denervated controls), MCL partial tear and denervated MCL partial tear. At three days, two weeks, six weeks or sixteen weeks post-surgery, cohorts of six rabbits from each experimental group were killed. Control rabbits were assessed at two weeks. Ligaments were harvested, RNA extracted and RT-PCR was performed using rabbit-specific primers.

In the denervated injury group, mRNA levels of angiogenesis genes MMP-3 and MMP-13, matrix components Collagen I and III and growth factors TGF-ß and NGF had all increased at two-weeks post-injury, in comparison to non-denervated (p< 0.05). We also found increased levels of MMP-3 and NGF mRNA in the denervated group at sixteen weeks post injury (p< 0.05). The mRNA levels of the housekeeping gene GAPDH were increased in the denervated group only at three days post injury (p< 0.05). Of note, TGF-ß mRNA levels were significantly decreased in the denervated group at three days post injury (p< 0.05).

Contrary to our initial hypothesis, denervation increases mRNA levels for many important molecules during the early stages of MCL healing. Additional research will be required to explain how and why denervation impairs ligament healing.

No previous study has shown that innervation regulates mRNA levels in healing ligament.


I.D. Dickey R.R. Hugate J.S. Reach M.E. Zobitz R. Zhang M. G

Trabecular materials show great promise for soft-tissue attachment to prosthetic implants. Results with Tantalum have been very encouraging, however, it remains unclear if this in-growth is secondary to the specific metal or its generic structure,. If structure, is there a specific tolerance with respect to porosity and pore size? In a canine model, bulk blocks of porous alumina ceramic were shown to be completely ingrown by four weeks. The type material was not a factor, and effect of pore size revealed that there is a wide tolerance in facilitating in-growth with the larger pores having the greatest attachment strength (p=0.004).

This study examines the in-vivo soft tissue in-growth potential of porous alumina ceramic and the effect of three distinct pore size ranges on this process.

Alumina ceramic implants of fixed porosity (~ 85%) were designed in three pore size ranges (100–200, 250–400 and 600–800 μM). Using an established canine model, six implants (two of each type) were implanted in the dorsal subcutaneous tissues of tweleve mature canines and examined histologically and mechanically at four, eight and sixteen weeks with respect to type, amount and strength of soft tissue in-growth.

Soft tissue in-growth was grossly evident in all implants at each time interval, and in each pore size. Microscopic examination revealed neo-vascularized in-growth throughout the implant, without evidence of inflammation or foreign body reaction. Numerous blood vessels were visible at the implant interface and within the porous alumina ceramic structure. With peel testing, the weakest attachment strength was with the small pore size with no differences between the medium and large pore sizes. An increase of attachment strength in each pore size was observed over time.

This study suggests that architecture of porous structures in general, and not the type of material used, confers the biologic activity and that there is a wide tolerance for pore size in facilitating this process in soft tissue in-growth. Further study of other inert foam structures will be useful in further defining the assets and limitations of this genre of trabecular materials as a whole.

Funding: Stryker Orthopaedics, Mahwah, NJ

Please contact author for figures, graphs, and/or diagrams.


I.D. Dickey J.S. Reach R. Talac M.E. Zobitz J.E. Adams S.P. Scully D.G. Lewallen

Reliable soft tissue attachment to prosthetic implants remains a great clinical challenge in adult reconstruction and oncology. Past efforts using tendon alone have been universally disappointing. With the introduction of trabecular metals, new possibilities present them selves in dealing with this problem. Using an established canine supraspinatus tendon model, reliable and physiologic soft tissue attachment to a trabecular metal prosthesis was achieved, with near normal strength and function. This suggests that this new genre of material can possibly provide better options in dealing with this difficult problem.

Direct attachment of tendon to an endoprothesis has applications throughout the field of orthopaedics. The purpose of this study was to devise a soft-tissue attachment device using tantalum foam metal which would allow for early soft tissue reconstruction strength and long term biologic in-growth fixation.

A foam metal tendon attachment prosthesis was designed. Using a validated tendon attachment model, twenty-three skeletally-mature canine supraspinatus tendons were sharply detached and then reattached to the greater tuberosity. Ultimate strength, stiffness and gross morphological changes were recorded immediately after surgery and at three and six weeks.

Tendon-implant strength as percent of normal rose from thirty-nine percent at surgery, to sixty-seven percent at three weeks, and ninety-nine percent at six weeks (standard deviations thirteen, nineteen, and eighteen percent). Stiffness of construct also approached normal tendon: forty-seven percent at surgery, sixty-two percent at three weeks, and ninety-four percent at six weeks (standard deviations seventy-seven, nineteen, and eighteen percent). Supraspinatus muscle volume decreased from ninety seven (percent of normal) at surgery, to seventy-nine percent at three weeks. By six weeks, the muscle had recovered to ninety percent of normal volume. Gross and histologic analysis revealed complete tendon in-growth and attachment to the prosthesis with the formation of Sharpey’s fibers

This study suggests that tendon attachment to a metallic endoprothesis is possible. Near normal physiologic strength and stiffness was achieved six weeks post surgery. Future study should ascertain the micro-anatomy of this attachment and delineate the mechanical conditions necessary for soft tissue in-growth.

Funding: Zimmer, Inc., Warsaw, IN

Please contact author for pictures, graphs and diagrams.


B. LaRue É. Anctil

Anatomical variations in the attachment between the tendon of the flexor hallucis longus (FHL) and of the flexor digitorum longus (FDL) are not clearly detailled in the medical literature. Twenty-four cadaver specimens were dissected and the distal anatomical relationship between the FHL and the FDL were analyzed and measured. There are three configurations of the attachment between the tendon of the FHL and of the FDL. The absence of a tendon link seems to be more common than has been published to date in the medical literature. We have also shown that the same patient may have a different configuration on each foot.

Anatomical variations in the links between the tendon of the flexor hallucis longus (FHL) and of the flexor digitorum longus (FDL) are not clearly detailled in the medical literature.

There are three configurations of links between the tendon of the FHL and of the FDL. The absence of a tendon link seems to be more common than has been published to date in the medical literature.

A surgeon who wants to preserve the distal function of the FDL after transferring the proximal portion of the latter should perform surgical tenodesis initially or explore the FHL-FDL attachment and perform tenodesis when a type-3 configuration is discovered.

We distinguish three different configurations of the distal link between the FHL and the FDL. In type 1, a tendinous band from the FHL is attached to the FDL (42%, 10/24). In type 2, a tendinous band from the FHL is attached to the FDL and another one from the FDL is attached to the FHL (42%, 10/24). In type 3, there is no attachment (17%, 4/24). In no case is there only an attachment from the FDL to the FHL. In four cadavers a different configuration was present on each foot. The diameter of the attachment compared with the “donor” tendon varied between 37 and 53%.

Twenty-four intact cadaver specimens were dissected and the distal anatomical relationship between the FHL and the FDL were analyzed. The width of the tendons and their attachments were measured to the nearest half-millimetre.


T. Haque R. Hamdy M. Kotsiopriftis D. Lauzier S. Nakada

Bone Morphogenetic Protein 7 (BMP7) is a powerful osteoinductive substance that could stimulate bone formation in difficult conditions including distraction osteogenesis. However, to be effective, large unphysiological doses are required. Blocking the expression of BMP antagonists could amplify the effects of BMP7, allowing smaller doses of BMP7 to be used without altering its osteogenic potential. In this study, BMP7 antagonist Noggin was shown to be upregulated following BMP7 injection in a rabbit distraction osteogenesis model suggesting a role for Noggin in controlling BMP7 activity. Blocking Noggin expression may thus permit smaller doses of BMP7 to be used effectively.

Distraction osteogenesis (DO) is an excellent method to form new bone. However, the long duration the external fixator has to be kept on until the new bone consolidates, could lead to numerous problems. BMP7 may accelerate bone formation in DO. However, large doses of BMP7 may be necessary. In this study, we investigated the expression of BMP7 antagonist Noggin in DO.

Noggin may control BMP7 activity through a negative feedback mechanism. Blocking Noggin may amplify the effects of BMP7, thus permitting the use of smaller doses of BMP7 effectively in DO.

Using smaller doses of BMP7 – while maintaining its powerful effects – may decrease side effects and render this drug more affordable economically.

Noggin is normally expressed in DO. Its expression is upregulated by local application of BMP7. Its expression is co-localized to the same cells that express BMP7 and its receptors.

The right tibia of sixteen rabbits was lengthened using a uniplanar fixator. The rabbits were divided into two groups: one received seventy-five micrograms recombinant BMP7 and the other placebo. All injections were performed one week after start of distraction. Rabbits were sacrificed ten minutes, one day, two days and two weeks following the injections. The expression of Noggin was studied in the distracted tissue by immunohistochemistry.

Noggin may play a role in DO. Blocking its action may have huge clinical implications, by permitting the use of smaller – but equally effective – amounts of BMP7.

Funding: CIHR, FRSQ and Shriners of North America


K.A. Hildebrand M. Zhang

Ligaments, menisci and joint capsules were obtained from experimental knees with post-traumatic joint contractures and their unoperated contralateral controls in 6 rabbits. Relative mRNA expression was altered for six of seven matrix molecules, growth factors and _-SMA (myofibroblast marker) in the joint capsule, four of seven molecules in the ACL, and two of seven molecules in the MCL and medial meniscus. The joint capsule had the most molecules with altered expression corresponding to it’s acknowledged key role in joint contracture development. Changes in molecular expression of several joint structures in post-traumatic contractures is similar to changes seen following ligament injury.

To evaluate alteration of mRNA expression in ligaments, meniscus and joint capsules in post-traumatic contractures. mRNA expression was altered most frequently in the joint capsule.

The mRNA expression alterations in the joint capsule reflect it’s significant contribution to contractures.

The right knee had a stable intraarticular fracture coupled with Kirschner wire immobilization while the left knee was not surgically manipulated. The rabbits (n=6) were sacrificed two weeks later, and the ACL, MCL, posterior joint capsule and medial meniscus were obtained from both knees. Semiquantitative RT-PCR was used to evaluate relative mRNA expression of selected matrix molecules, growth factors and _-smooth muscle actin (_-SMA), a myofibroblast marker. Glyc-eraldehyde-3-phosphate dehydrogenase, a housekeeping gene, served as a normalization. Optical density measures of the gels were used for analysis. Statistical comparisons were made with a paired t-test. Statistical significance was p< 0.05.

Relative mRNA expression was altered for six of seven molecules in the joint capsule, four of seven molecules in the ACL, and two of seven molecules for the MCL and meniscus. For the joint capsule, relative mRNA expression in the contracture capsule was 2-4x greater than the expression in the control capsules, except for TIMP one where the expression in the contracture capsule was 1/3 of the control capsules. As has been noted with other joint injuries (ligament instability), several structures in the joint display altered molecular expression as was found in this model of joint injury, post-traumatic joint contractures.

Please contact author for tables and/or graphs.


D.L. Burnes M. Hardisty S. Roth P. Basran M. Christakis J. Rubenstein E. Chow C. Whyne

Using serial CT scans, this project aims to develop a clinical research tool that analyzes changes in vertebral density in spines involved with metastatic disease. Tracking of total vertebral body and tumor volume alone was investigated. A program was developed to semi-automate the segmentation of the region of interest followed by image registration to superimpose the segmentation onto spatially aligned serial scans. Based on analysis of a simulated metastatic vertebra, generating a voxel distribution histogram from the vertebral body best quantified density in serial scans. This quantification method may improve clinical decision-making and treatment options for patients with vertebral metastases.

To develop a clinical research tool to serially track tumor involvement in vertebrae with metastatic disease by quantifying changes in CT attenuation.

Segmentation of the vertebral body and analysis of the voxel distribution within the region provides the most accurate method of quantifying changes in tumor involvement for the metastatic spine.

A quantitative method to assess the progression or regression of disease may improve clinical decision–making and treatment options for patients with spinal metastases.

The vertebral body segmentation was more accurate at tracking tumor involvement (voxel distribution histogram: 96.8% +/− 0.75% accuracy, mean density error: 4.7% +/− 0.8%) than segmenting the tumor volume alone (voxel distribution histogram: 86.1% +/− 3.6% accuracy, mean density error: 14.1% +/− 4.8%).

A program was developed to semi-automatically segment the total vertebral body and tumor volume alone from CT scans of metastatically involved vertebrae. Image registration through user-defined landmarks and surface matching was used to spatially align serial scans, and the initial segmentation was superimposed with the aligned scans. Changes within the segmentation between CT scans were tracked using mean density and a voxel distribution histogram. A cadaveric vertebra with a simulated tumor was scanned at five orientations with 20° offsets to determine the accuracy of the methods. Error primarily resulted from unavoidable re-sampling during alignment of the scans.


E. P. Abraham D.I. Alexander S. Bailey

Preliminary results suggest that a new rhBMP-2 formulation may provide an alternative for autologous bone graft in two-level posterolateral fusions

The purpose of this study was to compare the success of instrumented two level fusions using a new rhBMP-2 formulation versus iliac crest bone graft (ICBG). In this formulation, rhBMP-2 was at a concentration of 2mg/cc in a Biphasic Calcium Phosphate (60% hydroxyapatite/40% tricalcium phosphate) ceramic granule carrier. Twenty-nine patients were enrolled in this multicentered, prospective, randomized study. Either 30cc of rhBMP-2/BCP or fresh ICBG were used. Clinical evaluations were done preoperatively, at discharge and 1.5, three, six, twelve and twenty-four months including Oswestry Disability Index SF36, back pain and leg pain questionnaires. CT scan and xrays were independently assessed at six, twelve, and twenty-four months. Fusion criteria included bilateral bridging trabecular bone on each level, less than 3mm translation, less than five degrees angulation . Seventeen patients received ICBG and twelve received rhBMP-2/BCP. With the use of rhBMP-2 average OR time was reduced from 3.8 to 2.9 hours. Twenty-nine patients (100%) have reached twenty-four month followup. Clinical improvements were similar in both groups, however, fusion success was much improved with the use of rhBMP-2. At twenty-four months all patients receiving rhBMP-2/BCP were fused versus 58% of ICBG patients. These results suggest that rhBMP-2/BCP may have improved fusion success in challenging two level posterolateral fusions as compared to ICBG.


M. Hardisty S. Bisland O. Ramadan S. Burch S. Roth A.J.M. Yee C. Whyne

Photodynamic therapy (PDT) is a promising new treatment for spinal metastases; however, the effects of PDT on bone are largely unknown. This study assessed the impact of PDT on spinal stability in rats at high (non-therapeutic) drug and LASER light doses. Spinal stability was assessed using stereological measures attained from in vitro μCT scans. High doses of PDT were shown to cause a reduction in vertebral density. Postoperative paralysis was also noted in a subset of animals treated. Tumour-involved vertebrae are already mechanically weakened; as such it is essential to establish a safe and efficacious therapeutic window for vertebral PDT.

This study assessed the effect of high doses of photodynamic therapy (PDT) on biomechanical stability and bone density of lumbar vertebrae.

PDT can cause damage to the vertebral bone and induce paralysis when treatment is applied at very high doses in the rat spine.

PDT is a promising new treatment for spinal metastases however, it is important to understand its effect on vertebral bone in order to closely define the therapeutic window for safety and efficacy.

Trabecular bone density decreased from L1–L3 in normal, untreated rats. The L2 vertebra when treated with high dose PDT was shown to have decreased bone density as compared to both L1 and L3. As expected, tumour-bearing rats had lower vertebral densities than normals.

Rnu/Rnu rats were separated into normal controls, normals treated with PDT and tumour-bearing rats. Rats treated with PDT received an intercardiac injection of 2.5mg/Kg BPD-MA. The drug was activated through administration of 500J (300mA) of a non-thermal 690nm LASER adjacent to the L2 vertebral body. After one week, in vitro μCT scans were taken of L1–L3 and stereological quantities measured.

The demonstrated reduction of bone density as quantified one week following treatment is important when considering spinal stability in the potential use of PDT to treat vertebral metastases. We have observed that the therapy can induce paralysis when treatment is applied at high doses in the rat spine. The intermediate and long-term effects of PDT on bone remain unknown and require ongoing study.


C. Larson A.S. Younger M.A. Awwad G. Devries J.P. Veri S.G Sjovold T. Oxland

Testing of cadaver ankle specimens was conducted to investigate the changes in kinematics with lateral ligament reconstructions. Testing included an intact condition, after injury at the ATFL and CFL sites, and separately a Brostrom repair and an anatomical gracil-lis graft reconstruction. Calcaneal range of motion was determined about the axis of applied moment in plantarflexion-dorsiflexion and in inversion-eversion directions. The injury and reconstructions were most sensitive during IE applied moment. Both reconstructions appeared to behave similar to intact motion. Failure of some Brostrom repairs however, suggest that the gracillis-graft reconstruction is initially a stronger repair.

Limited research has biomechanically investigated lateral ankle ligament reconstruction procedures. The objective of this study was to determine the changes in ankle kinematics with a dual ligament Brostrom repair and an anatomical gracillis graft reconstruction.

Seven cadaveric ankle specimens were tested independently in an intact condition, after an ATFL/CFL injury model, and two reconstructions. The anatomical graft reconstruction wove a gracillis tendon through the calcaneus and fibula to dually reconstruct the ATFL and CFL, and anchored to the talus. Moments were applied to the calcaneus for three cycles in plantarflexion-dorsiflexion (PD) and inversion-eversion (IE) while allowing unconstrained motion. Three dimensional motions of the calcaneus and tibia were optoelectronically tracked. Range of motion (ROM) was calculated about the axis of applied moment for the calcaneus with respect to the tibia.

The ROM increase from the intact condition with the injury model was only significant for IE (p=0.001). No significant differences were found between intact and any treatments in the PD configuration. In IE, both the graft reconstruction and the Brostrom repair were significantly different from the injury model (p=0.002 and p=0.015 respectively), where the gracillis reconstruction appears more similar to the intact condition. For two specimens the Brostrom repaired ATFL failed during applied inversion moment.

The injury and reconstructions were most sensitive during IE applied moment. Both reconstructions appeared to behave similar to the intact condition. Failure of some Brostrom repairs however, suggest that the gracillis-graft reconstruction is initially a stronger repair.

Funding: Workers Compensation Board of British Columbia


Hongfa Wu P. Poncet J. Harder F. Cheriet H. Labelle R.F. Zernicke J.L. Ronsky

The pathogenesis of scoliosis progression remains poorly understood. Seventy-two subject data sets, consisting of four successive values of Cobb-angle and lateral deviations at apices for six and twelve-months intervals in the coronal plane, were used to train and test an artificial neural network (ANN) to predict spinal deformity progression. The accuracies of the trained ANN (3-4-1) for training and testing data were within 3.64° (±2.58°) and 4.40° (±1.86°) of Cobb angles, and within 3.59 (±3.96) mm and 3.98 (±3.41) mm of lateral deviations, respectively. The adapted technique for predicting the scoliosis deformity progression has promising clinical applications.

Scoliosis is a common and poorly understood three-dimensional spinal deformity. The study purpose is to predict scoliosis progression at six and twelve months intervals in the future using successive spinal indices with an artificial neural network (ANN).

The adapted ANN technique enables earlier detection of scoliosis progression with high accuracy. Improved prediction of scoliosis progression will impact bracing or surgical treatment decisions, and may decrease hazardous X-ray exposure.

Seventy-two data sets from adolescent idiopathic scoliosis subjects recruited at the Alberta Children’s Hospital were used in this study. Data sets composed of four successive values of Cobb angles and lateral deviations at apices for six and twelvemonth intervals (coronal plane) were extracted to train and test a specific ANN for predicting scoliosis progression.

Progression patterns in Cobb angles (n = 10) and lateral deviations (n = 8) were successfully identified. The accuracies of the trained ANN (3-4-1) with the training and testing data sets were 3.64° (±2.58°) and 4.40° (±1.86°) of Cobb angles, 3.59 (±3.96) mm and 3.98 (±3.41) mm of lateral deviations, respectively. These results are in close agreement with those using cubic spline extrapolation techniques (3.49° ± 1.85° and 3.31 ± 4.22 mm) and adaptive neuro-fuzzy inference system (3.92° ±3.53° and 3.37 ±3.95 mm) for the same testing data.

ANN can be a promising technique for prediction of scoliosis progression with substantial improvements in accuracy over current techniques, leading to potentially important implications for scoliosis monitoring and treatment decisions.

Funding: AHFMR, CIHR, Fraternal Order of Eagles, NSERC, GEOIDE.


C. Bergeron F. Cheriet J.M.M. Thiong H. Labelle

This research sought a mathematical model to relate the postero-anterior (PA) and lateral (LAT) views of the spinal curve in scoliosis in an attempt to justify the acquisition of only One X-ray, thereby reducing patient exposure to harmful X-radiation while preserving complete 3D characterization of the spine. Using powerful developments in functional statistics and machine learning, no such relation could be found. Thus, this research sustained the clinical decision to acquire two biplanar X-rays and supported current research in 3D spinal curvature analysis.

Scoliosis is monitored through full spinal X-rays, and this serial protocol causes an increased incidence of cancer development. This research sustains the clinical decision at Hôpital Sainte-Justine in Montréal and elsewhere to acquire postero-anterior (PA) and lateral (LAT) X-rays, despite the increased exposure to X-radiation. Indeed, geometrically, these two views are required to reconstruct the spine in 3D. However, under the assumption of strong physiological patterns between the PA and LAT views of the spinal curve, one of these X-rays may be redundant for some or all patients. The purpose of this study was to seek this a priori assumption.

To this end, a database consisting of three hundred and sixty-nine spinal reconstructions from distinct patients was used. Two powerful geometric modeling approaches were exploited: functional data analysis and minimum noise fractions. These resulted in five comprehensive, uncorrelated and noise-insensitive features in each plane. Simple linear regression yielded no relation that was statistically significant (p< 0.05) and genereralizable to a set of previously unseen samples. Therefore, nonlinear relational modeling was attempted using support vector regression, a recent advance in machine learning theory. This tool was incapable of identifying a robust regression, suggesting that the PA and LAT views are mathematically independent. Thus, this study highlights the necessity of two biplanar X-rays to evaluate scoliotic deformities and fully characterize spinal shape. Further, this study supports the practical insufficiency observed by clinical staff with respect to current 2D scoliosis classifications that has resulted in current efforts to propose 3D classification schemes.


A.M. Choo J. Liu M. Dvorak W. Tetzlaff T.R. Oxland

Spinal cord damage was compared after an injury was inflicted by three clinically relevant mechanisms (contusion, dislocation, and distraction). A novel SCI multi-mechanism system has been developed. Central hemorrhage was common to all mechanisms. Increased membrane permeability was localized to the injury epicenter in contusion but spread further in distraction. Dislocation showed intermediate characteristics exhibiting both local neuronal losses at the epicenter and extended regions of membrane permeability. These preliminary observations suggest that distinct injury mechanisms result in differences in the primary damage of the spinal cord.

This work compared primary damage after spinal cord injury (SCI) inflicted by three clinically relevant mechanisms.

Different injury mechanisms result in regional differences in damage to the spinal cord.

Differences in acute damage may help guide targeted therapies following SCI.

At greater distances from the lesion, dextran was excluded from neuronal somata and in the white matter only distinct accumulation was seen at the Nodes of Ranvier. At the injury site, hemorrhage was common to all mechanisms although more diffuse in the distraction injuries. Increased membrane permeability was localized to the injury epicenter in contusion but spread further in distraction. Dislocation showed intermediate characteristics exhibiting both local neuronal losses at the epicenter and extended regions of permeability.

A novel SCI multi-mechanism system was developed which uses an electromagnetic actuator to permit the modeling of injuries along any direction. Dextran was infused into the cisterna magna 1.5 to 2 hours prior to injury in order to visualize increases in membrane permeability. Stereotaxic clamps were designed to rigidly hold the lower cervical vertebrae of deeply anaesthetized rats permitting displacements at speeds of 100cm/s. A range of displacements was used in this pilot series: 0.9 to 1.1mm contusion, 2 to 6mm dislocation and 3 to 8mm axial distraction. Animals were sacrificed at five minutes in order to analyse the primary injury. These preliminary observations suggest that distinct injury mechanisms result in regional differences in the primary damage of spinal cord gray and white matter.


J.M. Mac-Thiong H. Labelle É. Berthonnaud R. R Betz

When evaluating and treating patients with spinal disorders, a significant knowledge of the normal spinopelvic balance is of primary importance. This study documents the spinopelvic balance in normal children and adolescents, and describes a scheme of correlations between morphological, shape and orientation parameters of the spine and pelvis. It is found that the pelvic incidence regulates the sacral slope and pelvic tilt. In addition, shape and orientation parameters of adjacent anatomical regions are interdependent, and their relationships result in a stable posture with minimum energy expenditure.

Evaluate the correlations between spinopelvic parameters in normal children and adolescents.

Seven parameters were evaluated from the lateral standing radiographs of two hundred and eighty-two normal subjects aged three to eighteen years old: thoracic kyphosis (TK), thoracic tilt (TT), lumbar lordosis (LL), lumbar tilt (LT), sacral slope (SS), pelvic tilt (PT) and pelvic incidence (PI). Statistical analysis was performed using Pearson’s coefficients.

The mean PI (morphological parameter) was 49.0±11.3°. The mean values for shape parameters were 41.4±8.5°, 48.0±12.0° and 44.3±11.2° for SS, LL and TK, respectively. The mean values for orientation parameters were 7.5±8.1°, −7.0±5.1° and −2.6±5.0° for PT, LT and TT, respectively. There was no significant difference between males and females. PI was significantly related to SS and PT. Significant correlations were found between orientation and shape parameters of adjacent anatomical regions.

This study describes a scheme of correlations between morphological, shape and orientation parameters of the spine and pelvis. It is found that the pelvic incidence regulates the sacral slope and pelvic tilt. In addition, shape and orientation parameters of adjacent anatomical regions are interdependent, and their relationships result in a stable posture with minimum energy expenditure.

This study presents a postural model in order to better understand the spinopelvic balance in normal children and adolescents. This model could help to evaluate the influence of pelvic morphology on the progression and treatment of pediatric spinal deformities.

This research was funded by an educational/research grant from Medtronic Sofamor Danek, by the Canadian Institute of Health Research, by the Fonds de Recherche en Santé du Québec and by the Fondation de recherche et d’éducation en orthopédie de Montréal (FREOM).


P. Poncet J. Jaremko J. Harder R.F. Zernicke J.L. Ronsky

Spine and torso models were generated concurrently with x-rays for twenty-three patients undergoing scoliosis brace treatment. Clinical indices of spinal deformity and torso surface asymmetry indices were computed from models obtained when patient was first recruited and at approximately one year’s follow-up. Significant correction changes of the torso shape were detected in indices including orientation of cross-sectional principal axes of inertia (p=0.048) and Back Surface Rotation (p=0.08) though spinal corrections were from not significant to subtle (0.20_p_0.88). Trunk asymmetry should be assessed for an objective evaluation and understanding of the effect produced by a specific treatment.

To assess changes in torso geometry and spinal deformity during treatment of idiopathic scoliosis with rigid brace.

Relationship between torso surface geometry and spinal deformity when a rigid brace is applied is essential for better understanding of brace treatment mechanism and optimal application of external forces.

Three-dimensional torso surface models were generated concurrently with postero-anterior x-rays for twenty-three patients undergoing scoliosis brace treatment, when first recruited and at approximately one year’s follow-up. Torso asymmetry indices describing principal axis orientation, back surface rotation, and asymmetry of the centroid line, left and right half-areas and the spinous process line were computed. The statistical paired t-Test (95% CI) was performed to test the probability that no difference exist after one year of treatment in both spinal and torso asymmetry indices.

After one year follow-up patients showed a mean increase of only 2° for the major Cobb angle. This was consistent with not significant to subtle corrections found in clinical (p=0.88) and computed (p=0.75) Cobb angle, lateral deviation (p=0.20), orientation of plane of maximum deformity (p= 0.58) and maximum vertebral axial rotation (p=0.83). Furthermore, significant correction changes of the torso shape were detected in the orientation of cross-sectional principal axes (PAX) of inertia (p=0.048) and Back Surface Rotation (p=0.08).

Here we have shown that we can acquire 3D torso surface and reliably measured a set of indices of transverse torso asymmetry. Future work will look at indication of predictive potential of torso surface indices.

Funding: AHFMR, CIHR, Fraternal Order of Eagles, NSERC, GEOIDE.


M. A. Hunt T. B. Birmingham T R. Jenkyn I C. Jones P J. Fowler J. Robert Giffin

Measures of lower limb alignment and knee joint load during walking were evaluated before and six months after medial opening wedge high tibial osteotomy (HTO) in ninety-five patients with knee medial compartment osteoarthritis (OA). Full-length standing radiographs were used to calculate the mechanical axis angle, and a gait analysis was performed to calculate the external adduction moment about the knee. Results indicated significant decreases in mechanical axis angle and peak adduction moment. These findings provide an indication of the early success of HTO in reducing the extent of lower limb malalignment and knee joint load during walking.

Medial opening wedge high tibial osteotomy (HTO) is intended to correct lower limb malalignment, resulting in decreased medial knee joint load and improved function. Due to the potential for the amount of alignment correction to change over time after surgery, frequent follow-up evaluations are encouraged.

To evaluate the early changes in lower limb alignment and medial knee joint load experienced during walking after medial opening wedge HTO.

Ninety-five patients (seventy-nine males, sixteen females; age range = 21–76 years; BMI range = 18.0–38.5) with knee joint OA affecting primarily the medial compartment underwent radiographic and gait analyses pre-surgically and six months following HTO. Full-length standing radiographs were obtained on both occasions and used to measure the static mechanical axis angle. Three-dimensional kinetic and kinematic data were also collected and combined to calculate the external knee joint adduction moment, an indirect measure of knee joint load. Paired t-tests indicated the mechanical axis angle (mean decrease = 8.32 degrees, 95% CI = 7.54,9.10) and peak external knee joint adduction moment (mean decrease = 1.61%BW*ht, 95% CI = 1.25,1.95) significantly decreased post-operatively (p< 0.001). These results indicate less varus angulation and reduced medial knee joint load following HTO.

These preliminary findings suggest that medial opening wedge HTO is an effective surgical treatment for improving alignment and reducing knee joint load.

Although these early results are promising, future research is required to determine the long-term success of this surgery in the treatment of knee OA.

Funding:

CIHR, NSERC, Arthrex Inc.


S.M. Guerra L.M. Ferreira G.J.W. King J.A. Johnson

This study investigated the effect of the articulation position on joint load transfer in total elbow arthroplasty. To quantify loading, an adjustable humeral component, instrumented with a load cell, was developed to measure ulnohumeral loads in-vitro. Computer guidance was implemented to accurately place the linked articulation into eight cadaveric elbows. Axial compression and bending about the flexion axis produced the greatest loads during simulated active elbow flexion. An anteriorly malpositioned flexion-extension axis resulted in increased joint loads during flexion. Translational positional errors were more influential than rotational position on articular loading.

To quantify the relationship between total elbow arthroplasty position and elbow joint loading.

Eight cadaveric upper extremities were tested using a motion-controlled testing device, which simulated muscle activity. Computer guidance was employed to accurately position a linked implant consisting of a custom-designed adjustable humeral component and commercial ulnar component. The testing apparatus was instrumented with a six-degree-of-freedom load cell to measure axial and bending loads. Seven implant positions were tested including anterior-posterior translation (−5.0, −2.5, 0.0, 2.5, 5.0 mm) and internal-external rotation (−5, 0, 5°) during supinated and pronated flexion.

The resultant joint force decreased for all prosthetic hinge positions as elbow flexion increased (p< 0.001). Anterior hinge positions produced greater ulnohumeral loads (p< 0.001) and moments (p< 0.001) than posterior hinge positions during simulated elbow flexion. The greatest bending moment occurred about the flexion axis which reached maximum magnitudes during mid-flexion. Implant hinge malrotation did not have a significant effect on axial (p=0.07) or bending (p=0.6) forces experienced at the joint. The distance between the flexion (hinge) axis and the muscular line-of-action of flexors is reduced with anterior hinge placement, likely increasing the force necessary to produce flexion.

An anteriorly malpositioned flexion-extension axis resulted in an increase in joint loading during flexion and should be avoided during elbow arthroplasty.

This is the first reported study to measure the effect of elbow prosthesis positioning on joint loading. The knowledge gained about joint loads should improve future prosthetic designs and treatment options.

Funding: Canadian Institute for Health Research.

Please contact author for graphs and/or diagrams.


C. Graham W. Dust

This study assesses a method of optimizing the polyethylene-cement interface when cementing a constrained liner into a pre-existing acetabular shell. We tested several configurations of liner modification including random roughening, 2mm and 4mm wide grooves Statistical analysis showed that the grooved liners had significantly higher moment to failure than both the unmodified and roughened liners. There was no difference between the 2 and 4mm grooved liners.

The purpose of this study was to answer the question: what liner preparation will provide the most stable polyethylene – cement interface?

Two and 4mm circumferential grooves and meticulous cementing technique can significantly increase the strength of the polyethylene-cement interface.

All samples failed at the polyethylene – cement interface. Statistically significant differences were found between the following groups: unmodified vs. 2mm (p=0.005) and 4mm groove (p=0.012) and roughened vs. 4mm groove (p=0.011).

Modification of a constrained liner with circumferential grooves may improve the stability of the cement interface enough to make this a more reliable technique in revision hip surgery.

Polyethylene was machined into 50mm diameter liners. These were cemented using PMMA into aluminum acetabular shells ensuring a 3mm cement mantle. Lever-out testing was performed on four groups; no modification, random roughening, 2mm and 4mm grooves.

When an acetabular component is well fixed/positioned, the option of cementing a constrained liner into the fixed shell is an option. Experience has shown that the most common mode of failure in this technique is the polyethylene-cement interface.

Funding: This study was funded by the Division of Orthopedics, Department of Surgery, and the Department of Mechanical Engineering, University of Saskatchewan.


C. A Busch R.B Bourne S.J MacDonald R.W McCalden J. Martell C.H Rorabeck

Despite favourable wear characteristics of compression molded HMWPE in vitro preliminary data show no statistical difference in wear between RAM extruded HMWPE and compression moulded polyethylene. This study reviews AP and lateral radiographs for wear using the Martell technique at two, five years and maximum follow up (mean 88.2 months).

Reduced implant survivorship due to aseptic loosening has prompted research into alternative bearing materials. Simulator testing is useful but clinical studies are the gold standard to evaluate the wear characteristics of new bearing materials.

On hundred and twelve patients matched for sex, age, body mass index, primary pathology, Charnley grade, and follow up underwent uncemented total hip replacement using an identical implant. Group One (sixty-four patients) had a RAM extruded liner (GUR 4150 HP) and Group Two (forty-eight patients) had a compression molded liner (Montell H 1900). HMWPE sterilisation regimes were identical. AP and lateral radiographs were analysed for wear using the Martell technique at two, five years and maximum follow up (mean 88.2 months).

Preliminary data show a linear and volumetric wear rate in Group One of 0.067 mm/yr and 26 mm3/year respectively between two years to maximum follow up. Similarly, the wear rates for Group Two were 0.132 mm/yr and 45 mm3/year respectively. There was no statistical difference in acetabular osteolysis between Group One (16.3%) and Group Two (15%) patients at maximum follow up.

Despite favourable wear characteristics of compression molded HMWPE in vitro preliminary data show no statistical difference in wear between RAM extruded HMWPE and compression moulded polyethylene. Quality of the wear debris is more likely to be important in producing aseptic loosening than actual wear rate.


A. Younger M. Manzary C. Meakin G. DeVries J. A. McEwen K. Inkpen

Patients were randomized between surgeon chosen pressure (control) and an automatically determined tourniquet pressure(study) group. Of the study group 94/106 (88.7%) had good to excellent fields compared to the control group where 100/132 (75.8%) had good to excellent fields (p< 0.05). In the study group, 5% failed to obtain an automatic pressure. Of the remainder, the average tourniquet pressure was 198 +/− 20.2 mHg compared to 259.6 +/− 4.4 mmHg for the control group (p< 0.0001). The automatic measurement of limb occlusion pressure resulted in better operative fields at a lower pressure.

To compare the quality of the operative field that results from using an automatic limb occlusion pressure measurement (study group) versus the tourniquet cuff pressure chosen by the surgeon (control group).

A module allowing rapid determination of tourniquet pressure from limb occlusion pressure was attached to a Zimmer ATS tourniquet machine. Using a coin toss, patients were randomized to the study or control groups. All patients underwent elective foot and ankle operations using a wide contoured tourniquet cuff.

Of two hundred and forty-three patients, one hundred and twelve were assigned to the study (automatic) group and one hundred and thirty-two to the control (surgeon selected) group. Six patients (5.4%) failed to obtain a limb occlusion pressure measurement due to anatomical constraints (toe or thigh shape) or equipment problems, leaving one hundred and six in the study group. The average measurement time to determine limb occlusion pressure was 20 +/− 6 seconds. The mean tourniquet pressure for the study group was 198.5 +/−20.2 mmHg, and 259.6 +/−4.4 mmHg for the control group (p< 0.0001). Of the study group 94 (88.7%) had good to excellent fields compared to the control group where one hundred (75.8%) had good to excellent fields (p< 0.05).

An automatically determined tourniquet pressure reduced the tourniquet pressure and improved the incidence of good to excellent operative fields compared to surgeon chosen pressures. The distribution curve of automatically determined tourniquet pressure indicates that 16% of patients will have a failed field if a standard pre-selected pressure of 250 mmHg is always chosen, in part explaining why pre-selected pressure may cause a poorer operative field.


J.K. Bow K. Summers B. Singh S.J. MacDonald

T cells have been implicated in the pathogenesis of osteolysis. The goal of this study was to compare the ratios of CD4+ T cell populations in total hip arthroplasty (THA) patients with and without osteolysis. We found no significant differences in the frequency of peripheral blood CD4+CD25+ regulatory and effector T cells, serum IL-10 and TGF-β concentrations, and immuno-suppressive ability of regulatory T cells from patients with osteoarthritis prior to THA, and THA patients with and without radiographic evidence of osteolysis.

CD4+ T cells are critical in regulating immune-mediated conditions. This study compared the frequency of CD4+ T cell subpopulations in the peripheral blood of patients with and without osteolysis following total hip arthroplasty (THA).

Numbers of CD4+CD25hi regulatory T cells, CD4+CD25moderate effector T cells, and CD4+CD25+ T cells in the peripheral blood of thirty patients with osteoarthritis prior to primary THA, thirty patients with asymptomatic THAs and no radiographic evidence of osteolysis, nineteen patients with asymptomatic THAs with radiographic evidence of early osteolysis (not requiring revision surgery) and nine patients scheduled for revision THA for osteolysis were determined by flow cytometry. Serum IL-10 and TGF-β levels were measured using ELISA kits. Results were compared by t-test and rank sum test. CD4+ CD25hi regulatory T cells and CD4+ CD25neg T cells were isolated from blood using a MACS cell isolation kit, co-cultured for three days, and T cell proliferation determined by [3H]-thy-midine uptake.

The frequency of CD4+CD25hi regulatory T cells, CD4+CD25moderate effector T cells, and CD4+CD25+ T cells were similar in each study group. Regulatory T cells from patients with and without osteolysis had a normal functional ability to inhibit CD4+ T cell proliferation. Serum levels of the regulatory T cell-derived cytokines IL-10 and TGF-β were also comparable between groups.

Our data suggests that CD4+ T cell immune responses are normal in THA regardless of the level of osteolysis, in contrast to previous studies that have implicated T cell hypersensitivity in the pathogenesis of osteolysis surrounding THA.


D.D.R. Naudie N. Kitamura S. Leung C. A. Engh

This study evaluates forty-four consecutive autopsy specimens of the senior author’s own patients in attempt to locate and measure periacetabular bone defects and correlate this information with their communication pathways with the joint space.

The purpose of this study was to evaluate autopsy retrieved hemipelves of previously well-functioning total hip arthroplasties (THAs) with computed tomography (CT) to better understand patterns of osteolysis around modular uncemented acetabular components.

Forty-four hemipelves containing titanium porous-coated modular acetabular components were retrieved at autopsy, imaged with CT, and analyzed to determine the location and volume of osteolytic lesions. The mean age of the patients at the time of surgery was seventy years. The mean time in situ for the implants was eight years.

A total of forty-six osteolytic lesions were identified in twenty-eight of the forty-four cases (64%). Thirty-one of forty-six lesions (67%) had one or more apparent communications with the joint space. We identified four types of communication pathways between osteolytic lesions and the joint space: around the rim, through a central dome hole, in association with a screw or screw hole, or around a non-ingrown interface. The mean volume of lesions that had a clear communication pathway was significantly larger than those lesions that did not have a clear communication pathway (p=0.012). Thirteen of the fifteen lesions that did not have a clear communication with the joint space represented bone defects that had existed prior to total hip arthroplasty.

Osteolysis was commonly observed at early time intervals around modular uncemented acetabular components. The communication with the joint space is important for developing osteolysis, as well as in the detection of true osteolytic lesions.


J.R. Davey D. Camazzola T. Hammond

Sixty-two consecutive primary total hip arthroplasties were prospectively randomized to receive either hydroxyapatite coated (thirty-five hips) or nonhydroxy-apatite coated (twenty-seven hips) femoral prostheses. At a minimum eleven-year followup fifty-one hips (forty-four patients) were evaluated. Only one femoral stem had been revised (secondary to traumatic periprosthetic fracture). Radiographs were available for thirty-nine hips. None of these femoral stems were loose. Harris Hip scores were evaluated for thirty-six unrevised hips and did not differ significantly between the two groups. There appears to be no significant advantage to hydroxyapatite coating for this femoral prosthesis at an average follow-up of thirteen years.

There are a paucity of long term randomized controlled trials on results of hydroxapatite coating of femoral prostheses. The purpose of this study was to update the results of a prospective randomized study of a proximally pourous coated, tapered titanium femoral component with and without hydroxyapatite coating.

Sixty-two consecutive primary total hip arthroplasties done by one surgeon in fifty-five patients were prospectively randomized to receive either hydroxyapatite coated (thirty-five hips) or nonhydroxyapatite coated (twenty-seven hips) femoral prostheses. At a minimum eleven year followup, three hips (three patients) were lost to followup, and a further eight patients had expired (eight hips). The remaining surviving cohort of fifty-one hips (forty-four patients) were evaluated clinically, including Harris Hip Scores, and radiographically.

At an average of thirteen years followup, only one femoral stem had been revised (secondary to traumatic periprosthetic fracture), that being in the hydroxyapatite group. There were eight acetabular revisions in the hydroxyapatite group (thirty-four percent) and four acetabular revisions in the nonhydroxyapatite group (sixteen percent). Radiographs were available for thirty-nine hips. None of these femoral stems were loose. Harris Hip scores were evaluated for thirty-six unrevised hips and did not differ significantly between the two groups.

Using endpoints of femoral revision, radiographic loosening, and Harris Hip Scores there appears to be no significant advantage to hydroxyapatite coating for this femoral prosthesis at an average follow-up of thirteen years.

Funding: Biomet, Warsaw IN


S. Takaki C.E. Dunning

The torsional strength of cemented implants is likely influenced by stem geometry. Five straight stems with different cross-sectional shapes (circular, oval, triangular, round-rectangular, sharp-rectangular) were custom-machined. The stems were cemented into tubes using bone cement, and subjected to torsion (2.5deg/min)(n=7). At initial failure (crack through the cement mantle or loss of cement-stem adhesion), the sharp-rectangular stem resisted over 33% more torque than the other four stems (p=0.13). At ultimate failure (5° stem rotation), the resistance provided by the circular stem was less than 12% of either rectangular stem (p< 0.05). Additional studies are needed to determine the effects of long-term loading.

To determine the influence of cross-sectional implant stem shape on cement failure under torsional loading.

The sharp-rectangular stem provided the greatest torsional resistance against initial failure. At ultimate failure, the two rectangular stems performed better than the other stems, with the circular stem providing the least torsional resistance.

A stem design that provides increased resistance to torsion will, in all likelihood, improve the longevity of cemented stemmed implants.

Five straight stems with different cross-sectional shapes (circular, oval, triangular, round-rectangular, sharp-rectangular) were custom-machined. Each stem was cemented in a square aluminum tube using Simplex® cement (Stryker, Michigan, USA). A materials testing machine was used to apply torsion to the stem at 2.5 deg/minute until failure. ‘Initial failure’ was defined as the appearance of a crack through the cement mantle and/or the loss of cement-stem adhesion. ‘Ultimate failure’ was defined as 5° of stem rotation. Results (n=7) were compared using one-way ANOVAs with post-hoc Student-Newman-Keuls tests (p=0.05). The sharp-rectangular stem withstood over 33% more torque at initial failure than the other stems (p=0.13). At ultimate failure, the circular stem provided significantly less torsional resistance than the other four stems (p< 0.05), and was able to resist less than 12% of the torque applied to either rectangular stem. These results suggest shape may play a role in the onset of implant loosening due to torsion. Further studies are required to explore other shapes and to examine the effects of cyclic loading and cement soaking.

Funding: Natural Sciences and Engineering Research Council, University of Western Ontario


T.B. Birmingham M.A Hunt A. Specogna T.R Jenkyn I.C. Jones P.J. Fowler J.R. Giffin

The peak external knee adduction moment during walking gait has been proposed to be a clinically useful measure of dynamic knee joint load in patients with knee osteoarthritis. However, there is limited information about the reliability of this measure, or its ability to detect change. The test-retest reliability and sensitivity to change of peak knee adduction moments were evaluated in thirty patients with varus gonarthrosis. Indices of relative and absolute reliability were excellent (intra-class correlation coefficient = 0.85, standard error of measurement = 0.36 % BW*Ht), and the sensitivity to change following high tibial osteotomy was high (standardized response mean = 1.2).

To estimate the test-retest reliability, measurement error and sensitivity to change of the peak knee adduction moment during gait.

Thirty patients (44”11 yrs, 1.7”0.09 m, 87”20 kg, twenty males, ten females) with varus gonarthrosis underwent gait analyses on two pre-operative test occasions within one week, and on a third test occasion six months after medial opening wedge high tibial osteotomy. Three-dimensional kinematic and kinetic gait data were collected during self-paced walking and used to calculate the peak knee adduction moment.

An intraclass correlation coefficient of 0.85 (95%CI: 0.71, 0.93) indicated excellent relative reliability, and a standard error of measurement of 0.36 %BW*Ht (95%CI: 0.29, 0.49) indicated low measurement error. The peak knee adduction moment after surgery (1.66”0.72 %BW*Ht) was significantly (p< 0.001) lower than before surgery (2.58”0.72 %BW*Ht). A standardized response mean of 1.2 (95%CI: 0.77, 1.6) indicated the size of this change was large.

Based on 95% confidence levels, these results suggest the error in an individual’s peak knee adduction moment at one point in time is 0.70 % BW*Ht, the minimal detectable change in an individual’s peak adduction moment is 1.0 %BW*Ht, and it is sensitive to change following treatment.

The peak knee adduction moment during gait has appropriate reliability for use in studies evaluating the effect of treatments intended to decrease the load on the knee. When considering measurement error, the knee adduction moment is also appropriate for clinical use in evaluating change in individual patients.

Funding: CIHR, Arthrex Inc.


B.J. Morquette Q. Shi P. Lavigne J. Fernandes M. Benderdour

We demonstrated for the first time that HNE, a lipid peroxidation end product, plays a role in osteoarthritic (OA) cartilage degradation. The level of HNE/protein adducts increased in synovial fluids from OA patients and in cellular extracts of OA chondrocytes treated with free radicals donors (H2O2 or SIN). We have found that HNE induces MMP-13 synthesis and activity but in contrast inhibits type II collagen and TIMP-1 synthesis. By immunoprecipitation approach, we demonstrated the formation of HNE/type II collagen adducts in OA cartilage and their increased level in the presence of H2O2 or SIN.

To investigate the role of peroxidation end product, 4-hydroxynonenal (HNE), in osteoarthritic (OA) cartilage degradation.

Total HNE/protein adducts were quantified in synovial fluids or in cellular extracts of chondrocytes using a house Elisa. The formation of HNE/type II collagen adducts was analysed by immunoprecipitation. Type II collagen synthesis was analysed by Western blotting. MMP-13 activity and synthesis as well as TIMP-1 synthesis were measured by commercial kits.

Our data show that the level of HNE/protein adducts markedly increased in OA synovial fluids compared to normal subjects and in cellular extracts of OA chondrocytes treated with free radicals donors (H2O2 or SIN) compared to untreated cells. Using an immunoprecipitation approach, we demonstrated the formation of HNE/type II collagen adducts in OA cartilage and their increased level in the presence of H2O2 or SIN. Furthermore, we find that HNE induces MMP-13 synthesis and activity in a dose-dependent manner, but in contrast, inhibits type II collagen and TIMP-1 synthesis. Interestingly, HNE was proved to exert a dual effect in vitro, activating proMMP-13 at low molar ratio (MR~100:1) and inhibiting active MMP-13 at high molar ratio (MR > 1000:1).

The data generated in this study support the hypothesis that HNE plays a dual role in OA cartilage degradation. At posttranslational level, HNE promotes modification of type II collagen and MMP-13 by adducts formation. At transcriptional level, HNE inhibits type II collagen and TIMP-1 synthesis and induces MMP-13 synthesis and activity.

Support: This work was supported by FRSQ


M. McCaffrey F. Noftall P. Rhaman

The efficacy of intra-articular corticosteroids has led to their frequent use in the treatment of osteoarthritis (OA) of the knee. It is commonly believed that less soluble preparations given at higher doses provide longer lasting and more significant symptomatic relief. We performed a randomized controlled trial with corticosteroid preparations of different solubilities and dosages to test this longstanding but unproven belief. The pain subscale of the WOMAC was our primary outcome measurement. This study found no statistically significant difference between preparations or dosages. Regression analysis identified early onset of osteoarthritis as predictive of a positive treatment response.

To determine if the solubility or dosage of an intra-articular corticosteroid preparation effects treatment outcome when used for the treatment of symptomatic osteoarthritis of the knee.

One hundred and seventeen patients, thirty-nine in each treatment arm, were enrolled in the study. Patients were randomly assigned to one of three treatment arms: 40mg of methylprednisolone acetate, 80mg of methyl-prednisolone acetate or 40mg Triamcinolone acetanide. Patients were unaware of the preparation given. The IA injection was given at the commencement of the study period. Patients underwent clinical evaluation at baseline and at two weeks, four weeks and twelve weeks post injection. Patient’s symptoms were evaluated using the Western Ontario and McMaster Universities OA Index (WOMAC). Patient age, sex, age of onset of OA, history of trauma to the knee and BMI were also recorded and used to identify patient variables predictive of a positive treatment response.

No statistically significant difference between the three treatment arms was identified. Early onset of OA was identified as predictive of a positive treatment response.

It has been taught that physicians should use the least soluble preparation at higher doses (within suggested guidelines) to maximize patient treatment response when using intra-articular corticosteroids. This has always been based on theory and not fact. Our study is the first to scientifically disprove this claim. Solubility and dosage do not effect treatment outcomes. Patients with an early onset of OA seem to have a positive treatment response.

Ours is the first study to demonstrate these findings.


S. Hunter N. Schachar S. Timmermann K. Muldrew

Due to recent advances in diagnostic technology and an increased awareness among clinicians, osteochondral damage is being detected more frequently. Thus, there is a need to preserve and store articular cartilage for the repair of joint surfaces. Chondrocytes, embedded within extracellular matrix must remain viable during storage for successful tissue transplantation. We have been able to store osteochondral tissue for over a month and maintain high chondrocyte viability. Apoptosis can be minimized in articular cartilage during hypothermic storage if biopreservation media (XVIVO-10) is used. Cadaveric osteochondral dowels are a potential source of tissue for banking and allogeneic transplantation.

The purpose of this study was to:

Establish a timeline and optimal conditions for storing human articular cartilage (AC).

Determine a suitable source of AC for banking and transplantation.

Distinguish apoptosis from necrosis in human AC following hypothermic storage.

Forty fresh human AC samples from femoral condyle notchplasties were used to determine a storage timeline. Each sample was divided into three portions:

initial chondrocyte viability,

stored in phosphate buffered saline,

stored in Biowhitaker XVIVO-10.

All samples were randomly allocated to one of five time intervals (2–10 weeks). Following each time period final viability assays were conducted. Secondly, osteochondral dowels were drilled from eight cadaveric femoral condyles. Five dowels were obtained from each joint: one for initial viability/annexin V assays, the others were stored in PBS or XVIVO-10 for four and six weeks. Following storage, final viability, annexin V, and TUNEL assays were preformed.

Notchplasty samples stored in XVIVO-10 for four weeks had an average final viability of 68%, but an average loss in viability of only 6%. By one month the viability of samples stored in PBS had dropped to 5%. Osteochondral dowels stored in XVIVO-10 not only had greater chondrocyte viability, but less apoptosis.

Cadaveric dowels are a suitable source of osteochon-dral tissue for hypothermic storage and in turn allogeneic transplantation.

An osteochondral tissue bank would provide a reliable source of articular cartilage for repairing joint surfaces for patients who are not suitable candidates for total joint replacements.


K. Gordon A. Kedgley L. Ferreira J. Johnson G. King

This study quantified the joint reaction forces in the distal radioulnar joint using an instrumented ulnar head replacement implant. Muscle activity was simulated in-vitro to determine the effects on joint reaction force. Forces were found to linearly increase with simulated muscle load in all forearm positions for the biceps and pronator teres muscles. However, this did not occur for simulations of the supinator and pronator quadratus muscles, likely due to their broader insertion, smaller size and non-linear lines-of-action. This work has important implications in forearm biomechanical modelling, implant design, fixation and rehabilitation protocols following arthroplasty.

To determine the relationship between forearm muscle activity and joint reaction force (JRF) in the distal radioulnar joint (DRUJ).

The DRUJ reaction force is linearly related to the muscle activity of the PT and biceps, but not necessarily to the activity of the supinator and PQ.

This work has implications for biomechanical modelling, implant design, fixation and rehabilitation protocols following DRUJ arthroplasty.

JRFs were found to increase linearly with muscle load for all muscles simulated (biceps, pronator teres (PT), pronator quadratus (PQ), supinator) in all forearm positions tested (supination, neutral and pronation) (correlation coefficient r> 0.85, p< 0.01) with two exceptions; simulation of the PQ in the neutral position (r=−0.65, p=0.2), and the supinator in the pronated position (r=0.72, p=0.2). Biceps simulation generated larger JRF magnitudes in all positions compared to other muscles (p< 0.001), and the PQ generated larger JRF magnitudes compared to the supinator (p=0.05).

Ulnar head arthroplasty was performed with a replacement ulnar head implant instrumented with strain gauges to allow measurement of the DRUJ reaction force. An upper extremity joint simulator applied muscle loads in seven fresh frozen cadaveric upper extremities through computer-controlled pneumatic actuators. Load was varied in 10N increments from 10-80N (biceps and PT) and from 10-50N (PQ and supinator). A hand clamp was used to restrain the forearm in varying positions. The results illustrate that broad insertion and non-linear muscles may not be linearly correlated to joint reaction force in the DRUJ.

Please contact author for diagrams and graphs.


N.M. Jomha L.E. McGann G.K. Law R. Sharma

Cryopreserving agents (CPAs) can cryopreserve articular cartilage (AC) but their use is limited due to cellular toxicity. This study examined the time-dependent penetration of multiple CPAs into intact porcine AC. Porcine AC was immersed in CPAs for various amounts of time at three temperatures (4°C, 22°C, and 37°C). The results demonstrated an initial sharp rise in CPA concentration within the matrix for dimethyl sulfoxide and propylene glycol with maximum concentration after three to six hours. The trehalose and glucose concentration increased minimally even after twenty-four hours of exposure. The information from this study provides insight into the penetration kinetics of cryoprotectant agents into AC.

This study examined the time-dependent penetration of cryoprotectant agents (CPAs) [dimethyl sulfoxide (DMSO), propylene glycol (PG), trehalose and glucose] into intact porcine articular cartilage (AC).

Penetration of DMSO and PG into AC was rapid but time and temperature dependent while trehalose and glucose had poor penetration.

The information gathered from this study can determine concentrations of CPAs within the cartilage matrix to create cryopreservation/vitrification solutions while minimizing toxicity.

The results demonstrated there was a sharp rise in the CPA concentration within 15–30min exposure to DMSO and PG and the concentration peaked after three to six hours exposure at a concentration approximately 90% of the original concentration (6.5 molar). This was temperature dependent with slower penetration at lower temperatures. The trehalose and glucose had very poor penetration into the matrix at all temperatures, with a maximum penetration of 2% of the original concentration.

Dowels of porcine AC (10mm diameter) were immersed in high concentration of each CPA for various amounts of time (0min, 15min, 30min, 60min, 3hr, 6hr, and 24hr) at three temperatures (4°C, 22°C, and 37°C). The cartilage was excised and the amount of cryoprotectant within the matrix determined.

Successful cryopreservation of AC could improve clinical results of osteochondral allografting and provide a useful treatment alternative for large cartilage defects. However, successful cartilage cryopreservation is limited by chondrocyte death and matrix disruption due to inadequate CPA penetration.


M. Lincoln T. Trinh C. Lorincz M.R Doschak R.F Zernicke

Osteoarthritis (OA) involves pathology in both articular cartilage and subchondral bone. The osteoprotegerin (OPG)/receptor activator of nuclear factor kappa beta ligand (RANK-L) balance is known to modulate bone turnover. We compared the bony changes in human total knee arthroplasty (TKA) and cadaveric controls. A qualitative increase in subchondral and ligamentous insertional bone mineral density was observed on micro-CT sections of TKA bone compared with cadaveric controls. In-situ hybridization of digoxygenase (DIG)-labelled OPG riboprobes showed selective uptake in osteoblasts but not osteocytes or osteoclasts in TKA bone. Those data suggested that the upregulation of OPG expression by osteoblasts may have precipitated the bony hypertrophy of end-stage OA.

Altered joint mechanics produced by periarticular bone remodelling may precede the cartilage changes of osteoarthritis (OA). Recently, receptor activator of nuclear factor kappa beta (RANK), along with its soluble ligand (RANK-L), have been shown to induce both maturation and activation of bone-degrading osteoclasts. Activation of RANK on osteoclast cells by RANK-L is opposed by another soluble factor, osteoprotegerin (OPG). Thus RANK/OPG balance is important in regulating bone turnover. Here, we compared periarticular bone from patients with end-stage OA undergoing total knee arthroplasty (TKA) with those of cadaveric controls. We assessed bony, histological and molecular changes that are important in the pathogenesis of OA.

Using in-situ hybridization, we found increased staining of digoxygenase (DIG)-labelled OPG in osteoblasts of TKA bone. A corresponding increase in subchondral and insertional bone was seen on micro-CT (μCT) sections from TKA bone in comparison with cadaveric controls. Those changes were accompanied by marked articular cartilage degeneration on histology.

This study is the first of which we are aware that directly assessed the role of OPG in inducing the bony changes seen in human end-stage OA. We used μCT to compare corresponding samples qualitatively from TKA and cadaveric bone. Adjacent sections underwent hybridization of digoxygenase (DIG)-labelled OPG riboprobes to assess gene expression in situ. Finally, samples were stained and analysed for histology.

Bony hypertrophy may be a result of overexpression of OPG that occurs as an important feature of OA pathophysiology.

Funding: This work was supported by a grant from the Hip Hip Hooray Fund of the Canadian Orthopaedic Research Foundation (CORF) and the Wood Professorship in Joint Injury Research. There was no commercial funding for this research project.


N.M. Jomha L.E. McGann H. Elmoazzen A. Yao A. Poovadan J.A.W. Elliott

Cryoprotectant toxicity has become more relevant because of increased use of high concentrations of cryoprotectants for vitrification of biologic tissues. A single toxicity model that integrates cryoprotectant concentration, time and temperature is essential to optimize the cryopreservation of tissues. The Weibull probabilistic distribution has been used in environmental toxicology research. This objective of this study was to fit the Weibull model to experimental data for chondrocyte recovery from articular cartilage exposed to various concentrations of dimethyl sulfoxide at different temperatures as a function of time. This study indicated that the Weibull model is an appropriate model to describe cryoprotectant toxicity to chondrocytes in articular cartilage.

This study was designed to examine the toxicity of dimethyl sulfoxide (DMSO) on chondrocytes in porcine articular cartilage (AC) as a function of time, temperature and concentration.

The Weibull model is suitable for modeling cryoprotectant toxicity in cartilage and can be further extended to other cellular and tissue systems.

The model provides a simple method to predict toxicity and to assess the feasibility of cryopreservation protocols.

The model proved to be a good fit for the entire data set of concentration, temperature and time, yielding an R2 value of 0.87 and a maximum discrepancy of 20% between the experimental data and the model. Estimates of the model’s parameters within a confidence interval of 95% were found to be: _=30±2, _=0.67±0.05, _C=0.38±0.03, _T=−2300±300 and _CT=700±100.

Sliced porcine AC was exposed to DMSO (1, 3, 5, 6M) at different temperatures (0, 22, 37°C) for various durations. Cellular viability was determined by membrane integrity stains. Experimental data for chondrocyte recovery was fit to the global Weibull probabilistic distribution model using SPSS SigmaPlot 2000 to estimate the five parameters.

A model integrating concentration, time, and temperature of exposure is required to optimize addition and removal protocols of high concentrations of cryoprotectant for cryopreservation. The Weibull distribution is a simple and flexible model used to describe similar processes. In the current study, chondrocyte viability decreased with increased concentration, temperature and time of exposure. The model indicated a significant interaction between the toxic effects of concentration and temperature.


J. Hall

Several recent studies have shown an increased incidence of symptomatic non-unions and malunions after non-operative treatment of displaced clavicle fractures. Our multicenter randomized control trial comparing sling treatment and plate fixation shows statistically significant improvement in patient oriented outcome measures at all time points measured over one year of follow-up. Non-operative group complications included six non-unions, one symptomatic malunion and one patient with reflex sympathetic dystrophy in thirty-four patients. Complications in the operative group included one wound dehiscence and two patients requiring plate removal in thirty-seven patients. This study supports plate fixation of acute clavicle fractures in selected cases.

To compare patient oriented outcomes of non-operative and operative treatment of displaced clavicle shaft fractures.

Operative fixation of displaced clavicle shaft fractures provides statistically significant improvement in functional outcome over sling treatment at one year of follow-up.

This study supports operative fixation of displaced clavicle shaft fractures in selected cases.

Seventy-one of one hundred and twenty patients have at least one year of follow-up. Non-operative group (N=34) consisted of twenty-four males with an average age thirty-two injuring fourteen dominant clavicles. The operative group (N= 37) consisted of thirty-three males with an average age of 34.5 years injuring twenty-one dominant clavicles. CSS and DASH scores were statistically different at all time points measured (p=0.001, p=0.021 respectively). Complications in the non-operative group included one patient with RSD, one symptomatic malunion and six patients with non-unions requiring ORIF. In the operative group, two patients experienced local plate irritation and one late wound dehiscence.

Randomization was by sealed envelope. Non-operative treatment was symptomatic in a sling, while operative patients underwent ORIF. CSS, DASH and SF-36 scores were collected at six weeks, three months, six months and twelve months. Statistical analysis was completed by repeated measures multivariate analysis using SPSS.

Recent studies have shown a higher incidence of symptomatic malunions and non-unions after sling treatment. Currently, sling treatment is standard of care for these fractures. Our study shows statistically signifi-cant improvement in functional outcome with operative treatment with few complications. This study supports operative treatment of displaced clavicle shaft fractures in selected cases.

Funding: OTA, Zimmer Inc

Please contact author for graphs and diagrams.


G.Y. Laflamme G. Berry S. Gagnon P. Beaumont

Although new locking plates allows for secure fixation of osteoporotic fractures in the proximal humerus, extensive soft tissue dissection is needed for their insertion. We report on a prospective clinical trial of the first thirty patients treated with plating of the proximal humerus though a minimally invasive percutaneous approach. All fractures healed within the first 6 months with no avascular necrosis or axillary nerve injury. At the latest follow-up, the median Constant score was sixty-eight and the mean DASH score was twenty-seven. This study suggests that percutaneous plating can be a safe and effective method of fixation.

To evaluate the safety and efficacy of minimally invasive plating of the proximal humerus using validated disease-specific measures.

Percutaneous insertion of a locking proximal humerus plate is safe and produces good early functional and radiologic outcomes.

Plate fixation of the proximal humerus fractures may now be more desirable with the use of a biological approach by limiting surgical insult and allowing accelerated rehabilitation.

All fractures healed within the first six months with no loss of correction. Two reoperations were needed to remove intra-articular screws placed too long. No infection or avascular necrosis were seen. At the lastest follow-up, the median Constant score was sixty-eight points, with an age ajusted score of seventy-six. The mean DASH score was twenty-seven points. Only age was independantly predictive of both the Constant and DASH functional scores.

During a period of one year, thirty patients were operated with use of the LCP proximal humerus plate (Synthes) through a 3cm lateral deltoid splitting approach and a second 2 cm incision at the deltoid insertion. The axillary nerve was palped and easily protected during insertion. Only two-part (N=22) and three-part impacted valgus type (N=8) were included in this study since they can be reduced indirectly thru this percutaneous technique. The average follow-up was thirteen months (eight to twenty months). All patients had the Constant and DASH evaluations.


D.M. Beingessner C.E. Dunning R.A. Stacpoole J.A. Johnson G.J.W. King

Passive and active elbow flexion was performed in eight cadaveric arms to determine the effect of Type 1 coronoid fractures and suture repair on kinematics. Testing was performed in ligamentously intact and MCL deficient elbows; with radial head arthroplasty (RHA); with an intact coronoid, following a Type 1 fracture, and with suture repair of the coronoid. There was an alteration in elbow kinematics and stability following Type 1 coronoid fractures that was not corrected with coronoid repair. Suture fixation of the coronoid is probably unnecessary if the lateral ligaments are repaired and the radial head is repaired or replaced.

To determine the effect of fixation of Type 1 coronoid fractures on elbow stability and kinematics in ligamentously intact and medial collateral ligament (MCL) deficient elbows with radial head arthroplasty (RHA).

Type 1 coronoid fractures cause changes in elbow kinematics and stability that are not corrected with suture repair.

Suture fixation of Type 1 coronoid fractures is probably unnecessary if the lateral ligaments are repaired and the radial head is repaired or replaced.

With intact ligaments, there was an increase in valgus angulation following a Type 1 coronoid fracture (p< 0.05) that was not corrected with fixation. With MCL deficiency, there was no change in valgus angulation for all coronoid states. For both ligament states, there was an increase maximum varus-valgus laxity after a Type 1 coronoid fracture with forearm pronation (p=0.03) that was not corrected with fixation (p=0.4). Kinematic data was collected from eight cadaveric arms during passive and simulated active elbow motion. The protocol was performed in stable and MCL deficient elbows with RHA. Testing occurred with the coronoid intact, following Type 1 coronoid fracture, and with suture repair of the fracture. Valgus angulation and maximum varus-valgus laxity were measured.

With intact ligaments, Type 1 coronoid fractures cause an alteration in elbow kinematics and laxity that is not corrected with suture fixation. With MCL disruption, Type 1 coronoid fractures have no effect on elbow kinematics and a small effect on laxity that is not corrected with coronoid repair.

Funding: Research and Institutional Support received from Wright Medical Technologies.

Please contact author for graphs and/or diagrams.


P.A. Martineau S. Bergeron L. Beckman T. Steffen E. J. Harvey

Radial-sided avulsions of the TFCC (Palmer 1d) remain a challenging pathology to treat. No current procedures have addressed these injuries successfully and reproducibly. Ten preserved dissected cadaveric forearm specimens with intact TFCC and without ulnar positive variance underwent biomechanical testing. Specimens were tested intact, then with Palmer 1d TFCC lesion and finally post-reconstruction. Measurement of total displacement with a −20N to 20N load was performed. The results indicate that our novel anatomic intra-articular reconstruction of unstable radial-sided TFCC avulsions was successful in restoring baseline stability to the DRUJ without interfering with pronation or supination.

Radial-sided avulsions of the TFCC (Palmer 1d) remain a challenging pathology to treat. No current procedures have addressed these injuries successfully and reproducibly. We tested a novel intra-articular reconstruction to address unstable radial-sided TFCC avulsions.

Ten preserved dissected cadaveric forearm specimens with intact TFCC and without ulnar positive variance underwent biomechanical testing using an MTS machine. Measurement of total displacement with a −20N to 20N load was performed. Specimens were tested intact, then with Palmer 1d TFCC lesion and finally post-reconstruction. All tests were performed at neutral, maximal pronation and maximal supination.

Mean total displacements of the specimens at neutral rotation were: 4.122mm ± 0.363 for the intact specimens compared to 11.839mm ± 0.782 after creation of the tear (p< 0.000002) and 3.883mm ± 0.655 for the reconstructed specimens (p=0.77). In maximal pronation mean total displacements were: 2.378mm ± 0.250 intact vs. 4.922 ± 0.657 torn (p< 0.0007) and 2.124mm ± 0.339 post-reconstruction (p=0.61). In maximal supination mean total displacements were: 1.438mm ± 0.222 intact vs. 5.704mm ± 1.258 torn (p< 0.006) and 1.004mm ± 0.091 post-reconstruction (p=0.07). All specimens obtained the same maximal pronation and supination pre and post-reconstruction.

Restoration of stability and joint function have never been achieved with previous reconstruction attempts of radial-sided TFCC avulsions. Current procedures are unable to restore DRUJ stability without a significant sacrifice of motion. Our anatomic intra-articular reconstruction of unstable radial-sided TFCC avulsions succeeded in restoring baseline stability to the DRUJ without interfering with pronation/supination.


R. Grewal J.C. McDermid D.S. Drosdowech G.J.W. King

This cohort study reports outcomes of patients with comminuted radial head fractures treated with a modular radial head arthroplasty. Twenty-six patients (mean age = fifty-four) were prospectively followed at three, six, twelve, and twenty-four months following surgery. Patient satisfaction with this procedure was high. This data indicates favorable results using a modular radial head arthroplasty with rapid improvement in disability and physical impairment occurring in all measures in the first six months and further improvement in most patients up to two years. The Mayo Elbow Performance Index was at one year and eighty-four at two years.

To investigate the objective and subjective outcomes of unreconstructable radial head fractures treated with a modular radial head arthroplasty.

This data indicates favorable results using a modular radial head arthroplasty with improvement in satisfaction, disability and physical impairment occurring in all measures in the first six-months and continued improvement for up to two-years.

Comminuted radial head fractures are challenging to treat with ORIF. Radial head arthroplasty is an alternative treatment that compares favorably to reported results for ORIF of similar fractures.

Significant improvements were noted over time in self-reported and measured impairments as follows: ASES pain: baseline = 30/50, two years = 15/50; ASES function: baseline = 5/36, two years 27/36; MEPI one year = eighty-two, two years = eight-four. At two years, little impairment was observed compared to the unaffected side in grip 22/26 kg, flexion 141°/145°, or pronation 74°/79°. Moderate differences were noted in extension 28°/2°, supination 57°/72° and strength measures: extension = 29/38, flexion = 31/40, supination = 43/65, pronation = 37/53 (Nm). Patient satisfaction was high at three months (9/10) and remained high at two years (9.1/10).

A cohort of twenty-six patients (seventeen female, mean age fifty-four) with non-reconstructable radial head fractures was treated using a modular metallic radial head arthroplasty (Evolve TM, Wright Medical Technology, Arlington, TN). All patients were prospectively followed at three, six, twelve and twenty-four months. Self-report of limb function, general health, measured ROM and isometric strength were assessed by an independent observer.

Funding Institution research foundation support was provided by Wright Medical Technology. None of the authors received direct compensation for commercial products related to the content of this study.


M. Bhandari J. Busse P. Leece O.R. Ayeni B.P. Hanson E.H. Schemitsch

Little is known about the psychological morbidity associated with orthopaedic trauma. Our study aimed to determine the extent of psychological symptoms and whether patient psychological symptoms were predictive of outcomes following orthopaedic trauma. Overall, trauma patients experienced higher intensity of psychological symptoms than population norms. Psychological symptoms, patient age, and ongoing litigation predicted functional outcomes. Patients may benefit from early interventions by social workers and psychologists to process their psychological states post injury.

Little is known about the psychological morbidity associated with orthopaedic trauma.

Our study aimed to determine the extent of psychological symptoms and whether patient psychological symptoms were predictive of outcomes following orthopaedic trauma.

All patients attending ten orthopaedic fracture clinics at three University-affiliated Hospitals were approached for study eligibility. All consenting patients would be requested to complete a baseline assessment form, a 90-item symptom checklist-90R (SCL-90R), and the Short-Form–36. The SCL-90R constitutes nine dimensions (Somatization, Obsessive-compulsive, Interpersonal sensitivity, Depression, Anxiety, Hostility, Phobic anxiety, Paranoid ideation, Psychoticism) and three global indices (Global severity index, Positive symptom distress index, positive symptom total). We conducted regression analyses to determine predictors of quality of life among study patients.

Of two hundred and fifteen patients, 59% were male at a mean age of 44.5 years. Over half of patients had lower extremity fractures. Trauma patients experienced greater psychological symptoms than population norms. Overall, trauma patients experienced higher intensity of psychological symptoms than population norms. Patient functional outcomes were predicted by patient age, ongoing litigation, and Positive Symptom Distress. This model predicted 21% of the variance in patient function. Patient somatization was an important psychological symptom resulting in increasing intensity of symptoms. Smoking, alcohol, open fracture, surgeons’ perception of technical outcome, level of education, and time since injury were not predictive in this model.

Psychological symptoms, patient age, and ongoing litigation predicted functional outcomes. Patients may benefit from early interventions by social workers and psychologists to process their psychological states post injury.

Funding: This study was funded in part by research grants from AO North America and Regional Medical Associates, McMaster University. Dr. Bhandari was funded, in part, by a 2004 Detweiler Fellowship, Royal Colleges of Physicians and Surgeons of Canada. Dr. Busse is funded by a Canadian Institutes of Health Research Fellowship Award.


A.A. Kulidjian C. Forthman D. Ring J.B. Jupiter M. McKee

In the past, the treatment of acute elbow fracture-dislocations has emphasized repair to the medial collateral ligament (MCL), with favorable results. We report improved results using a strategy based on lateral-sided repair (lateral collateral ligament, radial head, coronoid) without MCL repair. In forty-seven patients, this strategy resulted in a high degree of success with no residual instability (valgus or otherwise). The dynamic stabilizers of the elbow activated through early postoperative motion, are important adjunct to stability. We have devised a reproducible radiographic method to demonstrate this.

To review the surgical treatment of elbow dislocations without surgical MCL repair, and to determine if early active motion aids in restoring stability and concentric joint reduction.

In the setting of acute fracture-dislocation of the elbow, concentric elbow stability with excellent functional results can be achieved using laterally-based surgical strategy without MCL repair. The dynamic stabilizers of the elbow, activated through the early motion, assist in providing joint congruity and stability.

Forty-seven patients with acute elbow fracture-dislocations requiring operative treatment were treated at two university-affiliated teaching hospitals and evaluated an average of twenty-one months after injury. The protocol consisted of repair of the ulna and coronoid, repair or replacement of the radial head, and repair of the LCL, and early motion. The MCL was not routinely repaired. The LCL origin had been avulsed and reattached in all patients. One patient had a second procedure related to malpositioned radial head prosthesis. A stable mobile (average one hundred and one degree arc) articulation was restored in all patients. There was no evidence of valgus instability in any patient. Early motion was initiated at a mean of two weeks postoperatively. Postoperative ulnohumeral joint space opening improved from 4.9 ± 1.2 mm in the early postoperative period to 2.0 ± 0.5 mm (p < 0.00003) at final follow-up. We believe this is due to the effect of the dynamic stabilizers, which were allowed to function through early motion.


J. Potter E.H. Schemitsch C. Jones L.M. Wild M.D. McKee

When deciding on treatment for displaced mid-shaft clavicle fractures, patients often inquire if repair of (potential) nonunion results in outcome similar to acute fixation. We used objective muscle strength testing and patient-oriented outcome measures to examine this question. Late reconstruction of nonunion following displaced mid-shaft fractures of the clavicle results in restoration of objective muscle strength similar to that seen with immediate fixation. However, there was a significant loss in muscle endurance as well as a trend towards a decrease in outcome scores (DASH, Constant) following late reconstruction. This information is useful in surgical decision making and in counseling patients.

Using objectively measured strength and patient-oriented health-status instruments, we sought to determine if delay in repair of displaced, mid-shaft clavicle fractures negatively affected shoulder strength or outcome.

Late reconstruction of clavicle nonunion results in restoration of objective muscle strength similar to that seen with immediate fracture fixation, but there was a significant loss in muscle endurance as well as a trend towards a decrease in outcome scores (DASH, Constant).

All patients had sustained completely displaced, closed, isolated mid-shaft clavicle fractures. Fifteen patients had immediate plate fixation (mean 0.6 months post-fracture) and fifteen had plate fixation for non-union (mean fifty-eight months post-fracture). Objective muscle strength testing on the BTE was done a mean of twenty-nine months post-fixation (normal contralateral limb as control). There were no significant differences between acute fixation and delayed reconstruction groups with regards to strength of shoulder flexion (acute = 92.4%, delayed = 89.4%, p=0.56), shoulder abduction (acute = 98.8%, delayed = 96.7, p=0.75), external rotation (acute = 98.4%, delayed = 91.9%, p=0.29), or internal rotation (acute = 96.3%, delayed = 97.4%, p=0.87). However, there was a trend for improved Constant scores (acute = 94.5, delayed = 90, p=0.09) and the DASH scores (acute = 3.4, delayed = 9.0, p=0.09) in the acute fixation group. We found a significant decrease in muscle endurance with regards to shoulder flexion (acute = 107.0%, delayed = 71.1%, p=0.007) and a trend towards weaker shoulder abduction (acute = 103.1%, delayed = 88.7 %).

Funding: Mr. Potter was supported by a St. Michael’s Hospital Summer Student Scholarship


M. Bhandari P. Tornetta

Risk information is understood differently when it is presented in absolute or relative terms; the latter overemphasizes the magnitude of risk. How surgeons communicate risk may influence patient choice. We evaluated whether presenting information about the benefits of surgery in absolute and relative terms affects an individual’s decision to accept or reject alternative surgical procedures in hip fracture management. Our findings show how framing risk in relative terms affects the perception of risk and influences patient choice. Surgeons must use care in utilizing relative risk reduction in the absence of actual risk data.

Risk information is understood differently when it is presented in absolute or relative terms; the latter overemphasizes the magnitude of risk. How surgeons communicate risk may influence patient choice.

To evaluate whether presenting information about the benefits of surgery in absolute and relative terms affects an individual’s decision to accept or reject alternative surgical procedures in hip fracture management.

We administered a face-to-face survey to fifty patients attending the fracture clinic. We asked patients to consider a scenario and to decide which treatment alternative they preferred based upon risk presentation. We presented risk in five ways: absolute risk difference, relative risk reduction, relative risk, number needed to treat, and odds ratio.

Patients were most likely to favor internal fixation when the mortality results comparing internal versus arthroplasty were presented as a relative risk reduction. Patients continued to favor internal fixation despite being presented with a significantly increased risk of revision surgery. Lower level of education and those patients who had not experienced a fracture were significantly associated with their perceptions about method of presentation.

Our findings show how framing risk in relative terms affects the perception of risk and influences patient choice. Patients concerns about mortality, even if non-significant differences are presented, outweigh concerns about significant increases in revision surgery with internal fixation. Surgeons must use care in utilizing relative risk reduction in the absence of actual risk data given our findings that may over-estimate the relative benefits of one procedure over another.


P.E. Beaulé M. LeDuff N. Harvey

Thirty-seven hips in thirty-four patients, mean age forty-one, underwent surgical dislocation of the hip with chondro-osteoplasty for the treatment of femoroacetabular impingement. At a mean follow-up of 2.1 years (2.0–4.0), the pre & post-operative outcome scores were for the: WOMAC 59.2 to 81.0 (p< 0.001), UCLA Hip Scores for pain 4.2 to 7.6;walking 7.3 to 8.6;function 6.2 to 8.1;activity level 4.3 to 6.9 (p< 0.05); and SF-12 physical 37.4 to 48.0 (p< 0.003) & mental 46.0 to 51.6 (p< 0.01). No hips have undergone further reconstructive surgery. Complications: one failure of fixation of the trochanteric osteotomy and one excision of bilateral ectopic ossification. No cases of osteonecrosis.

The purpose of our study was to evaluate the early clinical results and quality of life outcome after chondro-osteoplasty of the femoral head/neck junction for the treatment of femoroacetabular impingement.

An offset correction by surgical dislocation of the hip joint is a safe and an effective procedure in the treatment of femoroacetabular impingement commonly associated with labral tears.

Femoro acetabular impingement is a due to an absence of concavity at the anterolateral head neck junction associated with labral pathology. At short-term followup correction of the bony abnormality has improved functional outcome both from a disease-specific and health-related standpoint.

Thirty-seven hips (eighteen males; sixteen females) with persistent hip pain mean age forty-one (twenty-four to fifty-two) underwent 3-Dimensional CT of the pelvis and MR Arthrography prior to undergoing surgical dislocation with chondro-osteoplasty of the femoral head/neck junction. Preoperatively, the mean alpha angle of Notzli was 65.6(range, 42.0–95). At a mean follow-up of 2.1 years (2.0–4.0), the pre & post-operative outcome scores were for the: WOMAC 59.2 to 81.0 (p< 0.001), UCLA Hip Scores for pain 4.2 to 7.6;walking 7.3 to 8.6;function 6.2 to 8.1;activity level 4.3 to 6.9 (p< 0.05); and SF-12 physical 37.4 to 48.0 (p< 0.003) & mental 46.0 to 51.6 (p< 0.01). No hips have undergone further reconstructive surgery. Complications: one failure of fixation of the trochanteric osteotomy and one excision of bilateral ectopic ossification. No cases of osteonecrosis. Nine hips had removal of painful internal fixation.


S. McKenzie B. Weening R. Ogilvie D. Petruccelli J. de Beer

A radiographic review of sixty-nine lateral closing wedge high tibial osteotomies and forty-two medial opening wedge osteotomies was conducted. Patellar height and tibial slope were measured. The Blackburne-Peel (BP) and Insall-Salvati (IS) ratios were used to measure patellar height. Our results show that 18.8% and 47.6% of the lateral closing wedge group had patella-infera (PI) according the the BP and IS ratios respectively. No opening-wedge cases demonstrated patella infera with either ratio. Tibial slope was found to be significantly more neutral in the closing wedge group versus the opening wedge (−2.2° vs. −7.28° respectively).

Patients undergoing HTO typically require a definitive arthroplasty procedure at an average of six years post-HTO. Total knee arthroplasty can be complicated by the presence of PI which compromises exposure and increases the risk of patellar tendon avulsion leading to suboptimal results. The current study compares the incidence of PI between lateral closing and medial opening wedge HTO’s.

Conversion of opening wedge HTO to TKA should have less technical challenge and improved outcomes as compared to lateral closing wedge HTO conversions. This is attributable to the absence of PI.

Of the closing wedge group, 18.8% and 47.6% were found to have PI according to the BP and IS ratios respectively. Of the opening wedge group there were no cases of PI found with either ratio. Tibial slope was found to be significantly more neutral in the closing wedge compared to the opening wedge group (−2.2° vs. −7.28° respectively).

The study cohorts were abstracted from surgeon records. Sixty-nine closing wedge and forty-two opening wedge HTO’s were identified. Lateral 30° flexion x-rays were measured for patellar height and tibial slope. Both the Blackburne-Peel (BP) and Insall-Salvati (IS) patellar height measurements were used.

From this data we can conclude that in our study population the incidence of PI in the opening wedge group was 0% thus negating the potential deleterious effects of PI at the time of knee arthroplasty.


J. Rudan D. M. Angada J. Yach R. Ellis W. Long

Periacetabular osteotomy provides a joint preserving option for the treatment of acetabular dysplasia but is generally considered technically demanding, which has limited its widespread application. This study evaluates a new computer enhanced technique for a trans-trochanteric periacetabular osteotomy. This multi-use computer interface designed and used at Kingston General Hospital and Queen’s University has been previously and successfully used in many different types of surgical procedures. Interim results show few complications and accurate guidance.

To develop a new periacetabular osteotomy technique that can be performed safely and reliably using computer-enhanced technology.

This technique has enabled us to perform periacetabular osteotomies with few complications and increased accuracy of component alignment and sizing.

Using this computer-enhanced technique, periacetabular osteotomy may become a more common procedure in the practice of hip reconstruction.

Candidates include adults with symptomatic acetabular dysplasia. Pre-operative radiographs and CT scans are obtained. The scan is digitized to create a 3D model used for osteotomy planning. A trans-trochanteric approach is used to the acetabulum. An intra-operative plan is followed for osteotomy cuts. Fixation is achieved with two pelvic reconstruction plates. Peri-operative data on correction, complications and clinical data (WOMAC and SF36), and xrays and one year 3D CT scans are collected prospectively. This procedure has been performed on eighteen patients with an average centre edge angle correction of ninteen degrees. The computer guidance system has given accurate information in all but one case, which was successfully completed with limited guidance. No cases of intra-articular or posterior column fractures, nerve injury or AVN have occurred. Two cases of trochanteric pull-off were revised without complication. One case of delayed union of the pubic rami osteotomy was bone grafted and subsequently healed. One case of radiographic, but not clinical heterotropic ossification occurred in a patient with contraindications to prophylaxis. This new technique provides a reliable and reproducible option for acetabular correction with low complication rates.


J.A. Grant N.G. Mohtadi

The original RCT demonstrated that a limitedly-supervised post-ACL reconstruction rehabilitation program was both clinically more effective and less costly than the traditional physiotherapy-supervised program. This study contacted patients from the original RCT a minimum of two years post-surgery to evaluate whether or not the clinical findings of the RCT were upheld over the long term. This study of eighty-eight patients has upheld the original findings in that the patients who performed the limitedly-supervised (home-based) program had a significantly higher mean disease-specific quality of life score compared to the patients who performed the physiotherapy-supervised rehabilitation program.

To determine whether or not there were any differences in long-term outcome between those patients who performed a physiotherapy-supervised rehabilitation program (PT) and those who performed a primarily home-based rehabilitation program (H) in the first three months following ACL reconstruction.

Patients were originally randomized, before ACL reconstruction surgery, to either the physiotherapy-supervised (seventeen physiotherapy sessions) or home-based program (four physiotherapy sessions). Eighty-eight of the original patients were able to return two to four years following surgery to assess their long-term clinical outcomes. Primary outcome: the Mohtadi ACL disease-specific quality of life questionnaire (ACL QOL). Secondary outcomes: bilateral difference in knee extension and flexion range of motion, sagittal plane knee laxity, relative quadriceps and hamstrings strength, and IKDC score. Unpaired t-tests were used to compare the two groups across the continuous variables. A Chi square test was used for the categorical data.

The home-based group had a significantly higher (p = 0.02, 95% CI [18.4, 1.7]) mean ACL QOL score (80.0 ± 16.2) compared to the physiotherapy-supervised group (69.9 ± 22.0) a mean of forty months post-surgery. There were no significant differences between the two groups with respect to any of the secondary outcome measures.

This long-term study upholds the short-term findings of the original RCT in that the home-based rehabilitation program is more effective than a more physiotherapy-intensive program for patients in the first three months following ACL reconstruction.

Given the resource savings demonstrated in the original RCT, the home-based program is clearly economically-dominant (i.e., clinically more effective and less expensive).

FUNDING: Calgary Health Region


S. Griffin A. Kirkley

A reliable and valid measurement tool, The Western Ontario Meniscal Evaluation Tool (WOMET) was developed to assess the benefit of conservative and surgical interventions for meniscal pathology. A methodologic protocol designed by Guyatt was used for the development. This measurement tool can be used as the primary outcome tool in clinical trials evaluating the outcome of patients in this population. It can also be used to monitor a patients’ progress in private practice.

The purpose of this study was to develop a measure of quality of life, which is reliable and valid, to assess the benefit of conservative and surgical interventions for meniscal pathology.

Health-related quality-of-life measurement tool development

A modified methodologic protocol designed by Guyatt was used to develop the Western Ontario Meniscal Evaluation Tool (WOMET) a disease-specific quality of life measurement tool for patients with meniscal pathology. The stages were: 1) item generation, 3) item selection, 4) pretesting. Evaluation of the WOMET included testing reliability, responsiveness and validity.

The final instrument, the Western Ontario Meniscal Evaluation Tool has sixteen items representing the domains of physical symptoms (nine items), sports, recreation/work/lifestyle (four items), and emotions (three items). The instrument proved to be valid by demonstrating predicted correlations with previously published knee measurement tools. Reliability at two weeks was high with an intraclass correlation coefficient of 0.833. The new instrument was also more responsive than other knee measurement tools.

Since the patients own perception of changes in their health status is the most important indicator for success of a treatment, this measurement tool can be used as the primary outcome tool in clinical trials evaluating the outcome of patients in this population. It can also be used to monitor a patients’ progress in private practice


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E. Harvey J. Theodoropoulos C. Seguin E. Iakoub

A tantalum AVN implant was used in sixteen patients with advanced AVN (Grade 3/4). No reports have been published of use of this implant in advanced disease. Outcomes included radiological, SF36, Harris hip score and secondary surgeries. HHS improved from fifty-two to seventy. SF36 scores approached controls. At over one year average follow-up five patients are revised to THA, however, all hips except one have at least minor pain. Revisions occurred in older patients or those with 100% head involvement. In younger patients, with up to 50% head involvement, this technique seems to be a viable option for advanced AVN. Evaluation of tantalum AVN implants in patients with advanced AVN. In younger patients, with up to 50% hip head involvement, this technique seems to be a viable option for advanced AVN. Revisions in general are in older patients or those with 100% head involvement.

Most treatment options have had poor outcomes with advanced AVN. Surgeons generally perform THA or core decompression in these cases. Market pressure for a non-vascularized option to fill the channel after decompression has resulted in new implants. A tantalum device has been designed to fill the post-core decompression channel to allow subchondral support. This is a minimally invasive procedure with theoretically low morbidity. The average orthopedic surgeon would have no difficulty in the use of this implant.

HHS improved from fifty-two to seventy. SF36 scores were below age-matched controls. At over one-year average follow-up five patients are revised to THA, however, all hips except one have at least minor pain. Revisions in general are in older patients or those with 100% involvement. In younger patients, with up to 50% head involvement, this technique seems to be a viable option.

This device was used in a prospective cohort of sixteen patients with advanced AVN (Grade 3/4) with femoral head fracture/collapse. Operative technique including reduction of the fracture allows for improved results. Outcomes included radiological parameters (advancing disease, placement, ingrowth), SF36, Harris hip score and secondary surgeries.


N. Graveleau J. DaSilva R. Litchfield P. Fowler R. Giffin

Thirty-six patients with anterior cruciate ligament (ACL) insufficiency and varus malalignment were treated with combined ACL reconstruction and medial opening wedge high tibial osteotomy (HTO). Average follow-up was twenty-five months. All patients had improved ligamentous stability and twenty-five patients returned to full activities. Osteotomy union rate was 100%, mechanical axis angle was corrected from six degrees varus to neutral and the mechanical axis deviation was corrected from 2cm medial to 1cm lateral. We experienced four complications, including one deep infection. Combining ACL reconstruction and HTO simultaneously accomplishes a ligamentously stable knee with corrected alignment, allowing patients to return to activity.

To determine clinical outcome after combined ACL reconstruction and medial opening wedge high tibial osteotomy (HTO).

ACL reconstruction with medial opening HTO can be a beneficial procedure in properly selected patients presenting with complaints of both pain and instability. Correction of varus mal-alignment may provide protection for articular cartilage and improve joint stability.

Concomitant medial opening HTO performed at time of ACL reconstruction allows patients to return to activities after one procedure with a ligamentously stable knee, corrected alignment, and potential protection of articular cartilage.

Thirty-six patients who underwent ACL reconstruction along with medial opening HTO were retrospectively evaluated postoperatively at an average of twenty-five months.

Average age was thirty-seven years at time of surgery. All patients were recreationally active. Pre-operatively all patients had knee pain and instability, varus angulation, and twenty-two patients had previous knee surgery. Semitendinosus/gracilis grafts were used in all patients, and osteotomies were fixed with Puddu plates. Postoperatively patients had improved ligmentous stability with radiographic and clinical evidence of osteotomy healing, and all but nine patients have returned to full activities. We experienced four complications: one ACL failure, one case of anterior laxity with tibial tunnel widening, and two infections. On average, MAD was corrected from 22mm medial to 10mm lateral; mechanical axis angle was corrected from 6.4 degrees of varus to 0.2 degrees of valgus; tibial slope was increased from 9.1 degrees to 10.3 degrees, and patellar height ratio was decreased from 0.9 to 0.8.


J. Girard H. Migaud C. Chantelot P. Laffargue A. Duquennoy

Thirty-nine cementless hip replacements using metal-on-metal articulation were consecutively implanted in thirty patients less than fifty years of age and compared with a matched control group of cementless replacements using ceramic-on-polyethylene articulation. The Harris hip score at follow-up (minimum five years) for the metal-on-metal was 94.9 (range, 74–100). After the same follow-up, the results of the ceramic-on-polyethylene were significantly worse: nine osteolyses and seven surgical revisions related to wear. Five-year survival rates were 97% +/− 2% for the ceramic-on-polyethylene and 100% for the metal-on-metal. The metal-on-metal may be recommended to prevent wear problems in younger and more active patients.

The aim of the current study was to assess the results of metal-on-metal articulating components inserted as a primary hip replacement in patients under the age of fifty, comparated with a matched control group using ceramic-on-polyethylene.

Patients and methods

The inclusion of patients was: under fifty years of age and a diagnosis of arthrosis or necrosis of the femoral head.

Femoral stem and cup migration was detected. A variation over five millimeters between the follow-up radiographs was considered as migration.

At the follow-up in 2003, the cobalt concentrations in the whole blood were assessed in the metal-on-metal cohort. The detection limit of cobalt in the whole blood was 0.06 μg/L.

None of the components had migration.

At a mean follow-up of sixty-nine months, the median concentration of cobalt in the whole blood was 0.62μg/L. Only eight patients had cobalt levels greater than 1 μg/L.

Considering a reoperation with the exchange of one of the components as end point, the five year survival rates were 100% for the metal-on-metal group and 97% + 2 for the ceramic-on-polyethylene group. Our study suggests that the metal-on-metal articulation gives a significant improvement in terms of resistance to wear when compared with these conventional bearing components. Our results suggest the metal-on-metal articulation with cementless components can be recommended in the young and active patient to prevent the occurrence of wear and osteolysis. A careful assessment of patients with high levels of whole-blood cobalt should be performed.

Funding: Aucun


M. Volesky A.R. Pickle B. Bessette R. Wilkinson G. Dervin D.H. Johnson

This prospective, randomized clinical comparison of tibial fixation in 4-bundle hamstring ACL reconstruction, evaluated mechanical results (laxity) between BioScrew XtraLok® (Linvatec) and Intrafix® (Mitek Products) at six months. One hundred and three sequential patients undergoing ACL reconstruction by three surgeons with identical technique were recruited. KT-1000 arthrometer manual maximum measurements were taken at six weeks, six and six months post-operatively.

At six weeks and three months, KT-1000 side-to-side differences between the groups are not statistically significant (student-t test, p=0.87 and p=0.34, respectively). In clinical results at six months, tibial fixation with Bioscrew XtraLok has significantly decreased laxity compared to the Intrafix device (p=0.017).

This prospective, randomized clinical comparison of tibial fixation in hamstring ACL reconstruction evaluated mechanical results (laxity) between BioScrew XtraLok® (Linvatec, Largo, FL) and Intrafix® (Mitek Products, Norwood, MA) at six months.

After Ethics Review Board approval and sample-size calculation, one hundred and three sequential patients undergoing ACL reconstruction were recruited. Inclusion criteria were: absence of other ligamentous injury or previous knee surgery, and a normal contralateral knee.

After drilling tunnels, patients were allocated to a study arm (XtraLok® or Intrafix®) by a computer-generated randomization table. In all patients, EndoButton® (Smith & Nephew, Andover, MA) was used for femoral fixation and the Mitek tensioner was employed.

The patients were assessed with KT-1000 arthrometer manual maximum measurements taken at six weeks, three and six months post-operatively by independent clinicians. Mean measurements between the two groups were compared using the student-t test at the above intervals.

At six months, eighty-seven of one hundred and three (84%) patients were available for follow-up; 43 XtraLok (XL), and forty-four Intrafix (IF). There was no significant difference between groups in mean age and gender. KT-1000 arthrometer side-to-side differences at six weeks were 1.04mm (XL) versus 1.14mm (IF), and 0.96mm (XL) versus 1.38mm (IF) at three months. At these intervals, differences between the groups are not statistically significant (p=0.87 and p=0.34, respectively). At six months, KT-1000 side-to-side difference was 1.26mm (XL) versus 2.41mm (IF), which is statistically significant (p=0.017).

In clinical results at six months, ACL fixation with Bioscrew XtraLok shows decreased laxity compared to the Intrafix device.


D.S. Garbuz M. Xu B. Sobolev C.P. Duncan B.A. Masri

This prospective cohort study examined the relationship between waiting time for elective total hip arthroplasty (THA) and changes in pre- to post-operative quality of life. It included one hundred and forty-seven patients who entered the waiting list for primary THA with osteoarthritis. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire was used to assess patients at surgical consultation time (baseline) and one year post-operation. Baseline WOMAC score was a significant predictor for follow-up WOMAC score. Expedited access to THA results in a larger proportion of patients showing “better than expected” function at twelve months after the operation.

This study examined the relationship between waiting time for elective total hip arthroplasty (THA) and changes in pre- to post-operative quality of life.

Expedited access to THA results in a larger proportion of patients showing “better than expected” function at twelve months after the operation. The odds of a “better than expected” functional outcome decreased by 8% for each additional month on the wait list.

The study provides the estimates of decreased probability of “better than expected” outcome given a prolonged waiting time. Our study indicates that timely access to THA is needed for optimal post-operative outcome.

Baseline WOMAC score was a significant predictor for the follow-up WOMAC score in function (p=0.0005), pain (p=0.0036), and stiffness (p= 0.0004). Waiting for six months or less doubled the odds of achieving a “better than expected” functional outcome compared to longer waits (p= 0.05).

This prospective cohort study included one hundred and forty-seven patients who entered the waiting list for primary THA with osteoarthritis. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire was used to assess patients at the surgical consultation time (baseline) and one year post operation. Regression models were used to determine the “expected” outcome for a certain individual baseline score. By using expected HRQOL outcome, we identified patients whose benefit from THA is better than expected. Logistic regression models were used to assess the relationship between waiting time and the probability of “better than expected” outcome.


D Chivas K. Smith M. Tanzer

This is the first study to determine if closure of the posterior capsule during revision total hip arthroplasty (THA) results in a reduction in the historically high dislocation rate. Seventy-nine consecutive patients undergoing revision THA with a posterolateral approach and closure of the posterior hip capsule were retrospectively reviewed. At a mean follow-up of fifty-seven months (range twenty-four to one hundred and twenty months), there were only two dislocations (2.5%). The historically high dislocation rates with the posterolateral approach in revision THA, can be significantly decreased with posterior capsular closure from approximately 15% to 2.5%.

To determine if closure of the posterior capsule during revision total hip arthroplasty results in a reduction in the historically high dislocation rate.

The dislocation rate after revision THA with a posterior approach can be minimized by repairing the posterior capsule and rotators.

The historically high dislocation rates with the pos-terolateral approach in revision THA, can be significantly decreased with posterior capsular closure from approximately 15% to 2.5%.

A retrospective study was carried out to review seventy-nine consecutive revision THAs. In all cases, the surgery was done by a single surgeon using the posterolateral approach. In every case, the posterior capsule was meticulously repaired at the end of the procedure. All patients had a minimum two- year follow-up and no patients were lost to follow up.

At a mean follow-up of fifty-seven months (range twenty-four to one hundred and twenty months), there were only two dislocations (2.5%). Both dislocations occurred early postoperatively were anterior. One occurred in a high risk case- a proximal femoral replacement with a trochanteric osteotomy, high hip center and skirted head. The other was due to a technical error, with the cup being excessively anteverted. There were no late dislocations or subluxations.

The dislocation rate after revision THA with a posterior approach can be minimized by balancing soft tissues, correct implant alignment and repairing the posterior capsule and rotators.


N. Greidanus B. Masri D. Garbuz J. Gaida C. Duncan

We compare two applications of minimally invasive hip arthroplasty (MISTHA) with regards to early complication rate and consumption of health care resources. Complications are associated with both manifestations of MIS surgical technique. Two- incision MIS THA is associated with fewer days in hospital in comparison with one incision MIS THA, however requires a greater amount of operating room resources. This paper is among the first to compare two- incision with one incision MISTHA. Two- incision MISTHA may benefit efforts to reduce health resource utilization associated with hip arthroplasty procedures providing that operating room resource consumption and complication rates are not excessive.

A comparative cohort study to evaluate two-incision versus single-incision minimally invasive hip arthroplasty: assessment of early complication rate and health care resource utilization

To evaluate and compare two applications of minimally invasive hip arthroplasty (MISTHA) with regards to early complication rate and consumption of health care resources

One hundred and sixty-five patients received MISTHA from 2002–2004 at a tertiary referral hospital. Patients received two incision (sixty-six patients) or one incision surgery (ninety-nine patients) which was performed according to standard technique. T-test, chi square, fisher’s exact test were used to compare cohorts of MISTHA patients with regards to early complications and consumption of health care resources while in hospital.

At baseline the two cohorts were not different with regards to age, gender, comorbid status, BMI, and pre-operative WOMAC, Oxford-12, SF-12 (p> .05). Major and minor complication rates were similar in the two cohorts (p> .05). Utilization of operating room resources was greater with the two incision group (mean twentyfive minutes more OR time) however length of stay (mean two days less in hospital) and post-operative analgesic use was significantly reduced (p< .05). Complications and operating room resource consumption were highest early in the surgeons’ experience with these procedures.

Complications are associated with both manifestations of MIS surgical technique. Two- incision MISTHA is associated with fewer days in hospital, however requires a greater amount of operating room resources.

This paper is among the first to compare two- incision with one incision MISTHA. Two- incision MISTHA may benefit efforts to reduce health resource utilization associated with hip arthroplasty procedures providing that operating room resource consumption and complication rates are not excessive.


P.A. Vendittoli M. Lavigne A. Roy S. Mottard

The dramatic improvement in clinical function after total hip arthroplasty (THA) has been well-documented. Gait studies, however, demonstrate abnormal gait pattern after THA. THA patients may complain of thigh pain, leg length inequality, instability and reduced range of motion. Surface replacement arthroplasty (SRA) has the benefit of restoring a more normal hip anatomy and biomechanics, which could improve clinical function and patient satisfaction after surgery. We compared the clinical function and patient satisfaction in a group of young patients randomized to receive SRA or THA. The results are presented and discussed.

The dramatic improvement in clinical function after total hip arthroplasty (THA) has been well-documented. However gait studies demonstrate abnormal gait patterns after THA, and patients may complain of thigh pain, leg length inequality, instability and reduced range of motion. Surface replacement arthroplasty (SRA) has the benefit of restoring a more normal hip anatomy and biomechanics, which could improve clinical function and patient satisfaction after surgery.

All patients eligible for the study were randomised to receive uncemented metal-metal THA or a hybrid metal-metal SRA. Clinical data were prospectively collected pre-operatively and at three, six and twelve months post-operatively. WOMAC score, SF-36, Merle D’Aubigné, and other clinical data, along with patient satisfaction, were compared.

One hundred and fifty patients were randomized. Both groups demonstrated a very high satisfaction rate. Although there was a tendency for the SRA group to participate in more demanding activities at six months post-operatively, no difference was found in clinical function scores. Two isolated dislocations occurred in the THA group and none in the SRA group. There were no other significant complications in either group.

The few short-term clinical data reported in the literature for new generation SRA implants demonstrate an excellent outcome comparable to THA. Despite enthusiasm about total hip resurfacing, no direct prospective comparative study with THA has been published in the literature. This study confirms the safety and benefits of metal-metal SRA of the hip in the early post-operative period.

Funding: This research project was funded by Zimmer, Warsaw


D.A.L. O’Brien R.B. Bourne S.J. MacDonald R.W. McCalden C.H. Rorabeck

Fifty-one prospectively followed Contour_ acetabular reconstruction cages, inserted through the direct lateral approach, were reviewed at three years minimum follow-up (range 3 to 6.4 yrs.). To date, four reoperations were required (two each for sepsis and instability) with no failures due to aseptic loosening. The Kaplan-Meier Survival Rate for any reoperation was 87% at 6.4 years. Short to mid-term follow-up of a single type of acetabular reconstruction cage, inserted through the lateral approach, demonstrated this to be a successful reconstruction option in the management of large acetabular bone defects.

This study reports the mid-term results of a single design of acetabular reconstruction cage inserted through the direct lateral approach.

At minimum three years follow-up (range 3 to 6.4 yrs.), there were no failures due to aseptic loosening with only four of fifty-one cases requiring reoperation (two sepsis, two instability).

This review supports the use of the reconstruction cage, inserted through the lateral approach, for large defects that cannot be managed with a hemispherical porous implant.

The use of the reconstruction cage in our center is reserved for large defects that cannot be managed with a hemispherical porous implant because of insufficient bone stock for initial implant stability and/or host bone contact for in-growth. Fifty-one consecutive prospectively followed Contour_ (Smith and Nephew) acetabular reconstruction cages, inserted through the direct lateral approach, were reviewed at three years minimum follow-up (range 3 to 6.4 yrs.). The majority of cases were AAOS Type Three and Four defects in which morsellized allograft was used in forty-nine cases and structural graft in three cases. Harris hip scores improved from 32.1±17.8 pre-op to 65.3±24.1 at most recent follow-up. Defining any acetabular reoperation as a failure, four of the fifty-one cages were considered to have failed giving a Kaplan-Meier Cumulative Survival Rate of 87% at 6.41 years. Two reoperations were for recurrent dislocation and the other two for sepsis. None of the fifty-one cages have been revised for aseptic loosening to date.


R. Leighton W.M. Ricci J. Schwappach K. Coupe M. Tucker A. Blackwell R. Sanders

Antegrade femoral nailing through the greater trochanter, using nails designed for piriformis entry, is associated with varus and iatrogenic comminution. Nails designed for greater trochanter insertion theoretically reduce these complications, but clinical outcomes comparing these to piriformis entry remain unknown. We compared femoral shaft fracture repair with a nail designed for trochanteric entry to an identical nail without a trochanteric bend inserted through the piriformis fossa.

The trochanteric nail was easier to insert with decreased operative and fluoroscopy time. It resulted in equally high union rates, low complication rates, and functional results similar to conventional nailing through the piriformis fossa.

Trochanteric antegrade nailing of the femur is thought to be advantageous over conventional antegrade nailing due to improved ease of insertion, but is unproven. This study compares results of femoral shaft fracture treatment using a nail designed specifically for trochanteric entry, Trigen TAN, to results using an identical nail without a trochanteric bend inserted through the piriformis fossa, Trigen FAN.

A femoral nail specially designed for trochanteric insertion resulted in equally high union rates, equally low complication rates, and functional results similar to conventional antegrade femoral nailing through the piriformis fossa. As a result of increased ease of insertion, decreased operative time and decreased fluoroscopy time, the greater trochanter entry portal, coupled with an appropriately designed nail, represents a rational alternative for antegrade femoral nailing.

Insertion of a specially designed femoral nail though the trochanter is faster, easier, and requires less fluoroscopy time than conventional antegrade nailing through the piriformis fossa.

Overall, there was < 10° malalignment and no iatrogenic fracture comminution. The average operative time was 21% greater using the FAN nail than using the TAN nail, (p=.08). The average fluoroscopy time was 61% greater for the FAN group than for the TAN group, (p< .05). Trends in functional outcome (Lower Extremity Measure) were similar for both groups.

One hundred and eight patients treated for a femoral shaft fracture were included in this study. Ninety-eight patients were treated with either a Trigen TAN nail (n=38) or Trigen FAN nail (n=53); seventeen patients with insufficient follow-up were excluded from analysis.

Funding:Smith & Nephew, Memphis TN


M. Dunbar J.T. Blake P. VanBerkel L. Molloy A. Hennigar

Data from the wait list management system and hospital databases was used to develop a computer model simulating the resource requirements required during patient flow into, through, and out of orthopaedic surgery for TKR, THR and knee arthroscopy. Results from the simulation model suggested that inpatient beds, rather than operating room time was the constraining resource and an extra twenty-five beds and 30% more OR time would stabilize and subsequently reduce the wait time at the institution. In addition, simulations suggested that pooling surgeon wait lists reduced patient wait time. Simulation models are an effective resource allocation decision-making tool for orthopaedic surgery.

To develop and implement a wait list simulation model to analyze the existing system and guide resource allocation decision-making at the QEII Health Sciences Centre.

The simulation model suggests an immediate increase in inpatient surgical beds from sixty-six to ninety-one followed by a 30% increase in OR time in thirty months to stabilize and subsequently reduce patient wait times.

Simulations showed that pooling surgeon waiting lists reduced patient wait time, however, dividing orthopaedics resources among two facilities had little effect. Adding twenty-five beds reduced the wait time growth rate substantially, but not to zero, while adding fifty beds reduced the wait time growth rate to zero. Adding twenty-five beds and 30% more OR time had the same result as adding fifty beds.

Simulation models can be effective for guiding resource allocation decisions for orthopaedic surgery. Recommendations based on the wait list simulation model results were immediately adopted by the provincial Department of Health.

A simulation model of the orthopaedic surgery system at the institution was created using Arena simulation software. Empirical statistical distributions were developed based on Wait List Management System and administrative data to assign values to model variables: number of patient referrals seen per office session; proportion of patient referrals actually converting to a surgery booking; type of procedure required; admission status; time required for surgery; and length of stay. The model was tested, and validated. Several scenarios with adjusted levels of resources variables (OR time, number of surgeons, length of stay, inpatient bed availability) were simulated.


K.A. Lefaivre P.A. Blachut H. Chan

Fifty-six patients, with a median fourteen years follow-up of isolated tibial shaft fracture treated with an IM nailing, underwent functional evaluation with SMFA and SF-36 questionnaires, as well as an injury specific questionnaire. Thirty-three also underwent clinical and radiological evaluation.

Overall, SF-36 scores (PCS 49.9, MCS 52.0) were near normal. Five (15.2%) had physical findings of venous stasis, while a third reported symptoms A third had at least mild OA on radiographs (knee-seven, ankle-eleven). A third of patients had a loss in ankle dorsiflexion, and more than half reported knee pain that was limiting to at least one activity.

We conducted a study to evaluate the long term functional outcomes and disabilities of patients with an isolated tibial shaft fracture treated with intramedullary nailing.

We identified two hundred and fifty eligible patients from the VGH Orthopaedic Trauma database between 1987 and 1992. A total of fifty-six patients agreed to participate. All were evaluated with the SF-36 and SMFA functional questionnaires, as well as an injury specific questionnaire focusing on knee pain, and symptoms of venous insufficiency. A sub-group of thirty-three patients were evaluated radiographically and by physical examination. We had a median follow-up of fourteen years, with a range from twelve to seventeen years.

The SF-36 scores (PCS 49.9, MCS 52.0) were comparable to population norms. Of the questionnaire group (n=56), fifteen denied knee pain with any activity, while twenty-nine had knee pain that was limiting to at least one type of activity. With respect to swelling, eighteen reported asymmetrical swelling affecting the injured limb. However, in the examination group, only five had objective evidence of venous stasis. Knee range of motion was essentially equivalent to the unaffected side, while thirteen patients had a restricted range of motion of the ankle. Radiographically, seven patients had at least mild OA of at least one knee compartment, while eleven had at least mild OA of the tibio-talar joint, despite near anatomic fracture healing.

At a median fourteen years following tibial nailing of isolated tibial fractures, patients function very well, but objective and subjective evaluation shows not insignificant sequellae.


J. de Beer R. Gandhi A. Rungi D. Petruccelli A. Adili M. Hubmann

Retrospective review of four thousand two hundred and fifty-two patients undergoing TJR at a single high-volume arthroplasty centre to determine prevalence and timing of myocardial infarction (MI) following TJR. The incidence of peri-operative MI was 1.5%, with a mean of three days to time of MI. This cohort was comprised of 55% females with a mean age of seventy-five years. We found poor correlation between pre-operative risk assessment using the Modified Multifactorial Index score. Our findings suggest that there is a minimum length of stay compatible with patient safety given the inadequacy of currently available preoperative risk assessment tools.

This study was undertaken to evaluate the prevalence and timing of peri-operative myocardial infarction in patients undergoing total joint replacement (TJR).

Despite the pressure toward decreasing length of stay following TJR surgery, we suggest that there is a minimum length of stay compatible with patient safety given the inadequacy of currently available preoperative risk assessment tools.

The prevalence rate of peri-operative MI was 63/4252(1.5%), with a mean time of three days (range 0–18) to MI. Furthermore, there was a predominance of females (55%) and a mean age of seventy-five years among this cohort. We found poor correlation between pre-operative risk assessment using the Modified Multifactorial Index score.

Patients who suffered an acute MI following elective TJR surgery between April 1998 and April 2003 were abstracted from the Hospital CIHI database of four thousand two hundred and fifty-two patients. The role of preoperative risk assessment and risk reduction strategies were also evaluated.

The previously reported rate of MI is 0.3 % and 0.9% following unilateral and bilateral TJR respectively. The reported frequency of MI tends to increase with older age (> 70 yrs) and male gender. There is emerging information that these rates may be grossly under-estimated. Prosthetic arthroplasty is major surgery and regardless of the surgical technique, patients remain at risk for complications.


B. LaRue J.F. Gimaël É. Anctil C. Loranger S. Ricard

Entre Janvier 1998 et Février 2001, 39 patients avec une fracture du 5e distal du tibia furent traités primaire-ment à l’aide d’un enclouage centromédullaire vérouillé statique. La population étudiée est composée de 24 hommes et 15 femmes, âgés de 40 ans en moyenne. Le suivi moyen est de 12,9 mois.

Une union osseuse a été obtenue pour toutes les fractures. Le temps moyen de consolidation fut de 21,5 semaines (incluant un cas à 68 semaines). Quatre patients on présenté un retard d’union, et une chirurgie additionnelle fut requise chez trois d’entre eux. Deux patient ont présenté une malunion. Ces deux cas étaient associés à une fracture du péroné distal qui n’avait pas été ostéosynthésée.

Les fractures du tibia distal demeurent un défi thérapeutique pour le chirurgien orthopédique. L’enclouage centromédullaire alésé verrouillé statique est une méthode d’ostéosynthèse sécuritaire et efficace pour ces fractures, tel que démontré dans notre série.

L’enclouage centromédullaire est désormais considéré comme la méthode d’ostéosynthèse la plus appropriée dans le traitement des fractures déplacées de la diaphyse tibiale. Son usage s’est étendu aux fractures des tiers proximaux et distaux du tibia. Par contre, beaucoup moins de preuves sur l’efficacité d’un tel traitement existent.

Les fractures du tibia distal demeurent un défi thérapeutique pour le chirurgien orthopédique. L’enclouage centromédullaire alésé verrouillé statique est une méthode d’ostéosynthèse sécuritaire et efficace pour ces fractures, tel que démontré dans notre série. Le montage offre une stabilité suffisante pour la mobilisation et la mise en charge précoce. L’adhérence à une technique minutieuse est requise et permet d’éviter une malunion.

Notre série confirme la place de l’enclouage centromédullaire comme méthode d’ostéosynthèse primaire des fractures du 1/5 distal du tibia.

Entre Janvier 1998 et Février 2001, 39 patients avec une fracture du 5e distal du tibia furent traités primaire-ment à l’aide d’un enclouage centromédullaire vérouillé statique.

La population étudiée est composée de 24 hommes et 15 femmes, âgés de 40 ans en moyenne (16 à 79 ans). Le suivi moyen est de 12,9 mois (7 à 24 mois)

Une union osseuse a été obtenue pour toutes les fractures. Le temps moyen de consolidation fut de 21,5 semaines (incluant un cas à 68 semaines). Quatre patients on présenté un retard d’union, et une chirurgie additionnelle fut requise (dynamisation du clou) chez trois d’entre eux.

Deux patient ont présenté une malunion, soit 5o de varus dans un cas et 7o de valgus dans un cas. Ces deux cas étaient associés à une fracture du péroné distal qui n’avait pas été ostéosynthésée.

Aucune perte de réduction n’a été notée en postopératoire.

Cinq complications furent notées, soit un bris de matériel (vis de verrouillage n’entrainant pas de séquelle foinctionnelle et ne requérant pas de réopération), deux syndromes du compartiment et deux atteintes neurologiques (sciatique poplité externe). Aucune infection ni problème cutané ne sont survenus.

En moyenne, la mise en charge fut autorisée à 5,8 semaines postopératoire.

Financement: Aucun


M. Bhandari G. Matthys J.M. Matta

There has been considerable debate regarding the factors that predict clinical and radiographic outcomes in patients with acetabular fractures and associated posterior hip dislocations. We used a prospective database of acetabular fractures to identify variables associated with clinical and radiographic outcomes. Quality of fracture reduction was identified as the only significant predictor of radiographic grade, clinical function, and development of post-traumatic arthritis. Our findings support Letournel’s report that quality of the fracture reduction remains the most important factor associated with outcome in patients with acetabular fractures and concomitant posterior hip dislocations.

There has been considerable debate regarding the factors that predict clinical and radiographic outcomes in patients with acetabular fractures and associated posterior hip dislocations.

To identify variables associated with clinical and radiographic outcomes.

Utilizing a prospective database of acetabular fractures, we identified patients with posterior hip dislocations operatively managed within three weeks of injury and having a minimum of two years of follow up. Demographic information, operative findings, and outcomes were recorded. We conducted a series of uni-variable analyses to determine whether any independent variables were significantly associated with the dependent variable.

Among one hundred and nine eligible patients with posterior hip dislocations, the most common fracture types included the posterior wall and transverse with associated posterior wall fractures. An anatomic reduction of the fracture was achieved in ninety-six patients. At their most recent follow up, the majority of patient maintained a good to excellent radiographic grade. Of those who underwent clinical outcome grading (ninety-four patients), 83% achieved good or excellent outcomes. Overall radiographic grade correlated with each domain of the clinical grade including ambulation, range of motion, and pain. Quality of fracture reduction was identified as the only significant predictor of radiographic grade, clinical function, and development of post-traumatic arthritis. All patients with poor reductions and imperfect reductions, respectively, had developed arthritis compared to 24% of patients with anatomic reductions.

Our findings support Letournel’s report that quality of the fracture reduction remains the most important factor associated with outcome in patients with acetabular fractures and concomitant posterior hip dislocations.

Funding: This study was funded by a research grant from Stryker Orthopaedics, Los Angeles, California. Dr. Bhandari was funded, in part, by a fellowship from AO International, Davos, Switzerland and AO North America, Paoli, Pennsylvania.


C.W. Brown B. Deheshi G. Dervin

Femoral neck fractures in the elderly has a devastating impact on health and resources. Past trends suggest pinning un-displaced fractures in the more active elderly patients and resorting to arthroplasty in those less active. In our study the failure rate for un-displaced fractures (18.4%) was greater than that quoted in the literature and greater than the failure rate of fractures treated with arthroplasty (7.4%). Failures consisted of AVN (5), nonunion/malunion (1) and loss of fixation (1). This data suggests that arthroplasty would decrease the failure rate in our study group.

To evaluate the outcome of ORIF for un-displaced femoral neck fractures in the elderly at a tertiary care teaching hospital.

ORIF of femoral neck fractures in the elderly at our institution resulted in higher failure rates than quoted in the literature. A large multi-center randomized controlled trial is warranted to establish clear guidelines in the management of these injuries.

In our study the failure rate for undisplaced fractures was greater than fractures treated with arthroplasty. The clinical relevance of this data suggests that not all un-displaced fractures go on to uneventful union.

Of the forty-five patients that met the inclusion criteria for un-displaced femoral neck fracture, seven of which were originally treated at our institution failed, resulting in 18.4% failure rate. In comparison, our complication rates for displaced femoral neck fractures treated with arthroplasty results in a 7.4% failure rate. Failures consisted of AVN (5), nonunion/malunion (1) and loss of fixation (1).

Retrospective study. Patients sixty-five to eighty years of age with un-displaced femoral neck fractures repaired by cannulated screw fixation from 1995 to 2001. X-ray confirmation was done when fracture was not described in the chart. Failure of pinning was defined as requiring re-operation or arthroplasty.

Recent studies argue in favor of arthroplasty for most displaced femoral neck fractures. Despite the limitations of our study, the failure rate of the un-displaced femoral neck fracture is higher than that quoted in the literature, and suggests that arthroplasty would decrease the failures in our study group.


M. Flint R. Bell J. Wunder P. Ferguson A. Griffin

Forty-six patients with an uncemented proximal tibial endoprosthesis were reviewed following resection of a proximal tibial tumor. The mean age was thirty-four years and the majority were male. The most common malignant diagnosis was osteosarcoma. Oncologic and functional analysis was performed on these cases. At latest follow-up thirty of the patients remain alive with no evidence of disease and eleven had died. The most common complication was deep infection (7/46). Only six patients had mechanical prosthesis related complications. At latest follow up the average TESS score was 76.3 and MSTS score 75.5 with an average extensor lag of 6.5o.

To review the oncologic and functional results of a series of forty-six uncemented proximal tibia tumour replacements.

A retrospective review of our prospectively collected database revealed forty-six patients with an uncemented proximal tibial replacement following tumour excision. The data was analysed with respect to patient demographics, operative and prosthetic complications. Oncologic diagnosis and results and functional results were also reviewed.

The average age of the forty-six patients was thirty-four years (14–73) with thirty-three males and thirteen females. The most common diagnosis was osteosarcoma. There were four cases of benign GCT. At an average follow-up of 85.8 months (11–170), thirty were alive with no evidence of disease while eleven patients had died of their disease. Four patients were alive with evidence of disease at latest follow-up and one patient had died of unrelated causes.

The most common operative complication was infection (9/46) with seven of these being deep infections requiring prosthesis removal, followed by mechanical problems including stem fracture (3/46) and bushing failure (3/46) also requiring operative intervention.

Functional assessment revealed an average extensor lag of 6.5o with an average ROM of 83.6o, average TESS scores of 76.3 and MSTS 93 scores of 75.5.

Large series of uncemented proximal tibial endoprostheses are uncommon in the literature. In our series there is a low rate of aseptic loosening at an average seven year follow-up, but this is offset by problems including infection and prosthetic fracture. Overall the functional and oncologic results remain satisfactory.


I.L.D. Le R. Buckley R.K. Leighton

These results support the use of an injectable, in situ hardening calcium phosphate paste to prevent the early loss of calcaneal height and maintain a more anatomic calcaneal reduction.

The purpose of this prospective randomized controlled trial was to determine whether ORIF plus an injectable bioresorbable calcium phosphate paste (_-BSM) is superior or inferior to ORIF alone in the treatment of calcaneal bone voids encountered after operative treatment of displaced intraarticular fractures of the calcaneus.

Forty-four patients (forty-eight displaced intraarticular calcaneal fractures necessitating operative fixation) presenting to a Level One trauma center were enrolled into the study and randomized 1:1 to receive ORIF and injection of _-BSM or ORIF alone. All patients had a standardized ORIF thru a lateral approach by a single surgeon (R.B.).

The primary outcome measure was the maintenance of post- operative Bohler’s angle at six weeks, three months, and six months. Other outcome measures included the SF-36 and LEM (Lower Extremity Measure) Score at six months.

Five patients with seven calcaneal fractures were lost to follow up leaving thirty-nine patients with forty-one calcaneal fractures (85%) for analysis. Twenty-one were randomized into the ORIF and _-BSM group and twenty into the ORIF alone group. There was no statistical difference between the two groups with regard to age, sex, mechanism of injury, initial Bohler’s angle, or type of fracture.

There was no difference between the groups in the degree of collapse of Bohler’s angle at six weeks and three months when compared to initial post-operative values. However, at six months the mean collapse of the _-BSM and ORIF group was 5.6° and ORIF alone was 10.6°. This was statistically significant (p< 0.01).

Funding: Industry supported: DePuy, a Johnson & Johnson Company

Analysis and data collection performed independently.


R Leighton W.M. Ricci J. Schwappach D. McGinnis M. Tucker K. Coupe

Reducing exposure to radiation is a concern to physicians and supporting staff. Little is known about the factors leading to increased exposure in intramedullary nailing of long bone fractures. This study examines antegrade and retrograde nailing of femur and tibia fractures. Factors that increased radiation exposure were obesity, severely comminuted fractures, nails inserted through the piriformis fossa, and insertion of more locking bolts in femoral nails. In addition, femoral nails required more radiation exposure than tibial nails.

Exposure to radiation is a concern to physicians. The purpose of this study was to determine factors associated with increased radiation exposure with intramedullary nailing of long bone fractures.

Femoral nailing through the piriformis fossa, highly comminuted fractures, insertion of more locking bolts (femur), and obesity are each associated with the higher radiation exposure.

Factors associated with increased radiation exposure are identified for tibial and femoral nailing.

Radiation exposure was higher for nailing of femur fractures (ninety-two seconds) compared to nailing of tibia fractures (sixty seconds). Exposure was greatest for insertion through the piriformis fossa (one hundred and twenty-one seconds) and least for retrograde insertion (seventy-four seconds) and intermediate for insertion through the trochanter (eighty-seven seconds). Obese patients (BMI > 30) had higher exposure times for both femoral (obese-one hundred and sixty seconds, non-obese-eighty-five seconds) and tibial nailing (obese-seventy-nine seconds, non-obese-fifty-five seconds). Only the most severely comminuted fracture patterns (Winquist IV) were associated with increased fluoroscopy time. Increasing number of interlocking bolts was associated with higher exposure for the femur but not the tibia.

One hundred and thirty-nine consecutive patients treated with intramedullary nailing for either a femoral shaft (OTA 32, n=71) or tibial shaft (OTA 42, n=68) fracture were prospectively evaluated in this IRB approved study. Radiation exposure (c-arm fluoroscopy time) was measured. Femur fractures were treated with either a retrograde nail (n=24), an antegrade nail inserted through the piriformis fossa (n=20), or an antegrade nail inserted through the tip of the greater trochanter (n=27).

Funding: Smith & Nephew


P. Ranger P. Dahan E. De Oliveira G. Berry M. Talbot J. Fernandes

Acute total knee dislocations are uncommon injuries for which some surgeons use artificial ligaments as their choice of graft for reconstruction. The goal of this study is to evaluate on a short and long term basis the stability and function of the LARS reconstructed knee. Flexion ROM was the only parameter which showed significant difference (p< 0.05) between subgroups. Therefore this treatment option for dislocated knee reconstruction seems to give good and lasting results even though patient’s quality of life may suffer.

Although a variety of options have been proposed for the treatment of knee dislocations, the optimal one remains controversial. Allografts and autografts have both been used for reconstruction of the cruciate ligaments. The purpose of this study is to evaluate acute reconstruction of both cruciate ligaments using Ligament Advanced Reinforced System (LARS) artificial ligaments.

We reviewed treatment of forty-eight acute knee dislocations. All patients had reconstruction of both cruciate ligaments with LARS ligaments. Patients were assed using SF-36, Lysholm and IKDC questionnaires as well as a physical exam. Stability of the reconstructed knee was evaluated radiologically using TELOS instrumentation. The controlateral knee was used as reference.

The forty-eight patients were subdivided into four groups of post-operative intervals ranging from six months to seven years. The average ROM was 120°of flexion and −1.4° of extension. The differential average TELOS for LCA, LCP at 30° and LCP at 90° were respectively 2.9 mm, 2.8 mm, 6.9 mm. and their average Lysholm, SF-36 and IKDC scores were 72.0, 72.5, 53.5. Statistical results showed no significant difference (p> 0.05) between subgroups in terms function, laxity and extension but did in flexion.

Our data show that patients treated by this method can regain a functional knee in terms of motion, stability and functional status and does not seem to deteriorate with time.

Knee reconstruction with artificial ligaments shows promising results at short and longer term even though it seems to affect quality of life in this population.

Financing: This study was partially financed by JK Orthomedic Inc.


E.H. Schemitsch R. Selby W.H. Geerts M.A. Crowther H.J. Kreder M. Bent P. Weiler

We report preliminary results from the first, multicenter prospective study designed to define the incidence of symptomatic (Venous Thromboembolism) VTE in patients with isolated leg fractures distal to the knee. Eight hundred and twenty-six enrolled patients have completed three months of follow up. By three months, only seven patients had sustained a symptomatic VTE with no fatal PE. Symptomatic and fatal VTE were infrequent complications after isolated leg fractures distal to the knee without thromboprophylaxis. Routine thromboprophylaxis may not be warranted in isolated leg fractures distal to the knee.

To report results from the first, multicenter prospective study designed to define the incidence of symptomatic Venous Thromboembolism (VTE) in patients with isolated leg fractures distal to the knee.

Symptomatic and fatal VTE are infrequent complications after isolated leg fractures distal to the knee without thromboprophylaxis.

Routine thromboprophylaxis may not be warranted in isolated leg fractures distal to the knee.

From August 2002 to April 2004, one thousand eight hundred and eight consecutive patients with isolated leg fractures distal to the knee were screened for entry at five hospitals in Ontario. Patients with major trauma, active cancer and previous VTE were excluded. Thromboprophylaxis was not allowed. Patients were followed prospectively for three months, with telephone calls at fourteen days, six weeks and three months. Suspected DVT and PE were investigated in a standardized manner.

Eight hundred and twenty-six enrolled patients have completed three months of follow up. The mean age was forty-five years (range sixteen to ninety-three) and 59.5% of this cohort was female. 99% of these fractures were unilateral and 97% were closed. Fractures included: fibula (38%), metatarsal (29%), phalanges (13%), calcaneus, talus or tarsal (10%), tibia (10%) and patella (7%). Only 11% of fractures were surgically treated. 88% of fractures received a cast or splint for a mean duration of 41+/− 20 days. Complete follow-up was available for 97.5% of this cohort. By three months only seven patients had sustained a symptomatic VTE (2 proximal DVT, 3 calf DVT, 2 PE) with no fatal PE-an incidence of 0.9% (95% CI 0.3 to 1.8%).

Funding: This study was funded by a research grant from Pharmacia


I.D. Dickey P.S. Rose B. Fuchs L. Wold S. Okuno C.P. Beauchamp F. H. Sim

The influence of advancements in imaging and chemotherapy on patient with dedifferentiated chondrosarcoma was determined. There were forty-two cases in which twenty-seven patients received adjuvant therapy. Median survival was eight months and five-year survival was 4.8%. There was no statistical difference (p=0.62) in survival between patients who did and did not receive chemotherapy, had wide versus radical resection, or had limb sparing versus sacrificing procedures. There were no statistically significant differences between patients treated prior to 1986 and those subsequently. Despite advances, dedifferentiated chondrosarcoma continues to carry a poor prognosis. The routine adjuvant chemotherapy in this population should be questioned

The long-term survival for patients that presented with dedifferentiated chondrosarcoma has historically been poor. A large clinical series has not been analyzed in the era of modern diagnostic and treatment modalities. The current study was performed to look at the influence of advancements in imaging and chemotherapy on patient outcome. A retrospective chart review of all cases of patients presenting with dedifferentiated chondrosarcoma at our institution from 1984–2000 was performed. This was done as an extension to a study published in 1986 prior to the era of modern chemotherapy.

There were forty-two cases in twenty-five men and seventeen women of average age fifty-six (range twenty-four-eighty-three years). MSTS grades at presentation were IIA(5), IIB(27), and III(10). Three patients underwent biopsy only, nineteen had limb sacrificing surgery, and twenty had limb sparing procedures. Surgical margins were intralesional in three, marginal in two, wide in twenty, and radical in fourteen. Twenty-seven patients received adjuvant therapy (twenty-two chemotherapy only, two radiotherapy only, three combined therapy). Median survival was eight months and five-year survival was 4.8%. There was no statistical difference (p=0.62) in survival between patients who did and did not receive chemotherapy, had wide versus radical resection, or had limb sparing versus sacrificing procedures. There were no statistically significant differences between patients treated prior to 1986 and those subsequently.

Despite advances in diagnostic modalities, surgical treatments, and adjuvant therapies, dedifferentiated chondrosarcoma continues to carry a poor prognosis. The routine use of current adjuvant chemotherapy and its inherent risks and benefits in this population should be questioned.


A.M. Griffin M. Shaheen P.C. Ferguson R.S. Bell J.S. Wunder

Twenty-three patients with scapular chondrosarcomas presented to our institution between 1989 and 2003. Twenty-two were treated surgically while one presented with metastases and was treated palliatively. Fourteen patients underwent partial scapulectomy and eight had a Tikhoff-Linberg procedure. There were no local recurrences and only two patients have suffered a systemic recurrence at mean follow-up of fifty-two months. Mean functional scores were: TESS – 88, MSTS 1987 – 27 and MSTS 1993 – 84. Overall, the oncologic and functional outcome for these patients was excellent.

To examine the oncologic and functional outcome of patients treated for chondrosarcoma of the scapula.

Rates of local recurrence and metastasis for adequately treated chondrosarcomas of the scapula were very low and patient function was quite good.

Unlike previous reports in the literature, we found that scapular chondrosarcomas are highly amenable to limb salvage surgery and the oncologic and functional outcomes are excellent.

Retrospective review of our prospectively collected database for all patients treated surgically at our institution for scapular chondrosarcoma between 1989 and 2003.

Twenty-three patients presented with scapular chondrosarcoma, but one had spine metastases and was treated palliatively. Thus twenty-two patients were treated with limb salvage surgery. There were fourteen males and eight females. One patient presented as a local recurrence. Four tumors were grade one, sixteen grade two and two grade three. Eight were secondary to a primary benign primary tumor of bone. There were fourteen partial scapulectomies and eight Tikhoff-Linberg procedures. Surgical margins were positive in three cases. two patients received post-operative radiation and no patients received adjuvant chemotherapy. At last follow-up, twenty patients were alive with no evidence of disease (90.9%), one was alive with disease and one was dead of disease. There were two systemic recurrences and no local recurrences at an average follow-up of fifty-two months (range 12–113). Mean functional scores were: TESS – 88, MSTS – 1987 27 and MSTS 1993 – 84.


P.W. Clarkson A.M. Griffin C.N. Catton B. O’Sullivan P.C. Ferguson J.S. Wunder R.S. Bell

Many authors believe that size, histological grade and depth are the best predictors of outcome in soft tissue sarcoma. Enneking’s surgical staging system included compartmental status, and was intended to guide surgical intervention as well as provide prognostic information. Advances in surgical and radiotherapy techniques may mean that extracompartmental status is no longer a poor prognostic factor. We compared a group of popliteal fossa sarcomas with a group from the posterior thigh, and found that although the former group required more extensive surgery to obtain wide margins, their functional and survival outcomes were similar.

No single staging system has been generally accepted for extremity soft tissue sarcoma, although histologic grade, size and depth are widely accepted as prognostic indicators. Enneking outlined a surgical staging system which used compartmental status as a predictor of outcome. However, surgical reconstruction and adjuvant radiotherapy have advanced considerably. We wanted to know if a tumour arising in the popliteal fossa still had poorer survival or functional outcome in the light of these advances.

We identified twenty-three patients who had sarcomas of the popliteal fossa and forty-six patients who had sarcomas of the nearby posterior thigh compartment. Popliteal sarcomas were not of a different size or more likely to present with metastasis. Popliteal tumours more frequently required reconstructive techniques such as local or free tissue transfer and skin grafting than posterior thigh tumours (39.1% v 4.3% respectively). Popliteal tumours were also more likely to undergo a dissection or reconstruction of the major neurovascular structures of the lower limb (30.4% v 0% respectively). There was no difference in local or systemic recurrence rates between the groups. TESS and MSTS 1987 functional scores also showed no difference between the groups.

We conclude that popliteal fossa sarcomas require a greater level of surgical intervention to follow sound principles of sarcoma resection and achieve reconstruction of the ensuing soft tissue defect. However, if these principles are followed in a planned multidisciplinary setting, then survival and functional results similar to the posterior thigh can be expected.


D. Martin M. Sabeti A. Farshid T. Klemens K. Rainer

We describe a new method of reconstruction of the extensor apparatus after extensive resection of malignant tumours around the knee joint with a polyester ligament. Twenty- two patients after a mean follow up of eighteen months (six to thirty-six months) were treated. Six patients had excellent knee function with a lag of extension less than five degrees, four of less than twenty, three had less than forty degrees and six patients could not lift their limb extended against gravity, although no patient required any kind of walking aid. The mean Enneking Score was 81.5 the mean TESS Score was eighty-three.

Limb salvage surgery in primary malignant bone tumours is widely accepted as the surgical treatment of choice around the knee joint. Extraarticular resection for oncological radicality usually results in additional resection of at least part of the extensor mechanism

Since January 2000 we used a Polyester Band (LARS®) for either augmentation of a transposed muscle or as a complete soft tissue bridging after tumour resection in twenty-two patients (fourteen men, eight women) with a mean age of thirty-two (8–75). The HMRS tumour endoprosthesis was used for the reconstruction of the knee joint.

The location of the tumour was in the distal femur in ten cases and the proximal tibia in eleven. One synovial sarcoma arose at the lateral meniscus. The mean follow up was eighteen months (6–36) after implantation of the Lars® ligament. Patient’s functional outcome and satisfaction was eighty-three (65–92) at the TESS Score and 81,5 (43–92) at the Enneking Score, respectively. Six patients had excellent knee function with an extension deficit of less than five degrees. In four cases the extension deficit was less than twenty, in three cases it was less than forty. In six patients the active extension lag was more than forty degrees. However, their remaining quadriceps strength was sufficient for stabilisation of the knee joint during gait without any aids. At last follow up all implants were in situ without any signs of loosening. No patient had to be amputated because of septic complication.


B. Singh F. Khan

Twenty-two patients who underwent thirty-four Kellers’ excision arthroplasty were followed up at an average of thirty-five months. They were assessed using AFAOS, satisfaction and radiological evaluation. The average hallux score was eighty- five (fifty-two to one hundred) while the average lesser toe score was ninety- two (seventy-five to one hundred). The average pain score was thirty- six (twenty to forty) for the hallux and thirty-eight for the lesser toes (twenty to forty). 23/34(68%) had good to excellent, 6/34 (18%) had fair and 5/34(14%) had poor results. The great toe was moderately short, but most patients do not seem to mind this. 91% patients were satisfied with the results.

We undertook a retrospective study of Kellers’ excision arthroplasty done over the last seven years to assess the medium term results.

Twenty-two patients who underwent thirty- four Kellers’ excision arthroplasty were followed up at an average of thirty-five months. They were followed up using the AFAOS, patient satisfaction and radiological evaluation. The average age at the time of surgery was 67.4 years. There were seventeen females (twenty-five feet) and five males (nine feet). All patients underwent bunionectomy along with excision of proximal third of the proximal phalanx. Of these twenty underwent K wire stablization of the hallux following excision.

The average hallux score was eighty- five (range sixty-two to one hundred) while the average lesser toe score was ninety- two (range seventy-five to one hundred). The average pain score was thirty- six (range twenty to forty) for the hallux and thirty-eight for the lesser toes (twenty to forty). 23/34 (68%) had good to excellent, 6/34 (18%) had fair and 5/34(14%) had poor results. The average correction of the hallux valgus was 9o. The average IMT was 25o preoperatively and 18o postoperatively. The average shortening was 7 mm. Complications included two cases of transfer metatarsalgia and two cases of clawing of the lesser toes. One patient developed abscess which settled after incision and drainage. Thirty-one out of thirty-four patients were satis-fied with the final outcome and thirty out of thirty-four patients would have the operation on the other feet.

The great toe is moderately short, but most patients do not seem to mind this. 91% patients were satisfied with the results.


F.D. Lalonde R.C. Goodwin T.P. Gaynor A. Mahar R. Oka

Few published series demonstrate the complications of flexible intramedullary nailing of unstable tibial diaphyseal fractures in children. A retrospective review of nineteen patients was performed, as well as a biomechanical analysis. Two common implant configurations were compared, double or divergent C and medial C and S. Five patients (26%) had complications. Two angular deformities (> 10°) occurred with the medial C and S. The C and S demonstrated lower range of motion than the double c. Despite it’s inferiority in biomechanical testing, the double c construct was associated with fewer complications and is the authors’ preferred technique.

To summarize the complications seen with intramedullary flexible nailing of tibial diaphyseal fractures and to examine the clinical outcomes and biomechanical properties between two different fixation constructs (double C vs. C and S constructs).

A retrospective review of nineteen patients was performed, as well as a biomechanical analysis of stability in torsion and compression when using two types of implant configurations in a pediatric sized synthetic tibia model. Outcome measures included union rates, residual deformity, and complications. Five patients (26%) had complications. Union occurred in all cases. None required repeat operation. Two (11%) angular deformities (> 10°) occurred with the medial C and S construct, versus none with the double C. The C and S configuration demonstrated significantly lower range of motion (32 + 4 degrees) compared to the double c configuration (71 + 20 degrees) (p< 0.03). There was no statistical difference in failure load at 5mm of gap closure between the C and S configuration (105 + 62N) and the double c configuration (40 + 42N) (p=0.2).

The C and S construct was superior in biomechanical testing, however the double c construct had no angular deformities greater than ten degrees in the clinical series. Flexible intramedullary nail fixation is a straightforward technique that reliably produces good results. Despite it’s inferiority in biomechanical testing of a synthetic tibia model, the double c construct was associated with fewer complications and is the authors’ preferred technique.


A. Fawzi G. Beadle R. Torcotte R. Bill J. Wounder M. Isler

We evaluate the outcome (Functional, Oncological, and complications) after resection of pelvic sarcoma and reconstruction with the saddle prosthesis. Twenty-seven patients with a mean follow up of forty-five months. Fourteen patients were free of disease, eleven patients were deceased, and two patients were alive with disease. MSTS 93 was 51 %, MSTS 87 was15%, and TESS was 64 %. Infection occurred in ten, fracture in six, and dislocation in six patients. Vertical migration stabilized after two years. Five patients were retired, five had full-time employment, six were disabled, and eleven were deceased. Reconstruction with saddle prosthesis following resection for pelvic sarcoma is associated with significant morbidity.

Treatment of pelvic sarcoma is difficult. Of many techniques described for reconstruction of the pelvis following tumor resection, limited data exists to compare functional results.

To evaluate the outcome after resection of pelvic sarcoma and reconstruction with the saddle prosthesis.

This retrospective study includes twenty-seven patients who underwent saddle prosthetic reconstruction for pelvic sarcoma. Functional outcome was assessed with MSTS 1987 & 1993 and the Toronto Extremity Salvage Score (TESS). Oncological outcome parameters and complications were recorded.

We reviewed twenty-seven patients with a mean follow up of forty-five months. Seven (26%) patients underwent type II (periacetabular) pelvic resection, twenty had type II & III (periacetabular and pubis). Eleven patients received chemotherapy. None received radiation. Fourteen patients were free of disease, eleven patients were deceased, and two patients were alive with disease. The survival rate was 60%, 22% had local recurrence, and 22% had metastasis. Functional evaluation was completed in seventeen patients and the mean for MSTS 93 was 50.8 %, the MSTS 87 was15.3%, and the TESS was 64.4 %.

Infection occurred in ten cases, and there were five nerve palsies. Heterotopic ossification occurred in ten, fracture in six, and dislocation in six patients. Limb shortening was initially progressive but stabilized after two years and ultimately ranged between one and six centimeters. Five patients were retired, five had full-time employment, six were disabled, and eleven were deceased.

Reconstruction with saddle prosthesis following resection for pelvic sarcoma is associated with significant morbidity. However the functional results appear to confer an advantage when compared to the significant disability following hemipelvectomy


S. Walsh G. Berry R. Reindl E. Harvey

A variety of surgical procedures are reported for the management of large volumetric bone loss about the ankle. Although the success rates of these various methods are generally adequate for fusion, they commonly utilize autogenous bone graft and usually result in limb shortening. In seven patients a titanium spinal cage was utilized as a structural support augmented with bone graft for complex ankle arthrodesis. This technique offers immediate structural support, maintenance of limb length, and limits autogenous graft morbidity. Early results of ankle arthrodesis with this cage are encouraging with regard to fusion rates, aesthetic attribute and functional outcome.

To present a novel method of tibio-talar and tibio-calcaneal arthrodesis utilizing a titanium spinal cage for the management of bone loss.

Complex ankle arthrodesis management with a spinal cage offers reliable fusion rates (comparable with existing techniques) without limb shortening.

A variety of procedures are reported for the challenging management of bone loss in ankle arthrodesis. Although the success rates of these various methods are generally good, they commonly utilize large autogenous bone grafts and are subject to donor site morbidities. Most methods also require significant shortening with commensurate functional and aesthetic deficits.

Early results of ankle arthrodesis with a titanium spinal cage are encouraging with regard to fusion rates and functional outcome. A cohort of seven patients treated by this technique has resulted in a 100% fusion rate without loss of limb length. Hindfoot and SMFA scores have revealed good functional results for a usually devastating problem.

A titanium cage was utilized as a structural support for complex ankle arthrodesis with large volumetric bone loss. The cage was contoured at the time of each operation to fit in situ. This technique offers immediate structural support and reliable fusion while limiting autogenous graft morbidity and limb shortening.


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N. Aslam K. Nagarajah M. McNally

Chronic osteomyelitis is a very difficult condition to treat. It presents a considerable challenge. A structured approach with a multidisciplinary team is important.

Fifty-three patients with chronic femoral osteomyelitis were treated. Thirty-one cases followed fracture fixation, fourteen haematological, two knee fusion and two iatrogenic. Cierny and Mader grade was IV in twenty-eight cases(twelve non-unions). Union was achieved in eleven of twelve nonunions. 85% of cases were infection free with the current treatment. 92% union rate was achieved. Eradication of infection and functional preservation can be achieved by wide local debridement with good soft tissue coverage and skeletal stabilisation.

Chronic osteomyelitis is a very difficult condition to treat. It presents a considerable challenge. A structured approach with a multi-disciplinary team is important.

85% of cases were infection free with the current treatment. 92% union rate was achieved. Eradication of infection and functional preservation can be achieved by wide local debridement with good soft tissue coverage and skeletal stabilisation.

Fifty-three patients with chronic femoral osteomyelitis were treated. Mean age at onset was thirty-one years and mean duration of infection was one hundred and six months (range 2–504). Thirty-one cases followed fracture fixation, fourteen haematological, two- knee fusion and two iatrogenic. Cierny and Mader grade was IV in twenty-eight cases(twelve non-unions), III in twelve, II in two and I in eleven cases. Intramedullary disease was treated by reaming and cortical disease by local excision. Radical excision was done for local disease. Radical/segmental excision reserved for type IV disease. This was followed by dead space management (local antibiotics in thirty-eight patients), stabilization and iv antibiotics(four to six weeks). Infected nonunion was treated with excision and stabilization or Ilizarov reconstruction. Union was achieved in eleven of twelve nonunions. 85% of cases were infection free at a mean follow-up of thirty months (7–48).


J. Jarvis S. Garbedian G. Swamy

In order to determine the effectiveness of part-time bracing in juvenile idiopathic scoliosis (JIS) a retrospective review of thirty-four patients treated with a Charleston bending brace for JIS was undertaken. The patients were analyzed in three groups including:

success;

progression;

progression requiring surgery.

Of twenty-three patients meeting the inclusion criteria, nine achieved success, seven progressed, and seven required surgery. Success correlated with best in brace correction radiograph but not with initial curve magnitude. Part-time bracing is as successful as full-time bracing in JIS and better than the natural history.

In order to determine the effectiveness of part-time bracing in JIS, a retrospective review of thirty-four patients treated with a Charleston bending brace for JIS was undertaken.

Twenty-three patients met the inclusion criteria which included: curves greater than twenty degrees at initiation of bracing, Risser zero, bracewear more than twelve months, completion of the bracing program and Risser greater than or equal to four at final follow-up. Patients were analyzed in three groups, including

success (progression less than five degrees or less);

progression more than five degrees (but not requiring surgery) and

progression requiring surgery.

There were seven boys and sixteen girls with thirty-seven curves analyzed. Age at referral averaged 8.3 years. Average curve at time of bracing was thiry degrees. Length of bracing averaged 4.2 years with follow-up averaging 6.2 years. Nine patients met the criteria for success with seven patients progressing and seven patients requiring surgery. Of all curves, nineteen (51%) were successfully managed in the brace. Magnitude of curvature at initiation of bracing was not related to ultimate success, whereas success did correlate with higher best in brace correction radiographs.

Part-time bracing offers potential psychosocial and compliance benefits considering the length of treatment necessary in patients with juvenile idiopathic scoliosis. Although previous bracing studies have included some JIS patients, no authors have dealt specifically with the part-time bracing for JIS.

Part-time bracing is as successful as full-time bracing in JIS and better than the natural history.


T.P. Carey R. El-Hawary C.A. Black K.K. Leitch

The majority of pediatric proximal humerus fractures are successfully treated non-operatively. Significantly displaced fractures have traditionally been treated surgically with percutaneous pinning. This review of twenty-three surgically treated patients demonstrates a high rate of infection associated with percutaneous pinning. The technique of cannulated screw fixation offers a safe surgical alternative for the treatment of these fractures in the adolescent population.

To compare the results of percutaneous pinning to cannulated screw fixation for the treatment of pediatric proximal humerus fractures.

A high complication rate, including pin tract infection and loss of reduction, was observed in the percutaneous pinning group.

Given the rigid fixation afforded by cannulated screws and the minimal morbidity associated with proximal humeral physeal arrest in the older adolescent, this technique offers a safe alternative for the treatment of proximal humerus fractures.

Average age was 13.0 years for the pinning group and 14.7 years for the cannulated screw group. Regardless of fixation technique, all fractures healed completely with no difference in rates of physeal closure. Significant pin tract drainage was encountered in six of twenty patients treated with pinning: Two with Staphylococcus Aureus infection and one deep infection requiring surgical debridement. Loss of reduction and pin migration was noted in a seventh patient. The only complication observed in the cannulated screw group was a transient axial nerve paresthesia. There were no significant differences in operative time, rate of open reduction, or length of hospitalization (p> 0.05).

Twenty-three pediatric proximal humerus fractures treated operatively over a seven-year period were followed clinically and radiographically.

Thirty percent of the patients treated with pinning developed pin tract infections. Similar to femoral external fixation pins, proximal humeral pins also cross a large muscle group that may result in pin micro-motion. This may create persistent drainage that ultimately leads to infection.


T. Kostamo R.L. Choit B.J. Sawatzky S.J. Tredwell

Thoracoplasty has been described as primarily a cosmetic resection of the rib hump. The purpose of our study was to investigate whether removal of a normal spine stabilizer affected the correction of the spine, particularly in the sagittal plane. Thirty-eight adolescent idiopathic scoliosis patients who underwent thoracoplasty were compared with eighteen controls in terms of maintenance of correction and patient satisfaction using the SRS questionnaire. Thoracoplasty had no effect on curve correction in the coronal plane. It did show a significant effect on sagittal plane correction of the thoracic hypokyphosis without any significant detractors in terms of patient outcome

To investigate whether thoracoplasty affected spinal correction. We also compared patient outcomes thoracoplasty patients and controls, as well as long-term curve maintenance.

Thoracoplasty did increase the correction of thoracic hypokyphosis, without any significant detractors in terms of patient outcome.

Current understanding of the scoliotic curve as a three dimensional helix has led to increased recognition of the importance of sagittal contour and balancing the spine’s reciprocal curves to avoid problems such as flat back syndrome. Correction of the scoliotic curve intraoperatively may require the removal of spine stabilizers such as the disc and annulus, posterior facet and capsule, and thoracic cage stabilizers such as the ribs.

Thirty-eight patients who had either concave para-median or convex Steel mid-rib thoracoplasty were reviewed and compared to eighteen controls. Prospective patient outcomes using the Scoliosis Research Society instrument with an average of > one year follow-up were available for thirty patients. Degree of curve settle and maintenance of correction was measured on follow-up radiographs.

Thoracoplasty had no effect on curve correction in the coronal plane. It did show a significant effect on sagittal plane correction of thoracic hypokyphosis. The paramedian group showed a mean increase of tweleve degrees, the Steel group 8.7 degrees, and, the control group 3.1 degrees. No significant difference between pain, satisfaction, function, and self-image was found. Long-term radiographic follow-up (average three years) showed a mean coronal curve settle of 4.6 degrees (thoracoplasty) versus 3.1 degrees (non-thoracoplasty), and an accompanying improvement in sagittal plane correction of 4.2 and 3.0 degrees, respectively.


J. Jarvis M. Letts D. Davidson

Subtrochanteric femoral fractures are uncommon in children, consequently there are no good treatment guidelines in the literature. This series reviewed all subtrochanteric femur fractures in skeletally immature adolescents older than ten years treated at a pediatric trauma center. There were fifteen adolescents with open growth plates. Treatment was non-operative in four and operative in eleven. Each of the adolescents treated non-operatively developed an unsatisfactory result, while eight of the eleven who were treated operatively experienced a satisfactory result. These results suggest improved outcome with operative treatment in this patient population.

It was the purpose of this study to describe treatment options and make recommendations for management of subtrochanteric femur fractures among skeletally immature adolescents older than ten years of age.

This series consisted of a retrospective review of all cases of subtrochanteric fractures in adolescents with open growth plates. The outcome was classified on the basis of radiographic criteria.

There were fifteen adolescents with an average age of thirteen years and one month. The average length of follow-up was two years and nine months. Treatment was non-operative in four and operative in eleven, utilizing a variety of fixation devices. There was fracture union in each case, although there was one delayed union. Complications included limb length discrepancy in three, each of which were treated non-operatively, one transient peroneal nerve palsy and asymptomatic heterotopic ossification. One adolescent, treated with a rigid intramedullary rod, developed avascular necrosis of the femoral head. The result was unsatisfactory in each of the non-operative cases, while eight of the eleven treated operatively developed satisfactory results.

Children less than ten years of age may be treated non-operatively. However, in skeletally immature adolescents, operative treatment resulted in improved outcomes. Rigid intramedullary fixation is contraindicated in skeletally immature adolescents due to the risk of avascular necrosis of the femoral head.

This series is the first to emphasize treatment and make management recommendations regarding subtrochanteric fractures in this age group.

Internal fixation is more effective than non-operative treatment for subtrochanteric femur fractures in skeletally immature adolescents, however the ideal method of fixation requires further study.


B. Benoit Y. Laflamme B. Morin G. Grimard

The most commonly used surgical techniques used to treat recurrent or habitual patellar dislocation in the child do not specifically address the patella alta, one of the major causes of patellar dislocation. Twelve knees in eight patients had a lowering of the patella by total tendon transfer, lateral release and vastus medialis obliquus advancement. At two years of follow-up, only one knee had redislocated. Radiographically, the patellar height was anatomically restored in all other knees. All patients were pain free. This surgical technique is a good treatment option in the immature patient with recurrent or habitual patellar dislocation.

Patella alta is one of the major causes known to predispose children to recurrent or habitual patellar dislocation. However, the surgical treatment of such a condition, before squeletal maturity, is rarely if ever mentioned in the literature.

Twelve knees in eight patients were treated with a surgical procedure designated to correct patella alta, the major predisposing factor causing recurrent patellar dislocation. The technique involves lowering of the patella by total tendon transfer, lateral release and vastus medialis obliquus advancement. All patients were complaining of recurrent or habitual dislocations leading to functional disability. Patellar height was assessed radiographically by the Koshimoto index (PT/FT) and Caton-Deschamps index (AT/AP). The average at surgery was 10.9 years and mean follow-up was 45.1 months.

Follow-up revealed redislocation in one knee. This patient required a second operation to achieve patellar stability. At the latest follow-up, all operated knees were functionally stable and pain free. The average preoperative ratios were 1.28 (PT/FT) and 1.53 (AT/AP) which improved to 0.97 (PT/FT) and 0.96 (AT/AP) at the time of follow-up. Few complications were noted.

This technique is a valid surgical alternative to treat the immature patient presenting with functional disability related to recurrent or habitual patellar dislocation associated with patella alta.


U.G. Narayanan D.L Fehlings K. Campbell S. Weir S. Knights S. Kiran

This study describes the development and initial validation of a new disease-specific outcome measure of health status and burden of care in children with severe cerebral palsy. The instrument, Caregiver Priorities and Child Health Index of Life with Disabilities(CPCHILD), has thirty-six items spanning six domains:

Personal care/ADLs,

Positioning/Mobility,

Communication/Social interaction,

Comfort/Emotions & Behaviour,

Health,

Quality of life and additionally

Caregiver’s perspective on the Importance of these items to the child’s quality of life.

The CPCHILD is a reliable and valid measure of caregivers’ perspectives on the health status, functional limitations, and well-being of children with severe cerebral palsy.

Develop and validate a disease-specific measure of health status and well-being of children with severe cerebral palsy.

The Caregiver Priorities and Child Health Index of Life with Disabilities (CPCHILD) was constructed from recommendations of caregivers, health care providers, and review of other measures. The CPCHILD has thirty-six items spanning six domains. Items are rated on an ordinal scale. Standardized scores (0–100) are reported for each domain and in total. Primary caregivers(n=77) of children(5–18yrs) with cerebral palsy, categorized by the Gross Motor Function Classification System (GMFCS) level completed the CPCHILD. Caregivers of children with severe cerebral palsy(GMFCS-IV & V), also completed the PEDI, the CHQ, and a second administration of the CPCHILD two weeks after the first.

The mean CPCHILD scores for children with severe cerebral palsy(GMFCS-V) was fifty-nine (Range:35–93) and did not demonstrate the floor effects of the PEDI and CHQ. The mean CPCHILD scores for children in GMFCS levels I to V were 22.0, 38.2, 23.0, 44.5.8 and 59.3 respectively (p < 0.0001 by ANOVA). Reliability was tested in the 41/52 caregivers who reported no health status change between the twoadministrations of the CPCHILD. The intraclass correlation coefficient(ICC) was 0.94(95% CI: 0.90–0.97).

Children with severe cerebral palsy often undergo interventions to improve quality of life and ease burden of care. The CPCHILD seems to be a reliable and valid measure of caregivers’ perspectives on the health status, functional limitations, and well-being of these children. Further validation in a larger mutli-centred study is planned.

Funding:

Paediatric Orthopaedic Society of North America (POSNA) research grant award.

Bloorview MacMillan Foundation


K. Mulpuri H. Jackman S. Tennant R.L. Choit B. Tritt S.J Tredwell

Supracondylar humeral fractures are the most common elbow injury in children, usually sustained from a fall on the outstretched hand. Iatrogenic ulnarnerve injury is not uncommon following cross K wiring. NNH is the number of cases needed to treat in order to have one adverse outcome. A systemic review was undertaken to calculate relative risks, risk difference and number needed to harm following management of supracon-dylar fractures with cross or lateral K wires. It was found that there was one iatrogenic ulnar nerve injury for every twenty-seven cases that were managed with crossed K wires.

The aim of this study was to calculate the number of cross K wiring of supracondylar fractures of the humerus that would need to be performed for one iatrogenic ulnar nerve injury to occur.

Iatrogenic ulnarnerve injury is not uncommon following cross K wiring of supracondylar fractures of the humerus.

To date there are no clinical trials showing the benefit of cross K wiring over lateral K wiring in the management of supracondylar fractures of the humerus in children. If it can be confirmed that lateral K wiring is as effective as crossed K wiring, iatrogenic ulnar nerve injury can be avoided.

A systematic review of iatrogenic ulnar nerve injuries following management of supracondylar fractures was conducted. The databases MEDLINE 1966 – present, EMBASE 1980 – present, CINAHL 1982 – present, CDSR, and DARE were searched along with a meticulous search of the Journal of Paediatric Orthopaedics from 1998 to 2004. Of the two hundred and forty-eight papers identified, only thirty-six met the inclusion criteria. The papers where both lateral crossed K wires were used as treatment were identified for calculating relative rates, risk difference and number needed to harm.

NNH was 7.69. When a sensitivity analysis removing two studies that had five subjects or fewer and a 100% ulnar nerve injury rate was peformed, the NNH was 27.7. In other words, there was one iatrogenic ulnar nerve injury for every twenty-seven cases that were managed with crossed K wires.


C.W. Reilly R.L. Choit G.P. Slobogean

This study examined clinical and radiological outcomes following video assisted thoracoscopic surgery (VATS) for anterior release and fusion in the correction of paediatric scoliotic deformities. Nineteen patients who underwent VATS were compared with nineteen open thoracotomy patients to compare degree of correction and perioperative morbidity. Demographic parameters were similar between the groups and there was no significant difference in operative time or total blood loss. VATS offered the same degree of correction as open thoracotomies and has the potential to decrease post-operative morbidity while still allowing the same degree of correction as traditional open thoracotomies.

To compare the peri-operative parameters and outcomes of video-assisted thoracoscopic surgery (VATS) with open thoracotomy for anterior release and fusion in the treatment of paediatric spinal deformities.

VATS is a good alternative to open thoracotomy.

VATS has the potential to decrease post-operative morbidity while still allowing the same degree of correction as traditional open thoracotomies.

There were nineteen patients in each group, seventeen with idiopathic scoliosis in the VATS group and sixteen in the open group. Mean age, weight at surgery and pre-operative Cobb angle were similar (p=1.000, 0.8277, 0.0636, respectively). There was no significant difference in operative time per level between the VATS group and the open group (37.2 vs. 34.5 min, p= 0.2254) or total blood loss (908 vs. 823 ml, p= 0.4953). There were no major complications encountered in the VATS group, one patient in the open group experienced atelectasis and subsequent lower lobe collapse.

A detailed chart and radiographic review was undertaken to determine degree of correction, perioperative morbidity and complications, if any, of patients who underwent VATS between 1997 and 2004 at the author’s institution. A control group of patients who underwent open thoracotomy was used to determine if is there a significant difference in correction (Cobb angle) or in perioperative morbidity when using VATS versus open thoracotomy for anterior release and fusion in the correction of scoliotic deformities.

It appears that VATS offers the same degree of correction as open thoracotomies.


M. Goytan M. Campos–Benitz C. Peschken M. Johnson

Posterior segmental fixation of the cervical spine facilitates fixation in sub-optimal bone, abnormal anatomy, and complex deformity. Compared to lateral mass plates a screw rod construct provides a stable construct in osteoporotic bone or in cases where the lateral masses are fractured or missing.

To investigate whether a posterior cervical screw- rod construct is an effective, stable and safe means of posterior cervical fixation.

Retrospective evaluation of consecutive patients undergoing a posterior cervical stabilization with a screw- rod construct with clinical and radiographic evaluation.

Clinical variables included age, gender, neurologic status, surgical indication, number of levels stabilized, and number of screws. Note was made as to whether a laminectomy was performed and concomitant anterior surgery. Clinical and radiographic assessments were carried out immediately after surgery and at six weeks, three, six, twelve months and annually after surgery.

Eighty-three patients had five hundred and seventy-three screws placed from October 1998 to December 2003. Mean patient age was fifty-seven. Mean follow-up was twenty-three months, (one to sixty months). The underlying diagnoses were inflammatory arthritis thirty-three, spondylotic myelopathy twenty-nine and trauma in twenty-one patients. Forty-four patients (53% had motor deficit, forty-seven patients (57%) had sensory deficit. Fixation was carried out over an average of five levels (range – two to eight). Mean number of screws per construct was seven (range – four to fourteen). The instrumentation was successfully implanted in all despite lateral mass deficiencies (fracture, poor bone) and coronal and sagittal plane deformities. Late occipital fixation failure was encountered in one patient. There was no loss of alignment or surgical correction on follow-up radiographs.

A posterior screw-rod system allows for treatment of traumatic and degenerative and inflammatory conditions. Crossing the occipitocervical or cervicothoracic junctions is easily afforded. We have had excellent success without complications from screw placement or pseudoarthrosis.


E. Wai A. Gruscynski G. Johnson D. Chow J. O’Neil L. Vexler

Back pain is a complex problem affecting the majority of the population at some point in their life. This cross-sectional study evaluated patients presenting to a tertiary spine clinic with a primary complaint of back pain for modifiable lifestyle factors which may be associated with their back pain. Patients were also asked if any of these lifestyle factors had been addressed by primary care practitioners prior to referral to the spine surgeon’s office.

The purpose of this cross-sectional study is to evaluate the modifiable lifestyle factors which may be associated with back pain in patients presenting to a tertiary spine clinic with a primary complaint of back pain and to compare these lifestyle factors with the general population. A secondary objective is to determine whether patients with back pain were given any instructions with regard to modifiable lifestyle factors by their primary care practitioner.

Consecutive patients presenting to the orthopaedic spine surgery clinic at the Ottawa Hospital – Civic Campus are asked to complete a questionnaire upon presentation to the surgeon’s clinic and prior to their visit with the surgeon. Data being collected includes Body Mass Index, smoking history, physical activity history, perceived stress, and disability. Information is also being collected on sources of information about back pain including instructions given by primary care practitioners (physician, chiropractor, physiotherapist, massage therapist, acupuncturist, naturopath, and other). Data will be analyzed to determine the difference in modifiable risk factors between patients presenting to the spine surgery clinic and the general population. Data will also be tabulated for numbers of patients being given information on modifiable lifestyle factors by primary care practitioners.

To date fifty-two patients have completed the questionnaire. A significant difference has been noted between the number of morbidly obese (BMI > 30) patients presenting to the clinic and the general population. It has been noted that less than 20% of primary care physicians have talked about lifestyle modification with their patients prior to referring them to a spine surgeon.

It will be important to know what modifiable lifestyle risk factors this group of patients possesses and which of these modifiable lifestyle risk factors are actually being addressed by primary care practitioners prior to referral to spine surgeons.

The current waiting list for an appointment with a spine surgeon at the Ottawa Hospital is six to eighteen months. If surgeons can help primary care practitioners address some modifiable lifestyle factors with their patients prior to their referral, waiting times may be reduced or at the very least made more comfortable for patients.


R. Vaidya S. Bartol K. Wilkins F.R. T Nelson

RhBMP2 was used in thirty-six consecutive patients requiring interbody fusion with fifty-five levels (thirteen patients twenty levels ALIF, twelve patients seventeen levels TLIF, eleven patients eighteen levels ACDF) using anterior cervical locking plates and lumbar posterior pedicle screw constructs. All patients showed radiographic fusion at six months. Early lucency, subsidence, and increased pain occurred between six weeks and three months in 70% of ALIFS, 53% of TLIFS and 33% of ACDF’s. The average subsidence was 27% in ALIFS, 24% in TLIFS, and 53% in ACDF. Pain improved by the sixth month. We recommend alternative structural support when using RhBMP2.

To determine effectiveness of RhBMP2 in interbody fusion with machined allograft spacers (MTF Synthes Spine USA femoral ring, TLIF and fibular ring cervical spacers)

A prospective study of thirty-six consecutive patients requiring interbody fusion with fifty-five levels (thirteen patients twenty levels ALIF, twelve patients seventeen levels TLIF, eleven patients eighteen levels ACDF). Machined allograft spacers and RhBmp2 were supplemented with anterior locking plates in the cervical spine while the lumbar segments were supplemented posterior pedicle screws constructs. Patients were followed at two weeks, six weeks, three months, six months, one year. Patients were examined, had xrays, completed Oswestry scores, pain diagrams, and VAS for pain preoperatively and at every follow up appointment.

All the patients showed radiographic evidence of fusion at six months after surgery. Early lucency and subsidence of allografts was observed in 70% of ALIFS, 53% of TLIFS and 33% of ACDF’s. The average subsidence was 27% (range13–42%) in ALIFS, 24% in TLIFS (range 13–40%), and 53% in ACDF. Subsidence and reporting of increased pain occurred between the six- week and three month follow up after which patients improved.

Although high rates of early fusion can be accomplished with allograft spacers and rhBMP2 significant subsidence occurs in greater than 50% of lumbar cases and 30% of cervical cases due to early turnover and loss of structural support of the allograft. We recommend alternative structural support when using RhBMP2.


H. Labelle P. Roussouly S. Gollogly E. Berthonnaud H. Labelle M. Weidenbaum

This study using digitized radiographs and custom software demonstrates that patients with spondylolysis and low-grade spondylolisthesis have increased Pelvic and L5 Incidence as well as a more vertically oriented L5-S1 intervertebral disc than patients without radiographic abnormality of the spine. We propose that shear across the more vertical L5-S1 disc may underlie the etiology of spondylolysis when Pelvic Incidence is high, while a “nutcracker” mechanism may be involved when Pelvic Incidence is low.

The purpose of this study was to assess whether differences exist in sagittal alignment between normal controls and patients with spondylolysis or low-grade isthmic spondylolisthesis.

Standing PA and lateral spine radiographs from eighty-two consecutive patients with spondylolysis or low-grade spondylolisthesis (Average age nineteen, range 15–44) were retrospectively compared with those from one hundred and sixty normal volunteers. The films were digitized with a VIDAR scanner and key landmarks were determined. Customized software was then used to measure geometric indices. Pelvic Incidence (PI), Sacral Slope (SS), Pelvic Tilt (PT), and L5-S1extension angle were compared between seventy-two patients with high PI (> 45°) versus ten patients with low PI (< 45°). Average high-PI vs. low-PI values were, respectively: PI (67.32° vs. 43.13°), SS (51.08° vs. 38.05°), PT (16.23° vs. 5.08°), and L5-S1ext (−8.69° vs. −9.57°). Furthermore, the range of values for L5-S1extension in the low-PI subgroup was much narrower (−17.81° to 0.93°) than that for the high-PI subgroup (−31.58° to 38.12°).

This study demonstrates that patients with spondylolysis and low-grade spondylolisthesis have increased Pelvic and L5 incidence, a more vertically oriented L5-S1 intervertebral disc, and less segmental extension between L5 and S1 than patients without radiographic abnormality of the spine. We propose that different mechanisms underlie the etiology of spondylolysis depending on the magnitude of the Pelvic Incidence. These data highlight the importance of seeing localized lumbosacral spine disorders in the context of global alignment of the entire spine and pelvis.

Funding: This research was assisted by support from the Spinal Deformity Study Group

This research was funded by an educational/research grant from Medtronic Sofamor Danek


F. Chandelier G. Baroud

To reduce vertebral fractures, emerging techniques such as vertebroplasty need to be improved by studying cement infiltration and leakage within bone. Thus we investigated samples extracted from lumbar spines using μCT to evaluate morphological parameters (trabecular thickness and separation, structural index). The specific finding is that relevant shifts of the trabecular thickness and separation Gaussian medians associated to sharpened distributions are related to donors’ age. These morphological parameters, correlated to common fluid laws, enable the prediction of bone cement flow within vertebrae and provide new ways for designing biomaterials and estimate key vertebroplasty parameters regarding time, pressure and injection site.

Osteoporosis, a pathological bone decay leading to fractures, is an economical burden on society. A prevalent fracture site is the spine. To avoid vertebral fractures, emerging techniques such as vertebroplasty are used. Nevertheless, the lack of knowledge relating to cement infiltration, distribution and leakage within vertebrae during cement injection interferes with an appropriate medical practice. This study, by assessing morphological parameters, aims at a better understanding of these processes.

The investigation includes size-controlled cylindrical samples (diameter of 18mm and height of 18mm), extracted from five lumbar spines (L1 to L5) of four female donors aged from forty-nine to eighty years old, analysed using micro-Computed Tomography technique (with a voxel size of 18μm*18μm*36μm) and three-dimensional computed reconstructions.

Then morphological parameters such as porosity, trabecular thickness, trabecular separation, tissue surface and structural index were extracted from the reconstructed volume using dedicated software.

The general findings are significant decreases in bone mass and mineral density while porosity increased and bone anisotropy remains unchanged. The specific finding is that relevant shifts of the trabecular thickness and separation Gaussian medians associated to sharpened distributions are related to donors’ age

Previously determined morphological parameters correlated to common fluid laws (Stokes, Reynolds) enable the prediction of bone cement flow, infiltration and leakage during vertebroplasty and thus provide new ways for designing and evaluating biomaterials and estimating key vertebroplasty parameters regarding time, pressure and injection site.

Please contact author for diagrams and graphs.


E. P. Abraham

The purpose of the study is to evaluate the outcome of two methods: Posterolateral fusion and instrumentation versus posterolateral fusion, instrumentation and interbody fusion using clinical and radiological criteria in demographically similar groups. This is a prospective cohort study of sixty-four patients randomized to two therapeutic strategies (Level II study).

Sixty-four patients were randomized to either instrumented posterolateral fusion (control) or combined instrumented posterolateral and interbody fusion (study) in one level degenerative disorders of the lumbar spine. Demographics of the groups were similar including age, gender and other variables. The demographics of the groups were similar for one level degenerative disorders—disc herniation, spondylolisthesis and spinal stenosis. The primary outcome was measured by the Oswestry Disability Index at two years. There was no statistically significant difference. Secondary outcomes (SF36, VAS, fusion rate, disc height maintenance, maintenance of deformity correction, adjacent segment degeneration) were statistically similar in both groups. In conclusion, no clinical advantage with interbody fusion versus posterolateral fusion alone.

Analysis of the correlation between the pedicle shape and the spinal canal anatomy in scoliotic anatomic specimens.

S. Parent1, H. Labelle, W. Skalli, J. de Guise,

13175 Côte Ste-Catherine, Montréal, Québec H3T 1C5.

The objective of the present study was to analyze the correlation between the pedicle shape and spinal canal anatomy in scoliotic specimens. Vertebral canal anatomy was evaluated in a series of thirty anatomic scoliotic specimens and compared to thirty normal specimens. Spinal canal enlargement inversely correlated with pedicle width modifications on the concavity of scoliotic curves. These findings suggest that changes in pedicle anatomy are secondary to local changes in spinal cord position.

Recent studies have demonstrated the close relationship between the spinal cord and the pedicle on the concavity of the scoliotic curve of patients with scoliotic deformities. The hypothesis of the present study is that changes in spinal canal shape are related to spinal cord position and resulting bone remodeling. This study evaluated the characteristic changes of spinal canal shape in anatomic scoliotic specimens.

Posterior elements morphology is closely related to the local spinal cord anatomy and its relationship with the bony architecture.

The characteristic posterior element changes seen in scoliosis are likely the result of local bone remodeling.

Spinal asymmetry was observed in scoliotic specimens when compared to normal specimens. Spinal canal was enlarged asymmetrically on the concavity of thoracic scoliotic curves (p < 0.01). Overall, canal surface was greater in scoliotic specimens when compared to normal specimens (p < 0.01). These changes were more important at the apex of the curve.

Spinal canal characteristic shape was evaluated in thirty scoliotic anatomic specimens and thirty normal anatomic specimens using twelve parameters representing measures of right and left hemi-canal length, width or surface area. The 3-D coordinates of eight points taken at the periphery of each spinal canal were recorded.

The results of this study support the hypothesis that spinal canal shape is modified by the spinal cord position and that posterior element changes seen in scoliosis are in part due to bone remodeling in response to local neural anatomy modifications.

Funding: Fonds de Recherche en Santé du Québec


B. Singh P.G.A. Kumar S. Burtt A. Dutta W.A. Scott

We undertook the current study to analyze the factors involved with failed previous stabilization surgery for patients with anterior or anteroinferior glenohumeral instability. Between 1997 and 2003 we treated seventy-four patients with traumatic unidirectional instability. The average age was thirty-two and the average follow up was fifty-eight months. There were sixteen females and fifty-eight males. All patients underwent a primary diagnostic arthroscopy followed by arthroscopic stabilization in forty-seven and open stabilization in twenty-seven cases. Ten had a recurrence of instability. Of these two had significant trauma. Of the remaining, six were in the arthroscopic group and two in the open procedure group.

Analyze the factors involved with failed previous stabilization surgery for patients with anterior or anteroinferior glenohumeral instability.

Between 1997 and 2003 we treated seventy-four patients with traumatic unidirectional instability. The average age was thirty-two years (range nineteen to forty-seven). There were sixteen females and fifty-eight males. The average follow up was fifty-eight months (range seven to eighty-three). All patients underwent a primary diagnostic arthroscopy followed by arthroscopic stabilization in forty-seven and open stabilization in twenty-seven cases. The arthroscopic procedure involved two Suretac II labral reattachment and capsular shrinkage using electrocautery. The open procedure involved a Bristow/Latarjet procedure using a delto-pectoral approach and reattachment of coracoid process using a single malleolar screw.

Ten patients had a recurrence of instability. Of these two had significant trauma, one each group. Of the remaining eight, six were in the arthroscopic group and two in the open procedure group. In the arthroscopic recurrence group, three had a large Hill Sach’s lesion and one a large Bankart Lesion. In the open procedure group, both had a large Hill Sach’s and Bankart’s lesion. This gave a recurrence rate of 12.7% in the arthroscopic group and 7.4% in the open group.

A large Hill-Sach lesion > 2mm is a contra-indication to arthroscopic repair and the optimum stabilisation procedure is an open repair (Bristow/Laterjet). Without a significant Hill-Sach’s lesion an arthroscopic Suretac II labral re-attachment is an effective way of achieving stability. Those who have a large Hill-Sach and significant Bankart’s lesion may need a combination of Bankart’s repair plus an extra-articular procedure like a Bristow/Laterjet procedure.


T. Sasyniuk N. Mohtadi R. Hollinshead M. Russell

The standard of reference by which many imaging studies and clinical tests are often measured is arthroscopy. However, the inter-rater reliability of a surgeon’s arthroscopic diagnosis a relatively unexplored area of investigation. The purpose of the study was to determine the inter-rater reliability among a group of experienced orthopaedic shoulder surgeons in evaluating the intra-articular structures involved in a real-time diagnostic shoulder arthroscopy using a videotape model. Given the conditions of this study, the agreement among experienced shoulder surgeons was structure dependent ranging from poor to very good and was influenced by the prevalence of pathology.

To determine the inter-rater reliability among a group of experienced orthopaedic shoulder surgeons in evaluating the intra-articular structures involved in a real-time diagnostic shoulder arthroscopy using a videotape model.

In this patient population, the agreement among experienced shoulder surgeons was structure dependent ranging from poor to very good and was influenced by the prevalence of pathology.

For educational, research and legal reasons, it is important to objectively demonstrate that intra-operative findings can be reproduced. To date, this is a relatively unexplored area of investigation within shoulder arthroscopy.

The video-review surgeon median overall agreements were as follows: anterior labrum=90%, inferior labrum=45%, superior labrum=60%, posterior labrum=65%, superior glenohumeral ligament(GHL)=50%, middleGHL=50%, anterior-inferiorGHL=25%, glenoid surface=35%, detection of Hill Sachs lesion=85%, biceps tendon=70%, supraspinatus tendon=85%, infraspinatus tendon=70%, subscapularis tendon=80%.

Twenty patients (nineteen males, one female) diagnosed with recurrent anterior shoulder instability with an average age of 27.9 years (15–44years) consented to participate. One experienced surgeon performed a standardized diagnostic shoulder arthroscopy following a modified Snyder 15-point protocol. All surgeries were videotaped. The operative protocol, clarity of videotape information and data collection forms were pre-tested to ensure accuracy. The patients’ clinical information, x-rays and videotaped arthroscopy were sent to six experienced shoulder surgeons. The surgeons reviewed the clinical information, assessed the intra-articular structures shown on the videotape and recorded their diagnoses on a standardized data collection form. The primary outcome was the median overall percent agreement for the video-review surgeons. This was calculated for each structure evaluated.


D. Ogilvie-Harris C.H. Choi

Arthroscopic subacromial decompression was carried out in one hundred and four consecutive patients who had stage II subacromial impingement with failed conservative treatment. The results were assessed preoperatively and at follow up using the UCLA score. After an average of 8.4 years follow up, the final results were as following; fifty-seven shoulders (55%) in excellent, twenty-five (24%) in good, sixteen (15%) in fair and six (6%) in poor. Late full thickness tears developed in 9% of patients and can be treated with an open repair of rotator cuff. Arthroscopic subacromial decompression was very effective for stage II impingement syndrome.

To assess the long term results of arthroscopic subacromial decompression in stage II subacromial impingement.

Arthroscopic subacromial decompression was very effective for stage II impingement. Late full thickness tears developed in 9% of patients and can be treated with an open repair of rotator cuff.

This technique is a viable treatment for the condition.

This is a prospective cohort study carried out in a University setting. Arthroscopic subacromial decompression was carried out in one hundred and twenty consecutive patients who had stage II subacromial impingement with failed conservative treatment. Sixteen were lost to follow up. The results were assessed preoperatively and at follow up using the UCLA score. After an average of 8.4 years follow up, the final results were fifty-seven shoulders (55%) excellent, twenty- five (24%) good, sixteen (15%) fair and six (6%) poor. All parameters – pain, function, muscle strength and motion – were improved significantly (p< 0.001). In the six poor results, two had late rotator cuff tears, three had recurrence of impingement with degenerative change and one had reflex sympathetic dystrophy. Late full thickness rotator cuff tears developed in ten shoulders after decompression. Re-operations were performed in four shoulders – three late open repairs of the rotator cuff tear resulted in good results with one poor rating. Arthroscopic subacromial decompression was very effective for stage II impingement syndrome. Late full thickness tears developed in 9% of patients and can be treated with an open repair of rotator cuff.


P. MacDonald J. Chahal H. Berard K. Kassiri M. Dyck

Expert North American shoulder surgeons were poled on the diagnosis and treatment of five shoulder conditions. To quantify inter-observer agreement in the diagnosis and treatment of shoulder instabilities, they chose one of five diagnostic conditions and one or more of seven treatment options. The greatest diagnostic and treatment differences were noted for a painful shoulder in a throwing athlete with subtle anterior instability and a patient with voluntary posterior instability with an asymptomatic sulcus sign. An arthroscopic approach was consistently preferred to open surgery. These inconsistencies highlight the need for standardized diagnostic criteria and more universal treatment plans.

To quantify inter-observer agreement in the diagnosis and treatment of shoulder instabilities among expert North American shoulder surgeons.

These inconsistencies, particularly in diagnosis, highlight the need for standardization of diagnostic criteria and guidelines working towards more universal treatments and evaluations of outcomes.

The greatest diagnostic differences were noted for a painful shoulder in a throwing athlete with subtle anterior instability(Ksc0.46, 55% agreement) and a patient with voluntary posterior instability with an asymptomatic sulcus sign(Ksc0.41, 50% agreement). The presence of an asymptomatic sulcus sign alone may have been mistakenly interpreted as inferior instability rather than inferior laxity. There was a high level of agreement in diagnosing anterior and bi-directional instability. An arthroscopic approach to treatment was consistently preferred to open surgery. The greatest differences in treatment choice were for the throwing athlete(Ksc0.38, 47% agreement on arthroscopic repair), a patient with voluntary posterior instability(Ksc0.34, 43% agreement on arthroscopic capsular repair) and a patient with bi-directional instability(Ksc0.23, 34% agreement on arthroscopic anterior Bankart repair).

Active members of the American Shoulder and Elbow Surgeons and JOINTS Canada (Orthopaedic Initiatives for National Trials of the Shoulder) were poled on the diagnosis and treatment of five shoulder conditions. They were to choose one of five conditions and one or more of seven treatment options. A Kappa coefficient of agreement was used to assess inter-observer reliability; a Ksc of 1 denotes perfect agreement on a category and a Ksc of −1 denotes perfect agreement on not endorsing a category.


R. Holtby H. Razmjou F. Moola H. Damecen S. Wright

The purpose of this study was to examine clinical outcomes of capsular plication using subjective outcome measures and objective clinical examination with emphasis on range of motion. Data of consecutive patients (twenty-five at six months and twenty at twelve months) who required arthroscopic stabilization over a period of three years were retrospectively reviewed. At six and twelve month post-operatively, the disease specific outcome measure, ASES, and relative Constant, showed significant changes in quality of life. There was no loss of external rotation at 0° and 90° of external rotation at one year post-operatively.

The purpose of this study was firstly to assess the effectiveness of capsular plication, in the treatment of instability related pathology, using subjective outcome measures and secondly to look specifically at the effect of this procedure on range of motion.

Suture capsular plication has been advocated as a less invasive technique to reduce symptomatic capsular laxity with less morbidity than traditional open techniques. There is, however, little evidence that this procedure has the same clinical effectiveness as open capsular shift procedures.

Arthroscopic capsular plication improves quality of life (QOL) in patients suffering from shoulder instability without significantly restricting external rotation.

Data of consecutive patients who required arthroscopic stabilization over a period of three years were retrospectively reviewed. Three outcome measures were used; one disease-specific and two shoulder specific measures:

the American Shoulder & Elbow Surgeons standardized shoulder assessment form and,

the Constant-Murley.

Analysis involved a paired T test between the means of each outcome measure pre and post-surgery.

Twenty-five patients had complete pre-op and six- month post-op data. Twenty subjects had complete pre-op and twelve- month post-op data. At six month post-operatively, the disease specific outcome, relative Constant, and ASES showed significant improvement in QOL scores (P< 0.000, 0.006, and, 0.004 respectively). At twelve- month post surgery, change in all measures remained statistically significant. There was no loss of range of motion in external rotation at 0° or 90° of abduction between initial and follow up assessments in the clinic.

Funding: This study was supported by the research funds of the Orthopedic & Arthritic Institute, Sunnybrook and Women’s College Health Sciences Centre.


H. Yepes A. Al-Hibshi M. Tang S.F. Morris C. Geddes W.D. Stanish

Shoulder Arthroscopy techniques may pose surgical risk to vascular structures that may cause active bleeding during surgery. The vascularity of the subacromial structures showed constant patterns of distribution and specific sources of bleeding were analyzed. Knowledge of the vascular anatomy may decrease the bleeding during subacromial arthroscopy surgery.

Shoulder Arthroscopy techniques may pose surgical risk to vascular structures that may cause active bleeding during surgery. A detailed anatomy map of frequent sources of bleeding is more than desired in order to properly identify these bleeding points, and avoid the unnecessary overuse of thermal tools and pressure pumps to control the hemorrhage.

Our purpose is to study the vascular anatomy of the subacromial space, and to map the major sources of expected bleeding during subacromial arthroscopy surgery.

Ten shoulders of five adult cadavers underwent whole body arterial perfusion with a mixture of lead oxide, gelatin and water. The shoulders were dissected, photographed, tissue specimens were radio graphed, scanned and analyzed with a digital software analyzer. Careful dissection of the different arteries of the subacromial bursa, and anatomic landmarks of the walls were documented. Correlations of bleeding areas during subacromial arthroscopic surgery and cadaver dissection were carried out. A vascular map of the bursa was created.

The vascularity of the subacromial structures showed constant patterns of distribution and specific sources of bleeding were analyzed. We divided this space into walls with their major arteries as follows: Anterior wall: Acromial branch of the thoracoacromial artery. Posterior wall: Acromial branch of the suprascapular artery. Medial wall: Anterior and posterior Arteries of the AC joint. Lateral wall: No major arteries identified. Vascularity of the roof and floor is also described.

The subacromial space is highly vascular. Knowledge of the vascular anatomy may decrease the bleeding during subacromial arthroscopy surgery.


N. Mohtadi R. Hollinshead J. Fletcher T. Sasyniuk

This randomized clinical trial utilizing the validated rotator cuff disease specific quality of life outcome measure (RC-QOL) and adequate power demonstrates no difference in outcome for full thickness rotator cuff tears comparing open to mini-open surgical techniques.

The purpose of the study was to compare standard open rotator cuff repair versus mini-open rotator cuff repair by measuring the disease specific quality of life in patients with rotator cuff injury.

This randomized clinical trial utilizing a validated disease specific outcome measure and adequate power demonstrates no difference in outcome for full thickness rotator cuff tears comparing open to mini-open surgical techniques.

The miniopen approach utilizing an arthroscoic acromioplasty provides no additional beneifit to the patient undergoing a rotator cuff repair.

The mean one year RC-QOL score for the open and mini-open groups were 85.3 (SD = 15.6) and 87.4 (SD = 12.0) out of a maximum of one hundred, respectively. This difference was not statistically significant (p = 0.572).

Seventy-two patients (forty-eight males/twenty-four females) with an average age of 56.4 years (thirty-three to eighty-two years) consented to participate in the study. Inclusion criteria involved: unremitting pain, failed conservative treatment of at least three months, weakness of rotator cuff, and positive diagnostic imaging indicating a full-thickness rotator cuff tear. Massive rotator cuff tears were excluded.

Prior to surgery, patients were randomized to either open or mini-open rotator cuff repair. Patients were assessed and outcomes were collected at three, six and twelve months after surgery. Primary Outcome Measure: Patient quality of life was quantified using the validated disease specific, reliable and responsive Rotator Cuff Quality of Life Questionnaire (RC-QOL) measured on a one hundred point visual analogue scale format. Secondary Outcomes: Range of motion, strength, American Shoulder and Elbow Surgeons Score, and the Shoulder Rating Questionnaire.


J. MacDermid R. Humphrey R. Richards

This study determined the validity of three patient self-report scales (PRWE, DASH and AUSCAN) to assess outcomes of CMC arthroplasty. Factor analyses did not support the described structure of the three scales. There was a strong relationship between pain or function subscales across different instruments (r> 0.80). Known construct testing regarding WSIB status and arthritis severity supported the discriminative validity of all scales (p< 0.05) except for the function (PRWE) and stiffness (AUSCAN) subscales (p=0.08). Separation of pain/function concepts may be difficult when evaluating outcomes in hand arthritis. The DASH is not unidimensional in this population

This study determined the concurrent validity of patient self-report scales to assess outcomes of CMC (carpometacarpal) arthroplasty.

The subscale structure of the PRWE, DASH and AUSCAN is not valid for a patient population with hand arthritis – Pain, function and stiffness do not differentiate as separate concepts. It appears as though function can be separated into separate components addressing strength and fine motor hand function on all three scales. The DASH was not unidimensional.

Reporting of outcomes following CMC arthroplasty should utilize either the questionnaires total scores or validated factors. Use of unvalidated subscales should be avoided.

Factor analyses did not support the described structure of any of the three scales. PRWE three subscales- two factors; AUSCAN – pain and stiffness items loaded on one factor, function items separated into two factors; DASH – four factors. The largest factor on the DASH contained items relating to symptoms and participation restrictions. Items relating to hand function also separated into a separate factor. Correlational analyses indicated a strong relationship between pain or function subscales across instruments ( r> 0.80) and low correlation with hand appearance (r< 0.20). Tests of known constructs on WSIB status or arthritis severity supported the discriminative validity of all scales (p< 0.05), except for the function subscale off the PRWE or the stiffness subscale of the AUSCAN (p=0.08).

Factor analyses, inter-scale correlations and tests of known constructs were conducted on the Patient Rated Wrist Evaluation (PRWE), Disability of the Arm, Shoulder, Hand (DASH) and the AUSCAN (osteoarthritis of the hand).


M. Dunbar L. Molloy A. Hennigar M. Davies

A centralized wait list management system (WLMS) for TKR, THR and knee arthroscopy was developed to collect accurate data on parameters of patients’ wait for surgery. A priority metric rating patient priority was implemented. Data from hospital enterprise systems related to aspects of patients’ wait for surgery was collected and imported. Patients’ functional status was significantly worse than population norms, they were adversely affected while waiting and are unsatisfied with their access to surgery. Traffic ratios (ratio of booked to completed surgeries) exceed the maximum value for a stable wait list and the waits for surgery exceed national and international recommendations for maximum wait-times.

To develop and implement a WLMS for TKR, THR and knee arthroscopy to enable the accurate and efficient collection of data on size of list, rate of list growth, rate surgeries are performed, health and functional status of patients, and surgeon rated priority.

Patients are adversely affected while waiting and are unsatisfied with the length of their wait. Traffic ratios exceed the maximum value for a stable waitlist. The priority metric has face validity for rating patient acuity.

SF36 and WOMAC scores were three to four standard deviations worse than the population norm, over 50% of patients felt wait time would negatively affect outcome, 80% felt waits should be twelve months or less, and over 50% were unsatisfied with access to surgery. VAS scores were normally distributed with good face validity. Wait times are one hundred and thirty to three hundred days for arthroplasty and ninety to four hundred days for arthroscopy. Traffic ratios are 0.9 for arthroplasty and 1.5 for arthroscopy.

Prospective outcomes with respect to the wait list will allow determination of minimum acceptable wait times from administrative, surgeon and patient perspectives. Accurate and reliable collection of wait list data provides a sound basis for future decision-making.

Surgery bookings were centralized. A priority metric based on a visual analog scale (VAS) with a single question asking the surgeon to rate the patient priority was implemented. A cross-sectional postal survey was conducted. Data from hospital enterprise systems related to aspects of patients’ wait for surgery was collected and imported into the WLMS.


C. MacDonald A. Zahrai R.M. Walker J. Rooney E. Schemitsch J. Wright J.P. Waddell

The purpose of this study was to determine which activities are important to patients and to determine the severity of those problems. The five most important activities were walking outside, driving, walking indoors, stair climbing and daytime pain. Importance of these did not change postoperatively. The five most severe problems causing limitation were a limp, stiffness, loss of energy, daytime pain and locking. All these activities become statistically less severe over twenty-four months. Activities that are important to patients are different than the problems that are ranked by severity. Surgeons can educate patients that the severity of problems do improve over time following TKA.

The objectives of this study were:

to determine the five most important activities and five most severe problems for patients prior to total knee arthroplasty (TKA) using the Patient Specific Index (PASI) and

to determine the pattern of change in these activities over twenty-four months following TKA.

Activities that are most important to patients are different than problems that patients find severe. Important activities remain important over time. Severe problems become less severe over time.

Functional activities and PASI scores improve after TKA. Surgeons can educate patients that the problems they find most severe preoperatively do improve over time following TKA. Important activities remain important.

Patients scheduled for elective primary (or revision) TKA at two tertiary care teaching hospitals were enrolled in the study, excluding those not fluent in English and those undergoing TKA for a tumour, acute fracture, or an infection of the prosthesis. Patients completed the PASI pre-operatively, six, twelve and twenty-four months post-operatively.

One hundred and nineteen subjects were enrolled, nineteen were excluded. The five most important activities (ten- point scale, ten is most important) preoperatively were (mean; 95% CI): walking outside (6.25; 6.23–6.27), driving (6.17; 6.12–6.22), walking indoors (6.14; 6.12–6.16), climbing stairs (6.12; 6.10–6.14), and daytime pain (5.84; 5.81–5.87). These activities were not statistically less important over time. The most severe problems were limping (4.81; 4.77–4.85), stiffness (4.59; 4.56–4.62), lack of energy (4.51; 4.47–4.55), daytime pain (4.46; 4.43–3.39) and locking (4.38; 4.27–4.49). These were significantly less severe at twenty-four months (p < .001).


B.J. Shore C.A. Busch R. Bhandari S. Ganapathy S.J. MacDonald C.H. Rorabeck R.B. Bourne R.W. McCalden

This Blinded Randomized Clinical Trial outlines: how peri-articular intra-operative multimodal analgesia significantly reduces post-operative analgesia requirement. Sixty-four patients undergoing total knee replacement were randomised to receive a peri-articular intra-operative injection containing ropivacaine, ketorolac, epimorphine and epinephrine or nothing. Patients who received the injection demonstrated greater satisfaction and pain relief. Finally, patients in the injected group did not show any signs of cardio and central nervous system toxicity.

Post-operative analgesia can be associated with troublesome side effects. Good peri-operative analgesia facilitates rehabilitation, improves patient satisfaction and may reduce hospital stay. The purpose of this study was to assess a novel cocktail for peri-articular analgesia after total knee replacement.

Sixty-four patients undergoing total knee replacement were randomised to receive a peri-articular intra-operative injection containing ropivacaine, ketorolac, epimorphine and epinephrine or nothing. The anaesthetic analgesic regime was standardised. All patients received patient controlled analgesia (PCA) for twenty-four hours post surgery, followed by standard analgesia. VAS pain scores during activity and at rest and patient satisfaction scores were recorded pre and post operatively and at six week follow up. PCA consumption and overall analgesic requirement were measured.

PCA use at six, twelve and over twenty-four hours post surgery was significantly less in patients receiving the injection (p< 0.01, p=0.016, p< 0.01). Patient satisfaction in PACU and four hours post operation was greater (p=0.016, p=0.013). VAS for pain during activity in PACU and at four hours were significantly less (p=0.04, p=0.007) in the injected group. The average ROM at six weeks was no different. Overall hospital stay and the incidence of wound complications were not different between the two groups.

Peri-articular intra-operative multimodal analgesia significantly reduces post-operative analgesia requirement. Patient satisfaction and pain relief is greater in the injection group. No cardio and central nervous system toxicity was observed.

Our novel cocktail of ketorolac, epimorphine, epinephrine and ropivacaine provides superior pain relief with no adverse side effects.


S.J. MacDonald J.T. Marr R.B. Bourne C. Rorabeck

The Self Aligning (SAL I) total knee prosthesis (Sulzer, Winterthur) is a first generation cruciate retaining mobile bearing implant allowing unrestricted rotation and up to 5 mm. of translation. A consecutive series of two hundred and three SAL I components in one hundred and sixty- seven patients were implanted between 1990 and 1994 and were reviewed clinically and radiographically. Quality of life outcomes (SF-12 and WOMAC) were also reviewed pre-operatively and regular intervals. This first generation mobile bearing knee implant in this series, continues to function well at a minimum ten years follow-up, with a mechanical failure rate (8%) comparable to fixed bearing designs.

A consecutive series of SAL I total knee arthroplasties were performed between 1990 and 1994 and were reviewed clinically, radiographically and with standardized quality of life outcome tools, including the SF-12 and the Western Ontario MacMaster Osteoarthritis Index (WOMAC).

Patient demographics, radiographs, and multiple validated outcome measures (WOMAC, SF12, Knee Society Clinical Rating System) were evaluated pre-operatively, at three, twelve, and twenty-four months and every two years thereafter.

The series included two hundred and three SAL I implants in one hundred and sixy-sevenpatients. There have been sixty-nine patient deaths (eighty-five procedures), nine patients (eleven procedures) now reside in nursing homes and are unable to return due to medical complications, two patients (three procedures) could not be located. Nine-teen patients/procedures have had revision surgery. Therefore, seventy-six patients (ninety-three procedures) were evaluated with over ten year follow-up (average 10.89 years, range 10.03–13.72). Indications for revision included, sepsis (three), aseptic loosening (eight), instability (two) and poly-wear (six). The KSCRS was assessed for all remaining patients at greater than ten years including pain (45.83), function(65.60), range of motion extension(0.13) and flexion(113.82) as well as the results of the WOMAC (pain-4.36, joint stiffness-2.29, function-18.66, total- 15.92) and SF-12 (Mental-55.37 Physical- 34.99).

The SAL I mobile bearing implant continues to perform comparably to fixed bearing cruciate retaining designs.

This first generation mobile bearing knee implant continues to function well at a minimum ten years follow-up, with a mechanical failure rate (8%) comparable to fixed bearing designs.


R. Gandhi D. Petruccelli A. Adili M. Winemaker J. de Beer

A prospective evaluation was undertaken utilizing the SF12 score, Oxford Knee score, Knee Society Score (KSS), visual analog pain score, and a non-validated questionnaire to determine patient self-perception of leg alignment after knee arthroplasty, and impact of satisfaction with alignment on clinical outcomes. 21/84 (25%) patients were dissatisfied with their new leg alignment and this group subsequently reported greater pain scores (p< 0.001) and lower SF12 scores (p< 0.002). Oxford Scores and KSS showed no difference between groups. We suggest that patient satisfaction with postoperative lower extremity alignment is an important issue affecting subjective outcomes in total knee arthroplasty (TKA).

This study was undertaken to determine how patients perceive their leg alignment after knee arthroplasty and whether their level of satisfaction with alignment affects clinical outcomes.

The results of this study suggest that there may be some benefit to preoperative counselling on what to expect in regard to leg alignment following surgery. Additionally, given the adverse impact of dissatisfaction with limb alignment on subjective outcomes, we suggest that patient satisfaction regarding leg alignment should be considered for inclusion in the design of subjective outcomes measures for total knee arthroplasty.

21/84(25%) patients were dissatisfied with their new leg alignment while all but one had an anatomic axis between 4–100 valgus radiographically. This group subsequently reported greater pain scores (p< 0.001) and lower SF12 scores (p< 0.002). At six months follow-up, there was no difference between groups on the Oxford Knee or KSS (p> 0.05).

A non-validated questionnaire was utilized to prospectively ask patients to self-rate their alignment, their satisfaction with their alignment, and their pain scores on a visual analog scale (VAS). Additional outcome measures included pre and postoperative SF-12, Oxford Knee and KSS.

There is still no consensus regarding any one single scoring system with regard to clinical outcomes of primary TKA. Also, it has been widely reported that surgeons often perceive outcomes of TKA with more success than patients. 21/84 of our patients were dis-satisfied with their alignment while all but one had an anatomic axis between 4–100 valgus radiographically.


E.R. Bogoch B.M. Jolles

The purpose of this study was to evaluate the mid- and long-term outcomes of total knee arthroplasty in adult patients who have advanced juvenile idiopathic arthritis (JIA).

Between 1989 and 2001, twenty-two knees of JIA adult patients were treated with primary arthroplasty. Surgical challenges included fixed valgus and flexion deformity. All patients were evaluated (mean 8.0 years) using established and new scoring systems.

Knee arthroplasty provided relief of pain and stiffness and moderate improvement in range of motion in this severely affected patients. Although outcomes were scored poorly on established instruments, patients rated their benefits of the operation highly.

To evaluate the mid- and long-term outcomes of total knee arthroplasty in adult patients who have advanced juvenile idiopathic arthritis (JIA).

Between 1989 and 2001, twenty-two knees in fourteen adult patients with severe JIA were treated with primary arthroplasty. Surgical challenges included relative condylar and patellar overgrowth within a contracted, inelastic soft tissue envelope, osteoporosis, small sized bones and fixed valgus and flexion deformity including ankylosis. All patients were evaluated (follow-up: mean 8.0 years) using established and new scoring systems (postoperatively at follow-up and preoperatively by recall)..

Patients’ postoperative pain and stiffness VAS were significantly less than preoperative scores, with mean changes of 8.8 and 7.2, respectively. A mean post-operative flexion arc of 77° (range 30°–130°) was observed. All lower limbs were post-operatively aligned between 0° and 5° of mechanical valgus. Incomplete radiolucent lines were present in 27% of knees, but were not associated with clinical symptoms. Final SF-36, EQ-5D and WOMAC scores were relatively low, but 82% of patients rated themselves satisfied with the functional outcome, 100% with pain relief, and 100% stated that the outcome met or exceeded their expectations. Issues deemed by JIA patients to be important were identified by the patient specific questionnaire (PASI-pg), but not by SF-36, EQ-5D or WOMAC.

Knee arthroplasty provided relief of pain and stiffness and moderate improvement in range of motion in this severely affected adult JIA patients. Although outcomes were scored poorly on established instruments, patients rated their satisfaction with and benefits of the operation highly.

Funding:

B. Jolles received a Ligue Vaudoise contre le Rhumatisme Award for her work on Rheumatoid Arthritis.


M.H. Mahoney J.S. Guerin R. Bourne S.J. MacDonald R. McCalden

The Genesis II total knee prosthesis was a successor to the Genesis I TKR in which three degrees of external rotation was built into the femoral component to improve patellofemoral tracking and eliminate rotational incongruity. The midterm (minimum five year) results of three hundred and forty-three Genesis II cemented components were reviewed in three hundred and twenty-four patients. Kaplan-Meier survivorship was 98% at a mean 7.6 years.

The focus of this study was to analyze the minimum five- year results of patients receiving either a cruciate-retaining, posterior stabilizing, or mobile bearing Genesis II TKR. Further analysis was performed to delineate differences between subsets of this population.

Data from a consecutive series of three hundred and twenty-four patients receiving three hundred and sixty-seven Genesis II TKR’s between February 1996 and July 1999 was collected. Patients were evaluated pre-operatively, at six weeks, three months, six months and annually thereafter, using the Knee Society Clinical Rating System and the Western Ontario MacMaster Osteoarthritis Index. A Kaplan-Meier Survivorship was performed on the consecutive series. Statistical analyses were used to delineate significant differences between subsets of patients.

There were three hundred and sixty-seven procedures (one hundred and sixty-nine cruciate-retaining, one hundred and sixty-six posterior stabilized and six mobile bearing designs) performed on three hundred and twenty-four patients. At the time of evaluation, forty-five (13%) patients were deceased, twenty-four (7%) patients were unavailable for evaluation and nine (2%) knees had been revised. A 98% implant survivor-ship was calculated at a mean time of 7.6 years.

These are the first mid-term (minimum five year) clinical results of the Genesis II TKR, which continues to function well. Kaplan-Meier survivorship was 98% at a mean 7.6 years.


J. de Beer A. Al Rabiah D. Petruccelli A. Adili M. Winemaker

Retrospective analysis of three hundred and seventy-one obese (BMI _ 30) and two hundred and forty-nine non-obese (BMI < 30) primary unilateral TKA patients with minimum one-year follow-up to determine influence of obesity versus non-obesity on clinical outcomes following primary unilateral total knee arthroplasty (TKA) for osteoarthritis. Obese patients fare just as well as non-obese patients, experiencing a greater degree of improvement in observed and self-reported outcome measures.

Multiple factors determine outcome of TKA. This study aimed to determine influence of obesity versus non-obesity, as measured by body mass index (BMI), on clinical outcomes following primary unilateral total knee arthroplasty (TKA) for osteoarthritis. Compared to non-obese patients, obese patients had inferior preoperative clinical scores, but achieved comparable ultimate clinical outcomes.

Despite inferior preoperative clinical scores, obese patients undergoing primary TKA for osteoarthritis can expect the same ultimate clinical outcome as non-obese patients.

Statistically significant differences for; mean age of obese 69.2 ±9 and non-obese 73±8 (p< 0.0001), with a higher preponderance of obese females, 70.2% vs. 30% male (p=0.033).

Despite statistically significant differences among all preoperative clinical outcomes including; KSS clinical (p=0.019), KSS function (p=0.02), Oxford (p=0.02), and flexion (p=0.001), there were no statistically significant differences among these outcomes at one-year postoperative. No statistical difference among surgical outcomes, hospital length of stay, pain scores or stair climbing ability at any interval.

Retrospective analysis of three hundred and seventy-one obese (BMI _ 30) and two hundred and forty-nine non-obese (BMI < 30) primary unilateral TKA patients with minimum one-year follow-up. Statistical analysis to determine differences in demographics, surgical time, intraoperative complications, hospital length of stay, and clinical outcomes including; flexion, KSS and Oxford score, pain-level and stair climbing ability at six-week, six-month, and one-year postoperative. Patients with previous high tibial osteotomy, ORIF, or receiving associated WSIB benefits were excluded.

Obese patients fare just as well as non-obese patients, experiencing a greater degree of improvement in observed and self-reported outcome measures.


A.E. Kedgley G.A. Mackenzie L.M. Ferreira D.S. Drosdowech G.J.W. King K.J. Faber J.A. Johnson

This study was conducted to determine the effect of passive and active muscle loading on humeral head translation during glenohumeral abduction. A shoulder simulator produced unconstrained active glenohumeral abduction using several sets of loading ratios. Significantly greater translations occurred in passive motion as compared to active motion between 30 and 70 degrees of elevation in three dimensions and in the anterosuperior plane. No difference was found between the active motions. Also, translations of the humeral head decreased with active simulation of abduction emphasizing the importance of the rotator cuff muscles in creating and maintaining the ball-and-socket kinematics of the shoulder.

This in-vitro study was conducted to determine the effect of passive and active loading on humeral head translation during glenohumeral abduction.

Five cadaveric shoulders were tested using a shoulder simulator designed to produce unconstrained abduction of the humerus. Forces were applied to simulate loading of the supraspinatus, subscapularis, infraspinatus/teres minor, anterior, middle, and posterior deltoid muscles using four different sets of loading ratios. These were based on:

equal loads to all cables (Constant-Constant);

average physiological cross-sectional areas (pCSAs) of the muscles (pCSA);

constant (Constant EMG), and

variable (Variable EMG) values of the product of electromyographic data and pCSAs.

In three dimensions, significantly greater translations occurred in passive motion as compared to active motion between 30 and 70 degrees of elevation (p< 0.001). No difference was found between the active motions. Similar results were observed in the two-dimensional resultant translations in the anterosuperior plane of the scapula, with more translation occurring during passive motion (3.6 ± 1.1mm) than active (2.1 ± 1.0mm) (p=0.002), and no significant differences between the active loading methods (Figure 1). The majority of translation tended to occur in the superior-inferior direction for all loading ratios employed.

It was clearly shown that the translations of the humeral head decreased with active simulation of abduction. These findings are in agreement with other in-vivo and in-vitro investigations.

This emphasizes the importance of the rotator cuff muscles in creating and maintaining the ball-and-socket kinematics of the shoulder.


D. Williams D. Petruccelli W. Elliott S. Bauman J. de Beer

It is known that activity level correlates with wear in total joint arthroplasty. UCLA activity score surveys were sent to four hundred and sixty-seven knee and hip arthroplasty patients with good/excellent clinical outcomes as determined by one-year postoperative Knee Society (KSS) and Harris Hip (HHS) scores. The UCLA activity score was correlated with clinical outcomes and demographic data. Average UCLA score was 6.2 for hips, 6.3 for knees, indicating moderate activity levels. Hip arthroplasty UCLA score significantly correlated with age, gender and one-year Oxford score. Knee arthroplasty UCLA score significantly correlated with gender, one-year functional KSS and Oxford score.

Arthroplasty patients are often warned to avoid high level activities for fear of implant loosening, failure or increased polyethylene wear. Patients with good/excellent clinical outcomes may however be inclined to participate in higher demand activities. There is need for specific information regarding patient profile and activity level following TJR.

Current recommendations for activity among TJR patients may not be justified. Longer-term follow-up will elucidate specific activities which may be permissible or detrimental to implant survivorship.

Survey response rate was 70.2% among THA patients at mean 40.7months. Mean UCLA score was 6.2/10, indicating moderate activity. Mean outcome scores; one-year HHS 94.8, Oxford 6.6. UCLA score significantly correlated with age, gender and one-year Oxford.

Survey response rate was 81.8% among TKA patients at mean 36.6months. Mean UCLA score was 6.3/10, indicating moderate activity. Mean outcome scores; one-year KSS clinical 95.9, KSS function 95, Oxford 18.2. UCLA score significantly correlated with gender, one-year KSS function and Oxford.

No significant differences among clinical outcomes and survey non-respondents.

UCLA activity score survey of two hundred and twenty-five primary TKA and two hundred and forty-two primary THA patients. Patients abstracted from prospective database and pre-selected for good/excellent outcomes based on KSS and HHS at one-year. Clinical outcomes included Oxford Hip/Knee scores. UCLA, demographics and clinical outcomes correlated using Pearson’s correlation.

UCLA scores indicate the average TJR patient maintains a moderate activity level. Younger male patients with low Oxford can be expected to participate in higher level activities. One THA patient underwent subsequent revision despite moderate activity level.


M.K. Gilbart B. Fuchs Juerg Hodler C. Gerber

The practice of rotator cuff repair rapidly moves towards arthroscopic techniques especially for single tendon tears. Although the clinical results are relatively well established, the structural results of open rotator cuff repair and their correlation with the clinical outcome are poorly known. In order to provide a baseline for future studies using other repair techniques, this study was carried out to assess the structural changes in the repaired musculotendinous unit and to correlate these findings with the clinical outcome after rupture and repair of an isolated full thickness single tendon tear of the rotator cuff.

To prospectively assess the quality of an open rotator cuff tendon repair technique, to determine how structural changes of rotator cuff muscles are affected by tendon repair, and to correlate the structural results of MRI studies with the clinical outcome.

Direct open repair of a complete, isolated single tendon tear of the rotator cuff resulted in significant improvement in function and objective evidence of tendon healing on MRI. Successful direct repair was not associated with recovery of preoperative muscular atrophy or fatty infiltration when comparing Goutallier stage fatty infiltration between pre and postoperative patients.

The age and gender-adjusted Constant score increased significantly from an average of 63.9% preoperatively to 94.5% postoperatively (p< 0.0001). Pain improved significantly from 6.8 points to 13.2 points on a visual analogue scale. (p< 0.0001). Activities of daily living increased from 11.2 points preoperatively to 17.9 points postoperatively (p< 0.0001). Anterior elevation, abduction and internal rotation improved significantly for subscapularis and supraspinatus repairs, but there was no significant change in external rotation. The overall rerupture rate was 12.5%. There was no significant improvement or recovery of muscular atrophy or fatty infiltration after tendon repair.

Thirty-two consecutive open repairs of a single tendon tear of the rotator cuff were analysed. The supraspinatus tendon was involved in twenty-two patients and the subscapularis tendon in ten patients. All tendons were repaired using an open technique, a modified Mason-Allen suturing technique, and transosseus fixation with non-absorbable suture material knotted over a bone augmentation device.


S.S. Bajammal D. Petruccelli A. Adili M. Winemaker J. de Beer

To evaluate the effect of implant articular geometry on postoperative range of motion (ROM) after primary total knee arthroplasty for osteoarthritis, we conducted a retrospective case-control study of one hundred and twenty patients (sixty in each group) comparing Scorpio® Posterior Cruciate Substituting implant using Superflex® versus traditional tibial insert. Cases and controls were matched 1:1 for surgeon and gender. Both groups had similar baseline characteristics. Except for KSS Clinical Score at six months (mean: 92.8 for Superflex® versus 87.6 for traditional insert; p=0.029), there was no statistically significant difference between the two groups in knee scores or ROM up to one-year postoperatively.

To evaluate the effect of implant articular geometry on postoperative range of motion (ROM) after primary TKA.

Despite the advent of high flexion knee designs, surgical technique and patient driven factors remain the overriding determining factors for ultimate flexion range achieved following TKA.

One hundred and twenty patients (sixty in each group) were included. Both groups had similar baseline characteristics. Except for KSS Clinical Score at 6 month (mean ± SD: 92.8 ± 5.8 for Superflex® versus 87.6 ± 14.6 for traditional insert; p=0.029), there was no statistically significant difference between the two groups in knee scores or ROM. Flexion at one year for Superflex® was 113.5° ± 10.5 compared with 113.2° ± 11.9 for traditional tibial insert (p=0.869).

Retrospective cohort study of a prospectively gathered database of TKA’s performed at a high-volume arthroplasty center from 1998 to 2003. Inclusion Criteria: primary TKA for osteoarthritis using Scorpio® Posterior Cruciate Substituting implant with Superflex® tibial insert versus traditional insert. Exclusion Criteria: WSIB, prior history of septic arthritis, and previous knee surgery. Cases and controls were matched 1:1 for surgeon and gender. Postoperative care was standardized. Data points included demographics, operative details, pre- and post-operative Knee Society Score (KSS), Oxford Knee Score and range of motion at six weeks, six months and one year postoperatively. P< 0.05 was considered statistically significant.

Despite improvements in knee prostheses design, patient factors and surgical technique remain the most important determinants of outcome in primary TKA, particularly ROM.


A.J. Beggs K.R. Gurr

We are reporting our case series of lumbar total disc endoprostheses. Oswestry and SF-36 scores were obtained from patients preoperatively and postoperatively for discs in situ for six, twelve and twenty-four months. Oswestry scores improved from fifty-three to thirty-two at six months (N=34); fifty-five to thirty-one at twelve months (N=28); and fifty-two to twenty-five at twenty-four months (N=17). SF-36 scores improved from thirty to fifty-four (physical) and forty to sixty-two (mental) at six months; twenty-nine to fifty-five (physical) and thirty-eight to sixty-three (mental) at twelve months; and twenty-nine to sixty-two (physical) and forty-one to sixty-seven (mental) at twenty-four months.

We report our results using the Charité III Endprosthesis in the treatment of degenerative disc disease.

Short term outcome for patients having undergone total disk arthroplasty support cautious optimism for continued implantation. Continued close follow-up is essential

Total disk arthroplasty for the treatment of degenerative disc disease is increasing in popularity. Expected FDA approval of several implants make accurate functional outcome reports essential to guide practice.

Disc replacements in situ for six months (N=34) improved in Oswestry scores from fifty-three to thirty-two. SF-36 physical scores for the same cohort improved from a mean of thirty to fifty-four and mental scores from forty to sixty-two. At one year (N=28), Oswestry scores improved from fifty-five to thirty-one. SF-36 physical scores improved from twenty-nine to fifty-five, and mental scores from thirty-eight to sixty-three. At two years (N=17), Oswestry scores improved from fifty-two to twenty-five. SF-36 physical scores improved from twenty-nine to sixty-two, and mental scores from forty-one to sixty-seven.

Using very narrow indications for application of this technique we have implanted fifty-one total disc arthroplasties. Cohorts were analyzed for outcome based on duration in situ of the implant. Through careful follow-up we have identified the following trends based on validated objective outcome measures including the Oswestry low back index and the Short Form 36. These outcome measures in addition to data reported separately demonstrating clear maintenance of interdiscal lumbar range of motion allow for cautious optimism regarding the continued application of total disc arthroplasty.


R. Leighton

Retrospective data over an eight-year period was collected on twenty-four young patients with non-union of a femoral neck fracture who were followed to union. The cause of each nonunion was identified and a classification of the nonunions was established in order clarify treatment options. Patients were treated by a single surgeon. The treatment protocol was based on the classification of the femoral neck nonunion. There were no nonunions in the treated patients; however two patients who showed signs of avascular necrosis prior to treatment ultimately developed AVN.

Femoral neck nonunion occurs in 20–30% of displaced femoral neck fractures. If the femoral head is viable, the treatment goal is femoral neck union to maintain it. Treatment options depend on the cause of nonunion. To clarify treatment options, a classification of nonunions was developed.

The treatment regime developed was based on the type of nonunion. We believe that subclassification of the femoral nonunion improves the selection of treatment options. This classification-based treatment does not reduce the incidence of avascular necrosis, but does seem to guarantee union while permitting excellent function of the hip joint

A classification system based on the cause of the non-union clarifies treatment options to maintain the femoral head and produce union of the femoral neck.

Based on the analysis a classification proposal relating to treatment was developed. In the original treatment group there were no nonunions but two cases of ultimate avascular necrosis— both showed signs of AVN on bone scan prior to treatment.

Classifications:

Type I – Inadequate fixation or non-anatomic reduction (eight patients)

Type II – Loss of fixation with displacement (fourteen patients)

Type III (Rare) – Fibrous nonunion with no displacement and intact fixation (two patients)

Twenty-four patients were treated by one surgeon and followed to union over eight years. The results were examined retrospectively to categorize cause of non-union and treatment protocol. A classification system that describes classes of nonunions and treatment for each type was developed.


M. Paliwal D. G. Allan B. Barnhart R. Trammell

Purpose: The purpose of this study was to monitor serum cobalt (Co) and chromium (Cr) levels in patients after metal-on-metal resurfacing hip arthroplasty with the Cormet 2000® prosthesis, and to evaluate the effect of patient characteristics, prosthesis characteristics, clinical and radiographic measures on metal levels.

Methods: Serum Co and Cr levels were determined in 32 patients with Cormet resurfacing prostheses at 0.5, 1 and 2 years postoperatively using ICP-MS and are reported as & #61549;g/L. Control levels were measured in 20 patients without implants.

Results: Medium Co and Cr were 0.21 and 0.16 in controls without implants. Medium Co at 6 months (2.65), 1 year (3.62) and 2 years (2.80), and Cr at 6 months (3.74), 1 year (4.73) and 2 years (4.68) were signifi-cantly increased in the Cormet group when compared to control levels (p < .0001). Metal levels did not correlate with cup inclination, component position, head size, age, weight, sex or Harris Hip scores. Markedly elevated Co (35, 63) and Cr (13, 70) levels were found in two patients with excessive cup abduction. In addition, one patient with a loose implant that required revision had markedly elevated Co (19) and Cr (44) levels.

Conclusions: Significantly increased levels of cobalt and chromium were released from Cormet 2000 articulations at all time points. Excessive cup abduction was associated with markedly elevated ion levels indicating that accurate cup placement is an important consideration in resurfacing arthroplasty. The significantly increased trace metal levels following resurfacing with the Cormet prosthesis is a concern and warrants further monitoring.


A. Kedgley R. Bicknell J. Delude L. Ferreira C. Dunning G. King K. Faber D. Drosdowech J. Johnson

Purpose: This in-vitro study was conducted to assess the effect of a computer-assisted method of performing shoulder hemiarthroplasty, in comparison to traditional techniques, on passive glenohumeral joint kinematics during abduction.

Methods: Seven pairs of fresh-frozen cadaveric shoulders were tested. One specimen from each pair was randomized to the computer-assisted technique, while the contralateral shoulder underwent a traditional hemiar-throplasty using standard surgical guides by an experienced shoulder surgeon. A simulated four-part proximal humerus fracture was created in each shoulder and was reconstructed using a modular shoulder hemiarthroplasty system (Anatomical Shoulder Hemiarthroplasty System, Centrepulse Orthopaedics Inc, Austin, TX). CT data and computerized simulations of anatomical characteristics were used in the computer-assisted technique. An electromagnetic tracking device (Flock of Birds, Ascension Technologies, Burlington, VT) in conjunction with custom-written software (LabVIEW, National Instruments, Austin, TX) enabled real-time intra-operative feedback.||Passive abduction of the glenohumeral joint was conducted and the resulting motion was quantified using the aforementioned tracking device. Coordinate systems, created on both the humerus and scapula from digitized anatomical landmarks, were used to transform the kinematic data into clinically relevant parameters. Statistical analyses were performed using one-way Analyses of Variance (ANOVAs) followed by post-hoc Student-Newman-Keuls multiple comparisons (p< 0.05).

Results: In the superior-inferior direction, a significant difference in joint kinematics (p=0.011) was found between the computer-assisted and the traditional technique, with the traditional technique resulting in a more inferiorly positioned humeral head at all angles of elevation. There was no difference in translation between the native shoulders and the computer-assisted hemiarthroplasty (p> 0.05). In the anterior-posterior direction there was no difference measured in the position of the humeral head between the two surgical techniques, which were both similar to the native shoulder (p> 0.05).

Conclusions: This is the first known study to examine the effects of a computer-assisted method for performing shoulder hemiarthroplasty. Our results show that the computer-assisted approach should allow improved restoration of glenohumeral joint kinematics relative to conventional techniques, potentially resulting in improved patient outcomes and implant durability.


M. Paliwal D. G. Allan

Purpose: The purpose of our study was to compare serum titanium levels in patients with the three-piece modular AcuMatch® and one-piece nonmodular Versys® titanium femoral components.

Methods: Blood samples were obtained at multiple time points for four years after the surgery in patients with the Versys® one-piece (47 patients) or AcuMatch® three-piece (70 patients) femoral stems. Control levels were measured in 20 patients without titanium implants. Titanium (Ti) levels were measured using high resolution inductively coupled-plasma mass spectroscopy by a technician blinded to the patient groups.

Results: Medium Ti was significantly lower in the control group (.21 & #61549;g/L), when compared to patients with one- and three-part stems at all follow-up periods (p < .02). At 1 and 2 years post-operatively, medium Ti levels in the three-part group (3.1 and 3.4 & #61549;g/L) were significantly higher than levels in the one-part group (1.7 and 1.6 & #61549;g/L) (p < .004). At 3 and 4 years, medium titanium levels were not significantly different in the one-part group (2.5 and 2.7 & #61549;g/L) when compared to the three-part group (3.5 and 3.1 & #61549;g/L) (p > .05).

Conclusions: The intraoperative flexibility provided by modular femoral stems may be offset by increased wear at modular junctions. Ti levels were significantly higher in patients with a highly modular three-part femoral stems at 1 and 2 years but no significant difference was found at 3 and 4 years postoperatively. Continued monitoring of these patients is warranted to determine if metal levels can be used to evaluate stem performance.


C. Albert Y. Park H. Frei G. Fernlund Y. Yoon T. Oxland

Purpose: In-vitro mechanical tests are often used to pre-clinically assess the primary stability of hip endopros-theses. There is no standard protocol for these tests and the test conditions used vary greatly. This study examined the effect of the abductor muscle and the anterior-posterior component of the hip contact force (Fap) on the primary stability of cementless stems.

Methods: Cementless stems were implanted in 12 composite femurs which were divided into two groups: group 1 (N=6) was loaded with the hip contact force only, whereas group 2 (N=6) was additionally subjected to an abductor force. The cranial-caudal component of the hip contact force was the same in both groups, i.e. 2.3BW at 13° from the femur long axis. Each specimen was subjected to three Fap levels: 0, 0.3BW (walking), and 0.6BW (stair climbing). The implant translation relative to the femur was measured using a custom-built system comprised of 6 LVDT sensors. The resultant migration and micromotion were analyzed using an ANOVA with the abductor a between-group factor and Fap a within-group factor, followed by SNK post-hoc analysis with a significance level of 95%.

Results: Implant motion was not significantly affected when the Fap was increased from 0 to 0.3BW. However, without abductor, increasing Fap from 0.3 to 0.6BW increased migration and micromotion by an average of 291& #956;m (285% increase), and 15& #956;m (75%) respectively. With abductor, increasing Fap to 0.6BW increased migration by 87& #956;m (79%) but did not affect micromotion. The abductor did not significantly affect stem motion at lower Fap, but at Fap = 0.6BW motion was 50% lower compared with hip contact forces only.

Conclusions: Based on these results, inclusion of either abductor and/or Fap has little effect on implant motion when simulating walking. However, stair climbing (higher Fap) generates greater bone-implant motion compared to walking loads, and this effect is greatest in the absence of an abductor force. Funding: Other Education Grant Funding Parties: The Michael Smith Foundation for Health Research


A. Petit O.L. Huk D.J. Zukor F. Mwale J. Antoniou

Purpose: Articular surface replacement (ASR) is an alternative for young patients considered for hip replacement. The in vivo release of ions from these surfaces has yet to be well evaluated. The purpose of the present study was to compare the concentrations of metal ions in blood of patients with ASR and metal-on-metal (MM) total hip arthroplasty (THA).

Methods: Blood was collected 6 months after implantation time into Sarstedt Monovette® tubes for trace metal analysis from patients having ASR (n=61), 28 mm-head MM THA (n=18), and 36 mm-head MM THA (n=25). The concentrations of cobalt (Co), chromium (Cr), and molybdenum (Mo) were analyzed by inductively coupled plasma-mass spectroscopy (ICP-MS).

Results: The median Co level was not significantly different between the 3 groups (2.35 ppb, 2.00 ppb, and 2.50 ppb for the 28 mm MM THA, 36 mm MM THA, and the ASR patients, respectively). The median Cr level was significantly lower in the 36 mm MM THA patients (0.10 ppb) compared to the 28 mm MM THA (0.15 ppb) and the ASR (0.40 ppb) patients. The median Mo level was significantly lower in the 36 mm MM THA patients (1.30 ppb) compared to the 28 mm MM THA (2.00 ppb) and the ASR (1.50 ppb) patients.

Conclusions: Our results show that the level of ions in 36 mm MM THA patients was lower than in 28 mm MM THA patients. This can be explained by the fact that 28 mm MM bearings are resistant to microseparation during the normal gait cycle, which is theoretically accompanied by a reduction of fluid film lubrication and increased potential for the production of wear debris. Our results also show that the ion levels in patients having ASRs is similar to that observed in 28 mm MM THA patients but higher than in 36 mm MM THA patients. The diametric clearance of ASRs is typically much greater and the potential for a ‘suction fit’ may be less, leading to higher ion production. The concentration of ions in long-term follow-up remains however to be elucidated. Funding: Educational Grant from the Canadian Orthopaedic Foundation


M. Charles C. Busch C. Rorabeck J. Brandt C. Hayden G. Krishnamoorthy

Purpose: To assess the clinical utility of a computer-based program (discrete dynamic contour method of boundary refinement; Matlab®) to quantify the location and extent of periprosthetic osteolysis around cemented total knee arthroplasties.

Methods: The radiographs of 171 primary Anatomical Modular Knee arthroplasties were reviewed by three independent, blinded raters using Matlab® software program. The location, size (mm2), polyethylene sterilization technique, alignment, presence or absence of femoral osteolysis and patient characteristics was recorded.

Results: The mean duration of follow-up was 8.47 ± 1.10 years with minimum in vivo wear interval= 2.0 years. The overall incidence of radiographically apparent osteolysis was estimated at 30.41%. Furthermore, the average intra-class correlation coefficient for this measurement technique for three independent observers was found to be significant for medially and laterally located zones of osteolysis (I.C.C. value = .7801; 95% C.I. = .7161–.8316; (p< .05). There was a statistically significant trend towards higher rates of osteolysis occurring within the series of polyethylene inserts gamma irradiated in air. Lowest rates of osteolysis were measured in the series sterilized in gas plasma (27.09 mm2 per year vs. 16.24 mm2 per year respectively; p< .001).

Conclusions: The Discrete Dynamic Contour method of boundary refinement represents an acceptably reliable means by which one can quantify the location and extent of osteolysis based upon digitalized radiographs of total knee replacements.


R. Austman C. Dunning G. King C. Dunham K. Gordon

Purpose: To develop an experimental testing method to measure bone strains as a function of multiple implant stem designs in a single specimen, and to show the efficacy of this method with an application in the distal ulna.

Methods: Twenty-four strain gauges were applied to the surface of an isolated cadaveric ulna to measure anterior-posterior (AP) and medial-lateral (ML) bending loads at six locations along its length. The bone was potted in a custom-designed jig and positioned in a materials testing machine. Loads (5-25N) were applied to the ulnar head while strains were recorded. The ulnar head was removed and an 8cm threaded rod (diameter=5.8mm) was cemented into the canal, and subsequently removed after cement curing. This established a threaded cement mantle that would accept various threaded stem designs. To show the efficacy of this technique, testing was repeated with 5 and 7cm stems. The entire canal was then filled with cement and testing repeated to determine the effect of the residual cement void.

Results: All 24 strain gauges provided quality signals throughout the testing period. Strain varied linearly with load (R-squared=0.94–0.99). The initial threaded rod was easily removed, and there was no difficulty in placing subsequent stems within the mantle. Comparing the 5 and 7cm stems, little difference in strains was observed for the most proximal gauges (2%), with higher variations in the stem exit regions (17%). The cement-filled canal exhibited distal strains similar to the intact baselines (average 2% difference at 25N).

Conclusions: A reliable method has been developed that allows multiple stems to be tested in a single bone. Observed strain differences are therefore a function of implant parameters only (such as stem length), and are not influenced by differences in bone properties as occurs when testing multiple specimens. The layer of threaded bone cement did not impact the native bone strains. This experimental method will be useful to compare stem designs in a variety of bones, avoiding the need for large numbers of specimens due to the repeated measure experimental protocol.


C. Mcdonald J. Brownhill G. King T. Peters J. Johnson

Purpose: Accurate determination of the flexion-extension axis of the elbow is critical to the successful placement of elbow arthroplasties, articulated external fixators and ligament reconstructions. We expect axis alignment using computer-assisted techniques to improve the outcome of these procedures. For image-based procedures, registration (i.e. the transformation needed to align two sets of points) during surgery is critical for accurate alignment. A surface-based registration technique, employing a hand-held laser scanner, was evaluated against a stand-alone paired-point registration method to determine whether it led to improved alignment of the elbow’s flexion-extension axis.

Methods: Twelve cadaveric distal-humeri were selected for registration. To perform paired-point (TP-PP) registration, key anatomical landmarks (capitellum, trochlear sulcus and distal humeral shaft) were digitized using a tracked-probe (TP) and an electromagnetic tracking device (Flock of Birds, Ascension Tech). Using the geometric centers of these landmarks, TP-PP registration to CT data was performed. Surface registration was achieved using the iterative closest point (ICP) least-squares algorithm and the results were evaluated for two devices; registration employing the tracked-probe (TP-ICP) and registration employing a hand-held laser scanner, HHS-ICP (FastSCAN, Polhemus). For surface registration, to be consistent with the amount of the joint exposed during a typical surgical procedure, only the articular surface was used for alignment.

Results: Registration error (Figure 1) was lowest for the HHS-ICP method with a mean of 0.8±0.3-mm (maximum error, 1.4-mm) in translation, compared with a mean error of 1.5±0.5-mm (maximum error, 2.4-mm) for the TP-ICP method and 1.9±1.0-mm (maximum error, 4.4-mm) for the TP-PP method (p< 0.001). Errors in TP-PP registration were greatest in the coronal plane while TP-ICP registration often resulted in an error along the transverse plane (Figure 2).

Conclusions: Overall, the reliability of surface-based registration combined with the implementation of the hand-held laser scanner demonstrated greater registration accuracy. A reliable surface-based registration technique may lead to a more accurate determination of the elbow’s flexion-extension axis during surgical procedures, leading to improved joint motion and implant longevity. The implications of these results can also be extended to other joints that employ comparable computer-assisted surgical techniques.


M. Tanzer D. Karabasz J. Krygier J.D. Bobyn

Purpose: A porous tantalum cylindrical shaped implant (Osteonecrosis Intervention Implant, Zimmer, Warsaw, IN) has been designed to provide subchondral bony support of the subchondral plate, be osteoconductive and allow revascularization of an osteonecrotic femoral head. This study evaluates retrieved implants obtained at the time of conversion to total hip arthroplasty to determine the ability of this device to fulfill its objectives. |

Methods: Eighteen femoral heads with the tantalum implant still in situ were evaluated with contact radiographs and scanning electron microscopy to assess femoral head and bony anatomy, bone growth into the implant and femoral head revascularization. Retrievals from 12 males and 6 females with an average age of 46 years old (range, 31–61) and Stage I or II osteonecrosis were evaluated. |

Results: At a mean of 13.4 months (range, 3–36) postoperatively, all femoral heads demonstrated subchondral collapse. The bone surrounding the implant remained necrotic with no evidence of revascularization or healing. Ingrowth was marginal and averaged less than 5%.

Conclusions: This tantalum implant in its present design and surgical technique does not appear to uniformly provide structural support and promote healing of early osteonecrosis of the femoral head. This retrieval study suggests that successful results with this implant in certain cases of early osteonecrosis may be more attributable to the surgical technique requiring a core decompression, rather than the implant itself. |


B. Shore R. Bourne S. MacDonald R. McCalden C. Busch C. Rorabeck R. Bhandari S. Ganapathy

Purpose: Post-operative analgesia using opioids or epidural analgesia can be associated with troublesome side effects. Effective peri-operative analgesia facilitates rehabilitation, improves patient satisfaction and may reduce hospital stay. Locally administered analgesia is effective, avoids systemic drug related side-effects and may be of benefit in minimally invasive joint replacement. This study compares the effects of a peri-articular injection cocktail in patients undergoing total knee and hip replacement surgery

Methods: 128 patients undergoing total knee (TKR) and hip (THR) replacement were randomised to receive a peri-articular intra-operative injection containing ropivacaine, ketorolac, epimorphine and epinephrine or nothing. The anaesthetic analgesic regime was standardised. All patients received patient controlled analgesia (PCA) for 24 hours post surgery, followed by standard analgesia. VAS pain scores during activity and at rest and patient satisfaction scores were recorded pre and post operatively and at 6 week follow up. PCA consumption and overall analgesic requirement were measured.

Results: Both TKR and THR patients used significantly less PCA 6 hours after surgery (p = 0.02 THR, p< 0.01 TKR). TKR patients receiving the injection used significantly less PCA use over 24 hours post surgery (p = 0.013). VAS for pain at 4 hrs post operation was significantly lower in the both groups (p = 0.003 TKR)(p = 0.017 THR). VAS for pain during activity at 24 hours was significantly less (p = 0.001) in the injected TKR group. Overall hospital stay and wound complications were not different between the groups.

Conclusions: Peri-articular analgesia significantly reduces post-operative analgesia requirement in TKR and THR patients. Greater satisfaction and pain relief was seen in TKR patients compared with THR.


S. Kearns A. Daly P. Murray D. Bouchier-Hayes

Purpose: Compartment syndrome (CS) is a unique form of skeletal muscle ischaemia. N-acetyl cysteine (NAC) is an anti-oxidant with beneficial microcirculatory effects. We aim to assess the effect of NAC administration on CS induced muscle injury.

Methods: Sprague-Dawley rats (n=6/group) were randomised into Control, CS and CS pre-treated with NAC (0.5g/kg i.p. 1 hr prior to induction) groups. In a post-treatment group NAC was administered upon muscle decompression. Cremasteric muscle was placed in a pressure chamber in which pressure was maintained at diastolic minus 10 mm Hg for 3 hours inducing CS, muscle was then returned to the abdominal cavity. At 24 hours and 7 days post CS contractile function was assessed by electrical stimulation. Myeloperoxidase (MPO) activity were assessed at24-hours.

Results: CS injury reduced twitch (50.4 ± 7.7 vs 108.5 ± 11.5, p< 0.001; 28.1 ± 5.5 vs. 154.7 ± 14.1, p< 0.01) and tetanic contraction (225.7 ± 21.6 vs 455.3 ± 23.3, p< 0.001; 59.7 ± 12.1 vs 362.9 ± 37.2, p< 0.01) compared with control at 24hrs and 7 days respectively. NAC pre-treatment reduced CS injury at 24 hours preserving twitch (134.3 ± 10.4 , p< 0.01 vs CS) and tetanic (408.3 ± 34.3, p< 0.01 vs CS) contraction. NAC administration reduced neutrophil infiltration (MPO) at 24 hours (24.6 ± 5.4 vs 24.6 ± 5.4, p< 0.01). NAC protection was maintained at 7 days preserving twitch (118.2 ± 22.9 vs 28.1 ± 5.5, p< 0.01) and tetanic contraction (256.3 ± 37 vs 59.7 ± 12.1, p< 0.01). Administration of NAC at decompression also preserved muscle twitch (402.4 ± 52; p< 0.01 versus CS) and tetanic (402.4 ± 52; p< 0.01 versus CS) contraction, reducing neutrophil infiltration (24.6 ± 5.4 units/g; p< 0.01).

Conclusions: |NAC provides extended protection to skeletal muscle against compartment syndrome induced injury by both direct reducing neutrophil mediated tissue toxicity and by reducing neutrophil recruitment to the site of injury.


S. Becker M. Garoscio M. Ogon

Purpose: After vertebroplasty and kyphoplasty the recurrent fracture risk after kyphoplasty is inferior to vertebroplasty, but the risk is still eminent. The reduction of kyphosis is strongly related to the age of the fracture, therefore the reduction and the correction of the kyphosis varies. We investigated the indication of a prophylactic kyphoplasty of adjacent levels to the fracture site in order to decrease the postoperative refracture risk.

Methods: Prospective randomized clinical study, 2 groups: monosegmental kyphoplasty versus bi- or mul-tisegmental kyphoplasty with prophylactic level superior to the fracture. F/U 6 months with X-rays.

Results: Group 1: monosegmental stabilization: (23 pat. 4 male, 19 female, 23 levels). 5 refractures. 3 refractures adjacent to the kyphoplasty, 2 cases not related to the primary stabilization. In 3 cases cement leakage was seen as direct cause of the refracture. |Group 2: pro-phylactic stabilization (27 pat. - 4 male, 23 female, 27 prophylactic levels). 7 refractures, all adjacent to kypho-plasty. In 3 cases cement leakage as cause of recurrent fracture. No statistical difference between both groups was found, however in 6 out of 12 recurrent fractures we found intradiscal cement leakage as the direct cause of the fracture.|

Conclusions: No statistical difference between both groups (group 1: 22% refracture risk, group 2: 26% refracture risk, p=1). Therefore we do not see the need for a generalized prophylactic stabilization of adjacent levels with kyphoplasty. However, we conclude that it is crucial to avoid any leakage, which has a direct impact on the fracture rate, only in those cases we advise a prophylactic stabilization at the leakage site. In general kyphoplasty is preferable to vertebroplasty due to generally decreased leakage and embolism rate.


H. Wu J. Ronsky F. Cheriet R. Zernicke

Purpose: The purpose of this study was to detect any possible prognostic factors which may affect the spinal deformity progression and their relationships in idiopathic scoliosis.

Methods: The stereo-radiograph of whole spine at each visit was reconstructed with two spinal x-ray images in PA 0° and 20° using DLT techniques. Sequential data sets with 3, 4 or 5 successive values of prognostic factors were extracted from 111 consecutive patients (12.3±2.3 yrs, Cobb angle 30.2±12.4°) and separated into the stable and the progressed groups, based on a progression threshold of Cobb angle 5° and 10°. The prognostic factors included gender, curve pattern, age, curve magnitude, apex location, lateral deviation and spinal growth. Effects of those factors were conducted by comparing them between two groups (statistical significances p< 0.05) and the relationships were determined using Pearson’s correlation coefficient (r).

Results: The progressed subjects were predominantly females (50–79%) with double curves. Double curves progressed on both curves RT and LL at the same times and alternatively. There were no significant differences of initial ages and ages with maximum curve magnitudes between two groups. Initial and maximum curve magnitudes were significantly large in the progressed group, but no significantly different between maximum curve magnitudes in the stable group and initial curve magnitude in the progressed group. High curve apex locations were observed in the progressed group. Initial and maximum apex lateral deviations were clearly different in two groups and correlated with curve magnitudes from well to excellent (r = 0.43–0.98). The relationships between the spinal growth and the curve progressing were not consistent (r = −0.6 – +0.6). There were no evidences to show the significant differences of spinal growths between groups and genders.

Conclusions: Scoliosis progression is case dependent. Double curves dynamically progress between curve regions. Initial curve magnitudes have more significant effect on the progression than initial ages. A great progression can be expected from curves with high apex location. Apex lateral deviations are changing with curve magnitudes and spinal growths and, however, the curve magnitudes are not always increased with spinal growths. Funding: 2 Funding Parties: Alberta Provincial CIHR Training Program in Bone and Joint Health


E. Schemitsch R. Walker R. Zdero J. Waddell

Purpose: The purpose of this study was to compare the biomechanical behavior of locking plates to conventional plate and allograft constructs for the treatment of periprosthetic femoral fractures.

Methods: Twenty synthetic femora were tested in axial compression, lateral bending and torsion to characterize initial stiffness and stiffness following fixation of an osteotomy created at the tip of a cemented femoral component. Stiffness was tested with and without a 5mm gap. Axial load to failure was also tested. Four constructs were tested: Construct A – Synthes locked plate with unicortical locked screws proximally and bicortical locked screws distally; Construct B – Synthes locked plate with alternate unicortical locked screws and cables proximally and bicortical locked screws distally. Construct C – Zimmer cable plate with alternate unicortical non locked screws and cables proximally and bicortical non locked screws distally. Construct D – Zimmer cable plate in same fashion as construct C plus anterior strut allograft secured with cables proximally and distally.

Results: In axial compression, construct D was significantly stiffer compared with all other constructs in the presence of a gap, with no differences between groups without a gap. For lateral bending stiffness, construct D was significantly stiffer than the other groups with and without a gap. In torsional testing, construct D was significantly stiffer than all other constructs in the presence of a gap. With no gap, construct D was significantly stronger than construct B. There were no significant differences between constructs A and B in all testing modalities. Axial load-to-failure ranged from 5561.5 to 6700.2 N. There were no significant differences in axial load to failure.

Conclusions: This study suggests that a single locked plate does not provide the same initial fixation stiffness as a plate-allograft strut construct in the setting of a gapped osteotomy. This may be particularly important in the setting of a comminuted fracture or with bone loss. In these settings, a construct with a lateral plate and an allograft strut placed anteriorly at 90 degrees to the plate, may be optimal.


S. Becker A. Tuschel M. Ogon

Purpose: A complete collapse of osteoporotic vertebral fractures is difficult to treat. Restoration of vertebral height is very difficult, if ever possible. Kyphoplasty has been shown to restore vertebral compression fractures; however the best results are achieved in fractures without total collapse. Nevertheless some fractures develop osteonecrosis and pseudarthosis which can be easily seen on X-ray. For those cases we performed a retrospective study in order to evaluate the capacity of kyphoplasty in those difficult situations.

Methods: We analyzed the pre- and postoperative X-rays of vertebra plana treated between 2002 and 2005. Vertebral height (vh -anterior, middle and posterior) and kyphotic angle were measured with a digital imaging system. 2 independent examiners classified the preoperative X-rays into fractures with osteonecrosis/pseud-arthrosis (group 1) and without osteonecrosis (group 2). Statistical analysis with the non-parametric Mann-Whitney test was performed.

Results: Between 2002 and 2005 we performed 315 kyphoplasties. A total collapse of the vertebra (vertebra plana) was treated in 15 cases. Mean age 76 years, SD 5.2 years, average time of treatment after fracture 4 months. Osteonecrosis was persistent in 8 cases. The osteonecrosis group found a statistically significant higher degree of vertebral reconstruction (p < 0.013 - group 1: anterior vh 33%, middle vh 37,8%, posterior vh 19,1%; group 2: anterior vh 4,9%, middle vh 17,5%, posterior vh 1,8%). No significant difference was found in the analysis of the pre- and postop. kyphotic angle which could be due to the small sample size as the mean values are three-fold elevated in group 1 (p = 0.146, group 1: restoration mean 9,1° - maximum 18°; group 2: restoration mean 3,5° - maximum 13°).

Conclusions: Osteonecrosis is a positive predictive sign for the potential of vertebral reconstruction. Vertebral height can be significantly improved in those patients and the major changes of the kyphotic angle are possible. Even after 4 months, correction of the deformity is possible with kyphoplasty. However, without this sign, restoration of the vertebral height and correction of kyphosis is limited to rare cases.


K. Alsaleh M. Ghert N. Colterjohn

Purpose: To determine the surgical and functional outcome of an anatomically based approach to hip reconstruction for metastatic bone disease.

Methods: Records of 123 consecutive patients who underwent hip arthroplasty for metastatic bone disease were reviewed. Sixty one patients (63 hips) had pelvic involvement that required periacetabular reconstruction. Sixty two patients (64 hips) had proximal femoral involvement but no acetabular disease. Operative technique was guided by the extent of column and dome disease in addition to the extent of involvement of the femur. Demographic variables, functional data (ECOG scores) and survival data were analyzed.

Results: : The cohort included 94 females and 29 males, mean age 62 years (range, 39–85). Breast, lung and kidney were the most common primary sites. The average time from initial primary diagnosis to surgery was 42 months. The average time from initial primary diagnosis to surgery was significantly longer for those with breast cancer compared to those with other primary sites (65 vs. 21 months, P< 0.001). Average blood loss was 788 ml (range, 200–3800 ml) and average operative time was 2.3 hours (range, 2–6 hours). There were three perioperative deaths. Functional scores improved from an average of 2.7 preoperatively to 1.4 postoperatively (P< 0.05). Two patients required closed reduction, two required open trochanteric repair and one required ace-tabular revision. Median survival time was 15 months (range, 0–172 months). Patients with breast cancer enjoyed longer survival compared to patients with other primaries (21 vs. 9 months, P=0.02).

Conclusions: Despite the moderate risk of operative complications, an anatomically based approach to reconstruction of metastatic hip disease is effective in improving functional outcome and quality of life in many patients.


J. Antoniou C. Demers A. Michalek J. Iatridis T. Goswami G. Beaudoin L. Beckman M. Alini F. Mwale

Purpose: Quantitative MRI is currently being tested as an early and non-invasive diagnostic tool of disc problems prior to the appearance of symptoms. The aim of the present study was to determine the effects of cyclic loading and enzymatic digestion on quantitative MRI, biochemical composition, and mechanical properties of intervertebral disc tissue.

Methods: Bovine tail segments consisting of three discs were subjected to 16h of cyclic compression loading (50N–300N–50N at 1Hz) or left unloaded for 16h while in saline solution at 37°C. Prior to loading, the nucleus pulposus were injected with either a trypsin or buffer solution. MR examinations were carried out in a 1.5T Siemens` Avanto system to measure T1 and T2 relaxation times, magnetization transfer ratio (MTR), and trace of the apparent diffusion coefficient (TrD). The nucleus pulposus and annulus fibrosus were dissected and analyzed for contents of water, glycosaminoglycan, total collagen, and denatured collagen. Cylindrical nucleus pulposus and annulus fibrosus tissue plugs were harvested, prepared, and tested under confined compression to measure compressive modulus (HA) and hydraulic permeability (k). ANOVA and linear regression analyses were performed (p< 0.05).

Results: Loading decreased the T1, T2, and TrD of NP while it increased MTR. Only water content in the nucleus pulposus was significantly influenced by loading. T1, water content, and k of the annulus fibrosus tissue were significantly reduced with loading.|Enzymatic treatment of the nucleus pulposus had no effect on its MR properties, but increased the percent of denatured collagen and thus decreased HA. None of the biochemical, mechanical, and MR parameters of the annulus fibrosus changed with trypsin treatment.

Conclusions: Dynamic loading of the disc segments for 16h decreased the permeability of both disc tissues. This was consistent with the measured drop in tissue hydration and was observed as a decrease in T1. Targeted trypsin digestion of the nucleus pulposus was confirmed with no detectable changes in the biochemical, biomechanical, or MR properties of the annulus fibrosus. Future studies will address additional quantitative MR parameters such as T1-rho, a higher strength magnet, and different enzymatic treatments. Funding: Other Education Grant Funding Parties: Canadian Institutes of Health Research, McGill William Dawson Scholar Award, and Whitaker Foundation


L. Gordon M. Hardisty T. Skrinskas F. Wu C. Whyne

Purpose: Effectively quantifying metastatic tumour involvement in the spine requires accurate vertebral segmentation. Automated techniques such as thresholding or region growing have difficulty defining boundaries between tumour tissue and surrounding soft tissue if lytic disease breaches the vertebral cortical shell. It is hypothesized that the application of image registration techniques may afford a potential solution to automating segmentation of metastically-involved vertebrae with cortical shell destruction. The objective of this study is to validate deformable registration as a means to automate the segmentation of tumour-bearing vertebrae through the transformation of atlas segmentations.

Methods: CT scans were collected from 6 patients (T4-L5) with spinal metastases secondary to breast cancer. Healthy levels from the patients were cropped and segmented using a combination of thresholding and manual delineation (Amira 3.1.1, TGS Berlin) to obtain the atlas for each vertebral level. After spatial alignment, metastatically involved vertebral levels were segmented by a registration of the atlas scan by automated affine registration (Amira) and refined by demons deformable registration (ITK, NLM Bethesda). The algorithm was tested through comparison of 10 vertebral bodies (thoracic and lumbar) segmented using the automated approach against a gold standard segmentation produced by semi-manual thresholding. The quality of the automatic segmentation was determined by calculating how many voxels were concurrently within both automatic and manual segmentation of the scan.

Results: Deformable registration successfully segmented metastatically involved vertebrae with and without breach of the cortical shell. Similar performance was evident when using an atlas from an adjacent level as compared to using an atlas of the identical vertebral level. Quality of the automatic segmentation ranged from 87.67%–96.22% concurrency. Comparisons of inter-user semi-manual segmentations yielded a similar maximum of 96% concurrency. Analysis speed was 10 to 15 times faster using the automated technique.

Conclusions: By maintaining the atlas morphology, atlas-based segmentations are able to accurately differentiate between trans-cortical tumours and surrounding soft tissue, overcoming problems inherent to more conventional automated segmentation techniques. Clinical application of this segmentation algorithm centers on tumour quantification and tracking progression of treatment effect and metastatic disease pathology. Funding: Other Education Grant Funding Parties: Canadian Breast Cancer Research Alliance, Sunnybrook & Women`s College Research Institute


F. Mwale G. Marguier H. Wang A. Petit O. Huk D. Zukor J. Antoniou

Purpose: To develop an improved understanding of the in vivo behavior of intervertebral disc (IVD) cells for determining the phenotype of a differentiated stem cell in tissue engineering applications.

Methods: Nucleus pulposus (NP) and annulus fibrosus (AF) cells were isolated from adult bovine tails while notochordal cells were extracted from fetal bovine intervertebral disc. Ten million cells (of each cell type) in 500 & #61549;l of DMEM were then injected subcutaneously in C57Bl/6 mice. After 2 weeks, the mice were sacrificed and the specimens harvested. They were examined grossly, histologically and by scanning electronic microscopy (SEM) for the evidence of IVD-like structure formation. Proteoglycan was assessed by the GAG assay and PCR for analysis of gene expression. Control tissue (from bovine NP and AF) were directly fixed in glutaraldehyde, without any isolation technique and examined in SEM.

Results: After 2 weeks, SEM examination of specimens from AF and NP closely resembled normal bovine AF and NP. Of special interest here was the finding that some mice injected with cells from the AF developed an organized arrangement of parallel collagen fibres while NP cells injected mice had an amorphous structure with few collagen fibers. The GAG assay showed pro-teoglycan content for each samples, ranging from 3.8 microg to 26 microg. The morphology of the specimens retrieved from notochordal cells injected mice were also amorphous punctuated with thin collagen fibrils.

Conclusions: This study demonstrates that subcutaneous injection of bovine disc cells in mice can result in formation of disc structures similar to those of the bovine IVD. We believe that the cellular communication of the bovine disc cells is maintained in the mouse leading to architectural organization of the collagen fibers with the mouse as a source of nutrients. This technology may be useful in determining the phenotype of a differentiated stem cell for tissue engineering of IVD.


F. Wu D. Burnes L. Gordon M. Hardisty T. Skrinskas P. Basran C. Whyne

Purpose: The objective of this study was to establish an automated and objective method to quantitatively characterize the extent, spatial distribution, and temporal progression of metastatic disease in the bony spine.

Methods: Serial patient CT scans from GE Light-speed Plus CT Scanners were standardized to 120kVp, 1.25mm/2.5mm slice interval/ thickness, standard reconstruction, and 0.468mm/0.468mm pixel spacing. From 3D reconstructed CT images, trabecular regions within vertebral bodies (VBs) were segmented through atlas-based deformable registration (ITK, NLM, Bethesda). Voxel intensity histograms (voxel counts vs. Hounsfield Units) were used to characterize 32 healthy and 11 metastatically involved vertebrae (T5 to L5). Healthy histograms were fitted to Gaussian regression curves and compared using one-way repeated measures ANOVA (p< 0.05). Tumours were segmented as connected areas with voxel intensities between specified thresholds (Amira 3.1.1, TGS, Berlin).

Results: Histograms of healthy vertebrae were found to be Gaussian distributions (avg. RMSD = 30 voxel counts). The Gaussian mean & #956; ranged from 120 to 290HU, presumably due to inter-patient differences in age and activity. However, the histogram data sets were not significantly different (p> 0.8) across intra-patient vertebral levels T5-L5. Consequently, the Gaussian parameters, & #956; and standard deviation & #963;, determined from fitted healthy histograms could be used in adjacent metastatic levels to define patient-specific lytic and blastic thresholds for tumor segmentation. The ideal lytic and blastic segmentation thresholds were determined to be & #956;−& #963; and & #956;+2& #963; respectively: i.e. while histograms of metastatic VBs were non-Gaussian (RMSD of 56 voxels), subtracting from them the tumourous regions segmented accordingly restored the Gaussian nature of the distributions (RMSD of 24 voxels). Metastatic involvement can then be quantified from histograms of metastases in terms of: (1) lytic/ blastic volumes from areas under the curves; (2) severity of the pathologic involvement from the distribution and range; (3) tumor progression over time or treatment effects by taking the difference between sequential scans.

Conclusions: This proposed histogram-based method for characterizing spinal metastases shows great potential in extending the quantitative capacity of CT-based radiographic evaluations, especially in tracking meta-static progression and treatment effectiveness in clinical research applications. Funding: Other Education Grant Funding Parties: NSERC and CBCRA


D. Petruccelli S. Gyomorey S. Shaughnessy M. Butcher J. De Beer M. Winemaker

Purpose: Peri-implant osteolysis after total joint arhtro-plasty (TJA) is a major cause of implant loosening. Cellular responses to wear particles have been reported to play a role in asceptic loosening due to their cytotoxic nature to cellular components. Purpose of this study is to evaluate the effect of orthopedic implant wear particles on immature osteoblasts in an in-vitro setting in order to further understand the mechanisms involved in asceptic loosening of implants.

Methods: Stromal cells from femurs of 30 day-old Swiss Webster Mice were isolated, cultured in-vitro, and incubated with Titanium and Ceramic (smooth and angular) particles in the micrometer size range. After 9 days of incubation the cells were assessed for Alkaline phosphatase (ALP) activity or stained for cellular changes consistent with apoptosis.

Results: Here we report both a dose-dependent decrease (P< 0.05) in ALP activity and a significant increase in programmed cell death when murine stromal cells were cultured with orthopedic implant wear particles of differing compositions. Ceramic wear particles were consistently less toxic at lower concentrations (1 x 107 to 2 x 107 particles/ml) than were wear particles composed of titanium. However, at high concentrations (4 x 107 particles/ml) all particles regardless of composition were equally toxic. These findings suggest that ceramic particles may be less cytotoxic to bone marrow stromal cells/osteoblasts than are titanium particles.

Conclusions: Previous studies have suggested that inflammatory responses to orthopedic wear particles are responsible for the asceptic loosening of orthopedic implants. In the current study however, we found that wear particles may also induce cellular apoptosis of primary bone forming cells. This suggests that the asceptic loosening of orthopedic implants may be independent of inflammatory processes, and that implant material selection should be directed, in part, by its inability to cause programmed cell death.


P. Bishop P. Wing M. Boyd C. Fisher M. Dvorak

Purpose: The clinical sequelae associated with acute sciatica have been traditionally attributed to mechanical compression of the spinal nerve root by a herniated disc (HD). More recent studies have demonstrated that the HD induces the release of inflammatory mediators and that a tumor necrosis factor alpha-inhibiting agent can resolve the symptoms.|Selective nerve root block (SNRB) involves the transforaminal application of steroid under fluoroscopic guidance adjacent to the selected nerve root. Well-defined criteria for patients that will most likely benefit from SNRB remain unclear. The goal of this study was to determine whether or not the morphology (i.e. posterolateral, sequestrated, foraminal, far lateral) of HD influences the therapeutic value of SNRB treatment.

Methods: An observational cohort study of 37 patients with acute sciatica of less than 12 weeks duration, McCulloch scores of 4 or 5 and evidence of HD on MRI scan at the appropriate level was completed. Disc morphology was determined by blinded interpretation of the MRI scans by a Musculoskeletal Radiologist. Outcome measures included the Modified Roland-Morris Disability Questionnaire (RDQ), administered on the day of, and 6 weeks following, the SNRB procedure and the Visual Analogue Scale (VAS) filled out by the patient immediately before, 30 minutes after and 6 weeks after SNRB.

Results: Of the 37 patients enrolled in this study, the HD morphology was classified as: posterolateral 20, sequestrated 9, foraminal 6, far lateral 2. 35 of 37 patients (95%) reported a 30 minute VAS score of less than 3/10. 14 of 20 patients (70%) with posterolateral HD reported > 3 point improvement in RDQ and > 5 point improvement in VAS at 6 weeks post procedure. 1 of 9 patients (11%) with sequestrated HD showed the same level of improvement in RDQ and VAS scores. None of the patients with foraminal or far lateral HD reported > 1 point improvement in RDQ or > 2 point improvement in VAS scores.

Conclusions: Patients with posterolateral HD were found to have significantly more favorable outcomes from SNRB than those with sequestrated, foraminal or far lateral HD morphology.


S. Fening H. Kambic J. Scott A. Van Den Bogert S. Mclean A. Miniaci

Purpose: Previous research has reported that increasing the posterior tibial slope through an opening wedge osteotomy results in an anterior shift in the position of the tibia relative to the femur. However, the effect of this on anterior cruciate ligament (ACL) strain remains insufficiently understood. The purpose of this study was to examine the relationship between tibial slope and tibial translation, as well as between tibial slope and ACL strain. It was hypothesized that increasing the posterior tibial slope would result in an increase in anterior tibial translation thereby increasing strain in the ACL.

Methods: Five cadaveric knees were subjected to a randomized experimental design study. One knee was excluded due to failure of a strain gauge during experimentation, resulting in data for four knees. The femoral and tibial portions of the knee were potted with PMMA and fixed using fixation pins. An anterior-based osteotomy was performed with no osteotomy plate present. A strain gauge was then placed in the anteromedial bundle of the ACL. Each knee was mounted at a flexion angle of 15° and loaded with various combinations of A-P loads (18N, 108N, 209N) and axial loads (216N, 418N), according to the study design. Osteotomies of 5mm and 10mm were then performed and measurements of strain and tibial translation were taken after each according to the study design. Tibial slopes were determined through lateral fluoroscopic imaging.

Results: As posterior tibial slope increased, anterior tibial translation increased as anticipated. However, contrary to expectations, as posterior slope increased, ACL strain decreased. One explanation for this result could be that by performing the osteotomy, the insertions sites of the ACL were being moved closer together resulting in increased ACL laxity. At higher slope angles, translation levels off, suggesting constraint of some tissue besides the ACL.

Conclusions: Although increasing the tibial slope through opening wedge osteotomy leads to an anterior tibial translation, there is no increase in strain on the ACL. Further studies are needed to examine the effect of opening wedge osteotomy on other soft tissue restraints of the knee.


V. Lee C. Dunning T. Jenkyn

Purpose: To develop a computerized inverse dynamic 3D model of the upper limb, focussing on the elbow.

Methods: Anatomic bony landmarks were identified in one cadaveric arm using an electromagnetic tracking device (Flock of Birds, Ascension Technologies, VT). The articular surfaces of the radiohumeral and ulnohumeral joints were digitized, thereby identifying the areas over which the contact forces could act. Attachment sites of the medial collateral (MCL) and lateral collateral (LCL) ligaments and the major muscles (BRA=brachialis, BIC=biceps, BRD=brachioradialis, TRI=triceps) were also digitized to create line-of-action vectors. These data were fed into custom-written software (MATLAB®, The MathWorks Inc., MA) that simulated flexion with gravity as external loading, and calculated the forces exerted by the joint structures. As an indeterminate system, computerized mathematical optimization solved for the internal loads using a cost function that minimized the sum of forces squared.

Results: Model outputs were comparable with results from previous muscle activity and cadaveric studies. Force ratios among the elbow’s prime movers at 30 degrees of flexion agreed quite closely with previous findings (Funk et al, 1987), with percent differences of 11% (BRA), −5% (BIC), −6% (BRD), and −1% (TRI). Overall, the brachialis force was the highest throughout flexion, being the prime mover, while extensor (triceps) activity remained quiet through mid-range. The magnitude of the radiohumeral contact force showed a decreasing pattern through the arc of flexion, similar to the trend found experimentally by others (Morrey et al, 1988). The results also demonstrated stabilizing forces supplied by the MCL, but not the LCL.

Conclusions: Current understanding of upper extremity loading is very limited. Creating an accurate computerized model of the elbow joint, would reduce the need for experimental testing with cadavers, which are always of limited availability. While stability of the elbow has been experimentally investigated, this model will be able to quantify the forces within the stabilizing structures. By establishing a normal baseline of these forces, surgical procedures and joint replacement designs can be validated. Thus, this model can provide a significant contribution to upper extremity biomechanics research and clinical treatments.


E. Dare P. Poitras J. Kaupp S. Waldman D. Carlsson G. Dervin M. Griffith M. Hincke

Purpose: The objective of this project is to determine the suitability of modified fibrin hydrogels as scaffolds for articular cartilage tissue engineering. The attractive feature of the fibrin system is that the gel precursors are available in autologous form. We have previously demonstrated that genipin, a naturally occurring cross-linking agent, stabilizes the fibrin gel.

Methods: Human articular chondrocytes were isolated from articular cartilage harvested from consenting patients undergoing total knee arthroplasty. The human cells were encapsulated into fibrin gels where gelation was induced by combining fibrinogen, thrombin, and genipin. The resulting gels were evaluated for extracellular matrix (ECM) production, mechanical properties, cell viability, and biodegradation.

Results: No breakdown of the gels was detected during 5 weeks of cell culture. After several weeks in culture, histology indicates significant proteoglycan production by encapsulated cells, and collagen II and aggrecan were detected in this ECM by immunostaining. There was a greater accumulation of cartilage-like ECM in the gels cross-linked with genipin. Dynamic compression tests performed at 0.1 Hz for 10 cycles using an MTS machine indicate that accumulation of ECM was associated with increased stiffness of the material. Cell viability was assessed using live/dead staining, and was found to be > 50% after 24 hours and at 1 week in culture. The presence of genipin cross-linking did not significantly affect cell viability. Real-Time RT-PCR indicated that encapsulated chondrocytes show an increase in Sox9, collagen II and aggrecan expression over 5 weeks and that this is further increased in the presence of genipin. The gene expression results agreed with the enhanced ECM seen under these conditions by histology and immunostaining. The fibrin material was also implanted subcutaneously into rats and after 30 days the material was removed, sectioned and evaluated. Immunostaining indicated that while there was evidence of biodegradation, the material did not appear to cause an inflammatory response.

Conclusions: Modified fibrin hydrogels show potential as cellular scaffolds for articular cartilage tissue engineering. An in vivo orthopaedic model must now be developed to fully evaluate the potential of the fibrin gel. Funding: Other Education Grant


K. Harato Y. Suda H. Matsumoto T. Nagura T. Otani K. Matsuzaki Y. Toyama

Purpose: The purpose of this study was to investigate the relationship between knee flexion contracture and spinal alignment.

Methods: Ten healthy women (mean age 62) participated in this study. Subjects were examined with posture analysis system, using twelve retro-reflective markers (placed at bilateral acromion, bilateral anterior and posterior superior iliac spine, iliaccrest, greater trochanter, lateral knee joint, lateral malleolus, lateral calcaneus, and fifth metatarsal head), five cameras and a force plate. Unilateral (only right side) knee flexion contractures were simulated by using a hard brace at 0, 15 and 30 degrees. First, relaxed standing was measured without simulation, and then the same measurement was performed with each simulation. The posture without brace was used as control. The shoulder tilting angle was defined by the height difference in right and left acromions. The pelvic tilting angle was defined by the height difference in right and left superior posterior iliac spines. The anterior-bent of the trunk was defined by the slope linked right acromion and right iliac crest. The posterior-bent of the pelvis was defined by the slope linked right superior anterior iliac spine and right superior posterior iliac spine. Knee resultant force (% body weight) was calculated by using inverse dynamics technique.

Results: When contracture angle increased, the trunk was significantly tilted leftward (1.4 degrees at 30 degrees contracture), and the pelvis was significantly tilted rightward (1.8 degrees at 30 degrees contracture). In anterior-bent of the trunk, no significant difference was detected. The posterior-bent of the pelvis was significantly increased (1.5 degrees at 30 degrees contracture). The severer the right knee contracture, the smaller the right knee resultant force (41.5 at controls, 28.7 at 30 degrees contracture) and the larger the left knee resultant force (40.2 at controls, 59.9 at 30 degrees contracture).

Conclusions: This study showed the influence of knee flexion contracture not only in the sagittal plane, as the previous study reported, but also in the coronal plane. Severe unilateral knee flexion contracture can cause the lumbar spine bent convexly to the contracture side. This may result in Knee-Spine Syndrome.


C. Tkaczyk A. Petit F. Mwale J. Antoniou D. Zukor M. Tabrizian O.L. Huk

Purpose: One of the major concerns regarding metal-on-metal prostheses is the biological and biochemical activities of chromium (Cr) ions. Previous studies showed that Cr3+ ions form nanostructures in cell culture media and to date, there has been little attempt to understand the nature of implant-derived metal ions in adjacent tissues or in biofluid. The aim of this work was to determine the nature of proteins present in serum involved in the formation of Cr nanostuctures

Methods: RPMI 1640 and DMEM media supplemented with 5% human serum (HS) or 5% foetal bovine serum (FBS) were incubated for 1h at 37°C in the presence of 50 ppm of Cr3+ (CrCl3). Structures were then isolated and separated by SDS-PAGE. Proteins were stained by Coomassie blue and analyzed by liquid chromatography-quadrupole-time of flight-mass spectrometer (LC-Q-Tof-MS). Data were submitted to Mascot software for a search against the NCBI nonredundant database

Results: Results show that Cr-nanostructures can interact with proteins from both human and bovine serums. On SDS-PAGE, the molecular weights of the proteins were between 40 to 90 kDa. The LC-Q-Tof-MS results suggest that Cr-nanostructures are the result of the interaction with numerous proteins present in serum. However, the complete analysis of results demonstrates that only two proteins (in both RPMI and DMEM) are implicated in these nanostructures: albumin and trans-ferrin. For both proteins, at least 40 peptides matched to the complete sequence of the proteins. The ion scores (“peptide identity score”) were between 79 and 108. Ion scores > 45 indicate identity or extensive homology

Conclusions: Human serum contains more than 400 different proteins. Albumin, the major protein of human serum, has been shown to play a scavenger role by binding and transporting injected and ingested Cr. Albumin could also play an immunological role by addressing signals to defense cells, such as macrophages. Trans-ferrin, known as an iron-carrying protein, also plays a scavenger role for Cr. This suggests that the binding of Cr to these proteins may protect cells from the cytotoxic effect of Cr ions. However, the relation with Cr nano-structures in vivo remains to be determined


Y. Li J.A. De Guise R. Aissaoui N. Duval N. Hagemeister K. Boivin K. Turcot A. Roy R. Pontbriand

Purpose: To determine if some subsets of healthy subjects displayed other than a typical gait pattern and to identify which subsets have similar kinematic pattern to patients with knee osteoarthritis.

Methods: The healthy subject dataset consisted of 106 asymptomatic volunteers. These subjects were over 17 years of age, pain-free, had no record of surgery to the lower limb and no evidence or history of arthritic disease at the time of testing. The patient population consisted of 12 patients diagnosed with knee OA, evaluated within 6 months prior to the tests. The 3D movements of right knee joint were recorded using a functional knee analyzer with magnetic sensors while subjects walked on a treadmill at their own preferred speed. The magnetic sensors are non-invasive electromagnetic devices, which track the 3D positions and orientations of sensors relative to a source. The system has been shown to be accurate, especially in the frontal and transversal planes. K-means clustering analysis was chosen to identify the gait patterns among healthy subjects based on three components of the knee joint angles, and analyses of variance were performed to determine which parameters were different between subsets.

Results: Three gait groups or patterns were identified in the healthy subjects. The first group (G1) was characterized by a kinematic profile similar to the OA group. The second group (G2) had the highest external rotation angle, which was significantly different from OA group. The abduction angles were always greater in the G2 and G3 than in the OA group. This might be attributed to a valgus static alignment in G2 and G3 comparing to a varus alignment in the patient with OA.

Conclusions: The newly developed functional knee analyzer provided a non-invasive way to accurately measure 3D kinematic data which enabled cluster analysis to distinguish three gait patterns from 106 healthy subjects. The results suggested a strong correlation between static alignment and dynamic ad-abduction angles during the gait, which need to be investigated. Funding: Other Education Grant Funding Parties: NSERC, CIHR and FCAR


N. Greidanus J. Cibere A. Thorne N. Bellamy A. Chalmers N. Mahomed S. Trithart V. Combes K. Shojania J. Kopec J. Esdaile

Purpose: To evaluate the benefits of standardization on the reliability of the physical examination of the hip by rheumatologists and orthopaedic surgeons

Methods: Six subjects with mild to severe hip osteoarthritis (OA) were examined by 6 examiners (4 rheumatologists, 2 orthopedic surgeons) experienced in the assessment of hip OA using a 6x6 Latin square design. Subjects were examined, followed by a standardization meeting and, a day later, by post-standardization examinations. 33 hip examination maneuvers were evaluated, including range of motion, pain, tenderness, muscle strength, leg length and gait. The order of examinations was randomized for each examiner. For dichotomous signs, agreement was calculated as the prevalence-adjusted bias-adjusted kappa (PABAK). Ordinal and continuous variables were analyzed by ANOVA, using the proportion of variance due to rheumatologists to calculate a reliability coefficient (Rc).

Results: Subjects’ mean age was 61 years (range 49–65), mean BMI was 24 (range 21–30), mean WOMAC pain on walking was 52 mm (range 21–81mm). 23/33 (70%) hip examinations were reliable after standardization. Two new items resulted from the standardization meeting. Pre-/post-standardization reliability for select hip examinations using PABAK were as follows: Gait 0.06/0.52; pain on internal rotation 0.60/0.52; pain on external rotation 0.24/0.72; pain on flexion 0.46/0.82; Patrick test for hip pain 0.78/0.80; Thomas test 0.60/0.88; Trendelenburg test 0.36/0.06. Pre-/post-standardization reliability for select hip examinations using Rc were as follows: hip flexion strength 0.83/0.95; hip abduction strength 0.90/0.86; hip adduction strength 0.87/0.86; ROM internal rotation (supine) 0.87/0.94; ROM external rotation (supine) 0.87/0.80.

Conclusions: Moderate to very good agreement was present for many hip examinations prior to standardization. Improved reliability was achieved after standardization for many but not all hip assessments. This will be important for improved outcome studies of early hip OA.


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E. Sled P. Costigan T.D.V Cooke L. Sheehy

Purpose: To compare a computer-based program for measuring frontal plane leg alignment with a hand-measuring system.

Methods: Five patterns of frontal limb alignment, simulating full-length radiographs of healthy and malaligned limbs, were drawn in AutoCAD and exported as digital images. The patterns included variations in varus and valgus alignment and joint space slope. Copies of each pattern were given to 7 trained readers for analysis. The readers used a ruler and protractor to measure predefined angles and lengths following an established method which defines limb and joint margin landmarks to derive mechanical and anatomic (shaft) axes. Custom software was used to define the same landmarks on the digital copies of the patterns; the angles and lengths were calculated by the software, replicating the method above. A simple fixed calibration factor was used to convert the digital linear dimensions to their paper equivalent. The order of hand and computer analysis of the 5 patterns was randomized and each was repeated daily for 3 days. Measured angles included hip-knee-ankle (HKA), femoral condylar tangent-hip (CH), tibial plateau tangent-ankle (PA), condylar-plateau (joint orientation-CP) and angles between the femoral mechanical axis (FM), femoral shaft axis (FS), tibial mechanical axis (TM)and tibial shaft axis (TS). Repeated measures analysis of variance was performed to compare the methods, with a significance level set at p< 0.05.

Results: The analysis revealed differences between hand and computer measures in femoral lengths and apparent leg lengths (although these differences were less than 1 mm). Differences between methods were also obtained for CP and FM-FS angles (the differences in angles were less than 1 degree). The variance of the computer measures was the same as (19/55 measures) or significantly less than (35/55 measures) the hand measures, with the exception of angle CH on a single pattern. For all limb length measures and the angles HKA, FM-FS, FM-TS and FS-TS there were differences between the readers. There was no difference across days for any measure.

Conclusions: The analysis revealed similar results for limb alignment angles and for limb lengths between hand and computer methods. The computer application improved on the variance obtained with the hand measuring method, indicating a more precise system. Significant differences were found between readers, suggesting the need for standardization of methods for measuring alignment.


D. Holdsworth S. Rajesekaren D. Mcerlain D. Naudie K. Saidi

Purpose: Osteoarthritis (OA) is a complex disease process affecting both articular cartilage and underlying bone. An emphasis has been placed on understanding changes in articular cartilage that occur with disease progression, but comparatively little work has been done to understand changes in subchondral bone. The purpose of this study was to evaluate the architectural changes that occur in underlying osteoarthritic bone and to determine their relation to the stages of arthroscopic disease progression.

Methods: Three cadaver knees were evaluated and graded arthroscopically using the Marshall grading system. Representative bone plugs were then extracted from each compartment. Twenty-eight plugs were extracted and imaged using microcomputed tomography (microCT) scanner developed at the Robart’s Research Institute. Volumetric data for each plug biopsy was obtained in 20 minutes of scan time at an isotropic resolution of 68 μm voxels. The data acquired was analyzed using the GE Health Care Scan Control software and reconstruction utility. Subchondral bone thickness bone mineral density (BMD), trabecular thickness (TT), trabecular separation (TS), and structure model index (SMI) were collected and compared in the medial, lateral and patellofemoral compartments of the knees.

Results: No statistical difference was found in any of the parameters when compared with advancing arthroscopic disease progression. When the data was pooled into normal and osteoarthritic specimens, BMD was found to be significantly decreased (p < 0.05) in osteoarthritic bone. A decrease in BVF and an increase in SMI approached significance in osteoarthritic bone.

Conclusions: Further investigation is required for a complete understanding of the architectural changes that occur in subchondral bone with disease progression. A better understanding of OA would have clinical implications in primary and secondary disease prevention. Funding: Other Education Grant


C. Dunham R. Austman G. King J. Johnson C. Dunning

Purpose: Anterior flanges have been added to the humeral components of some total elbow arthroplasty systems. Surgeons have the option of placing a wedge of bone or bone cement between the anterior surface of the humerus and the flange in an effort to improve implant stability and load transfer. The purpose of this study was to quantify the cortical strains in the humerus after arthroplasty for different materials placed behind the flange.

Methods: Five fresh-frozen cadaveric distal humeri were thawed and cleaned of all soft tissues. Strain gauges were applied to the anterior and posterior surfaces to record bending and axial strains. The bending gauges were positioned just proximal to the location of the flange tip. Cantilever bending and axial compression were applied using a materials testing machine. Following intact testing, the humeral component of a total elbow was implanted by an experienced surgeon and fixed using bone cement. Testing was repeated three times, each with a different material behind the flange: no graft (simulating a humeral component without an anterior flange), cancellous bone graft, and cement graft. Strains were normalized to the intact state and for the applied moments. Data were analyzed using repeated-measure ANOVAs (p< 0.05).

Results: For bending, the strain values were approximately 80% of the intact values with no graft material, 80% with the bone graft, and 87% with the cement graft. These differences among the graft materials were not significant (p=0.5). Similar results were found for the axial strains (p=0.3).

Conclusions: The intention of the anterior flange is to transfer a portion of the load carried by the implant stem to the distal humerus, thereby reducing stress-shielding and improving strength of the construct. In this investigation that employed bending and axial loads, the presence of an anterior flange had no significant effect on load transfer through the distal humerus regardless of graft material used. This would suggest that for the humeral component employed in this study, the flange might not be fulfilling its intended purpose.


A. Cervinka D. Chess B.S. Gan

Purpose: Methylrosaniline, more commonly known as Gentian violet, is an inexpensive dye that has been used in medicine for 100 years. It has been shown, in the international literature, to have antimicrobial effects against Staphylococcus aureus, Staphylococcus epider-midis, and Pseudomonas aeruginosa. Methylrosaniline has the potential to exert an antibiotic effect while theoretically having a reduced selection pressure for resistant bacteria.

Methods: Standardized specimens consisting of Simplex P cement combined with Gentian violet, powdered tobramycin, powdered erythromycin/colistin, and no antibiotic were fashioned. These four groups were then tested against the species S. aureus, S epidermidis, and P aeruginosa using a Kirby- Bauer Agar disk diffusion test.

Results: Gentian violet showed antimicrobial activity against S aureus, S epidermidis, but not P aeruginosa. Tobramycin demonstrated activity against against all three and the preparation of erythromycin/colistin was only effective against S aureus.

Conclusions: Gentian violet demonstrates antimicrobial activity against the two most common infections in primary total joint arthroplasty.


P. Ferguson R. Zdero D. Leidl E. Schemitsch R. Bell J. Wunder

Purpose: Endoprosthetic reconstruction of the distal femur is the preferred approach for patients undergoing resection of bone sarcomas. The traditional How-medica Modular Resection System, using a press-fit stem (HMRS or Kotz prosthesis, Stryker Orthopaedics, Mahwah, New Jersey, USA) has shown good long-term clinical success, but has also been known to incur complications such as stem fracture. The Restoration stem, as a part of the new Global Modular Resection System (GMRS, Stryker Orthopaedics, Mahwah, NJ, USA), is currently proposed for this same application. This stem has a different geometry and provides the advantage of decreased risk of fracture of the component. The goal of this study was to compare the HMRS and Restoration press-fit stems in terms of initial mechanical stability.

Methods: Six matching pairs fresh frozen adult femora were obtained and prepared using a flexible canal reamer and fitted with either a Restoration or HMRS press-fit stem distally. All constructs were mechanically tested in axial compression, lateral bending, and torsion to obtain mechanical stiffness. Torque-to-failure was finally performed to determine the offset force required to clinically fail the specimen by either incurring damage to the femur, the stem, or the femur-stem interface.

Results: Restoration press-fit stems results were: axial stiffness (average=1871.1 N/mm, SD=431.2), lateral stiffness (average=508.0 N/mm, SD=179.6), and torsional stiffness (average=262.3 N/mm, SD=53.2). HMRS stems achieved comparable levels: axial stiffness (average=1867.9 N/mm, SD=392.0), lateral bending stiffness (average=468.5 N/mm, SD=115.3), and torsional stiffness (average=234.9 N/mm, SD=62.4). For torque-to-failure, the applied offset forces on Restoration (average=876.3 N, SD=449.6) and HMRS (aver-age=690.5 N, SD=142.0) stems were similar. There were no statistical differences in performance between the two stem types regarding axial compression (p=0.97), lateral bending (p=0.45), or torsional stiffnesses (p=0.07). Moreover, no differences were detected between the groups when tested in torque-to-failure (p=0.37). The mechanism of torsional failure for all specimens was “spinning” (i.e. surface sliding) at the femur-stem interface. No significant damage was detected to any bones or stem devices.

Conclusions: These results suggest that the Restoration and HMRS press-fit stems may be equivalent clinically in the immediate post-operative situation. Funding: Commerical funding Funding Parties: Stryker Orthopaedics


D. Petruccelli M. Winemaker M. Shawish J. De Beer

Purpose: Our purpose was to evaluate why some patients achieve excellent range of motion (ROM) following total knee arthroplasty (TKA) and to determine its relation to outcome.

Methods: We evaluated 618 primary unilateral TKA’s for osteoarthritis from a prospective arthroplasty database using a single implant design. 209 TKA’s with ROM greater than 120 degrees at one year follow-up were compared to 409 TKA’s with ROM less than 120 degrees to determine if age, BMI, gender, ASA class, and preop ROM differed between the two groups. Knee society and oxford knee scores were also compared both preoperatively and at one year follow-up using independent samples t-test. A multiple logistical regression analysis was performed to determine predictors of ROM.

Results: Preoperative ROM was higher (115 vs 106, p< 0.0001), BMI was lower (30.7 vs 32.9. p< 0.0001), and there was a higher proportion of males (p< 0.0001) in those patients with exceptional ROM at one year (> 120 degrees). Knee Society Score (93.7 vs 87.8, p< 0.0001) and Oxford Knee Score (20.4 vs 24.4, p< 0.0001) were superior in the exceptional ROM group at one year follow-up. In multiple logistic regression, only preoperative ROM (p< 0.0001) was a significant predictor of postoperative flexion range.

Conclusions: Body habitus may play a role in our ability to achieve exceptional flexion following TKA. Implant design has historically favoured male anatomy which may influence exceptional flexion range. Preoperative ROM still seems to be the biggest predictor of postoperative ROM. Perhaps timely surgical intervention, pre-habilitation and implant design choice can influence our ability to achieve exceptional ROM following TKA.


A. Kedgley S. Takaki P. Lang C. Dunning

Purpose: To compare the torsional stability provided by five implant stems with different cross-sectional geometries under cyclic loading.

Methods: Cemented stems with five different cross-sectional shapes – circular, oval, triangular, rectangular with rounded edges (round rectangular), and rectangular with sharp edges (sharp rectangular) – were custom machined from stainless steel. Stem dimensions were selected to fit within the humeral canal (based on a 6mm x 8mm dimensioning scheme) and shapes were based on commercially available-designs. Seven specimens of each stem shape were tested. ||The stems were potted in square aluminum tubes using bone cement, and allowed to cure for 24 hours prior to testing. A materials testing machine and a custom designed loading fixture were used to apply torsion to the stems. A sine wave loading pattern was applied until ultimate failure (5° of stem rotation) was reached. This loading pattern had a lower bound of 0.9Nm and an upper bound that started at 4.5Nm and was increased in increments of 2.25Nm every 1500 cycles. The load was cycled at 2Hz. Statistical analyses on both the number of cycles and torque to failure were performed using one-way ANOVAs followed by post-hoc Student-Newman-Keuls (SNK) tests (p< 0.05).

Results: Overall, ANOVAs showed an effect of shape on the number of cycles (p< 0.0001) and torque to failure (p< 0.001). SNK tests revealed the sharp rectangular stem provided the greatest resistance to torque (p-cycles< 0.001; p-torque< 0.001) compared to all other stems. Other significant differences resulted in the following ranking of the shapes: sharp rectangular, round rectangular, triangular, and circular = oval.

Conclusions: The results of this study agree with static testing previously conducted on the same set of stem shapes. Although the sizes of the stems were chosen to roughly replicate upper limb implants, these results may be extrapolated to larger stems such as for the hip or knee. To improve implant longevity, it is important that the best fixation possible be obtained through all available avenues, including improved cementing techniques, and optimal implant designs. An alteration in implant stem shape may assist in achieving this goal.


P. Kim M. Dunbar G.Y. Laflamme A. Conway H. Hrushowy

Purpose: A multicenter prospective evaluation of the Conserve Plus resurfacing implant (Wright Medical Technology) was undertaken to assess clinical and radiographic outcomes as well as ion levels. This study focuses on the serum, erythrocyte and urinary levels of cobalt and chromium in those patients undergoing hip resurfacing arthroplasty.

Methods: A subset of patients enrolled in a multicenter trial to assess hip resurfacing arthroplasty had serum, erythrocyte and urinary cobalt and chromium levels measured. Levels were assessed preoperatively, then at three months, six months then yearly thereafter. Clinical outcome measurements were performed with WOMAC and Rand questionnaires.

Results: Fifty-four out of 124 patients enrolled in the overall study had cobalt and chromium ion assessments performed. During the first year there was an increase in serum cobalt levels from 1.4 ug/l at 3 months to 2.4 ug/l at one year. Serum chromium levels increased from 1.4 ug/l at 3 months to 3.5 ug/l at one year. Erythrocyte cobalt levels increased from 0.8 ug/l at 3 months to 1.4 ug/l at one year. Erythrocyte chromium levels decreased from 1.5 ug/l at 3 months to 1.4 ug/l at one year. Urinary levels for cobalt increased from 12.7 ug/l at 3 months to 13.8 ug/l at one year. Urinary chromium levels rose from 4.0 ug/l at 3 months to 5.1 ug/l at one year.

Conclusions: Increasing ion levels were seen during the first year post hip resurfacing arthroplasty. Clinical outcomes demonstrate predictable improvements in pain and function consistent with hip replacement surgery. Resurfacing arthroplasty is a viable option to total hip arthroplasty for younger active patients. The clinical significance of increased cobalt and chromium ions remains unknown. Funding: Commerical funding Funding Parties: Wright Medical Technology Inc.


S. Frost C. Beauchamp M. Spangehl R. Donnely B. Goldberg

Purpose: The gold standard for treatment of infected total hip or knee replacements remains a 2-stage exchange arthroplasty. This includes aggressive irrigation and debridement, implant removal, insertion of antibiotic impregnated spacers, iv antibiotics, and eventual reimplantion with a definitive prosthesis. The purpose of this study was to quantify Vancomycin and Gentamycin synovial fluid levels at the time of reimplantation following a 2-stage exchange arthroplasty for a infected total hip or knee replacements.

Methods: The senior author performed 42 two-stage reconstructions using the prosthesis of antibiotic-loaded acrylic cement (PROSTALAC). Each 40g bag of Pala-cos-R cement was impregnated with Vancomycin 2g, Gentamycin 4.8g, and plus/minus ancef 2.0g (depending on penicillin allergy). At the time of reimplantation, the synovial fluid was immediately analyzed for levels of Vancomycin and Gentamycin.

Results: 17 patients were taken for stage II within 60 days (avg. 53). The synovial fluid vancomycin and gentamycin levels were 12.7 and 20.6 respectively. Twelve patients had stage II between 60 and 90 days (avg. 79). The synovial fluid vancomycin and gentamycin levels were 6.2 and 14.9 respectively. The remaining 13 patients underwent stage II beyond 90 days (avg. 192), and their synovial fluid vancomycin and gentamycin levels were 3.3 and 2.4 respectively. 40 of 42 patients had their infections eradicated.

Conclusions: in vitro evidence predicts that antibiotics elute rapidly from bone cement. The results of this study confirm that substantial doses of vancomycin, gentamycin, and ancef per bag of Palacos-R cement does confer long term synovial fluid antibiotic levels well above the minimal inhibitory concentrations required to treat infected total joints. When stage II reimplantation is done at greater than 3 months, synovial fluid antibiotic levels decline significantly.


C. Anglin J. Tonetti A. Hodgson K. Beadon B. Masri C. Duncan D. Garbuz N. Greidanus

Purpose: To examine whether neutral or valgus placement results in greater fracture strength ex vivo, when the femoral neck is notched superolaterally as sometimes occurs during hip resurfacing arthroplasty.

Methods: We loaded 10 paired fresh-frozen notched proximal cadaveric femora (8F/2M, 66 to 80 years) to failure. In each case, the right femur was implanted, using bone cement, with a machined resurfacing component aligned neutrally with respect to the femoral neck whereas the left femur was implanted at 10° valgus. The superolateral notch was 3 mm wide by 2 mm deep directly beside the component. Potted femurs were loaded to failure using an Instron materials testing machine. All 20 femora were scanned using Dual-Energy X-Ray Absorptiometry.

Results: The effect of neutral versus valgus placement was complex. (1) Two pairs slowly crushed; the remaining femurs exhibited a clear fracture. When only the fracture-type failures were analyzed, valgus placement resulted in fracture loads on average 22% higher than for neutral placement (paired t-test, p< 0.05). All femurs failed within the notch, as occurs clinically. (2) Femurs with high bone density (BMD> 0.65 g/cm2) showed a significant increase in fracture load (p< 0.05) whereas femurs with low BMD (< 0.65 g/cm2) were unaffected by component placement. BMD was highly correlated with fracture load (Pearson r=0.87, p=0.0003). (3) The greatest improvements occurred when the neck-shaft angle was relatively low, 128°–132°. (4) Two of ten femurs required larger head sizes at 10° valgus.

Conclusions: (1) Fracture load was primarily controlled by bone quality (BMD); (2) nevertheless, varus/valgus placement did affect the fracture load; (3) the magnitude and direction of this effect depended on fracture type, bone mineral density and the original neck-shaft angle; (4) for the level of bone quality typical of patients undergoing hip resurfacing, and for low-to-average neck-shaft angles (up to 132°), the fracture load for 10° valgus placement was significantly higher than for neutral placement. Funding: Other Education Grant


A. Hadjipavlou I. Gaitanis M. Tzermiadianos P. Katonis D. Pasku

Purpose: The purpose of this study is to evaluate the safety of methylmethacrylate cement balloon kypho-plasty (BK) when applied to five or six levels in the same sitting and the incidence and location of cement leakage.

Methods: Eighty nine patients (215 vertebral bodies-VBs) with osteoporotic compressive fractures (OCF), and 24 with osteolytic tumors (OT) (72 VBs) were treated with BK. Of patients with OCF, 27 were treated at one level, 26 at two, 21 at three, 7 at four, 6 at five, 2 at six levels. Of OT patients, 3 were treated at one level, 5 at two, 9 at three, 3 at four, and 4 at five.

Results: A drop in blood pressure of more than 25mmHg during cement injection was observed in four patients, and was not associated with the number of VB treated. The procedure was aborted in two patients. Otherwise no significant drop in arterial O2 was noted. One patient treated for 5 levels developed fever and tachepnoea for 24 hours after surgery. Arterial O2 and chest x-rays were normal. Pain significantly improved in 95% of patients with OCF and 98% of patients with tumors. In the osteoporotic group, kyphosis correction was achieved in 91% with a mean correction of 7.89°. Cement leakage occurred in 21/215 VBs (9.7%); Epidural: two (0.9%), intraforaminal: 1 (0.5%), intradiscal: 7 (3.2%) while through the anterior or lateral vertebral wall: 11 (5.1%). In the OT group leakage occurred in 6 VBs (8.3%), including 9 (7.0%) through the anterior or lateral wall and one (1.3%) intradiscal. None of the patients had any clinical consequences associated with cement leakage.

Conclusions: BK is a safe and effective procedure, even when applied for 5 or 6 levels. End plate fracture or vertebral wall lytic destruction can effectively be managed by eggshell balloon cementoplasty, thus minimizing the incidence of cement leakage. The incidence of cement leakage with KP (9.8%) is far less than that reported with vertebroplasty, (65.5% shown on CT scans).


J. Tan T. Oxland S. Singh Q. Zhu M. Dvorak C. Fisher

Purpose: The objectives of this study were to determine the effect of posterior instrumentation extension and/or cement augmentation on immediate stabilization of the instrumented level and biomechanical changes adjacent to the spinal instrumentation.

Methods: This study was designed for repeated measures comparison, using 12 T9-L3 human cadaveric segments, to test the effects of posterior rod extension and cement augmentation following T11 corpectomy. The spine was stabilized with a vertebral body replacement device and with posterior instrumentation from T10 to T12. The T12 pedicle tracts were over-drilled to simulate loosened screws in an osteoporotic spine. The T10 screws were not over-drilled but cemented so as to keep the superior segments constant. Flexibility tests were first carried out on the intact specimen, followed by 3 randomized surgical conditions without cement and lastly the 3 conditions after cement augmentation. The 3 conditions were: 1) no posterior extension rods to L1, 2) flexible extension rods, and 3) rigid extension rods. A combined testing/analysis protocol that used both the traditional flexibility method and a hybrid technique [Panjabi 2005] was adopted. Flexibility tests with +/−5 Nm pure moments in flexion-extension, axial rotation and lateral bending were carried out and vertebral bodies’ motion in 3-D were collected. Two-way repeated measures ANOVA analyses were carried out on ROM between cement augmentation (factor 1) and the posterior rod extension (factor 2) on each flexibility test direction. An alpha of 0.05 was chosen. Newman-Keuls post-hoc analyses were carried out to compare between surgical techniques.

Results: Using the flexibility protocol, a reduction in ROMs at the destabilized level was observed with cement augmentation of screws or extension with rigid or flexible posterior rods to adjacent distal level. With the hybrid protocol, ROMs at adjacent level (T12-L1) were reduced with rod extension, but not with cement.

Conclusions: The results of this study suggest that cement augmentation would enhance stabilization, but create possible adjacent level effects due to increased motion and strain, while additional flexible extension rods would reduce biomechanical changes at the level of extension. Funding: 2 Funding Parties: CIHR


P. Vendittoli A. Roy S. Mottard M. Lavigne

Purpose: Tribological studies suggest that larger metal-on-metal articulations would produce less wear than smaller diameter components. The aim of the present study is to describe whole blood Chrome and Cobalt ions concentration after metal-metal total hip arthroplasty (THA) and surface replacement arthroplasty (SRA).

Methods: 180 patients eligible for the study were randomized to receive uncemented 28 mm metal-metal THA or a hybrid metal-metal SRA. Whole blood samples were collected pre-operatively, at three, six months and one year post operatively. Chrome and Cobalt concentration were measured by mass spectrophotometry.

Results: At one year post op, whole blood levels of the were Cr 1.8 umol/L and Co 0.6 umol/L for the SRA and Cr 1.7 umol/L and Co 0.8 umol/L for the THA group (Cr, p=0.676 and Co, p=0.08). In comparison to pre-operative levels, the post operative levels significantly incresed for all elements Cr 1.9x and Co 3.8x for the SRA; Cr 1.3x and Co 3.4x. for the SRA group, Anova regression tests showed a significant relation between component size and Cr and Co metal ions levels; the larger the component, the lower the ions levels (Cr p=0.0285 and Co p=0.0442)

Conclusions: Using these specific implants, the increases whole blood metal ions were similar to the best results found in the literature for 28 mm metal-metal THA. Results of this study confirm the good tribologic performances of the Metasul large diameter metal-metal articulations. Funding: Commerical funding Funding Parties: Zimmer


I. Wong F. Farrokhyar E. Piccirillo N. Colterjohn

Purpose: To determine predictive factors for alloge-neic blood transfusion to aid in development of blood conservation strategies for the Hamilton arthroplasty population

Methods: A prospectively collected, retrospective study of 828 patients, who did not donate blood, treated with either primary total knee or total hip arthroplasty from 1998 to 2002 at Hamilton Henderson Hospital was carried out. A univariate analysis was performed to establish the relationship between all independent variables and the need for postoperative transfusion. Variables that were determined to have a significant relationship were included in a multivariate analysis

Results: The univariate analysis revealed a significant relationship between the need for postoperative blood transfusion and preoperative hemoglobin levels (p=0.000), age (P=0.000), and gender (P=0.005). However, the multivariate analysis only revealed significant relationship between the need for transfusion and pre-operative hemoglobin (P=0.000) and age (P=0.014). Patients with preoperative hemoglobin of > 150 g/L had a 10% risk of transfusion. Patients with preoperative hemoglobin of 141–150 g/L has 2.5 times greater risk, 131–140 g/L 4 times greater risk, 121–130 g/L 6 times greater risk, and < 120 25 times greater risk than patients with preoperative hemoglobin > 150 g/L.

Conclusions: The preoperative hemoglobin level and age were shown to predict the need for blood transfusion after total joint arthroplasty. These results of this will help to create guidelines for the Blood Conservation Program in HHSC.


F. Mwale H. Wang G. Marguier A. Petit D. Zukor O. Huk J. Antoniou

Purpose: Knowledge of factors regulating the turnover, repair, and degeneration of the intervertebral disc (IVD) is lacking. Although type II collagen (CII) fragments accumulate in the degenerative IVD, little is known of how they affect the degenerative process. In this study, the effect of a CII fragment, CII-(245–270), known to be critical in arthritis was investigated on gene expression of proteinases, collagen, and proteoglycan by bovine disc cells to determine its role in matrix turnover.

Methods: Cells isolated from the nucleus pulposus (NP) and annulus fibrosus (AF) of adult bovine tails were cultured in the absence (control) or presence of the fragment. The fragment CII-(245–270) (US Biological, Massachusetts) was dissolved in culture medium to a final concentration of 1& #956;g/ml. PCR was performed and products were visualized by ethidium bromide staining.

Results: Addition of the CII-(245–270) peptide at 1& #956;g/ml to NP and AF cells enhanced expression of genes for MMP-1, cathepsin K, and aggrecan after 48 hours compared with the control. MMP-13 was also upregulated in the NP. In contrast, the effect in the AF was time dependent. Type II collagen was upregulated throughout the culture time in the NP as opposed to the AF where its expression was enhanced only on day 2.

Conclusions: We have shown that the CII-(245–270) peptide can alter gene expression of proteinases, collagen, and proteoglycan in bovine disc cells. The present study reveals the complex interrelationships of gene expression in the disc that accompany fragmentation of type II collagen. This new information suggests that increased levels of these fragments, in degenerated discs, may stimulate disc breakdown but may also attempt to protect the disc, by unknown mechanisms Funding: Other Education Grant Funding Parties: AO foundation, Switzerland


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R. Turcotte D. Chivas B. Deheshi P. Ferguson M. Isler J. Wunder R. Bell

Purpose: To determine the outcome of patients 80 years old and greater that were diagnosed with a primary soft tissue sarcoma and if these patients should be treated as aggressively as younger patients.

Methods: One-hundred two patients were retrospectively reviewed.Well differentiated liposarcoma and der-matofibrosarcoma were excluded.

Results: There were 52 males. Average age was 84 years (80–94). Malignant fibrous histiocytoma was most common (36 patients) followed by leiomyosarcoma (22 pts) and liposarcoma (17 pts). Tumors were superficial in 25 patients and deep in 75. The lower extremity was most frequent site(70 patients), 27 patients had upper extremity involvement and 9 had a back lesion. MSTS stages were IA 6 patients, IB 22 patients, IIA 55 patients, IIB 9 patients, III 1 patient, and was unknown for 9 cases. Lesions were larger than 5cm in 80%. Four patients had no surgery, 89 patients had limb salvage, and 8 patients underwent amputation. Thirty-two patients had pre-operative radiotherapy, 30 patients had post-operative radiation, and 3 patients received both. No patients were given chemotherapy. The average follow up was 24 months (0–107months). Seventeen patients experienced local recurrence. Thirty-one patients developed metastatic disease. At latest follow-up 49 patients were alive without disease, 21 patients were alive with disease, 22 patients died of their disease, 8 patients died of another cause and the final status was unknown for 2 patients.. The MSTS functional score pre-treatment was 24 (11–72) and 31 (20–77) one year following treatment.

Conclusions: Elderly patients with soft tissue sarcoma have a poor outcome. Taking into account their associated medical condition, this group should likely be managed as younger patients although chemotherapy has no role according to our experience Funding: Other Education Grant Funding Parties: CIHR,|Stryker Canada


I. Ciobanu F. Mwale D. Giannitsios P. Roughley T. Steffen J. Antoniou

Purpose: In vivo, intertervertebral disc cells exist in a low oxygen environment ranging from 5% O2 for the annulus fibrosus (AF) cells to 1% O2 for the nucleus pulpous (NP) cells. Various conditions have been used for in vitro cell culture and seem that AF and NP cells can respond differently in the different systems, which may differ from the in vivo environment in terms of nutrient supply, O2 levels and biomechanical loading. The aim of this study was to determine how AF and NP cells respond to different O2 concentrations when cultured in a 3 dimensional system consisting of an alginate scaffold.

Methods: Bovine AF and NP cells were embedded in alginate beads and incubated in airtight polypropylene containers at different O2 concentration of 1%, 5% or 21%. Culture medium was changed every third day and the culture was carried out for 21 days. The pro-teoglycan content of the medium was analyzed using the DMMB assay. Cells were recovered from the alginate beads at two time points, day 8 and day 21 and RT-PCR was performed to amplify gene expression of GAPDH and aggrecan.

Results: In both cell types, the cumulative production of GAG increased with time in culture up to day 9, and then tended to plateau in the AF cells but continue to increase in the NP cells. At all time points, the level of GAG synthesis by NP cells was greater than by AF cells. All GAG synthesis trends were the similar at all O2 levels (1%, 5% and 21%).

Conclusions: In the alginate scaffold NP cells continue to exhibit their in situ behaviour by producing more proteoglycan than AF cells. Perhaps surprisingly, both cell types showed little change in GAG production with variations of O2 levels from 1–21%. This contrasts with other studies where GAG production is dependent on O2 concentrations. In the culture system used in this work, both cell types metabolize easily well at low oxygen as they do in normal conditions. Funding: Other Education Grant


S. Lewis Raja Rampersaud

Purpose: Report results of patients undergoing en-bloc resection of thoracic tumours with local invasion of the spinal column

Methods: Retrospective chart and outcome review

Results: The mean age was 59.1 (range 26–75) years. Patients underwent pre-operative radiation±chemotherapy. Anterior and posterior approaches were performed in all cases, staged a mean 16.2 days apart (range 4–51 days) in nine patients. There were eight non-small cell lung carcinoma, and four sarcomas. The mean total operative time was 12.8 hours(range 9–15). All patients survived the operative procedures and were discharged home. Mean hospital stay was 30.3 days(range 11–97). Positive tumour margins were present in 2 patients. Complications include need for revision thoracotomy, prolonged post-op intubation, one case of fatal PE, one superficial wound infection. Two patients died at four months post-operatively, (2/2 negative tumour margins) and one at 13 months(positive margin). Four patients were disease-free at > 1 year (range 13–40 months). The remaining patients have less than 1 yr f/u with 4/5 disease-free. Oswestry scores are 54.5 at latest f/u compared to 11.3 pre-op(p=0.007). SF-36 PCS and MCS were 35.5 and 51.1 pre-op compared to 25.6(p=0.3) and 38.3(p=0.03) post-op.

Conclusions: En-bloc resections offer curative resections at the expense of worse ODI and SF-36 scores. Staged surgeries allowed for an easier technical resection during the second stage.


M. Guyot M. Felx S. Leclerc M. Isler J. Doyon R. Turcotte P. Moffattm A. Moreau F. Moldovan

Purpose: Osteosarcoma (OS) is the most common type of cancer in children. OS demonstrates aggressive growth with a high risk of early, pulmonary metastasis. Here we investigated expression of malignancy-related factors in six osteosarcoma cell lines (SaOS, MNNG/ HOS, MG63, SW1353, SKES, SJSA), ten biopsies of primary OS and OS derived cells.

Methods: For this project, we are using RT-PCR and immunohistochemistry to detect PARP, ET-1, ETA and ETB receptor. We also, examined the expression of osteocrin by in situ hybridization. Zymography and Northern Blot were use to observe the presence of gela-tinases (MMP-2 and MMP-9) and finally, we showed the presence of ET-1(1–31) by Elisa-immunoassay.

Results: In OS tissues and cells, we observed ET-1, MMP-2, and ETA receptor overexpression, in contrast to under-expression of MMP-9 and ETB receptor. Additionally, in high malignant OS cells, MMP-2, MMP-3, MMP-13 and PARP were overexpressed and TIMP-1, TIMP-2 and TIMP-4 expressed at low levels. Using a new specific immunoassay for ET-1 (1–31) we showed presence of this alternative form of ET-1 in OS-derived cells. We also showed that, in cells exposed to ET-1, the inhibition of NF-kB pathway (NF-kB is an ubiquitous transcription factor playing a central role in differentiation, proliferation and malign transformation) drastically blocked MMP-2 production and activity, and that ET-1 induces NF-kB p65 unit translocation to the nucleus.

Conclusions: Thus, we concluded that expression of malignancy-related factors in parallel to the histological evaluation of these tumors, could be beneficial for malignancy understanding. Tumor cells invasion and aggressiveness of OS cells are the results, in part, of the tumorigenic potential of alternative forms of ET-1 generated by MMPs and enhanced in malignant microenvironment. These factors could be predictive for tumoral progression. Funding: Educational Grant from the Canadian Orthopaedic Foundation. Funding Parties: Canadian Orthopaedic Foundation (Carrol A. Laurin Award) and MENTOR program of CIHR


N. Germscheid M. Zhang K. Hildebrand

Purpose: To evaluate the role of myofibroblasts in post-traumatic contractures, studies were performed on the myofibroblast marker & #945;-SMA and myofibroblast up-regulators TGF-& #946;1 and the ED-A domain of fibronectin (ED-A) in joint capsules during early stages of post-traumatic contractures. Our hypotheses are mRNA expression of & #945;-SMA, TGF-& #946;1, and ED-A, and myofibroblast numbers, would increase in joint capsules of post-traumatic contractures when compared to contralateral and normal capsule.

Methods: Post-traumatic joint contractures were stimulated in right knees of 24 skeletally mature female rabbits by injury and immobilization. They were equally divided based on time of immobilization: 0-weeks, 2-weeks, 4-weeks, or 6-weeks. Contralateral limbs served as unoperated controls. Normal knee capsules were obtained from three age and gender matched rabbits. Posterior joint capsules were collected for semi-quantitative RT-PCR and mRNA levels of & #945;-SMA, TGF-& #946;1, and ED-A were evaluated in all four groups. Primers were normalized to GAPDH. Myofibroblasts were counted in the 4-weeks immobilization group. Immunohistochemistry was employed using a double labeling technique: monoclonal antibodies to & #945;-SMA and affinity purified antibodies to laminin. DAPI was applied to label nuclei. Statistical analysis was completed. Paired t-tests examining intragroup comparisons and ANOVA with posthoc tukey analyzing changes over time were used (significant if p& #8804;0.05).

Results: There was a significant increase in & #945;-SMA and TGF-& #946;1 mRNA expression in the posterior joint capsule of contracture knees when compared to contralateral control knees in all four groups. The mRNA levels for ED-A were significantly increased in the contracture group compared to the control group at 0-weeks. At 4-weeks immobilization, myofibroblasts were present in control and contracture tissue. Absolute myofibroblast numbers and percentage of myofibroblasts to total cells were significantly increased in contracture tissue compared to control tissue. There was no difference between total cells obtained from contracture and control knees.

Conclusions: Immediately upon injury (0-weeks), mRNA expression of & #945;-SMA, TGF-& #946;1, and ED-A increased in contracture knees compared to control knees. Myofibroblast numbers and percentage of myofibroblasts were elevated in contracture tissue compared to control tissue. It would appear mRNA changes occur immediately and are associated with increased numbers of myofibroblasts at 4-weeks.

Funding : Other Education Grant

Funding Parties : Alberta Heritage Foundation for Medical Research, Health Research Foundation, and Canadian Institutes of Health Research.


P. Duffy K. Trask L. Barron A. Hennigar K. Deluzio R. Leighton M. Dunbar

Purpose: The Less Invasive Stabilization System (LISS), Dynamic Condylar Screw (DCS) and Condylar Buttress Plate (CBP) are three common fixation methods for supracondylar femur fractures. The DCS and CBP are compression plates while the LISS uses locking screws to transfer load from bone to plate without compression. We developed a study to determine if the theoretical biomechanical advantages of the LISS would be evident in laboratory testing.

Methods: Identical AO type C fractures were created in eighteen composite femurs and fixed with either LISS, CBP, or DCS (6 each). Roentgen Stereophotogrammetric Analysis (RSA) was used for analysis. Reference markers were implanted into each bone segment. Biplanar x-rays were taken to give a three-dimensional representation of the fracture. The femurs were loaded axially in an Instron 1350 and subjected to cyclic loading (50kg ± 25 for 50000 cycles). After loading, the bones were x-rayed to determine relative motion between fracture segments. To examine inducible displacement under static loading, the femurs were x-rayed in an unloaded and loaded (50 kg) condition. Again, RSA was used for analysis.

Results: RSA-CMS software was used to analyze relative motion between the bone segments. After cyclic loading, the condylar buttress plate showed significantly more permanent deformation between the medial condyle and shaft of the femur than the DCS or LISS. Under static load, the LISS showed greater displacement than the other devices between the medial condyle and shaft, and between the lateral condyle and shaft.

Conclusions: The LISS demonstrated less permanent deformation but greater inducible deformation between the medial femoral condyle and femoral shaft, compared to the DCS and CBP. The results were statistically significant. These results may have clinical implications regarding the choice of fixation devices for this difficult fracture pattern.

Funding : Other Education Grant

Funding Parties : Capital Health Research Grant


M. Biddulph M. Gross J. Paletz

Purpose: To describe our experience with vascularised fibulas used in sarcoma limb salvage surgery using standardized patient outcome measures.

Methods: All vascularised fibulas and osteochondral allografts performed in the Capital District Health authority were assessed. A complete chart review and current functional assessment of the patients using the Toronto Extremity Salvage score (TESS) and the Musculosketal Tumour Society (MSTS) score were performed.

Results: Nineteen patients with 19 tumors were recorded. The tumors range from 11 osteosarcomas, 4 Ewing’s sarcoma, 3 Malignant Fibrous Histiocytoma’s and 1 Chondrosarcoma. Average age was 23. The patient demographics are 75% male, 42% smokers, 86% femoral lesions and 13 % presented with pathological fracture. There were 9 hip fusions, 3 knee fusions, 6 intercalary grafts and one osteochondral graft. There was 21 % mortality with 21% lung mets, 20% local recurrence, 15.7% rates of amputation or infection or and non union. Allograft fracture rates of 10% were noted. Two patients underwent numerous operations (18) due to non-compliance. Rate of surgical failures defined as patients requiring re-operation after 2 years is 21%. Of 19 patients 10 are working, 4 are unable and 4 are deceased and 1 lost to follow up. Average follow up is 9.8 years (range of 4–18). Our functional results include TESS averaging 57.5 with a range of 30–105 and MSTS scores of average of 16.8 with a range of 3–28 and a percent score average of 55.8. The average score on the subjective assessment question was 4 equaling a response of accept it and would do it again. The Halifax outcome and functional data corresponds well with that in the literature.

Conclusions: The biological repair of a combination of large Allografts with Vascularised Fibula’s is an excellent long term solution for construct survival with unrestricted patient activity.


C. Whyne T. Skrinskas A. Yee L. Gordon M. Akens M. Hardisty S. Burch B. Wilson S. Bisland

Purpose: There is a clinical need for novel effective local therapies to treat spinal metastases at significant risk for fracture. Photodynamic therapy (PDT) is a promising cancer treatment that employs wavelength specific light combined with a photosensitizing agent to induce localized tumour destruction by photochemical generation of singlet oxygen. Using minimally invasive techniques developed for vertebroplasty to deliver light within the vertebral body, PDT is proposed as a potential new treatment for spinal metastases; however, the effects of PDT on bone are largely unknown. This study aims to determine if PDT affects the structural integrity of normal vertebral bone.

Methods: Sixteen Wistar rats were randomly assigned to control, 1-week treatment or 6-week treatment groups. Rats treated with PDT received an intracardiac injection of 2mg/kg BPD-MA activated at 15 minutes post-injection through administration of a non-thermal 690nm diode laser positioned adjacent to the L3 vertebral body via fluoroscopic guidance (150J at 150mW). Rats were sacrificed at 1-week or 6-weeks following a single treatment. |In vitro & #956;CT scans were taken of L2-L4 and 3D stereological quantities measured using a semiautomated volume shrinkage thresholding technique within the trabecular bone centrum. L2, L3 and L4 vertebral bodies were individually tested biomechanically to failure in axial compression. Yield stress and stiffness were calculated from generated load displacement curves.

Results: Bone surface area and bone volume significantly increased with treatment, through trabecular thickening, at both 1-week and 6-weeks vs. control group. The treated group demonstrated an increase in yield stress at 6-weeks vs. control (27%, p=0.023). An increase in stiffness (45%, p=0.010) was found in the 1-week treatment group vs. control, but was not maintained in the 6-week group.

Conclusions: PDT is a promising new treatment for spinal metastases that appears to strengthen vertebral bone. Further research must determine the mechanism of this action and verify if similar effects will occur in metastatically-involved vertebrae. If PDT proves to be effective in both destroying tumour cells and in strengthening remaining bone, it may provide a very attractive minimally invasive treatment option for patients with spinal metastases.

Funding : Other Education Grant

Funding Parties : Canadian Breast Cancer Foundation, Ontario Chapter


M. Gross M. Biddulph

Purpose: To describe the technique and outcomes of patients requiring Lateral Gastrocnemius flaps for soft tissue coverage of the lateral side of the knee after sarcoma.

Methods: Four patients with sarcomas on the lateral knee capsule were identified. 1 patient had an Osteosarcoma of the proximal tibia resected, requiring reconstruction. 2 patients had Malignant fibrous hystiocytoma proximal to the lateral knee joint and 1 patient had a leiomyosar-coma who presented after 6 failed local resections. The length of follow up is from 13 months to 5 years, average 3.25 years. There were no graft failures. The average surface area of the resection was 118 cm2. There were two sarcoma recurrences requiring excision and radiation. There was one death due to metastases. The technique involves the releasing the gastroc flap down to the aponeurosis and then the careful dissection of the peroneal nerve with delivery of the muscle up behind the peroneal nerve to the lateral aspect of the knee. The flap is rotated fibrous layer down and the muscle readily accepts a meshed skin graft taken locally, giving this technique the advantage of reconstructing a capsule and creating a superior bed for accepting skin grafts.

Results: Average time to healing was 3.8 weeks. There have been no nerve injuries, no graft loss and all had a function range of motion. The functional results have been very reliable. Using the musculoskeletal tumour society score (MSTS) and the Toronto Extremity Salvage Scoring (TESS) system we had an average MSTS score of 21.5 with a percent of 71.5 and a TESS score of 44.5 for the living patients. These correlate to very good outcomes.

Conclusions: The lateral gastrocs flap has a reputation of being technically complex. Meller et al.(1997) report peroneal nerve injuries in 8 of 27 cases. This institution has no complications with this flap and recommends it for soft tissue defects that extend to the midline on the lateral aspect of the knee joint.


S. Becker O. Maissen I. Ponomarev T. Meury M. Alini I. Wilke

Purpose: Current research is focusing on the imitation of the optimal osteoconductive and osteoinductive properties of bone graft. We used in this study a β-trical-cium-phosphate scaffold impregnated with an osteogenetic transglutaminase (plasmatransglutaminase, FXIII, (Fibrogammin®)).

Methods: Release study: 27 & #946;-TCP discs (8x10mm) were impregnated with 10, 40 and 100 IU of FXIII. The release was measured with ELISA.|Animal study: A bilateral tibial metaphyseal defect (8.5 x 20 mm) was performed in eighteen adult sheep. The defects were filled with a & #946;-TCP cylinder (chronOS®, Synthes) in 16 sheep and left unfilled in 2 sheep (control group). The cylinders were impregnated with autologous venous blood, autologous bone marrow aspirate from the sternum and 125 IU FXIII in 4 sheep each or left unfilled and a daily dose of 1250 IU FXIII administered iv. over 14 days. After 6 and 12 weeks QCT, histology and histological analysis was performed.

Results: Release study: We found a linear release of FXIII with a plateau after 48 h. Until then on average 18% of the total dose was release from the scaffold. Animal study: The QCT analysis found unspecific changes in all group without any clear results regarding remodeling of the scaffold. The histological analysis showed the best bone ingrowth after 6 weeks in the bone marrow group and after 12 weeks in the local F XIII with on average 10% more bone ingrowth than in any other group. The best remodeling of the inner area in the scaffold was also seen in the local F XIII group.

Conclusions: FXIII is only partially released from a β-TCP scaffold. At least 80% of the dose remains in the scaffold after 48h. F XIII has a good osteogenetic property which is at least as good as bone marrow and better than venous blood; however a local application of F XIII is preferable to iv. administration. It stimulates osteoblast migration and proliferation in a β-TCP scaffold and causes a remodelling on the inside of the scaffold.

Funding : Commerical funding

Funding Parties : Grant by the AO Research Institute Davos, Switzerland and Synthes, Oberador, Switzerland


D. O’Gorman A. Burry K.J. Faber B.S. Gan J. Howard

Purpose: Frozen Shoulder Syndrome (FSS) frequently occurs in association with Dupuytren’s Disease (DD). Beta-catenin is a signaling pathway implicated in the pathogenesis of DD. The purpose of this study is to determine if beta-catenin is also associated with FSS.

Methods: Tissue obtained during shoulder arthroscopy for capsule release in patients with FSS was subjected to immunohistochemical staining (IHC) and Western Blot analysis. Control tissue was obtained from the rotator cuff interval from patients undergoing arthroscopy for rotator cuff syndrome.

Results: IHC analysis showed that the vast majority of cells within lesions expressed b-catenin while cells within marginal tissue stained weakly for b-catenin. Western blotting analysis of FSS specimens showed that lesional tissues expressed increasing amounts of b-catenin compared to RCS tissue.

Conclusions: Beta-catenin expression is upregulated in FSS. The current lack of knowledge about the biochemical mechanisms of FSS coupled with the limited therapeutic intervention available emphasizes the need for a better understanding of the basic biology of this fibrosing disorder.

Funding : Educational Grant from the Canadian Orthopaedic Foundation.


C. Johnson S. Bisland M. Diab B. Wilson S. Burch

Purpose: This study investigates the use of photodynamic therapy (PDT) in regulating bone development with a view to its potential role in treating Juvenile leg length discrepancy (LLD).

Methods: Transgenic mice expressing the luciferase firefly gene upon activation of a promoter sequence specific to the vascular endothelial growth factor (VEGF) gene were subject to benzoporphyrin derivative monoacid (BPD-MA)-mediated PDT in the right, tibial epiphyseal growth plate at the age of 3 weeks. BPD-MA was administered intracardially (2mg/kg) followed 10 mins later by a laser light (690 +/− 5 nm) at a range of doses (5-27J, 50 mW output) delivered either as a single or repeat regimen (x2-3). Contra-lateral legs served as no-light controls. Further controls included animals that received light treatment in the absence of photosensitizer or no treatment. Mice were imaged for VEGF related bioluminescence (photons/sec/steradian) at t= 0, 24, 48, 72 h and 1–4 weeks post PDT. FaxitronÔ x-ray images provided accurate assessment of bone morphometry. Upon sacrifice, the tibia and femur of the treated and untreated limbs were harvested, imaged and measured again and prepared for histology. A number of animals were sacrificed at 24 h post PDT to allow immunohistochemical staining for CD31, VEGF and hypoxia-inducible factor (HIF-1 alpha) within the bone.

Results: PDT-treated (10 J, x2) mice displayed enhanced bioluminescence at the treatment site (and ear nick) for up to 4 weeks post treatment while control mice were bioluminescent at the ear-nick site only. Repeat regimens provided greater shortening of the limb than the corresponding single treatment. PDT-treated limbs were shorter by 3–4 mm on average as compared to the contra lateral and light only controls (10 J, x2). Immunohistochemistry confirmed the enhanced expression VEGF and CD31 at 4 weeks post-treatment although no increase in HIF-1& #945; was evident at either 24 h or 4 weeks post PDT treatment.

Conclusions: Results confirm the utility of PDT to provide localized effects on bone development that may be applicable to other related skeletal deformities.


F. Mwale G. Marguier J. Antoniou O. Huk D. Zukor L. Chalifour

Purpose: To investigate the effect of amifostine and dexrazoxane on bone mass of the vertebrae and femurs of doxorubicin treated male rats.

Methods: Amifostine, Doxorubicin and Dexrazoxane were purchased from SMBD-Jewish General Hospital Pharmacy. Lactating Sprague Dawley dams with 14 male pups were purchased from Charles River Canada. At neonate day 10, rat pups were randomly divided into 4 groups of n=5. Pups were injected once intraperitoneally with either Phosphate Saline Buffer 1X (saline), or drugs, AMF (50 mg/kg), AMF + DOX (50 mg/kg +3 mg/ kg), or with AMF + DXR + DOX (50 mg/kg + 60 mg + 3 mg/kg, 20:1 DXR to DOX ratio). AMF and DXR were injected 30 minutes prior to the DOX injection. After injection, rat pups were returned to their mothers until weaning on neonate day 22. Rats were then sacrificed at day 38 (28 Post-Injection, PI). Bone mineral density (BMD) and micro computed tomography were analyzed.

Results: Dissection of male pups days 1, 5 or 9 post-injection did not reveal any intestinal or organ damage. AMF treatment alone led to a slight but not significant increase in the right femoral, left femoral and lumbar vertebral BMDs. Similarly, AMF + DOX or AMF + DXR + DOX treated rats had no significant change in either femoral and vertebrae BMD.

Conclusions: We recently showed that a single injection of DOX in young female rats is associated with low bone turnover resulting in vertebrae and femur bone growth deficits. However, no such a difference was detected when similarly treated males were examined. The role of sex steroid hormone at this age is unclear as sex hormones level are very low in neonates at the time of injection and the rats, male and female, were sacrificed prior to puberty. To define the role of sex hormone in the observed gender-specific drug susceptibility we plan on comparing the response of intact to ovariectomized female rats to the drug regimen.

Funding : Other Education Grant

Funding Parties : CIHR


M. Glazebrook W. Stanish M. Lee M. Langman

Purpose: To establish and validate animal model for Achilles tendon disease with subsequent examination of histology, biochemistry and biomechanics

Methods: Experimental rats were subjected to an over-exercise running regime. Achilles tendons were analyzed for histology, glycosaminoglycan content, collagen content, collagen subtype, collagen cross-linking (hydrothermal isometric tension testing), and mechanical properties.

Results: Experimental rat Achilles tendons demonstrated: decreased semi-quantitative grade for collagen organization (2.9 vs. 3.7, p < 0.05), decreased semi-quantitative grade for collagen staining (1.9 vs 3.5, p < 0.05) and increased nuclear numbers per high-power field (527 vs. 392, p < 0.05). Immunohistochemical analysis revealed a predominance of by fibroblasts or endothelial cells. The total collagen content remained unchanged (84.3 vs. 89.0% p=0.38), while the glycosaminoglycan content was increased (17.5 vs. 9.0% p=0.02). Differences in collagen cross-linking were characterized by a greater proportion of reducible intrahelical crosslinks. These differences did not translate into a decrease in ultimate tensile failure during mechanical testing (UTS of 77.8 vs. 88.8 N, p=0.26).

Conclusions: Over-exercise model produced Achilles tendons with histology and biochemistry consistent with the animal and human tendon disease and characteristic of a remodeling response not an inflammatory response.


M. Maru

Purpose: Our aim was to measure plantar foot pressures in normal individuals and to compare them with variations in patients with metatarsalgia

Methods: This was a case control study. We measured the plantar foot pressures in different parts of the foot in normal subjects of various ages and then compared this with foot pressures of patients with metatarsalgia. For measurement and statistical analysis, the plantar contact of the foot was divided into six anatomical divisions. The foot pressures were measured under the hallux, head of first metatarsal, over heads of second, third and fourth metatarsals, the fifth metatarsal, midfoot and hindfoot. This was measured using the FSCAN insole pedobarograph system (Tekscan, Inc, Boston, MA

Results: The foot pressures were measured in Kilopascals(Kpa). Independent T-tests was used to compare mean pressure distributions in the six anatomical divisions. We found the mean pressures through the 5th metatarsal head – 217(t=−2.32,p< 0.05) and midfoot 94(t=−3.17, p< 0.05), were significantly higher when compared to pressures in normal subjects ( table 1).

Conclusions: We have demonstrated increased pressures transmitted through the outer aspect of the sole of the foot, in patients suffering from metatarsalgia. This can be used further to plan any foot- orthosis or surgery to distribute pressures more evenly across the sole of the foot.


D. Penn H. Yepes M. Glazebrook T. Willet W. Stanish C. Foote

Purpose: The use of allografts for anterior cruciate ligament (ACL) reconstruction has gained increased popularity. The major benefits of allograft for ACL replacement include decreased morbidity, easier patient rehabilitation and include ease of surgical procedure, decreased harvest site morbidity and easier patient rehabilitation. Further, allografts have improved appeal because of better sterilization techniques, improve graft availability and decreased hospital costs.|The objective of this study was to perform mechanical testing on various types of allograft. Specimens for allograft reconstruction of the anterior cruciate ligament included tibialis anterior tendon, tibialis posterior tendon, Achilles tendon and bone patella tendon tissues

Methods: The allografts tested were used for deployment in patients suffering with anterior cruciate ligament disruptions. A total of fifty grafts were analyzed. The breakdown of graft types included 15 tibialis anterior tendon, 15 tibialis posterior tendon, 10 Achilles tendon and 10 bone patella tendon tissues. The test techniques included: cutting the tendons to a set thickness and length. The tendons were then mounted in a cryogrip and frozen with liquid Nitrogen to below zero. They were mounted into a servo-hydraulic testing machine and pre-loaded and pre-conditioned. The specimens were then stretched to failure at a set strain rate.

Results: No difference was found between the mechanical/material properties of the various tendon allografts – these included tensile strength and a high stress linear modulus assessments. The mechanical (structural properties) of the allografts were more dependant on the cross sectional area of the allograft than the type of allograft tissue.The greater the cross-sectional area of the allograft, the greater the strength and stiffness of the graft.

Conclusions: These findings have considerable clinical applicability in choosing an allograft for anterior cruciate ligament reconstruction.


J. Page R. Gregory

Purpose: Neck of femur fractures increasingly form a large bulk of in-patient admissions to trauma units. These patients often require multi-disciplinary input before discharge. Delayed discharge not only exposes patients to nosocomial infections, it places strain on limited bed numbers. The use of a single screening question at time of admission to identify those patients suitable for fast-track discharge was investigated.

Methods: Prospective study. 122 patients in the study. Basic epidemiological data was collected. At admission the patient was asked whether they were able to do their own shopping or not. Following discharge: the length of stay and discharge destination was recorded. Results were analysed using standard statistical methods

Results: 122 patients were identified. 43 of the patients(35%) able to do their own shopping. There was a significant difference in length of stay between the two groups as well as mortality rate. Those able to do their own shopping stayed in hospital on average 4 days longer. In the group who could do their own shopping, 100% were discharged home from the trauma ward.

Conclusions: This study demonstrated that through the use of a single question it is possible to identify elderly patients suitable for home rehabilitation. All those patients who could do their own shopping were discharged home from the trauma ward without need for transfer to an in-patient rehabilitation ward. All patients who could do their own shopping were assessed as suitable for discharge home once they had completed a basic course of rehabilitation. This resulted in a longer length of stay in hospital. Identifying this group of patients it is possible to reduce their average length of stay in hospital from 14 days to 5 days. This is achieved using a fast track system for elective arthroplasty patients, based on a system of home rehabilitation. This results in improved care for the patients as well as financial savings on in-patient care.


P. Zalzal O. Gabar D. Dobrjanski K. Behdinan J. De Beer M. Papini Z. Saghir

Purpose: The purpose of this study was to determine how to minimize intramedullary femur pressures, and therefore the risk of fat embolus syndrome, during surgical procedures which require preparation and instrumentation of the femoral canal.

Methods: To study intramedullary femur pressures and experimental model and a finite element model were developed. The experimental model ustilized a bone analogue which consisted of a porous plastic cylinder, having similar porosity and pore size to human femoral bone, with bone marrow being represented by a paraffin wax/petroleum jelly mixture. The finite element model consisted of a three dimensional analysis of a cylinder filled with bone marrow with a reamer advancing through it. Variables such as speed of insertion, fluid viscosity and relative diameters of the instrument and the inner diameter of the simulated bone were varied to see how they affected pressures.

Results: The intramedullary pressures increased with increasing speed of instrument insertion, increasing marrow viscosity, and increased diameter of the instrument relative to the inner diameter of the bone. Experimental and finite element results were in reasonable agreement.

Conclusions: We concluded that slower instrument insertion rates and a greater ratio of bone inner diameter to instrument diameter may minimize the intramedullary pressures and therefore minimize the risk of fat embolus syndrome. In addition, two novel techniques to analyze intramedullary femur pressures have been developed.

Funding : Education Grant

Funding Parties : NSERC


E. Schemitsch R. Walker M. Mckee J. Waddell

Purpose: The purpose of this study was to examine how the “ideal” tibial nail insertion point varies with tibial rotation and to determine what radiographic landmarks can be used to identify the most suitable rotational view for insertion of a tibial intramedullary nail.

Methods: Twelve cadaveric lower limb specimens with intact soft tissues around the knee and ankle joints were used. A 2.0mm Kirschner wire was placed in the center of the anatomic safe zone and centered on the tibial shaft. The leg was rotated and imaged using a fluoroscopic C-arm until the K-wire was positioned just medial to the lateral tibial spine (defined as the neutral anteroposterior radiograph). The leg was then fixed and radiographs were taken in 5 degree increments by rotating the fluoroscope internally and externally (in total, a 50 degree arc). Following this a second K-wire was placed in 5 mm increments both medially and laterally and the fluoroscope rotated until this second K-wire was positioned just medial to the lateral tibial spine. Radiographs were digitized for measurements.

Results: Given the presence of a 30 degree rotational arc through which the radiograph appeared anteroposterior, it was possible to improperly translate the start point up to 15 mm. Relative external rotation of the image used for nail placement led to a medial insertion site when using the lateral tibial spine as the landmark. A line drawn at the lateral edge of the tibial plateau to bisect the fibula head correlated with an entry point that was central or up to 5 mm lateral to the ideal entry point. The use of a fibula head bisector line avoided a medial insertion point.

Conclusions: Rotation of the tibia may result in up to 15 mm of translation of the start point that may be unrecognized. Relative external rotation of the film used for nail placement leads to medial insertion sites when using the lateral tibial spine as a landmark. The fibula head bisector line can be used to avoid choosing external rotation views and thus avoid medial insertion points.


S. Patil A. Port S. Green

Purpose: To biomechanically compare the stability provided by 2, 6.5mm cancellous screws versus that provided by 4, 3.5mm cortical screws in depressed tibial plateau fractures

Methods: We obtained 20 sawbone(solid polyurethane foam) blocks of dimensions 9x6.5x3.5cm. 10 of these blocks had a density of normal cancellous bone (20pcf) and 10 represented osteoporotic bone (10pcf). We created a depressed fracture(Schatzker type 3) using a coring saw. Each fracture had 4 depressed fragments, which were elevated and supported using either 2,6.5mm cancellous screws or 4, 3.5mm cortical screws. The fractures were loaded axially using the Lloyds materials testing machine. A force displacement curve was plotted. A depression of 5mm was considered to be failure.

Results: Osteoporotic model|The mean force needed to produce a depression of 5mm was 700.8N with the 4-screw construct and 512.4N with the 2 screw construct. This difference was significantly significant (p=0.007). |Non-osteoporotic model|The mean force requires to produce the same depression was 1878.2N with the 2-screw construct and 1938.2N with the 4 screw construct. The difference was not statistically significant (p=0.42).

Conclusions: A raft of 4, 3.5 mm cortical screws was biomechanically stronger than 2, 6.5mm cancellous screws in resisting axial compression in the osteoporotic bone model. There was no significant difference in the 2 constructs in non-osteoporotic bone model.


U. Debnath D. Parfitt A. Guha K. Hariharan

Purpose: To evaluate the outcome of salvage surgery with external fixation in these rare and severe lower limb injuries

Methods: Eight patients (7M: 1F) with mean age of 28 years (range −18 −35 years) were included. Four had Grade 3 open fractures of the distal tibia and 5 had open foot fractures. Two had neurovascular injuries. Four patients had associated injuries with mean ISS of 9 (range 8–16) and a mean MESS score of 3.5 (3–7). All had undergone some form of internal and external fixation within approximately 24 hours (8 hrs to 4 days). The mean follow up period was two years (range 1 – 4 years). At final follow-up patient’s health was measured using SF-36 questionnaire.

Results: Six patients had their fractures healed at a mean of 4.8 months (4–9 m). Two patients had fully functional foot with occasional complaints of painful ankle. Two patients had CRPS1 undergoing treatment. Two patients are unable to walk due to chronic pain and deformity. Comparison of the SF -36 scores with the age-matched UK normal controls without foot and ankle injuries showed significantly worse scores in physical function (PF: p< 0.01) and role physical (RP: p< 0.01) categories

Conclusions: Our surgical instinct dominates the decision-making favoring salvage with external fixation primarily rather than amputation in these young groups of patient. Should we be depleting our resources in salvaging these complex limb injuries?


G. Chan D. Sanders K. Willits R. Jenkinson X. Yuan

Purpose: Achieving accurate imaging in talus neck fracture management is important. Patient outcome relies on the ability to achieve and maintain anatomic reduction. The ability to visualize the reduction postoperatively using plain radiographs or computed tomography (CT) is limited. The purpose of this study is to assess the ability of radiostereometric analysis (RSA) to detect changes in talus fracture fragment alignment using an in-vitro model. This will be compared to the use of plain radiographs and CT.

Methods: Eight cadaveric human lower extremities were used as talus fracture models. Each talus was removed from the specimen and an osteotomy was created. RSA beads were inserted into the fragments. Anatomical reduction was achieved with two 3.5 mm cortical screws. A set of plain radiographs and RSA films was obtained. The fragments were displaced in a combined varus and supination direction. The degree of displacement was measured with a Vernier caliper and the rotation measured with a protractor. The imaging sequence was repeated in addition to obtaining CT scans with three dimension reconstruction. The RSA measurements were interpreted in a blinded fashion by an experienced researcher. Two independent blinded observers measured the displacement and rotation with plain films and CT. The results from each radiographic measurements were compared using ANOVA method to the experimental values.

Results: The average difference between the RSA measurements and the experimental measurements was 5.9mm while the difference between CT scan measurements and experimental values was 2.4mm (p=0.003). The average difference in rotation was not statistically significant between the three groups.

Conclusions: CT scan provides the most accurate assessment of talar neck malunion. Unfortunately, RSA is not a viable imaging technique for assessing talar neck displacement.

Funding : Other Education Grant

Funding Parties : Lawson Health Research Institute


J. Adlington H. Broekhuyse P. O’brien P. Guy P. Blachut R. Meek P. Lodhia

Purpose: To evaluate early and late perioperative complications and long term quality of life outcomes in patients having undergone immediate open reduction and internal fixation of acute high-energy tibial plateau fractures (AO C3).

Methods: Retrospective review of 70 AO C3 tibial plateau fractures managed with immediate open reduction and internal fixation at the Vancouver General Hospital from December 1987 to April 2004. Chart and database review was conducted for early and late perioperative complications, and patients were surveyed using three quality of life instruments: SF36, SMFA, and WOMAC.

Results: 3(4.3%) patients had died at the time of follow-up. Of the remaining 67, 49(73%) could be located and were contacted for follow-up. 28 of the 49 subjects (57%) completed the mail-out surveys (20 male, 8 female). Mean age of respondents at time of follow-up was 45.2±9.0 years. 10(36%) patients were pedestrians or cyclists struck by cars, 9(32%) were injured as a result of a fall, 5(18%) were motor vehicle collisions, 2(7%) were sustained by a direct blow, and 2(7%) were sustained by twisting mechanisms. Mean time from injury to OR was 56.0+84.3 hours. Duration of follow-up was 8.9+5.3 years. 4(14%) patients had open fractures. Fixation methods included immediate ORIF with a single plate in 24(86%) cases, dual plating in 3(11%) cases, and screws alone in one (3%) case. ISS and LOS scores were 11.4+6.8 and 15.7+8.0 respectively. One patient (3%) experienced an early perioperative complication of excessive soft tissue tension post ORIF requiring delayed skin closure. Late perioperative complications included 9(32%) cases of painful hardware, 2(7%) non-unions, 2(7%) superficial infections, 1(3%) osteomyelitis and 1(3%) mal-union. No patients required amputation. SMFA and WOMAC scores were 55.3+9.6 and 29.44+23.22. SF36v scores were 40.6+10.4(PCS) and 45.1+15.8(MCS).

Conclusions: Immediate open reduction and internal fixation with careful attention to soft tissues can be a viable management option for many high energy tibial plateau fractures. Complication rates are comparable to those of delayed definitive management of these injuries.


A. Mansoor

Purpose: To assess the long term radiological, clinical and psychological outcome of patients treated surgically for displaced acetabular fractures.

Methods: Over 79 patients were followed up in our outpatient clinic. AP pelvis and Judet view radiographs were taken and evaluated. This was followed by a detailed history and clinical examination. Outcome recorded using the modified Merle d’Aubigne scale. The SF36v2 questionnaire was also administered.

Results: Using the modified Merle d’Aubigne scale:

Excellent 18%, Good 51%, Fair 13% and Poor 18%. Using the SF36v2 health questionnaire (Norm based scoring 1998 US population where 50 is the average score):Transformed physical score (PCS) 44.54 and transformed mental score (MCS) 50.27.

Conclusions: The results represent the learning curve for a single surgeon specifically trained in this speciality. These results compare favourably with those of Matta (JBJS Nov 1996 78A), whose ‘excellent’ & ‘good’ results with a shorter follow up period was 76%. Letournel’s results at 12 years showed a 69% ‘excellent’ & ‘very good’ grade using a slightly different grading system.We have many patients in the ‘good’ grade that have normal walking and range of motion, but miss the ‘excellent’ grade because of slight or intermittent pain. |The results seem to support the surgical treatment of displaced ace-tabular fractures. Most studies show results for short term follow up. Long term follow up studies have implications in predicting the future with regard to medical legal claims.


R. Wang M. Blankstein R. Li E. Schemitsch

Purpose: The objective of this study is to investigate the effects of the Reamer-Irrigator-Aspirator (RIA) on fat embolism outcome, as compared to the standard AO reamer, utilizing physiologic parameters as outcome measures.

Methods: All animal procedures were approved by the Animal Care Committee. Fifteen animal experiments were completed. Following anesthesia, each pig was intubated and ventilated. Initial blood samples were analyzed for proper ventilation and acceptable baseline conditions (PaCO2 between 35–40 mm Hg). One third of the pig’s blood volume was withdrawn to simulate hemorrhagic shock. Each animal was kept in a state of hypovolemia for an hour before transfusion and resuscitation. Each pig underwent alternate assignment into either the RIA or AO group. The distal femur was exposed and reamed in a retrograde fashion, followed by cement pressurization with methylmethacrylate. Physiologic measurements included mean arterial pressure (MAP), pulmonary arterial pressure (PAP), partial pressure of arterial oxygen (PaO2), and cardiac output. Upon completion, the animals were euthanized. The data was analyzed using the SPSS statistical program.

Results: One animal in the AO group expired after cement pressurization associated with profound hypotension, pulmonary hypertension and eventual cardiac arrest. There was a statistically significant difference for PaO2 (P = 0.004), cardiac output (P = 0.002), and PAP (P = 0.005) between the AO and RIA groups. That is, by the completion of the experiment the RIA group had higher PaO2, lower PAP, and higher cardiac output measurements as compared to the AO group. There was no statistical significance between the two groups with respect to MAP (P = 0.468).

Conclusions: Using established physiologic parameters, there appears to be a difference between the standard AO reamer and the RIA in terms of fat embolism outcome. The RIA showed a more favorable outcome with respect to PAP, PaO2, and cardiac output. With its simultaneous irrigation and aspiration, the RIA may result in less intramedullary fat displacement into the systemic circulation.


P. Blachut

Purpose: The use of radiology is integral to Orthopaedic Trauma surgery and there has been increasing dependence on image intensifiers in the operating room. A study was undertaken to assess the radiation exposure of the surgeon.

Methods: One full time orthopaedic trauma surgeon has worn a dosimeter on his waist since November 1996, under a lead apron when using a large image intensifier and when using a mini C-arm. Since November 2001, a second dosimeter was worn at the neck, unshielded in all cases. Since June 2005, a ring dosimeter was worn on the dominant ring finger and the all surgical cases were prospectively documented in regard to the type of intensifier used and the amount of fluoroscopy used.

Results: In the nine years of monitoring the truncal dosimeter has never recorded any radiation. In four years of monitoring the neck dosimeter has recorded 5.72 mSv (average 1.4 mSv / yr). In last 2 months (6 months data will be available at the time of presentation), 99 operative cases were done. In 31 cases no intra-operative radiology was used, 33 cases used a mini C-arm and in 35 cases a large C-arm was used. A total of 40.2 minutes of mini fluoro time (average 1.22 minutes / case) and 118.09 minutes of full sized C-arm fluoro time (average 3.37 minutes / case) was used. In these 2 months the ring dosimeter recorded 5.4 mSv of radiation (annualized dose 32.4 mSv).

Conclusions: The International Commission on Radiological Protection annual recommended dose limits for “radiation workers” are: whole body 20 mSv, eyes 150 mSv and skin / hands 500 mSv. For members of the public these limits are 1 mSv, 15 mSv and 50 mSv, respectively. The exposure of an Orthopaedic Trauma surgeon fall well below the annual recommended dose limits in the industry but begin to approach the limits for the public. From this study it would appear to be safe not to use a lead apron for mini C-arm cases. The surgeons hands are exposed to the most radiation and strategies to reduce this exposure should be pursued.


H. Razmjou R. Holtby J. Wesselm P. Alexander F. Moola

Purpose: Purpose: Prognostic factors for a satisfactory result for repaired tears have been postulated to include patient age and size of tear. The purpose of this study was to examine the impact of rotator cuff tear size on pre-operative and 2 year post-operative perceived functional level of patients undergoing repair of the full-thickness tear.

Methods: Methods: Data of 88 consecutive patients were included in data analysis. Patients were categorized into two groups: small or moderate tear (SMT) group, and large or massive tear (LMT) group. Two self-report measures - the Western Ontario Rotator Cuff Index (WORC), and the American Shoulder and Elbow Surgeons (ASES) evaluation form - were used to examine disability at baseline, and two years after surgery for repair of the rotator cuff. The Constant Murley (CM), which evaluates range of motion, strength and self-report function, was also used at the two time periods. A two-way, repeated measures analysis of co-variance (ANCOVA) compared the two groups across the two times. Covariates were age and gender.

Results: Results: Fifty-two patients (mean age = 56.6±10.4) had small or moderate and 36 (mean age = 66.7±11.3) had large or massive full-thickness tears. The results of all measures at both time periods demonstrated poorer function for the LMT group (pre WORC 31.4, post WORC 59.0; pre ASES 37.0, post ASES 65.0; pre CM 49.3, post CM 69.6) compared to the SMT group (pre WORC 38.2, post WORC 67.2; pre ASES 43.4, post ASES 73.8; pre CM 55.3, post CM 80.7). Both groups had improved function at 2 years post-operatively, but the rate of change was similar in the two groups.

Conclusions: Conclusion: The results of this study indicate that the size of a full-thickness tear of the rotator cuff has an effect on shoulder function both pre and postoperatively, but not on the pattern of recovery.


B. Shore K. Faber G. King S. Patterson

Purpose: Metal radial head arthroplasty is a proven technique for the treatment of complex radial head fractures. Little previous research is available on the utility and longevity of metal radial head arthroplasty for elbow reconstruction. The purpose of this study was to evaluate the functional outcome of patients with metal radial head arthroplasty (RHA) for elbow reconstruction.

Methods: This was a retrospective review from one institution with three senior orthopaedic surgeons. 23 consecutive patients with 23 RHA were included in the study, 4 patients were lost to follow up. RHA was performed for conditions of rheumatoid arthritis, post traumatic radial head nonunion, post traumatic radial head malunion, elbow instability following previous radial head excision and failed silicone radial head implants. Patients were excluded from the study if they were treated for an acute injury with RHA (under 2 months from injury). There were 8 males and 15 females with a minimum of 2 year follow up. Analysis included chart review, personal interview, physical examination, radiographs and strength testing. Region specific questionnaires were used including: DASH, ASES, MEPI, PRWE, WOS and SF-36. Mean follow up was 9 yrs.

Results: Mayo elbow performance scores were excellent in 11 patients, good in 4 patients, fair in 4 patients and poor in 4 patients. Subjective patient satisfaction was averaged at 8.4 out of 10. Patients demonstrated significantly less isometric strength and grip strength in the affected versed unaffected elbow. There was no statistically significant difference seen in ulnar variance or ulnohumeral joint space between the affected and unaffected limbs.

Conclusions: In conclusion, RHA for elbow reconstruction is a safe procedure that provides patients with long term functional ROM and pain relief.


P. Duffy A. Furey J. Powell

Purpose: The purpose of this study is to evaluate the hemodynamic and pulmonary effects of intramedullary nailing with a removable filter placed into the common iliac vein.

Methods: Under general anaesthesia, a collapsible filter was inserted into the left common iliac vein in eight dogs and compared to a control group from a previous study. The left femora and tibiae were then pressurized by injection of bone cement and the insertion of intramedullary rods. Echocardiographic images and hemodynamic measurements including arterial blood gas, cardiac output, left atrial, right atrial, pulmonary arterial, and aortic pressure were recorded as baseline measurements and at 1, 5 and 15 minutes after medullary-canal pressurization. After fifteen minutes of pressurization the filter debris was evacuated, the samples sent for analysis and the filter was collapsed and removed. The dog’s hemodynamics were then monitored for a further fifteen minutes. The animals were killed and the lungs were harvested for histomorphometric analysis.

Results: Full hemodynamic and histomorphometric results of the lung tissue and debris collected from the evacuated filters are still pending at the time of this submission however initial findings indicate that the filter prevented an immediate increase in mean pulmonary artery pressure after canal pressurization. No large embolic event was visualized in any of the filtered dogs. In contrast, all animals in the control group demonstrated moderate-to-severe echogenic response with intense showering of echogenic material, including large embolic masses. Removal of the filter was safe and repeatable.

Conclusions: This experiment has shown that proximal venous blockade by means of a removable filter was able to reduce the size and the quantity of the embolic load on the lungs and the filter could be safely collapsed and removed after suctioning of the debris. High rates of embolization causing increased morbidity and mortality after intramedullary stabilization of pathological fractures and of traumatic fractures with concomitant lung injury have been reported. Prophylactic insertion of a removable temporary filter in this high-risk group prior to reamed intramedullary nailing may be beneficial.

Funding : Other Education Grant

Funding Parties : Synthes Canada


J. Davis P. Guy T. Lui-ambrose K. Khan

Purpose: To test a novel Patient Education and Physician Alerting (PEPA) intervention that seeks to improve the proportion of correct diagnosis and management of osteoporosis in older adults who have sustained a recent hip fracture secondary to a fall.

Methods: Design: Six-month randomized controlled trial. Participants were randomized either to the PEPA group (intervention) or the usual-care group (control). Participants and Setting: Forty-eight men and women aged 60 years and older who were admitted to Vancouver General Hospital for a fall-related hip fracture.|Measurements: The Diagnosis and Management Questionnaire (DMQ) was administered to all participants to determine the rate of investigation and treatment of osteoporosis. The responses were validated in part by physician report obtained for one half of the participants. Statistical Analyses: We compared the difference between the two experimental groups in the proportion of individuals who received bisphosphonate therapy within 6 months after their hip fracture using the chi-square test. The alpha level was set at P < 0.05. |

Results: To date, thirty-three of the 48 participants have completed this 6-month randomized controlled trial. Among these 33 participants, we found a significant difference between the two groups in the proportion of individuals who received bisphosphonate therapy after their hip fracture (p < 0.001). In the PEPA group, 70% (14 out of 20) were put on bisphosphonate therapy within 6 months after experiencing a fragility hip fracture. In contrast, 0% (0 out of 13) were put on bisphos-phonate therapy within 6 months after experiencing a fragility hip fracture in the usual-care group. Of the 78 individuals who were eligible for this study, 48 agreed to participate.

Conclusions: Currently, there is an established care gap for patients who sustain a fragility fracture. This cohort of individuals who fractured their hip did not receive guideline care unless recommended by the PEPA intervention letters sent to the participant delivered to the family physician. Patients who sustain a low-trauma hip fracture and are “at risk” for osteoporosis and do not receive recommended “best practice” care.

Funding : Commerical funding

Funding Parties : Aventis Pharmaceuticals


D. Sheps K. Hildebrand K. Keifer

Purpose: Classification systems for orthopaedic injuries are used in clinical care and research to allow for communication about the diagnosis, prognosis, treatment, and outcome of fractures and dislocations. The inter-observer reliability of the Hotchkiss modification of the Mason classification system and the AO classification system were evaluated to assess their reliability in classifying radial head fractures.

Methods: Forty-three consecutive fractures with and without other associated injuries were identified from the practice of a single sub-specialist orthopaedic surgeon. Their radiographs were compiled and all identifying marks were hidden. Five observers classified the radiographs according to each classification system. Percent agreement was calculated pair-wise between observers for each system. The mean percent agreement and 95% confidence intervals were calculated for each system. Additionally, the systems were collapsed, with types II and III combined for the Hotchkiss system, and the final digit dropped for the AO system. The mean percent agreement and 95% confidence intervals were then recalculated.

Results: The percent agreement for the Hotchkiss modification of the Mason classification system was 72.3% (95% CI 65.8% to 78.9%). The percent agreement for the AO classification system was 37.7% (95% CI 30.5% to 44.9%). The percent agreement for the collapsed Hotchkiss system was 89.3% (95% CI 86.6% to 92.0%). The percent agreement for the collapsed AO system was 67.4% (95% CI 54.6% to 80.3%).

Conclusions: The inter-observer reliability for the AO classification system had a low percent agreement, possibly reflecting the complexity of the system. Collapsing the AO system improved the percent agreement, however it still could be considered fair. The inter-observer reliability for the Hotchkiss modification of the Mason classification system was higher. However, when the lower end of the 95% confidence interval is taken into consideration, the reliability of the system could be considered fair. Collapsing this system did improve the percent agreement into what could be considered a good range, suggesting that this system may be able to reliably identify fractures requiring operative treatment.

Funding : Other Education Grant

Funding Parties : Alberta Heritage Foundation for Medical Research


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G.S. Athwal J.W. Sperling D.M. Rispoli R.H. Cofield

Purpose: Currently, there is little information available concerning the outcome of patients with infection following rotator cuff repair. Therefore, the purpose of this study was to review the incidence, management and outcomes of patients with rotator cuff repair complicated with deep infection.

Methods: Between 1975 and 2003, 39 cases of deep infection following rotator cuff repair were identified. The medical records and radiographs were retrospectively examined. At a mean follow-up of 8.2 years, seven patients had died and two patients had been lost to follow-up leaving 30 cases for outcome evaluation.

Results: The incidence of deep infection after rotator cuff repairs that were performed at our institution was 0.43% (21 of 4886 cases). The mean interval from rotator cuff repair to the time of infection diagnosis was 49 days. ESR and C-reactive protein were elevated in only 60% and 50% of patients, respectively. Propionibacterium was the most common organism isolated, infecting 51% of cases. A mean of 3.3 surgical debridements were necessary for the eradication of infection. At final follow-up, mean active abduction was 121° and mean external rotation was 44°. The ASES score averaged 67 points and the Simple Shoulder Test score averaged 7.3 points.

Conclusions: The data from this study suggests that the eradication of deep infection following rotator cuff repair is possible, however, substantial functional limitations are not unusual. Additionally, the treating surgeon should be aware of the high incidence of Propionibacterium and the importance of allowing a minimum of seven days of culture to identify this organism.


A.S. Rowland G.S. Athwal G.J.W. King

Purpose: Radial head replacement with a prosthesis that is too thick has been reported to be associated with stiffness, pain and capitellar wear. Radiographic widening of the lateral ulnohumeral joint following radial head replacement has been used as a criterion to diagnose overstuffing of the radiocapitellar joint. The purpose of this study was to show that widening of the lateral ulnohumeral joint is a normal anatomic variant and therefore cannot be used conclusively to diagnose radiocapitellar joint overstuffing.

Methods: Fifty normal standardized anteroposterior elbow radiographs from 50 patients with a mean age of 48 years were reviewed to evaluate variations in the joint space between the medial and lateral facets of the ulnohumeral joint. Using computer software at 4x magnification (GE, Fairfield, CT), two lines were drawn perpendicular to the lateral ulnohumeral joint and two lines perpendicular to the medial ulnohumeral joint. The difference in length of these two lines was used to assess how parallel the lateral and medial joint spaces are. The lengths of the two lines were averaged to compare lateral joint space thickness to medial joint space thickness.

Results: The width of the lateral ulnohumeral joint space (3.6mm & #61617; 0.8mm) was greater than the medial ulnohumeral joint space (2.8mm & #61617; 0.5mm) (p< 0.001). The lengths of the two medial joint space perpendicular lines were similar (p> 0.05), indicating the medial joint space is normally parallel. The lengths of the lateral joint space perpendicular lines were greater laterally (p= 0.02), indicating the lateral joint is not normally parallel.

Conclusions: The lateral ulnohumeral joint space is often wider than the medial ulnohumeral joint space on an anteroposteror radiograph of the normal elbow. While the medial ulnohumeral joint space is usually parallel, the lateral ulnohumeral joint space may be non-parallel and wider laterally, therefore, lateral joint space widening is not a reliable indicator of radiocapitellar joint overstuffing. A non-parallel medial ulnohumeral joint space may be suggestive of possible overstuffing of a radial head arthroplasty, however, comparison radiographs of the uninjured elbow is likely the best investigation to consider when overstuffing is suspected.


H. Razmjou R. Holtby M. Aarabi M. Aarabi

Purpose: The purpose of this historical prospective study was to compare the pre and post-operative range of motion (ROM) and quality of life outcomes 6 months post-operatively in patients with partial and full-thickness tears of the rotator cuff.

Methods: Data of 90 consecutive patients diagnosed with partial thickness tear (PTT) who had undergone decompression and or acromiploasty were compared with 90 patients (age and gender-matched) who had undergone repair of a full-thickness tear (FTT). The outcomes were objective pre and post-operative range of motion (ROM) in 5 directions and three patient-derived outcome measures; one disease-specific, the Western Ontario Rotator Cuff Index, and two shoulder specific measures: the American Shoulder & Elbow Surgeons standardized shoulder assessment form and, the Constant-Murley. A statistical paired t-test analysis was conducted between change (pre vs. 6 months) in ROM and QOL scores to examine the impact of severity on improvement between the 2 groups.

Results: Forty-three females and 47 males in each group (180 subjects in total) were included in the analysis. The mean age was 54.8 and 54.9 for the PTT and FTT groups respectively. The PTT group was significantly stiffer in pre-operative passive flexion (p=0.010), abduction (p=0.022) and active external rotation at 0 degree of abduction (p=0.040). The 6-month WORC, ASES, and relative Constant all showed significant improvement in quality of life in both groups (p< 0.0001). There was a statistically significant difference in passive external rotation at 0 degrees of abduction between groups with FTT group being stiffer than the PTT group (p=0.019) post-operatively. Change in ROM was not significantly different in all other directions.

Conclusions: The intent of this study was to compare the pre-operative and rate of improvement in two groups of patients suffering from different severity of pathology. The results indicate that quality of life improves significantly regardless of the extent of tear (partial thickness vs. full thickness). Patients with FTT may require a longer time to improve their range of motion in external rotation.


S. Patil M. Ramakrishnan J. Stothard

Purpose: To compare the analgesia provided by pure subcutaneous infiltration (Gale technique) of lignocaine with that provided by infiltration of lignocaine into the carpal tunnel in addition to the subcutaneous tissue (Altissimi technique) for carpal tunnel decompression

Methods: 20 patients with bilateral carpal tunnel syndromes were chosen for the study. Patients were randomised to receive one local anaesthetic technique on one side and the other on the other side. The pain scores were recorded intraoperatively and 2 and 4 hours postoperatively.

Results: 5 patients experienced intra-operative pain with the Gale technique, while one did with the Altissimi technique (p=0.15 using Mann Whitney U test). Postoperative analgesia at 2 hours was significantly better with the Altissimi technique (p= 0.009). Patients with the Altissimi technique also required less number of analgesic tablets over 24 hours post surgery (p=0.01).

Conclusions: We found no statistically significant difference in the intra-operative pain scores with the two techniques. However, postoperative pain relief was much better with the Altissimi technique.


D. Nguyen L. Ferreira J. Brownhill A. Kedgley J. Macdermid G. King D. Drosdowech J. Johnson K. Faber G. Garvin J. Mozzon

Purpose: Glenoid replacement remains challenging due to the difficult visualization of anatomical reference landmarks and highly variable version angles. Improper positioning of the glenoid component leads to loosening, early wear, and instability. The objective of this study was to develop and evaluate a tracking system for glenoid implantation. We hypothesized that Computer Assisted Glenoid Implantation (CAGI) would achieve a more accurate and reliable placement of the glenoid component compared to traditional methods.

Methods: 3D CT models of sixteen paired cadaveric shoulder specimens were reconstructed and angles were measured using 3D modeling softwares. Jigs were developed to track instruments and to correct for scapular motion. A standardized protocol for determining in real-time via electromagnetic tracking the glenoid centre, version, inclination and ultimate component placement was previously developed and validated in our laboratory. Specimens were randomized to either traditional or CAGI performed by one of two blinded fellowship trained shoulder surgeons. The mean age was 67 years (range 61–88). Native version and inclination were similar in both groups. All phases of glenoid implantation were navigated.

Results: CAGI was more accurate in achieving the correct version during all phases of glenoid implantation (p < 0.05; paired t-test). CAGI CONTROL Initial pin * 6.3 ± 2.9° Reaming *7.0 ± 3.9° Post drilling * 0.6 ± 0.4° 8.3 ± 4.6°|Post cement * 2.3 ± 2.0° 7.9 ± 3.6°|Post implant CT * 1.8 ± 0.9° 7.7 ± 4.0°. Table 1. Absolute values of the mean error ± SD of version angles obtained with either CAGI or the traditional method (goal = 0° version; * p < 0.05). The largest errors with traditional were observed during drilling and reaming where visualization was especially obscured by the reamer heads. The trend was to retrovert the glenoid. There was no difference with respect to inclination angles (p > 0.05).

Conclusions: Preoperative planning using CT imaging with 3D modeling and intra-operative tracking were combined to produce improved accuracy and reliability of glenoid implantation.

Funding : Other Education Grant

Funding Parties : National Sciences & Engineering Research Council research grant


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C. Martin

Purpose: Wrong sided surgery is a devastating, yet avoidable adverse event. The Committee on Orthopaedic Practice & Economics (COPE) position paper on wrong sided surgery in Orthopaedics in 1994 had proposed to develop a reproducible method of operating on the correct side and to educate the orthopaedic community about the standardized procedure and accept this as the standard of care. An update to the COA Membership on success of the position paper was published in the COA Bulletin in 2002. Correspondence from the Canadian Medical Protective Association (CMPA) had demonstrated that there were some encouraging results. There had been a reduction from approximately 13 cases per year in 1987 to five cases per year in 2000. The most common anatomical site involved the incorrect knee. Now 10 years after its acceptance as the standard of care in Canada for orthopaedic surgeons at the COA Meeting in 1995, have all cases of wrong sided surgery been eliminated?

Methods: A search of the CMPA files of malpractice claims as well as cases that were labeled as threats occurring between January 2001 and September 2005 naming a physician and involving the issue of wrong sided surgery were performed.

Results: A review of the synopses found 26 cases where wrong site surgery was the central issue. There were 9 cases in 2001, 10 in 2002, 3 in 2003, 3 in 2004 and 1 in 2005. The 26 cases were reviewed in detail and some of the general characteristics were identified. Of those 26 cases, 10 involved the incorrect knee; in 9 cases, an arthroscopy was performed on the wrong knee; in one case, a total knee replacement was performed on the wrong knee. Hand and foot cases usually involved the wrong finger or toe.

Conclusions: Despite the position paper from the COA (OPERATE THROUGH YOUR INITIALS), operating room policies, heightened awareness, information and educational sessions at all levels of training, wrong site surgery continues to recur. Review of the files for risks have identified the following trends: patients had been anesthetized, the extremity prepared and draped without the surgeon seeing the patient first, the surgical area had been marked by a person other than the surgeon, the medical record and/or radiographs were not available in the operating room, and the hospital policy was not followed. Surgeons need to be mindful that wrong sided surgery has not been eliminated, and educate their surgical team in its prevention.


R. Thakral F. Kheradmand M. Moynagh J. Varian J. O’beirne

Purpose: Trapezium excision and arthroplasty combined with ligament reconstruction as a treatment for first carpometacarpal joint arthritis is known to be associated with synovitis, prosthesis subluxation /dislocation and proximal migration of the metacarpal. To determine the effectiveness of our technique we used the objective and subjective outcome scores to assess the long term results

Methods: Ten patients (11 thumbs) underwent trapezium arthroplasty and ligament reconstruction procedure for grade III/ IV Eaton and Glickel arthritis. The FCR tendon was harvested split into half from proximal to its insertion site. The insertion site was left intact, the split tendon was passed through the first metacarpal base, passed along the radial side of the implant, through scaphoid and back to the 1st metacarpal as an entrapment technique. 7 female and 3 male patients with mean age of 53.9 comprised our series. Off the 10 patients 60% had surgery on their dominant hands.

Results: All the patients had excellent results at a mean follow up of 33.5 months. The mean score (Buck-Gramco) for the tip pinch, grip strength and subjective score for pain, function and dexterity was comparable to the contra-lateral side. The mean tarpezial space ratio calculated from plain x-rays at the follow up was 0.37cm (p< 0.01)|There was evidence of synovitis, prosthesis subluxation or shortening of the thumb.

Conclusions: This new method of securing the prosthesis does offer excellent results with good patient satisfaction


R. El-hawary L. Karol K. Jeans B. Stephens Richards

Purpose: Currently, clubfoot is initially treated with non-operative methods including Ponseti casting and the French physical therapy program (PT). Our purpose was to evaluate the function of children treated with these techniques.

Methods: Seventy-six idiopathic clubfoot patients were enrolled. Successful non-operative outcomes were achieved in 32 patients (44 feet) treated with casting and 44 patients (66 feet) treated by PT. Initial Dimeglio scores were 10–17. At average age 2.3 years (1.9–3.3yr), subjects’ gait was evaluated with a VICON 512 motion analysis system. Cadence and kinematic data was classified as abnormal if it fell outside of one standard deviation from normal.

Results: No statistical differences for cadence parameters were found between the two groups. Two kinematic patterns were identified: Children treated with PT walked with knee hyperextension (41% of feet)*, equinus (17%)*, and foot-drop (28%)*; whereas zero casted patients walked in equinus and only one demonstrated foot-drop. In contrast, the casted group demonstrated increased stance dorsiflexion (47%)* and calcaneus (18%). More PT feet had increased internal foot progression angle (34% vs. 13%)* and increased shank-based foot rotation (56% vs. 33%)*. Both groups had equal rates of normal sagittal-plane ankle motion (59% PT vs. 55%). [*p< 0.05].

Conclusions: Half of the two year-old patients treated non-operatively for clubfoot had normal sagittal-plane ankle motion. Less than 20% in each group experienced calcaneus and equinus gaits, respectively. These differences may be the result of performing percutaneous tendo Achilles lengthening as part of the Ponseti casting technique, but not as part of the PT program.


M. Glazebrook C.J. Foote T. Daniels A. Younger J. Lau D. Peter M. Penner K. Wing C. Stone M. Dunbar R. Leighton

Purpose: To assess patients quality of life, pain, and functional limitations with with endstage ankle arthritis (EAA) and compared this to a similar cohort of patients with endstage hip arthritis (EHA).

Methods: Preoperative data (Short Form SF36) was collected prospectively from patients (n=130) with end stage ankle arthritis and compared to a similar cohort of patients (n=130) with end stage hip arthritis. Patients with ankle arthritis were registered in the Canadian Orthopedic Foot and Ankle Society (COFAS) multi-center study investigating the clinical outcome of ankle arthroplasty and fusion and patients with hip arthritis were randomly selected from the Halifax Joint Replacement Registry Database.

Results: All symptom and functional SF36 subscales for patients with EAA or EHA, were approximately two standard deviations below normal population scores. All differences between ankle and hip SF36 subscales scores were less than 4 points (40% of STD) in both direct and adjusted comparisons. A direct comparison of SF36 scores revealed that patients with EAA had significantly worse mental health according to the SF36 Mental Component Summary Score (MCS) (p= 0.0059), physical limitations with work and daily activities - role physical score (p= < 0.0001), and general health (p= 0.0004). Patients with EHA reported poorer physical function (p= 0.0007) although the Physical Component Summary Score (PCS) for the SF36 was not significant (p= 0.0510). Total Summary SF36, Physical Component Summary (PCS), bodily pain, vitality, role-emotional, social functioning, and mental health subscales were all not significantly different between cohorts (p> 0.05).

Conclusions: Patients with EAA have devastating losses of quality of life, which are comparable to patients with EHA. These findings suggest that increased resources should be directed towards alleviating the severe pain and disability associated with ankle arthritis.


S. Donaldson A. Howard D. Hedden D. Stephens B. Alman J.G. Wright

Purpose: To assess the change in disease-specific quality of life associated with operating on patients with AIS, compared to non operative patients.

Methods: The Climent Quality of Life for Spinal Deformities Scale (QLPSD)was administered prospectively to 119 patients undergoing scoliosis surgery and 42 patients followed for bracing or observation. Change in quality of life after two years (adjusted for baseline quality of life) was used to estimate the short term benefit of scoliosis surgery. Bracing status was also analyzed at baseline as a covariate to determine its effect on improvement in quality of life.

Results: The operated group experienced an increase in quality of life of 4.3 points (95% C.I. 0.69, 7.88) on the 105 point Climent scale. Although statistically significant, this increase was lower than the 5.5 point cutoff we had defined a priori as clinically significant. Among the operative patients, there was no difference in the quality of life score between those braced at baseline (91.2) and those not (90.5) (p=0.73). In non operative patients, those braced had a baseline quality of life score of 88.2, and those not braced 83.3, this difference was also not significant (p=0.13).

Conclusions: Scoliosis surgery results in a small increase, of questionable clinical significance, in spine-related quality of life at two years.

Funding : Commerical funding

Funding Parties : This trial was funded by (in alphabetical order) Canadian Institutes of Health Research, DePuyAcroMed-Johnson & Johnson Medical Products, and Synthes, Canada.


S. Griffin K. Willits H. Sonneveld

Purpose: Posterior Ankle Arthroscopy (PAA) is a relatively new operative technique for a specific and under-recognized ankle problem, posterior ankle impingement. Prospective data on the old technique, posterior ankle arthrotomy, have shown an unacceptable high complication rate. Literature review on PAA found reports on surgical techniques and anatomical studies only. The purpose of this study was to perform a retrospective study, with short-term follow-up to determine the quality of life, function and clinical results after posterior ankle arthroscopy.

Methods: Twenty-three patients underwent a PAA between 1998 and 2004 at our centre. Fifteen patients (16 PAA) were available for follow-up. They filled out the LEFS-score, the AOFAS clinical rating systems, the SF-12, 3 satisfaction scales and also underwent an examination of their ankle.

Results: The mean follow-up time was 32 months (6–74 months). The mean age at time of surgery was 25 years (19–43 years). After surgery they spent on average two weeks on crutches needing pain medication for 1 week. The mean return to work was 1 month (0–3 months) and return to sport was 5 months (1–24 months). 94% of the patients returned to their preoperative level of sport. Complications included five patients with temporary numbness around their scar and one patient with temporary ankle stiffness. There were no permanent neurovascular injuries. The mean LEFS score at follow-up was 75 (65–80; best = 80). The mean AOFAS score was 91 (77–100: 100 = best). The mean SF-12 score was 51.80 PCS (30.77–60.53); 55,80 MCS (44.26–63.33). All reported they had improved after their surgery and would have the surgery again.

Conclusions: Functional and clinical evaluations after a PAA revealed that all of the patients were very satisfied with the result and showed excellent quality of life. Posterior ankle impingement is an under-recognised clinical entity which now has an effective treatment available. Increased clinical focus on this condition may reveal a higher incidence associated with other diagnosis. We are currently evaluating patients pre and postoperative in a prospective study


G. De Vries S. Rigonalli B. Nigg

Purpose: Previous gait studies in community ambulatory older adults show reduced walking velocity, shorter steps, ankle stiffness, and increased duration of double-limb support. A description of gait in very active older adults is needed.

Methods: Subjects: 13 senior athletes (age 65±4 years) and 13 young athletes (age 24±3 years). Inclusion criteria: running plus other activity, body mass index < 26, no systemic disease, no lower leg pathology. Outcome measures: Subjects were evaluated barefoot (walking 1.5 m/s) using a force platform, motion analysis (frontal, medial and plantar videography), and electromyography (EMG) of tibialis anterior (ta), peroneus longus (pl), gastrocnemius (gc), soleus (so), vastus medialis (vm), vastus lateralis (vl), rectus femoris (rf), biceps femoris (bf). Questionnaires were completed (Short Form 36 Health Survey (SF-36), Foot Function Index) and physical examination findings of the lower leg were documented.

Results: Senior subjects, compared to young subjects, had decreased passive ankle dorsiflexion (14° vs. 18°). Senior subjects had a higher incidence of hallux valgus deformity (43% vs. 8%), and dynamic clawing of the toes (29% vs. 8%). Other physical findings were similar between groups. Questionnaire scores were similar for both groups. |There was no difference between groups in duration of single- and double-limbed stance. Seniors, compared to young subjects, had increased muscle activity (normalized EMG signal, stance phase) in seven of eight muscles. The percentage difference was greatest in the lower leg muscles (gc=50% more active in seniors, so=30%, pl=30%, ta=15%). Upper leg activity was moderately increased: vm=15%, rf=6%, vl=6%. Only biceps femoris had decreased activity (−15%). Further analysis of EMG intensity, kinematics and kinetics are pending.

Conclusions: This study shows that even in healthy, active subjects, the foot and ankle is subtly altered with increasing age. Increased muscle activity may be a compensatory mechanism (i.e., to maintain overall performance). While our findings require further explanation, the characteristics documented in this study are in contrast to the shuffling gait often ascribed to older persons.


R. El-hawary D. Sucato S. Sparagana A. Mcclung E. Van Allen P. Rampy

Purpose: Few studies have analyzed spinal cord monitoring (SCM) during spine deformity surgery when neural axis abnormalities (NAA) are present. Our purpose was to compare the effectiveness of SCM between NAA and AIS patients.

Methods: This is a retrospective review of all patients from 1993–2002 with an isolated NAA who had SCM during spinal deformity surgery. These were compared to a randomly selected group of AIS patients during the same time period when techniques for somatosensory-evoked potentials (SSEP) and motor-evoked potential (MEP) monitoring remained the same.

Results: There were 41 NAA patients and 139 AIS patients. The age at surgery was similar (14.4 vs. 14.5 yrs), but there were more males (48.8 vs. 18.7%)* in the NAA group. For NAA patients, the most common abnormalities were syringomyelia (n=29) and tethered cord (n=5) for which 68% required neurosurgery. The preoperative curve magnitude was greater in the NAA group (65.9° vs 59.6°)* but there were no differences in surgical time (39.6 vs. 35.9 min/level) and estimated blood loss (99.4 vs. 82.0 cc/level) between the groups. There was a trend towards more surgical complications in the NAA group (7.3 vs. 3.6%). Good baseline values were achieved less often in the NAA group for SSEPs (85% vs 99%)* and MEPs (83% vs 100%)*. Significant deviations from baseline values were seen more often in the NAA group for SSEP (5.0% vs. 1.4%)* and MEP (4.0% vs. 2.5%)*. * (p< 0.05)

Conclusions: Obtaining baseline SCM values was more difficult and deviations from baseline were more common in the NAA patients when compared to AIS patients. However, SCM did not miss a neurologic injury and was found to be very useful and necessary during spine deformity surgery in the NAA population.


M. Javid J. Wedge

Purpose: Background: Treatment of Legg-Perthes disease in older children with greater involvement of the femoral head remains uncertain. Innominate or combined innominate and femoral osteotomies are generally performed to better contain and provide more coverage of the femoral head by the acetabulum and thus achieve a more spherical head and a congruent joint. The purpose of the study was to show the results of both surgeries.

Methods: We carried out a retrospective review of 43 hips in 41 patients (36 males, 5 females), with lateral pillar classifications of B (25 hips), B/C (12), and C (6), who had not responded to non-surgical treatment and all treated by one surgeon. They underwent Salter innominate (23 hips) or combined innominate and femoral osteotomies (20 hips). Mean age of the former group at surgery was 7 years, 11 months and of the latter, 10 years, 7 months. Combined osteotomy was performed in older children with more head involvement and stiff hips that did not respond to other treatments. Patients were evaluated with a mean follow-up of 9 years, 4 months using the Stulberg radiographic assessment.

Results: Results: Stulberg I or II (SI-SII) results were attained by 57% of the innominate osteotomy group and 30% of the combined. Eleven of 14 LPB hips in the innominate group and 5 of 11 in the combined became SI-II in contrast to 2 of 5 and 1 of 7 LPB/C hips, respectively. All 6 LPC hips were classified Stulberg III or IV (SIII-IV). Children younger than 8 years in the innominate group had better results than the older children (65% vs 33%) and those younger than 10 in the combined group did better than the older (43% vs 0%).

Conclusions: Conclusions: The LPB and LPB/C groups treated by innominate osteotomy had better results (more spherical heads) than those undergoing combined osteotomy, age proving a stronger prognostic factor than disease stage. The LPC led to aspherical congruent hips with either type of surgery, regardless of patient’s age. The outcome was better in LPB in children younger than 8 years of age and in LPB/C in those older than 8 years. Age of onset still remains the primary determinant of outcome in LCPD.


C. Kellett M. Assal

Purpose: There are many different operations for hallux valgus and it is often difficult to know which one to perform. Many of the patients who present with hallux valgus have first ray hypermobility. We use the metatarsocuneiform arthrodesis for the treatment of symptomatic Hallux Valgus with hypermobility of the first ray. We present a retrospective evaluation of the results for a consecutive series from one surgeon.

Methods: The patients were evaluated using the American Orthopedic Foot and Ankle Society Score (AOFAS) post operatively. The post operative complications were recorded and the surgical correction measured on the pre and post operative radiographs.

Results: 41 metatarsocuneiform arthrodeses were performed in 40 patients. The average hallux valgus angle was 36.8 pre operatively and 7.3 post operatively. The average intermetatarsal angle was 17.3 pre operatively and 6.9 post operatively. The average post operative AOFAS score was 86.4. There were no problems with wound healing. All the arthrodeses had fused at 3 months. Two patients required screw removal.

Conclusions: Metatarsocuneiform arthrodesis gives good clinical and radiological results in patients with hallux valgus and a hypermobile first ray.


T. Daniels N. Duggal S. Redekop M. Yeung

Purpose: 1/ To compare patients treated with both ankle arthroplasty or ankle fusion using validated functional outcome measures and a computerized motion analysis system that measures three-dimensional kinematics and temporal data. 2/ To compare the functional outcome and gait mechanics of ankle arthroplasty and ankle arthrodesis to a healthy control group.

Methods: Fifteen patients underwent seventeen ankle arthroplasties with the Scandinavian Total Ankle Replacement (STAR), twenty-three patients underwent ankle arthrodesis, and twenty-three healthy control patients were enrolled in this study. Assessment included: 1/ Ankle Osteoarthritis Scale (AOS) and general health status (SF-36). 2/ Gait data, including temporal-spatial, kinematic, and kinetic parameters using a seven-camera VICON 370 system (Oxford Metrics, UK). Comparison between groups was done using one-way ANOVA post hoc Bonferroni (p< 0.05).

Results: Kinematic gait parameters for post-op arthrodesis, post-op arthroplasty and a control group are summarized in Table 1. Postoperative arthrodesis patients had significantly reduced ankle range of motion in the sagittal and frontal plane when compared to both postoperative arthroplasty patients and a control group (p< 0.05). Forefoot range of motion was also significantly reduced in the sagittal and frontal planes for arthrodesis patients when compared to the control group, however there were no significant differences between patient groups or between arthroplasty patients and controls (p< 0.05).|Functional questionnaire (AOS) data for the three groups is summarized in Table 2. There were no significant differences in patient perception of pain and disability, however AOS scores compared between arthrodesis patients and a control group were significant (p< 0.05). No difference was noted in AOS scores between ankle arthroplasty and control patients at one year post operative.

Conclusions: Functional outcome analysis of treatment methods of end-stage ankle arthritis clearly shows the advantage of ankle arthroplasty over arthrodesis when comparing kinematic and outcome questionnaire data against controls. The results of this study will help determine the best surgical treatment for patients with end-stage ankle arthritis failing non-operative treatment.


M. Shekhman K. Inkpen N. Greidanus C. Anglin A. Hodgson J. Tonetti D. Garbuz B. Masri D. Duncan

Purpose: Hip resurfacing techniques utilize mechanical jigs to align a femoral guide-pin that directs implant placement. Errors in alignment may lead to premature failure. The purpose of this study was to compare femoral guide-pin placement using a computer-assisted surgical (CAS) navigation system to a currently available manual alignment device.

Methods: A computer-assisted navigation system was developed by our group. Target guide-pin position was determined for each cadaveric hip from radiographs. A guide-pin was driven into each hip using either the CAS method or a manual alignment jig (Durom; Zimmer) by a novice or expert surgeon respectively. Radiographic pin position was compared to the target and accuracy was compared between the two techniques.

Results: Guide-pin insertion trajectory using the CAS system was significantly less variable in varus/valgus alignment than the mechanical jig (2.0° SD vs. 5.5° SD; p < 0.05). Ante/retroversion variability was also lower using CAS (4.4° SD vs. 7.7° SD) as was alignment error (CAS: 2.0° ± 2.2° SD valgus vs. Durom: 3.3° ± 5.5° SD varus, p=0.17; CAS: 0.1° ± 4.6° SD anteverted; Durom 3.2° ± 7.7° SD retroverted, p=0.48) but not significantly. Both methods proved accurate in placing the pin within 2 mm from the centre of the neck axis. Procedure time was similar between the two methods

Conclusions: Computer-assisted surgical navigation significantly improves reliability of guide-pin placement. This technique may help achieve better femoral implant alignment regardless of experience and contribute to improving hip resurfacing outcomes.

Funding : Other Education Grant

Funding Parties : Zimmer/UBC Research Fund


U. Debnath A. Guha S. Karlakki G. Evans

Purpose: This is a retrospective study, analysing the long term outcome following Chiari osteotomy and varus derotation osteotomy, which was performed as a part of one stage surgical reconstruction for painful subluxed or dislocated hips in cerebral palsy patients

Methods: Between 1986 and 1993, 12 hips in 11 patients underwent the above procedure. Adequate hip reduction was achieved in 11 hips and an acceptable reduction in the other. Immediate pain relief and subsequent improvement in range of movement of the hip, sitting posture and ease of perineal care was recorded in all. Average age at the surgery was 14.1 (9.1–17.8) years. At the recent follow-up, patients were seen along with the parents or carers and reassessed for pain, sitting comfort, mobility and ease of perineal care. Radiographs were obtained and assessed for acetabular cover, degree of femoral head lateralisation, changes in the hip joint including secondary arthritic changes

Results: At an average follow-up of 13.4 years (range 8.1–17.2 years), all patients remain pain free and continue to maintain improved sitting posture and personal hygiene. Improvement to mobility was marginal, but those who were community walkers to begin with benefited the most. No significant progressive arthritic changes or lateral migration were seen in any of the patients except one, in whom only a partial reduction was achieved. Minor joint changes were seen in 2 other patients.

Conclusions: Overall, Chiari osteotomy produces lasting benefits and the possible avascular necrosis and secondary arthritic changes in the hip joint appear to be minimal when compared with the long term benefits


R. Friedman J. Longo K. Cherry M. Newman D. Jessup S. Bal

Purpose: Ceramic/ceramic bearing surfaces have the advantage of significantly decreased wear and high biocompatibility compared to CoCr/PE or ceramic/PE. The purpose of this randomized, controlled, multi-center, prospective study was to evaluate the clinical and roentgenographic results of 469 ceramic/ceramic versus 321 ceramic/PE THA at a 2 to 7 year follow-up.

Methods: The ceramic/ceramic THA had a polished alumina femoral head articulating with a polished alumina acetabular liner seated into the metal acetabular shell designed to avoid any impingement of the ceramic liner on the femoral component. Evaluations were completed preoperatively, at 6 months and yearly postoperatively.

Results: Mean age of the 790 patients was 59 years, with slightly more females. There were no significant demographic differences between the two groups. The main diagnoses were OA in 74% and osteonecrosis in 19%. Preoperatively the mean Harris Hip Score (HHS) and WOMAC scores were 44 and 41, respectively, and did not differ significantly between the two groups. At follow-up, the mean HHS was 93 for the ceramic/ ceramic THA and 93 for the ceramic/PE THA. The mean WOMAC scores showed no differences at follow-up. Roentgenographic analysis revealed one acetabular cup migration with a PE liner. One ceramic liner fractured upon insertion that was not properly positioned prior to impaction. Otherwise, there were no revisions or complications related to either bearing surface.

Conclusions: This short-term study has demonstrated efficacy and safety of a ceramic/ceramic bearing surface compared to the standard ceramic/PE surface currently used in clinical practice, with no failures or complications related to the bearing surface. Further follow-up is indicated to determine the long-term outcome.

Funding : Commerical funding

Funding Parties : Encore Orthopaedics


E. Schemitsch N. Aslam J. Saito K. Tokunaga J. Waddell

Purpose: In uncemented total hip arthroplasty, stem design is one of the important factors influencing bone remodeling. The purpose of this study was to determine the differences in bone remodeling between metaphyseal and diaphyseal fit stems.

Methods: Twenty-three patients undergoing total hip arthroplasty (28 hips) with metaphyseal fit stems were matched to 27 patients (32 hips) undergoing uncemented total hip arthroplasty with diaphyseal fit stems. Preoperative radiographs were assessed for canal fill, canal shape, and bone quality. Postoperative radiographs were assessed for frequency and time of appearance of peri-prosthetic bone remodeling including spot welds, cortical hypertrophy and pedestal formation. All patients were examined by a modified Harris Hip Score.

Results: The proximal canal shape and bone quality were similar in both groups. There was no difference in the frequency of spot welds at 1 year and 2 years. Spot welds were mainly located in Gruen zone 1. Cortical hypertrophy was greater (p < 0.05) at 6 months, 1 year and 2 years with the metaphyseal fit stem. Cortical hypertrophy was found only in Gruen zones 3 and 5. Halo pedestal formation was greater (p < 0.05) at 6 months with the metaphyseal fit stem but not at 1 year and 2 years. Calcar rounding was observed in 25 hips (90.0%) with metaphyseal fit stems and twenty hips (62.5%) with diaphyseal fit stems. At the last follow-up, average HHS was similar (90.6 +/− 1.5 / 91.7 +/− 1.7; metaphyseal / diaphyseal fit stems). No patient developed aseptic loosening.

Conclusions: This is the first study to determine differences in bone remodeling between a metaphyseal and a diaphyseal fixed stem in uncemented THA. After one year, the only significant difference between these two groups was cortical hypertrophy, which was greater in patients undergoing metaphyseal fit stem insertion. Both stem designs demonstrated bone remodeling with no differences in spot welds or pedestal formation. At two years, there was no functional difference between these two patient groups. To further elucidate the relation between radiographic and clinical results, longer term follow-up is required.


J. McAuley M. Moore A. Young C. Engh

Purpose: Radiographic signs of osseointegration have been well established for cementless femoral components, but not for cementless acetabular components. At our institution using principles similar to those applied to cementless femoral components, we have observed apparent radiographic signs of osseointegration of porous-coated cups. We then hypothesized that these signs could be used to predict bone ingrowth of porous-coated acetabular components

Methods: In a series of 119 total hip arthroplasties with porous-coated cementless cups, we reviewed post-primary and prerevision serial radiographs and proposed five radiographic signs for detecting osseointegration of a porous-coated acetabular component: absence of radiolucent lines, presence of a superolateral buttress, medial stress shielding, radial trabeculae, and an infero-medial buttress. We compared the predictability of each sign to intraoperative findings of cup stability and measured the sensitivity, specificity, and intra-observer agreement of each sign

Results: . In our population, ninety-eight cups had three to five radiographic signs of osseointegration; of these, ninety-five cups (97%) were found to be bone-ingrown at the revision operation. Conversely, twelve cups had only one or no sign; of these, ten (83%) were clinically unstable at the revision operation.

Conclusions: We concluded these five, readily detectable signs of acetabular osseointegration are very useful in predicting acetabular component stability found at surgery.


S. Kearns B. Jamal A. Burns M. Skutek R. Bourne S. MacDonald R. McCalden C. Rorabeck

Purpose: The young patient with hip arthritis remains one of the biggest challenges to arthroplasty surgeons. The difficulty of providing a long-lasting total hip arthroplasty (THA) has been clearly documented in the literature. The aim of this study was to assess the outcomes of uncemented THA’s performed in our unit in patients aged under 50.

Methods: In our unit information on all patients is recorded prospectively on an arthroplasty database. From this database we identified 273 uncemented THAs in 237 patients under the age of 50 performed in our unit between 1985 and 2000 with a minimum of 5 year follow up. Outcomes were assessed in terms of 10 and 15-year survival with revision for any reason as the endpoint. Hip scores at routine and most recent follow-up were also reviewed. All surviving implants were radiographically assessed for acetabular wear, component loosening and for the presence of osteolysis.

Results: The mean age of patients at the time of surgery was 41.1 years. 36 patients had bilateral THA. The overall 10 and 15 year survival was 88.7 ± 2.4% and 65.6 ± 4.8 % respectively. Femoral stem survival was significantly higher at 100 % and 98.4 ± 1.6% at 10 and 15 years. Acetabular component survival was 88.6 ± 2.5 % at 10 years and 65.9 ± 4.8 % at 15 years. In unrevised THA’s 56.9% had asymmetric polyethylene wear > 2mm. 2% had definite evidence of acetabular loosening. 25.5% had radiographic evidence of femoral cortical hypertrophy or spot-welds. The mean HHS pre–operatively, at 5 and 10-year follow-up was 46.4 ± 13, 90.7 ± 12.2 and 87.9 ± 14.7 respectively.

Conclusions: Uncemented THA is effective even in young active patients. The main challenges remain ace-tabular polyethylene wear and loosening. Femoral uncemented stems provide long-term functional fixation. Contemporary bearing surfaces in association with such stems may provide long lasting THA’s even in young active patients.


O. Safir V. Bubbar B. Liberman A. Gross R. Korley C. Kellett D. Backstein

Purpose: Many surgeons are now performing hip arthroplasty using a minimally invasive technique with the aim of reducing muscle damage and improving rehabilitation. We compared the learning curve of two MIS THA approaches: the two-incision mini and a modified Watson-Jones (G3) approach.

Methods: A retrospective review of 47 consecutive patients who underwent a THA using an MIS approach was conducted. All patients received an uncemented acetabular cup (Trilogy–Zimmer) fixed with 1 or 2 screws, and an uncemented femoral stem (ML taper, fiber metal taper, fully porous coated–Zimmer). Note was made of BMI, surgical time, incision length, blood loss, component positioning, hospital stay and perioperative complications.

Results: Twenty-one patients received a G3 and 26 received a 2 incision mini approach. The average BMI was 29.7 and 26.1 respectively. Average acetabular inclination was 37 for the G3 and 42 for the 2-incision mini. On average, the femoral component was positioned in neutral in the coronal plane for both approaches. Average surgical time was 121minutes for the G3 and 166 minutes for the 2-incision which also includes fluoros-copy time. Hospital stay averaged 5.4 and 6.8 days respectively. The skin incision averaged 8.9 cm for G3 a total of 9.8cm for 2-incision. Perioperative complications for the G3 included 1 lateral femoral cutaneous nerve palsy, 1 DVT, 1 PE and 1undisplaced intraoperative acetabular fracture. Complications for the 2-incision mini included 5 intraoperative fractures, 7 nerve injuries, 1 wound infection, 1 infection requiring revision and 1 PE.

Conclusions: The G3 minimally invasive approach for THA has advantages over the 2-incision mini: shorter operative time, no need for fluoroscopy, fewer days in hospital, shorter total incision length and lower complication rate. The G3 approach also offers the opportunity to bail out to a traditional approach, by extending the incision, should this be necessary.


M. Lavigne PA Vendittoli A. Roy J. Girard

Purpose: Femoral offset restoration is recognised as an important part of THA procedure to reduce the joint reactive force and improve stability. In SRA, femoral offset is often reduced due to the femoral component valgus position. The main objective of this study was to correlate the clinical function of SRA and THA patients with their different biomechanical hip reconstruction (femoral offset).

Methods: 156 patients aged 23 to 65 years old and suffering from advanced hip joint degeneration were randomly assigned to two treatment groups: the THA or SRA group. All surgeries were performed through a posterior approach. Standardized pre and post operative antero-posterior radiographs of the pelvis were made and clinical scores were assessed.

Results: Compared to the normal contra lateral side, the femoral offset increased on average 4.85mm (range -2.77 to 11.59mm, SD 3.31) for THA and decreased an average of 3.42mm (range −7.78 to 1.96, SD 2.12) for SRA (p=0.0001). In addition, offset restoration was within lees than 4 mm in 60.0% of the SRA group and 21.8% in the THA group (p=0.0001). There were no differences between the both groups in terms of clinical and subjective scores: the PMA and SF-36 scores were, respectively, in average 17.1 (SD 0.4) and 101 (SD 1.25) for THA and 17.0 (SD 0.4) and 101 (SD 1.14) for SRA. No relation was found between offset restoration and clinical scores for both groups.

Conclusions: In this study, surgeons were less precise reconstructing the femoral offset in the THA group compared to the SRA group. However, femoral offset was lower (reduced) in the SRA in comparison to THA. This significant decreased femoral offset in SRA, seems inherent to the preferential valgus positioning of the femoral component in that technique. The excellent clinical outcome reported with SRA does not suggest that restoring normal offset is as crucial for the success of SRA because no correlation was found between femoral offset and the clinical scores used.


D. Garbuz C. Duncan M. Awwad

Purpose: The purpose of this study was to compare postoperative quality of life in patients with dysplasia who underwent Bernese periacetabular osteotomy to those who had total hip arthroplasty.

Methods: Patients were included who had a diagnosis of dysplasia and were greater than 40 years old. Cases were patients who had a periacetabular osteotomy. Controls were patients who had undergone total hip arthroplasty. Patients were matched for gender, age, and comorbidity. There were 26 cases and 33 controls. Outcome tools were the Western Ontario McMaster Universities (WOMAC) osteoarthritis index, the SF-12, and the Arthroplasty Satisfaction Scale. T-tests were used to compare means between the groups. The chi-squared test was used to compare the percentage of patients who had very good, good, or poor outcomes between the groups. WOMAC scores were normalized on a 0–100 scale with 0 being worst and 100 being best. A WOMAC score > 75 was considered very good, 65–75 good, and below 65 poor.

Results: The mean follow-up was just over 4 years in both groups. There was a clinically and statistically significant difference in WOMAC pain and function scores favouring the total hip patients. Mean WOMAC pain scores were 89 vs 71 (p< 0.0050). Mean WOMAC function scores were 91 vs74 (p< 0.005). Ninety-seven percent of total hip patients had a good or very good result vesus 73% of the osteotomy patients (p< 0.05).

Conclusions: Total hip arthroplasty gives a more consistent and better return of quality of life in patients over 40 when measured at a mean of 4 years after operation. Future research should be directed toward preoperative and intraoperative factors that could improve the outcome of patients having an osteotomy in this age group.


W. Fisher B. Eriksson L. Boris K. Bauer A. Trupie M. Gent O. Dahl S. Haas A. Kakkar M. Huisman F. Misselwitx P. Kälebo L. Kwon M. Homering

Purpose: Thromboembolic events, such as deep vein thrombosis (DVT) and pulmonary embolism (PE), are a serious risk after major orthopaedic surgery. BAY 59-7939 is a novel, oral, direct Factor Xa inhibitor in clinical development for the prevention and treatment of thromboembolic disorders. The efficacy and safety of BAY 59-7939 for thromboprophylaxis have been determined relative to enoxaparin in two clinical trials, one after elective total hip replacement surgery, and one after elective total knee replacement surgery. This pre-specified analysis combines data from two multicenter, multinational, double-blind, dose-ranging studies; the hip surgery trial was performed in Europe, and the knee surgery trial in North America.

Methods: Patients (N=1343) were randomized to oral BAY 59-7939 at 2.5, 5, 10, 20, or 30 mg twice daily (bid), or subcutaneous enoxaparin (40 mg once daily starting 12 hours before hip surgery, or 30 mg bid starting 12 hours after knee surgery), continuing until mandatory bilateral venography was performed 5–9 days after surgery. The primary efficacy endpoint was a composite of DVT, PE, and all-cause mortality. The primary safety endpoint was major, post-operative bleeding.

Results: The primary efficacy endpoint occurred in 21.6%, 22.9%, 16.1%, 24.4%, and 19.3% of patients receiving BAY 59-7939 2.5, 5, 10, 20, and 30 mg bid, respectively, and 27.8% receiving enoxaparin (n=914). No significant dose–response relationship for efficacy was observed with BAY 59-7939 (P=0.39); this was potentially due to the efficacy achieved with the lower BAY 59-7939 doses. A significant dose–response relationship was observed for major, post-operative bleeding with BAY 59-7939 (P< 0.001), which occurred in 0.9%, 1.3%, 2.1%, 3.9%, and 7.0% of patients receiving BAY 59-7939 2.5, 5, 10, 20, and 30 mg bid, respectively, and 1.7% of patients receiving enoxaparin (n=1317).

Conclusions: This analysis showed that BAY 59-7939 has a wide therapeutic window for the prevention of VTE following major orthopaedic surgery, and, at doses of 2.5–10 mg bid, has similar efficacy and safety to the enoxaparin regimens.

Funding : Commerical funding

Funding Parties : This study was sponsored by Bayer HealthCare AG


M. Manzary B. Masri D. Garbuz N. Greidanus C. Duncan

Purpose: To evaluate and compare patient reported quality of life and satisfaction following metal on metal hip resurfacing and total hip arthroplasty procedures.

Methods: Patients receiving metal-on-metal hip resurfacing and primary total hip arthroplasty were assessed at baseline and followed prospectively with regards to outcomes of quality of life (WOMAC, Oxford-12, SF-12) and satisfaction. Patients receiving resurfacing were matched (1:3) to a cohort of THA on characteristics of age, gender, and comorbidity status. Sample size was selected to evaluate superiority using WOMAC function score with effect size of 0.5, alpha .05, power 80%. Univariate and multivariate analyses were performed.

Results: 222 patients were evaluated with regards to baseline socio-demographic characteristics and quality of life scores(56 resurfacing, 166 THR). Patient cohorts were not different at baseline pre-operatively with regards to age, gender, comorbidity status, WOMAC, Oxford-12, and SF-12 (p> .05). At minimum one year post-op both cohorts reported excellent outcomes. Patients receiving hip resurfacing had superior outcomes with regards to WOMAC function, WOMAC pain, and Oxford-12 hip scores (p< .05). However patients were similar with regards to outcomes of SF-12 mental status and patient-reported satisfaction.

Conclusions: Hip resurfacing and THA patients report excellent outcomes, however, patients receiving hip resurfacing report superior quality of life compared to a matched cohort of THA.


N. Greidanus C. Backman J. Kopec D. Garbuz B. Masri A. Aris J. Esdaile C. Duncan

Purpose: To evaluate the effect of outpatient physiotherapy versus a self-adminstered home exercise program on recovery following primary total hip arthroplasty.

Methods: Subjects awaiting primary total hip arthroplasty consented to participate in this prospective randomized clinical trial. Patients were assigned to participate in either an outpatient physiotherapy program or self-administered/self-directed home exercise program following discharge home from hospital. Multiple longitudinal measures were performed to adequately assess recovery over time. Primary outcome for comparison was WOMAC function at 4 months postoperatively, additional outcomes of timed-up-and-go, SF-36, HUI3, FSI. Primary outcome was evaluated using repeated measures analyses and regression models for longitudinal data.

Results: 100 patients were randomized to their respective interventions. The two cohorts were similar with regards to baseline characteristics of age, gender, and pre-op quality of life measures (p> .05). At 4 months post-op both groups demonstrated significant change from baseline function and were similar with regards to recovery and rate of recovery (p> .05).

Conclusions: While all patients demonstrated excellent recovery, patients receiving self-adminstered home exercise program did not demonstrate inferior outcome at the interval(s) assessed. Self-adminstered home exercise program may be an effective alternative rehabilitation program where physiotherapy services are limited or in specific subgroups of patients.

Funding : Educational Grant from the Canadian Orthopaedic Foundation


M-N Tahmasebi M. Saghari M. Moslehi A. Gholamrezanezhad

Purpose: Scintigraphy has been considered as competitive to MRI, but limited data are available on the accuracy of single photon emission tomography (SPECT) compared with MRI for the assessment of meniscal tears. Our objective was to assess the value of SPECT in comparison to MRI.

Methods: Between January 2003 and March 2004, sixteen patients were studied with both modalities and the accuracy rates of SPECT scan results, and MRI findings in the diagnosis of meniscal tears were compared. Arthroscopy was the gold standard.

Results: The respective sensitivity rate, specificity rate, and positive and negative predictive accuracies of MRI were 89%, 94%, 93%, and 79% and for SPECT those were 78%, 94%, 94%, and 88%. There was good agreement on the presence or absence of tears between two modalities (& #954; statistic = 0.699).

Conclusions: SPECT and MRI are both valuable imaging techniques. SPECT is a useful alternative when MRI is unavailable or unsuitable and it is beneficial when more possible accuracy is desired (such as when MRI results are either inconclusive or conflict with other clinical data).


J. Pan E. Schemitsch N. Aslam J. Waddell

Purpose: The purpose of this study was to evaluate total hip arthroplasty in the treatment of post-traumatic arthritis following acetabular fracture and to compare the long-term outcome of THA after previous open reduction and internal fixation or conservative treatment of the acetabular fracture.

Methods: Thirty-four patients (thirty-six hips) underwent total hip arthroplasty for arthritis resulting from an acetabular fracture. The mean age at the time of hip arthroplasty was 49 years. The mean follow-up was eight years and nine months (range, 4–17 years). The mean interval from fracture to arthroplasty was 7.5 years (range, 5 months-29 years). Twenty-three hips had been previously treated by open reduction and internal fixation and 12 hips had a conservatively treated fracture. An uncemented arthroplasty was performed in 31 hips, cemented arthroplasty in 2 patients and a hybrid replacement in 2 patients.

Results: Only 16 patients achieved and maintained a good to excellent result over the course of the follow-up. The mean Harris hip score improved from 44.5 points preoperatively to 72.76 points for operatively treated fractures (23 patients). The mean Harris hip score improved from 44.2 points preoperatively to 78.7 points for conservatively treated fractures (12 patients) (p> 0.05). Ten out of 35 hips required revision; 9 were revised because of aseptic loosening and one for infection with a total revision rate of 29%. Femoral bone quality was significant in predicting revision. No femoral radiographic loosening was found at latest follow-up. On the acetabular side, the rate of radiographic loosening was higher. There was no significant difference in bone grafting, heterotopic bone formation, revision rate, operative time and blood loss between the two groups (ORIF vs conservative treatment of acetabular fracture) (p> 0.05).

Conclusions: Outcome following total hip arthroplasty in the treatment of post-traumatic arthritis following acetabular fracture is less favourable than following primary osteoarthritis. Those patients initially treated conservatively had similar long term results compared to those treated primarily by open reduction and internal fixation. At long term follow-up, the main problem identified was osteolysis and acetabular wear.


P. Duffy M. McQueen A. Hayes

Purpose: External fixation is a popular treatment method of unstable distal radius fractures. There has been much debate and confusion however regarding the use of bridging versus non-bridging fixation. The aim of this study is to define the indications for bridging and non-bridging external fixation in the treatment of unstable distal radius fractures. The study also endeavours to evaluate the complications and pitfalls associated with this treatment and to determine if non-expert surgeons can reproduce successful outcomes.

Methods: Between January 1995 and December 2000, 641 patients with fractures of the distal radius were treated at our institution with external fixation. The fractures were treated either by bridging or non-bridging external fixation. Demographic data was collected prospectively for these patients including their hospital number, date of birth, gender, age at injury, mode of injury, type of external fixator and whether the fracture was an open or closed injury. Further information was collected retrospectively from review of case notes and x-rays and included AO classification, status of the operating surgeon, duration of fixation, and complications.

Results: Patients treated with bridging external fixation had significantly more mal unions in terms of dorsal angulation and shortening. The non-bridging fixators were better able to maintain and in some cases improve on the immediate post external fixation measurements. Minor pin tract infections were more common in the non-bridging group.

Conclusions: Non-bridging external fixation is the treatment of choice for unstable fractures of the distal radius with sufficient space for the placement of pins in the distal fragment. A predictable outcome with low complication rate can be expected.


O. Ayeni

Purpose: To determine if femoral neck shortening after cannulated screw fixation has a negative impact on patients’ quality of life.

Methods: Restrospective Observational Study. Database Review of 3 hospitals 1998–2003. Criteria: Inclusion: successfully treated hip# with cannulated screws. Exclusion:non union, malunion, implant failure, contralateral arthroplasty, death, dementia, illiterate, acute illness. Pts were evaluated with radiographic and outcome studies. Contralateral hip was the control for assessing radiographic parameters.

Results: 56 eligible, 13 met criteria (12 non displaced, 1 displaced). Average(avg)follow up:31 months. 8 pts had femoral neck shortening greater than 5mm, avg abductor moment shortening of 8+/− 2.7mm, avg femoral neck shortening of 6+/−1.9mm in shortened pts. Significant differences (sf-36 subscales)between shortened and non shortened pts. Role physical 53 vs 95 (p=0.04) and physical function 50 vs 91 (p=0.01).

Conclusions: Femoral neck shortening after fixation is associated with a negative effect impact on quality of life.


N. Saran R.C. Hamdy

Purpose: The goal of this study was to evaluate the use of dual energy x-ray absorptiometry (DEXA) to subjectively assess distraction osteogenesis callous regenerate strength to aid in the determination of when to remove the external fixator device in patients undergoing distraction osteogenesis for limb length discrepancies.

Methods: All patients that underwent distraction osteogenesis with either an Ilizarov or Orthofix frame from 1984 to 2005 at the Montréal Shriners Hospital Canada that had monthly DEXA scans prior to removal of their external fixators were included. The fixators were removed once two consecutive DEXA scans showed that the bone mineral density (BMD) had plateaued with a less than 10% successive increase in BMD. A retrospective chart and radiographical review was performed to assess the healing index and post fixator removal complications.

Results: 30 patients underwent 32 corrections. There were 29 lengthenings and 3 lengthenings with angular corrections. The average lengthening was 5.4 cm (3.6–9.1). The healing index average was 49 days/cm (20–77). All patients were progressed from partial to full weightbearing within 6 weeks of fixator removal. There were 2 post removal fractures. One patient fractured through the regenerate and another fractured through a proximal pin site.

Conclusions: Current methods of assessing distraction osteogenesis callous prior to removal of fixator are objective methods based on plain radiographs that have been shown to have poor interobserver reliability. Fractures occurring after fixator removal range between 10–15%. Using DEXA to determine when the regenerate bone mineral density and thus bone strength has plateaued yielded a post fixator removal regenerate fracture rate of 3% in our review. This new method of subjectively assessing the regenerate as compared to other objective radiological methods is a reliable alternative that safely predicts when to remove the fixator with a low post removal fracture rate while maintaining an acceptable bone healing index.


S. Ward E. Bogoch V. Elliot-Gibson J. Laughren D. Beaton

Purpose: To evaluate the impact of the Osteoporosis Exemplary Care Program (OECP) on orthopaedic surgeons’ practice patterns at St. Michael’s Hospital.

Methods: A chart audit was performed to collect data on two groups of 54 patients identified with fragility fractures. The intervention group consisted of patients treated during the first four months of the OECP, while the control (pre-intervention) group consisted of age, sex, and fracture-type matched patients treated prior to implementation of the OECP. Characteristics of the intervention and control groups were compared using chi-square tests. Multivariable logistic regression analysis was then performed to identify significant correlates of OP care.

Results: Preliminary results from 54 matched pairs (108 patients in total) indicate that the OECP group was more likely to have OP risk or OP diagnosis documented (unadjusted OR 2.49; 95% CI 1.05–5.87), as well as to be referred for further investigation of OP (unadjusted OR 3.08; 95% CI 1.37–6.91) or to receive treatment or follow-up related to OP (unadjusted OR 9.01; 95% CI 3.77–21.54). As one surgeon was known to have been providing a high level of OP care prior to implementation of the OECP, the analysis was repeated after removing his patients. In addition, the analysis was repeated after removing patients who were already being treated for OP at the time of their fragility fracture. In both cases, larger increases in the likelihood of OP documentation and care were observed. Through multivariable analysis, age and fracture type (i.e. wrist vs. hip) were found to be significant correlates of having received OP care for patients with fragility fractures treated prior to implementation of the OECP. Following implementation of the OECP, there were no significant correlates of receiving OP care.

Conclusions: Preliminary results indicate that the OECP had a significant impact on orthopedic surgeons’ practice patterns. Following implementation of the OECP all patients were equally likely to receive appropriate referral, treatment, and follow-up whereas, prior to implementation of the program, age and fracture type affected the likelihood that a patient would receive such care.

Funding : Commerical funding

Funding Parties : The Osteoporosis Exemplary Care Program is funded by an unrestricted program grant provided by Merck Frosst Canada and Co. Dr. Beaton is supported by a New Investigators Award, from the Canadian Institute of Health Research.


K. Mulpuri S. Tredwell R. Choit C. Reilly

Purpose: The purpose of this study was to assess the clinical, radiological, and functional outcomes following the treatment of a lumbar Chance fracture and to analyze the spectrum of associated abdominal injuries as seen in the Seat Belt Syndrome.

Methods: All patients diagnosed with L1 to L4 Chance fractures were included in this study. Patient data, injuries, treatment and complications were collected from hospital charts. A review of all available spinal radiology was done to measure pre-treatment, post-treatment and follow-up kyphosis angles. We have also described and calculated a Chance Fracture Deformity Index. Patients were seen in follow-up to assess for range of motion, tenderness and neurological status. A functional outcome questionnaire by the AAOS Pediatric Instruments was completed by the patients.

Results: Between December 1984 and February 2001, 27 patients aged 3 to 17 were treated for lumbar Chance fractures. The mean age at injury was 11.1 years. There were 17 females and 8 males. All injuries occurred as a result of a motor vehicle accident. Of the 25 patients, 17 were treated surgically. 12 patients had abdominal injuries. 3 cases involved abdominal arterial vascular trauma. Significant improvement in intra-vertebral kyphosis, segmental kyphosis, and vertebral kyphosis redmodelling (6.5 vs. 4 degrees) was noted in the operative group compared to the non-operative group. The disease specific AAOS Lumbar Spine Questionnaire scores were poor for pain and disability, 29.22, (26.41–31.98), but the SF-36 scores for both MCS and PCS were within the normal range, 47.79 (44.03–51.54) and 47.71 (42.59–52.82), respectively.

Conclusions: An abdominal and spinal CT must be taken when presented with a Chance fracture with abdominal symptoms. Injury type and kyphosis angle are the main factors that aid in treatment planning in paediatric lumbar chance fractures. A purely soft-tissue injury or a kyphosis angle greater than 20 requires surgical intervention.


R. Zdero

Purpose: The purpose of this study was to quantify cortical bone screw pullout force and extraction shear stress in synthetic femurs. The use of commercially available synthetic bone analogues has grown increasingly in the literature. They are commonly employed as human femur surrogates for use in biomechanical assessment of orthopaedic fracture fixation devices. However, whether screw purchase is the same in synthetic products as in human bone has not been addressed previously in the literature.

Methods: Three large left adult Third Generation Composite Femurs or 3GCF’s (Model #3306, Pacific Research Labs, Vashon, Washington, USA) were mounted in a test jig that allowed exposure of their cortical mid-shaft area. Standard 3.5 mm (40 mm length) orthopaedic bicortical screws (Synthes, Paoli, PA, USA) were inserted at 5 locations in each specimen along their diaphyseal length and extracted using an Instron test machine. The pullout strengths were recorded and extraction shear stresses were calculated. The tests were repeated on 3 other synthetic femurs using 4.5 mm (40 mm length) bicortical screws. The results were compared to existing adult human cadaveric and animal data from the literature.

Results: For 3.5 mm screws, pullout forces were measured (3.88 to 4.97 kN) and the effective extraction shear stresses calculated (23.70 to 33.99 MPa). The extraction shear stresses were in the range of that found in the literature on human cadaveric femurs and tibias (24.4 to 38.8 MPa). Similarly, for 4.5 mm screws, pullout forces were obtained (5.21 to 7.47 kN) and the extraction shear stresses computed (26.04 to 34.76 MPa). This overlapped with previously published extraction shear stress results for human femurs and tibias (15.9 to 38.9 MPa).

Conclusions: The commercially available 3GCF femurs provide a satisfactory biomechanical analogue to human femurs and tibias at the screw-bone interface during axial screw pullout.


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K. Droll P. Guy G. Perriera P. O’Brien

Purpose: Fractures of the femoral head are relatively uncommon injuries and usually occur following a traumatic dislocation of the hip joint. The purpose of this study was to evaluate self-reported functional outcome of patients who have sustained a femoral head fracture.

Methods: A search of the trauma database at a Level I trauma center between the years 1987–2003 was conducted. Sixty two patients, sustaining 63 femoral head fractures were identified. Two patient-based outcome measures, the Short Form-36 (SF-36) and Short Musculoskeletal Functional Assessment (SMFA) were used to evaluate functional outcome. Forty patients were lost to follow-up including three deaths.

Results: To date twenty-three subjects (13 male, mean age 37.3 +/− 15.6), with 24 femoral head fractures have complete functional outcome data. Ten hips (42%) were classified as Pipkin type I, 12 (50%) type II, 1 (4%) type III, and 1 (4%) type IV. The mean follow-up was 10.3 +/− 5.4 yrs. Mechanism of injury included motor vehicle collisions (18/24), and falls from height (6/24). The mean ISS was 11.3 +/− 5.3. Fifteen subjects were treated operatively (13 internal fixation, 1 excision, 1 open reduction only). Four hips failed initial treatment and required delayed total hip arthroplasty (THA). Subjects (n=20) not having a THA functioned below the Canadian normal population for SF-36 physical component score (mean 44.5 +/− 11.0, p < 0.03).

Conclusions: This is the first report of patient-based functional outcome following treatment of femoral head fractures. Physical function was significantly lower when compared to Canadian population norms.


R. Walker J. Waddell E. Schemtisch

Purpose: This cadaveric study examines how changes in femoral entry point for intramedullary instrumentation of total knee replacements affects femoral component positioning.

Methods: Twelve cadaveric lower limb specimens with intact hip, knee and ankle joints were obtained. Total knee navigation instrumentation was secured. Anatomical landmarks required for axes generation were obtained. An initial entry point was made at the center of the distal femur. An intramedullary rod was the introduced into the femur. Five and seven degree cutting blocks were placed onto the rod and positioned against the distal femur with the rotation parallel to the epicondylar axis. The navigation system was then used to generate a varus/valgus angle and flexion/extension angle with respect to the previously generated femoral mechanical axes. This allowed determination of an angle at which the distal femoral cutting block would need to be set to make a neutral distal femoral cut. The guide rod was removed and reinserted five times and measurements recalculated. Data was then collected with entry points 5mm medial, 5mm anterior and 5mm medial and anterior to the initial entry point.

Results: There was no significant difference in varus/ valgus angle with a central compared with 5mm anterior entry point and no difference with a 5mm medial versus 5 mm medial and anterior entry point. The valgus angle required to give a neutral distal femoral cut with a central entry point was 4.98o (SD 0.91o; range 3.5o–6.0o). The valgus angle for a 5mm medial entry point was 6.92o (SD 0.97o, range 5.5o–8.0o). With regards to the sagittal plane a 5mm anterior translation of the entry point changed the flexion/extension angle by 1.58o (SD 0.52o, range 0.5o–2.5o).

Conclusions: Small changes in the entry point can significantly affect component alignment. When moving more medial with the entry point a more valgus angle is required for the cutting block. An entry point at the deepest point of the trochlea may be more reproducible than an anteromedial one but requires a valgus cutting block closer to 5 degrees.

Funding : Commerical funding

Funding Parties : Stryker


S. Wotherspoon A. Danesh-Clough R. Bourne R. McCalden R. Leighton D. Petrie

Purpose: To comapre the clinical results and costs of a non-modular, all-polyethylene tibial component versus a modular tibial component in patients older than 70.

Methods: A multi-center (London, Ontario; Halifax, Nova Scotia) prospective randomized clinical trial was designed to compare modular metal-backed versus an all polyethylene tibial component in patients over 70 years. Primary outcome measures include Knee Society Clinical Rating System, WOMAC, SF-12, Kaplan-Meier Survivorship.

Results: Between September 1995 and August 1997, 127 total knee replacements (Genesis I, Smith & Nephew) were randomized to receive either a non-modular (all-polyethylene) tibial baseplate or a modular (metal-backed) baseplate. Minimum follow-up was 8 years. Excluding patients who died or became disabled due to medical problems, no consistent significant differences have been seen in regard to the WOMAC, SF-12, and Knee Society scores between the two groups. Kaplan-Meier Survivorship is 93% with a mean survival time of 9.36 years for the non-modular group and 94.1% with a mean survival time of 9.49 years for the modular group. The cost saving in the non-modular group was approximately $800 per TKR without any compromise in clinical outcome.

Conclusions: There was no difference found in the clinical outcome scores between an all polyethylene tibial baseplate and a modular tibial component in patients over 70 years of age. Non-modular tibial baseplates have a list price of 23–65% the cost of their modular counterparts. A high mortality rate exists in this age group limiting the numbers available for longer term review. The use of an all polyethylene tibial component is a cost effective and clinically successful alternative in the older patient requiring total knee replacement.


T. Whitehead K. Willits D. Bryant P. Fowler R. Giffin

Purpose: To compare lateral closing to medial opening wedge HTO for a similar angle of correction with regard to change in proximal tibial bony anatomy and posterior cruciate ligament tibial attachment integrity following standard tibial arthroplasty resection.

Methods: Ten cadaveric lower limbs were randomized by side to receive a 12° lateral closing or 12.5mm medial opening wedge HTO. Anteroposterior, lateral and long leg AP radiographs were performed before and after each osteotomy. Pre and post osteotomy measurements of the coronal proximal tibial angle (PTA), sagittal tibial slope and anatomical femorotibial angle were completed and change in angles calculated. Prior to osteotomy, the tibial PCL attachment area was calculated. Post osteotomy, a standardized tibial arthroplasty resection was performed and the remaining percentage PCL attachment area recorded.

Results: Initial radiographs demonstrated little variation between matched pairs. Compared to the medial opening wedge group, the lateral closing wedge specimens demonstrated a statistically significant greater mean change in the PTA of 3.5° (95% C.I., 2.0 to 5.1°, p = 0.003) and an overall tendency for posterior tibial slope reduction with a mean change of −3.4 ± 4.9°. The average osteotomy angle in the medial opening wedge specimens was 11.9 ± 0.7°. Following tibial arthroplasty resection, there was a significant difference in the remaining PCL tibial attachment percentage area of 84.6 ±14.9 % for medial opening wedge and 50.8 ± 19.3 % for lateral closing wedge for a statistically significant mean difference of 33.8 % (95% C.I. 5.1 to 62.4, p = 0.031).

Conclusions: Despite similar correction angles of 12° for lateral closing and 11.9° for medial opening, the former specimens demonstrated a greater alteration in proximal tibial bony anatomy compared to the latter. In the lateral closing wedge group, the tendency to reduce posterior tibial slope and produce a greater than anticipated change in PTA had a significant effect on the integrity of the PCL’s tibial attachment following tibial arthroplasty resection.


K. Harato R. Bourne J. Marr J. Overhauser

Purpose: The purpose of this study was to compare the outcomes of cruciate retaining (CR) and cruciate sacrificing (CS) total knee arthroplasty (TKA) in a multi-center randomized clinical trial with greater than 5 year follow-up.

Methods: One hundred and eighty five patients (189 knees) participated in a double-blinded randomized clinical trial. 96 cruciate retaining and 93 cruciate sacrificing total knee arthroplasties (Genesis II, Smith & Nephew, Memphis, TN) were performed between 1997 and 2000. All surgical procedures were performed by twelve surgeons at twelve medical centers. The average follow-up was 5.8 (5.0–7.3) years. Clinical outcomes (Knee Society Clinical Rating, WOMAC, SF-12, Radiographic Findings) were evaluated preoperatively and at the latest follow-up. Postoperative complications were also examined.

Results: There were no significant differences when comparing cruciate retaining knees to cruciate sacrificing knees in patient demographics and preoperative clinical evaluation. At the latest follow-up, clinical outcomes (CR versus CS) were as follows: Knee Society Clinical Rating (163±26 versus 165±29), knee flexion (114±11& #12539;versus 118±10& #12539; p< 0.05), WOMAC (12±7 versus 8±6, p< 0.05), and SF-12 (mental: 52±9 versus 58±4, physical: 41±11 versus 42±10). Radiographic outcomes showed there were no differences in radiolucent lines or loosening, and postoperative complication rate was also not significantly different.

Conclusions: In this randomized clinical trial, both posterior cruciate preserving (CR) and sacrificing (CS) total knee replacements offer excellent clinical outcomes at five or more years follow-up, with the cruciate sacrificing implant studied demonstrating small, but significant improvements in both range of motion, WOMAC, and disease specific outcomes.


R.S.J. Burnett W.J. Maloney R.I. Barrack M. Ponzar J.C. Clohisy

Purpose: Problem : Infection in TKA is a devastating yet common complication. 2-stage reimplant procedures are performed in the treatment of this condition. Purpose:To evaluate the clinical, radiographic, complications, and patient satisfaction results of 2nd stage reimplantation revision TKA with the use of a TTO. Technical aspects of TTO length, fixation, bypass, and complications are reported.

Methods: From 1996–2004 our database identified 25 revision TKA (12% of 206 revision TKA) performed using a TTO. In 20/25 cases the procedure was a 2nd stage reimplant. Demographics, infecting organism, Gustillo grade, clinical, radiographic, AORI defects, complications, patient satisfaction were evaluated prospectively. All patients were followed until radiographic union of the TTO.

Results: At a mean follow up of 22 mo(range,6–84) no patients were lost to follow-up. 24 (96%)TTO’s healed - 1 requiring revision ORIF. Prior to reimplantation, patients had undergone a mean of 3.3 prior knee surgeries(range,2–8). Prior extensor mechanism procedures had been performed in 43% of knees. Methicillin resistant staphylococcus was the infecting organism in > 50% of knees. 19 knees had a static cement spacer removed at revision. Time to 2nd stage reimplant was 39 weeks(range,15–68). Poor preop range of motion and stiffness (mean arc 430 , range 10–950) improved significantly postop (mean flexion 880 p< .05). 13 (56%) knees required an adjunctive extensor procedure at the time of TTO. TTO length averaged 8.8cm(range,8–10). Screws(15 knees), 2mm cables(6), wires(4) were used for TTO fixation. Mean stem bypass of the TTO was 63mm (−20 to 100). 21 (84%) patients were satisfied with the procedure, despite 8 knees(32%) requiring further surgery. 6 (24%) TTO complications occurred; 1 escape requiring fixation. All TTO’s had healed at recent follow up.

Conclusions: TTO is a useful procedure for exposure in 2nd stage revision TKA. TTO union is predictable(96%), despite technical complications. Recurrence of infection requiring further surgery did not compromise TTO results. Prior/concurrent extensor mechanism procedures were noted frequently.

Funding : Other Education Grant

Funding Parties : Wright Medical Technologies


M. Dunbar E. Laende A. Hennigar D. Amirault G. Reardon M. Gross

Purpose: The Advance Medial Pivot (MP) knee has higher congruency and postulated different kinematics than traditional posterior stabilized knee implants. This could lead to increased micromotion at the tibial component/bone interface potentially resulting in premature loosening. To investigate the stability of the MP knee we used maximum total point motion (MTPM) as determined with RSA to compare micromotion at the tibial component/bone interface between the Advance MP and PS knees.

Methods: A power calculation determined that a minimum sample size of 40 (20/group) was required. Sixty-six patients (48 females) with primary osteoarthritis of the knee were randomized to receive the Advance MP (n=36) or PS (n=30) knee. Three experienced knee surgeons followed a standardized surgical technique (PCL resection, patella resurfacing, RSA bead placement in polyethylene and tibia) and post-operative protocol (CPM as tolerated, no drains, WBAT). SF-36, WOMAC, PCS, KSCRS were administered to all patients pre-operatively and at 6, 12 and 24 months post-operatively and BMI was recorded. Within 4 days of surgery and at 6, 12 and 24 months post-operatively patients underwent bi-planar x-rays.

Results: Fifteen patients were lost to follow-up (2 infections, 1 death, 2 dropped out, 10 lost due to technical issues). There was no difference in MTPM between groups at 2 years. Physical function was better (p< 0.03) for the PS group at 6 months but there was no difference at 1 year.

Conclusions: There was no difference in MTPM between groups at 2 years post-op. The Advance PS knee appears to result in earlier post-operative improvements in physical function. The altered kinematics and increased congruency of the Advance MP knee does not seem to alter the forces at the tibial component/bone interface and therefore does not appear to be more prone to migration and premature aseptic loosening.

Funding : Other Education Grant

Funding Parties : Unrestricted grant from Wright Medical Inc.


G. Dervin A. Conway

Purpose: Resurgence in mobile bearing unicompartmental arthroplasty o the knee has come to Canada in last 3 years. This has been attributed to the popularity of minimally invasive surgery, improved instrumentation, and encouraging outcome results from the developers and others. A prospective study was undertaken at an academic institution to evaluate the initial experience with the first 400 Oxford knees.

Methods: Oxford unicompartmental knees have been implanted since Feb 2001 at our institution. A majority of these were entered into the Ontario Joint Registry. All others were retrieved from hospital records to capture 100% of all cases done form our institution. All surgeons attended an Oxford training course. The main outcome of interest was repeat surgery revision for any cause, including revision.

Results: Three hundred and fifty Oxford knees with minimum 1 year follow up were available for study. Three surgeons have implanted 90 % of the implants. Fourteen patients have come to revision surgery as of October 1, 2005 for an incidence of 3,7 %. Causes include rapid lateral compartment deterioration (6), persisting medial pain (6), and medial collateral ligament disruption (1). Ten were revised to ttoal knee arthroplasty (8 cruciate retaining and 2 posterior stabilized), except the ligament disruption, which was reconstructed with Achilles allograft. Two others had open debridement for medial pain. This rate of revision is higher than reported in literature. Severe obesity (BMI > 35) was a factor in 4 failures.

Conclusions: Our experience was not as successful as reported in the literature from the prosthesis designers. Causes include poor technique and inappropriate indications when scrutinized closely. The temptation to stretch indications must be tempered by acceptance of higher revision rate than reported in literature and should be part of informed consent. Survivorship should be institution specific and not that of original published data from the developers.


J. Bourque S. Patil B. Masri

Purpose: There is little information in the literature regarding outcomes of unicompartmental knee arthroplasty (UKA) in patients receiving worker’s compensation (WC). The purpose of the present study is to compare the outcomes of UKA in patients receiving WC compared to patients without WC.

Methods: Nineteen patients with a WC claim treated by UKA for medial compartment arthritis were compared to twenty patients who underwent similar procedure but had no WC claim. Average follow up period was 37 months (range 30–60 months). Outcomes were evaluated using Knee Society Score (KSS) data. T test was used for statistical analysis. Comparisons were also made with respect to conversion in to total knee arthroplasty (TKA).

Results: WC patients improved from a mean preoperative KSS of 47.4 (range 30–70) to 76.9 (range 55–99), while non-WC patients improved from 43.3 (range 35–63) to 90.7 (range 74–100). The difference in improvement between the two groups was statistically significant (p=0.004). Furthermore, the postoperative KSS in the non-WC patients was significantly higher than that of the WC group (p=0.007). There was no significant difference between the incidences of conversion to TKA between the two groups.

Conclusions: These findings suggest that patients with WC claims have poorer outcomes after UKA in comparison to non-WC patients.


M. Dunbar D. Wilson A. Hennigar D. Amirault G. Reardon M. Gross

Purpose: To investigate the stability of an uncemented Trabecular Metal (TM) tibial component we used maximum total point motion (MTPM) as determined with RSA to compare micromotion at the tibial component/bone interface between the uncemented Nexgen TM monoblock and cemented Nexgen cobalt chrome modular knee prostheses.

Methods: A power calculation determined that a minimum sample size of 40 (20/group) was required. Sixty-seven patients with primary osteoarthritis of the knee were randomized to receive the Nexgen TM monoblock (n=34; 20 female; mean age=66 years; mean BMI=32) or cobalt chrome modular (n=33; 19 female; mean age=65 years; mean BMI=33) posterior stabilized knees. Four experienced knee surgeons followed a standardized surgical technique (PCL resection, patella resurfacing, RSA bead placement in polyethylene and tibia) and post-operative protocol (CPM as tolerated, no drains, WBAT). SF-36, WOMAC, PCS, KSCRS were administered to all patients pre-operatively and at 6, 12 and 24 months post-operatively and BMI was recorded. Within 4 days of surgery and at 6, 12 and 24 months post-operatively patients underwent bi-planar x-rays.

Results: The TM group had greater initial migration but appeared stabilized at 1 year. There were 2 significant subgroups in the TM group based on migration at 6 months: one group had mean values of 2.1 mm while the other had mean values of 0.4 mm which was comparable to the modular group (0.6 mm). There was no significant migration between 6 and 12 months for both implants indicating good fixation to the proximal tibia. There were no differences between groups in the outcome measures, age and BMI.

Conclusions: There was no difference in MTPM between groups at 1 year post-op and all knees appeared well fixed to the proximal tibia by 6 months postop. The Nexgen TM monoblock tibial component seemed to be prone to greater initial migration but it does not appear to compromise long-term bony in-growth and fixation. Long-term survivorship of the TM tibial component should be the same or better than a cemented cobalt chrome tray.

Funding : Other Education Grant

Funding Parties : Unrestricted grant from Zimmer Inc.


J. McAuley M. Collier T. Eickmann G. Engh

Purpose: A retrospective review was done to evaluate survival of unicondylar arthroplasty and identify factors that increased the odds of revision. Our hypothesis was that younger age, increased weight, use of a thinner tibial component, polyethylene shelf aging.

Methods: 411 medial compartment unicondylar arthroplasties encompassing 12 designs were performed at one institution from 1984 to 1998. Patient age and weight averaged 67 ± 8 years and 83 ± 15 kg, respectively. Eighty-seven percent of the tibial components were metal-backed. Initial tibial component thickness averaged 8.5 ±1mm. Polyethylene shelf age averaged 1.3 ± 1.2 years.

Results: Four factors made revision more likely (p < 0.05, Cox proportional hazards regression): younger patient age, thinner tibial component, longer polyethylene shelf age. Gender and weight did not influence survival. With an endpoint of any component revision, Kaplan-Meier survival at nine postoperative years was 80% (95% confidence interval: 75% to 84%). In knees in which tibial component initial thickness was greater than 7mm and polyethylene shelf age was under 1 year, nine-year survival was 94% (95% confidence interval: 91% to 99%).

Conclusions: A 94% likelihood of survival at nine postoperative years may be a reasonable expectation when the procedure is performed with appropriate materials and designs..

Funding : Commerical funding

Funding Parties : Inova Health Care Services


G. Grimard J. Ouellet L-O Lévesque H. Labelle B. Poitras A. Moreau F. Moldovan B. Azzedine D. Wang I. Turgeon S. Leclerc K. Letellier C-H Rivard

Purpose: Recently, we highlighted a dysfunction in the melatonin signalling pathway in the osteoblasts from adolescent idiopathic scoliosis patients (AIS). The objective of this project is to verify if in the cells coming from the SIA patients, estrogens interfere with melatonin signalling pathways and to identify mechanisms through which these effects are carried out.

Methods: The effects of estrogens on the melatonin signalling pathway, in osteoblasts from AIS patients (n=7), were determined by measuring the capacity of the Gi proteins to inhibit the accumulation of cAMP. The osteoblasts were incubated in the presence of increasing amounts of melatonin (10–11 to 10–5 M) with or without 17-& #946;-estradiol in physiological concentrations (10–10 M) (n=7). Moreover, coimmunoprecipitations using anti-phosphoserine antibodies were carried out and then followed with a Western blot in order to detect melatonin receptors (MT1 and MT2).

Results: The intracellular level of cAMP is higher in the presence of a physiological concentration of 17-& #946;-estradiol among scoliotic patients compared to the level observed in the presence of melatonin alone. Moreover, the preliminary results of the coimmunoprecipitations seem to show an increase in the phosphorylation of proteins interacting with MT1 and MT2 receptors. The precise nature of these proteins remains to be identified.

Conclusions: These results seem to show the antagonistic effects of the 17-& #946;-estradiol on the melatonin signalling pathway in the osteoblasts from AIS patients. However, more cAMP dosages in the presence and absence of 17-& #946;-estradiol are underway so as to increase the number of patients. The results of this study could contribute to the development of the first molecular screening tests as well as the development of new therapeutic approaches.


C. Tschirhart J. Finkelstein CM Whyne

Purpose: The mechanical integrity of vertebral bone is compromised when metastatic cancer cells migrate to the spine, rendering it susceptible to burst fracture under physiologic loading. Risk of burst fracture has been shown to be dependent on the magnitude of the applied load, however limited work has been conducted to determine the effect of load type on the stability of the metastatic spine. The objective of this study was to evaluate the effect of multiple loading conditions and the presence of the ribcage on a metastatically-involved thoracic spinal motion segment.

Methods: A parametric biphasic finite element model was developed and validated against experimental data under axial compressive loading. Fifteen loading scenarios were analysed, including axial compression, flexion, extension, lateral bending, torsion, and combined loads. Axial loads were applied up to 800N and moment loads up to 2Nm. Multiple analyses were conducted with and without the ribcage to assess its impact on thoracic spinal stability. Vertebral bulge (VB) and load induced canal narrowing (LICN) were utilised as main outcome parameters to assess burst fracture risk.

Results: For single loads, pure 800N axial loading yielded the highest level of VB (0.48mm) and LICN (0.26mm). The smallest increases in VB were measured in 1Nm pure flexion (0.018mm). Combined loading scenarios also demonstrated that axial loading is the principal factor contributing to VB, as changes in VB for combined loads were no greater than 4.35% of VB under axial loading alone. Inclusion of the ribcage was found to reduce the potential for burst fracture by 27% under axial load.

Conclusions: Axial loading is the predominant load type leading to increased risk of burst fracture initiation. Rotational loading (bending, flexion and extension) led to only moderate increases in risk. The ribcage provides substantial stability to reduce overall risk of burst fracture. These findings are important in developing a more comprehensive understanding of burst fracture mechanics in the metastatic spine and in directing future modeling efforts. The results in this study may also be useful in advising less harmful activities for patients affected by lytic spinal metastases.

Funding : Other Education Grant

Funding Parties : Natural Sciences and Engineering Research Council


C. Tschirhart J. Finkelstein CM Whyne

Purpose: Stability of thoracic vertebrae affected by metastatic disease has been shown to be dependent on tumour size and bone density, but additional structural and geometric factors may also play a role in burst fracture risk assessment. The objective of this study was to use parametric finite element modeling to determine the effects of vertebral level, geometry, and metastatic compromise to the cortical shell on the risk of burst fracture initiation in the thoracic spine.

Methods: An experimentally validated parametric biphasic finite element model of a metastatically involved spinal motion segment was analysed with scenarios representing motion segments from T2-T4 through T10-T12. Variations in vertebral geometry, kyphotic angulation and endplate angulation were evaluated. Additionally, four scenarios with transcortical breach of the tumour were compared to a central tumour scenario to determine the effect of cortical destruction. Vertebral bulge (VB), load induced canal narrowing (LICN), and posterior wall tensile hoop strain (PWTHS) were utilised as the main outcome parameters to assess burst fracture risk.

Results: Burst fracture risk outcome parameters were largest in upper vertebrae, decreasing inferiorly at each subsequent level, with T11 exhibiting a 35.5% decrease in VB relative to T3, despite greater applied loads. An increase in endplate angles led to a 6.59% decrease in VB and a 2.38% decrease in LICN. A 5° increase in kyphotic angle further decreased VB and LICN by 7.29% and 4.34% respectively. Transcortical tumour scenarios led to an average decrease in PWTHS of 25.8%.

Conclusions: Patients affected by spinal metastases in upper thoracic vertebrae may be at greater risk of burst fracture. Decreased burst fracture risk with greater thoracic kyphotic angulation may be due to a change in loading direction for curved segments, reducing the amount of pure axial load applied. Decreased tensile hoop strains are generated during loading of transcortical tumours. This may be attributed to large deformation of tumour tissue through the breach in the cortical shell, reducing the potential for burst fracture. Improved burst fracture risk assessment in the thoracic spine may motivate more informed clinical decision-making.

Funding : Other Education Grant

Funding Parties : Natural Sciences and Engineering Research Council


E. Abraham

Purpose: Adjacent Segment Degeneration (ASD) can occur after spinal fusion. Disc degeneration, spinal stenosis, deformity, spondylolisthesis and fracture are observed. The incidence is unknown and its occurrance difficult to predict. Further major surgery is required to correct the clinical problem that exists although not all cases of ASD are symptomatic. The primary purpose of this study was to identify the incidence of ASD after multilevel(> /=3) thoracolumbar fusions for degenerative disorders. Risk factors for ASD were to be determined.

Methods: Over 400 spinal fusions of 3 levels or greater, minimum 5 year follow-up were assessed for ASD. Radiographic data were available from a prospective data bank. The radiological incidence of ASD was distinguished from those that were clinically significant as determined by Oswestry, back and leg pain scores. |Personal and telephone interviews were conducted along with most recent plain xrays. Data was analyzed (ANOVA) from a single surgeon’s practice. Radiographic assessment was performed by the author with radiologist’s opinions available.

Results: The incidence of ASD after extended spinal fusions overall was 20%. Clinically significant ASD requiring further surgery was 12%. The incidence varied according to location of the fusion, number of levels, age and preexisting disc degeneration and or deformity at the end vertebrae. Overall it was difficult to predict risk factors but trends were noted. Long fusions(greater than or equal to 3 levels) has a significantly high risk of ASD by 5 yrs after the index operation.

Conclusions: The incidence of ASD by 5 years post spine fusion of 3 or more levels is 20% in over 400 cases.12% of these index cases needed further surgery. ASD is a clinically significant entity that deserves study to aid in its prevention.


S. Jhaveri S. Lewis

Purpose: To determine whether skull-femoral traction is a predictor of final surgical correction in scoliosis surgery and obviates the need for anterior release in severe deformities

Methods: 20 patients underwent skeletal femoral traction with a maximum of 50% of their body weight with the use of supracondylar femoral pins. A unilateral pin was used in the presence of pelvic obliquity and bilateral pins in patients with a neutral pelvis. Counter traction was applied through Gardner Well tongs at approximately one third the weight. Pre-op radiographs were compared with dynamic films, intra-op traction films and immediate and final post-operative films. Complications related to traction were recorded. All patients underwent posterior alone surgery for their scoliosis corrections.

Results: The mean curve magnitude was 80.3 degrees. NO anterior releases were performed. Intra-operative traction provided a mean correction of 60%. Final surgical correction was 70%. Level pelvis was achieved in all patients with pelvic obliquity. Traction provided up to 80% of the final correction in older adult scoliotics (> 50 yo) thus minimizing the force required on the pedicle screws to achieve correction. No traction related complications occurred.

Conclusions: Intra-op skull-femoral traction aides in the correction of severe scoliotic curves. Excellent corrections were achieved without the need for anterior releases. Traction reduced pelvic obliquity in the neuromuscular patients. Reducing the magnitude of the curves facilitated exposure of the posterior spine and minimized forces applied to the pedicle screws during scoliosis correction.


W. Oxner A. Ngan

Purpose: To develop a regression equation using preoperative variables to predict the likelihood of transfusion intra- or post- operatively for patients undergoing elective spinal fusion surgery.

Methods: This study was a retrospective chart review of patients (n=774; 51% female; mean age=56 years; mean BMI=29) who underwent elective spinal fusion surgery between February 2001 and May 2005 at the QEII Health Sciences Centre in Halifax, Nova Scotia. The variables recorded were incidence of allogeneic and autologous transfusions (intra- and post-operatively), body mass index, age, gender, number of spinal levels fused, preoperative hemoglobin and hematocrit, ASA grade and pedicle screw and bone graft use.

Results: Spinal fusion of 4 or more levels (n=24) resulted in a transfusion rate of 83%, therefore, the regression equation was calculated using only spinal fusions of 1 to 3 levels (n=750; transfusion rate=14%). The number of spinal levels fused and preoperative hemoglobin levels were found to be significantly related to the likelihood of receiving a transfusion. A predictive logistic regression equation was derived (Prediction = 3.615 + 1.018 x Levels fused–0.052 x Preop Hgb) where a probability cutoff of 0.160 gave a sensitivity of 63.5% and a specificity of 81.2%.

Conclusions: The high sensitivity and specificity of the regression equation suggest that the results are clinically useful for determining whether alternatives to allogeneic transfusions should be investigated preoperatively for each patient undergoing elective spinal fusion surgery. The results could also have economic implications because implementing the use of a cell salvage device would be less costly than allogeneic units if the patient required a transfusion.


A. Al-belooshi S. Lewis R. Rampersaud

Purpose: The purpose of this study was to demonstrate the feasibility and early outcomes of one- and two-level lumbar decompression performed as an outpatient procedure.

Methods: A retrospective review was performed comparing lumbar “laminoplasty” (bilateral decompression from a unilateral approach) using a minimally invasive (MIS-group) technique (MetRxTM tubular retractor system) to open laminoplasty (Open Group). Comparison between groups was performed for patient demographics, radiographic and operative parameters, postoperative pain (VAS), analgesic use and adverse events.

Results: A total of 67 (Open–n=37/ MIS-n=30 [n=20: out patients] patient with a minimum follow-up of 6 months were analyzed. There was no statistically significant difference between groups for age, sex, BMI and radiographic parameters. The MIS group demonstrated a statistically significant reduction (mean = 24minutes) in operative time, estimated blood loss (63mls vs. 227mls), recovery room VAS scores (1.4 vs. 4.4) and total analgesic requirements by %50. None of the MIS group procedures performed on an outpatient basis required readmission. The length of stay for the n=10 inpatient MIS group (elderly patients) was also reduced compared to the open group (2.6 vs. 4.7 days, P= 0.035). The groups were comparable in operative and postoperative adverse events. No progression of preexisting spondylolisthesis has been noted in either group during the follow-up period. Furthermore, only one patient has required reoperation for mechanical low back pain in the MIS group and one patient for recurrent leg pain in the open group.

Conclusions: Minimally invasive outpatient decompression for 1–2 level spinal stenosis is feasible, provides acute perioperative patient and resource utilization benefits and appears to have comparable short-term clinical efficacy compared to open decompression. Long-term follow-up and validated outcomes assessments are currently being assessed.

Funding : Commerical funding

Funding Parties : Medtronic-Sofamor Danek


S. Lewis R. Rampersaud M. Singrahkia

Purpose: To determine the results and safety of patients undergoing|spinal cord level (SCL) pedicle subtraction osteotomy (PSO) for thetreatment of thoracic kyphosis.

Methods: Retrospective chart and radiographic review of 25 patients with severe thoracic kyphosis.

Results: The underlying diagnoses were: tumour (8), Scheuermann’s Kyphosis (4), degenerative/osteoporosis (3), fracture (3), inflammatory|(2), neurofibromatosis (2), congenital kyphosis (1), tuberculosis (1), and infected tumour (1). The osteotomy was combined with a lumbar PSO in|five patients. Three patients were treated with double thoracic|osteotomies. Two PSOs were extended transdiscally to debride the|infected disc. The mean focal PSO correction was 33.6° (range 9°–73°). The overall thoracic kyphosis measured from T5 to T12 improved from a|mean of 58.3° preoperatively to 37.1° postoperatively. Estimated blood|loss ranged from 400cc to 12500cc. All patients presenting with spinal|cord dysfunction neurologically improved postoperatively. There were 2 major neurological complications. One patient developed postoperative | progressive paraplegia following a prolonged period of intra- and | postoperative severe hypotension and coagulopathy. The other developed a| pseudoarthrosis five months postoperatively and suffered an incomplete|spinal cord injury during the subsequent revision. Other complications included: T3 radicular pain (1) -resolved; dural tears (2); respiratory failure -prolonged ICU admission(1); fractures proximal to the thoracic (2) and distal to lumbar (1) instrumentation; incomplete corrections of the sagittal alignment despite double osteotomies (2); wound breakdown associated with preoperative radiation (1).|

Conclusions: SCL-PSO is a feasible option for severe thoracic kyphosis. This procedure eliminates the need for anterior surgery; however, it does not reduce the potential for significant morbidity.


V. Stas S. Lewis N. Khattab R. Davey N. Mahomed

Purpose: The primary objective of this study was to determine if surgical treatment for spinal stenosis is comparable to total hip arthroplasty in improving patients’ self-reported quality of life.

Methods: An age, sex and time of surgery matched cohort of patients who had undergone elective primary 1–2 level spinal decompression (n=90) with (n=30/90) or without fusion for spinal stenosis (n=40 with degenerative spondylolisthesis) and elective primary total hip arthroplasty for osteoarthritis (n=90) were compared. The primary outcome measure was the preoperative and one year postoperative Medical Outcomes Study Short Form-36 (SF-36) questionnaire.

Results: The mean Physical Component Summary (PCS) / Mental Component Summary (MCS) for the stenosis compared to hip patients were 32.0/43.3 vs. 30.5/46.2 preoperatively (analysis between groups: p = 0.2/0.1) and 39.1/47.3 vs.44.1/46.1 postoperatively (analysis between groups: p = 0.003/0.4). The pre- and postoperative PCS significantly improved for both groups (p < 0.0001);however, the pre- and postoperative MCS improved in the stenosis group only (p = 0.04).

Conclusions: Studies have shown the significant impact on overall patient quality of life and cost-effectiveness of primary total hip arthroplasty. The results of this unique study show that surgical intervention for spinal stenosis also has a very positive overall effect on patients’ self-reported quality of life at one year follow up. This study provides data that supports the need for a long term prospective study and advocacy regarding waiting time initiatives and surgical resources for the treatment of patients with symptomatic spinal stenosis with a similar demographic to those with primary OA of the hip.


G. Swarmy E. Boyd S. Berven V. Deviren S. Hu D. Bardford

Purpose: To document clinical and radiographic outcome, and survivorship of long fusion constructs (> T12) stopping at L5.

Methods: Retrospective clinical and radiographic analysis of long fusions to L5 in an adult population, with follow-up greater than 5 years.

Results: We reviewed a consecutive series of patients with long fusion constructs ending at L5 from 1991–2000. 33 patients were identified with fusions from the thoracic spine to L5. 14 patients were excluded, including 7 deaths, 3 patients lost to follow-up, and 4 patients with incomplete radiographic and clinical data sets. There were 17 females and 2 males, with average age of 50 (range 25–73). 7 patients have since undergone extension of fusion to the sacrum, and comprised Group II; the remaining 13 patients comprised Group I. There was no association between preoperative radiographic characteristics of the deformity and outcome (coronal/ sagittal plane imbalance, curve magnitude). Specifically, the lumbosacral disk space appearance (disk height, lordosis) was similar in both groups preoperatively. Presence of postop degenerative changes at the lumbosacral disk did not correlate with outcome. Patients in group I and II had similar scores in SRS, ODI and SF-12 outcome measures. Some patients reported a change in functional status after revision to sacrum, including change in gait pattern, loss of twisting and bending ability, and more difficulty with perineal care. At least 4 patients in Group I are being considered for revision.

Conclusions: In conclusion, long fusions to L5 in an adult deformity population yields unpredictable results more than 5 years after surgery. Although of smaller magnitude than primary fusions to sacrum, stopping at L5 is associated with a significant revision rate. Some patients with long fusions to L5 have good function more than 5 years after surgery.


W. AL-Juhani

Purpose: The purpose of our study was to determine sensitivity, specificity and accuracy of the presence of joint line fullness on physical examination in detecting the presence of both meniscal tear and/or cyst as found on MRI and at arthroscopy . Furthermore, we sought to correlate the presence of joint line fullness with type of meniscal tear seen at the time of arthroscopy.

Methods: This was a prospective cohort study, consisting of 100 consecutive patients undergoing knee arthroscopy. Patients who had previous knee surgery or osteophytes on radiographs were excluded. All patients had detailed physical exam documenting the presence of joint line tenderness, joint line fullness and McMurray sign. 61 patients had an MRI preoperatively and therefore it was not a prerequisite to enter the study. MRI was used as the gold standard for determining the presence of a cyst whereas arthroscopy was used as the gold standard for tears. The accuracy, sensitivity, and specificity were calculated and correlated with the type of tear.

Results: Meniscal tears were found in 67 patients at arthroscopy. The accuracy, sensitivity and specificity of joint line fullness (JLF)(73%, 70% and 82% respectively) in detecting meniscal tears was superior to both joint line tenderness (JLT) and McMurray’s test. JLF also obtained the highest positive predictive value of detecting a tear (88%) compare to JLT (77 %)& McMurray’s test (76%). This value was even higher for detecting medial meniscal tear (91%) However, JLF didn’t correlate well with the presence of a cyst with low PPV (29%). Of those patients with joint line fullness on physical exam, (89%) had a horizontal cleavage component at arthroscopy.

Conclusions: Based on the findings of this study, we recommend the routine examination for Joint Line Fullness along with the other common tests to improve the accuracy of clinically diagnosing meniscal tears in particular medial meniscal tear. This may decrease the need for routine MRI for detecting meniscal tears.


J. Dasilva D. Pape P. Fowler R. Giffin

Purpose: Medial Opening Wedge High Tibial Osteotomy (MOWHTO) is a joint preserving procedure of the knee. Currently we understand the anatomical changes occurring in the varus/valgus plane, but our understanding of other anatomical changes are limited. The objective of this study is to determine immediate anatomical changes occurring about the knee following MOWHTO. Our hypothesis is that anatomical changes occur in all planes of motion. More specifically, we hypothesize that posterior tibial slope is increased and patellar height is decreased immediately following the osteotomy.

Methods: This study was prospective in design. Patients with knee OA were evaluated according to strict inclusion and exclusion criteria. Pre-operative clinical assessment, radiographic evaluation, and patient assessment scores were performed. Intraoperatively, patients had radiostereometric analysis (RSA) beads placed in a predetermined pattern. Intraoperative radiographs were taken. The MOWHTO was then performed. A second radiograph was then taken following the osteotomy. The radiographs were analysed using dedicated RSA computer software to determine anatomical changes.

Results: Eleven patients were included in this study. Average age was 50 years. Mean error and condition number were 0.70 and 74 respectively, indicating highly accurate and reliable results. Analysis of the proximal tibia showed an average valgus correction angle of 8.69 degrees. The average osteotomy size was 12.5mm (9–17.5). Posterior tibial slope increased on average by 2.07 degrees (+5.91–−1.56). Analysis of the patella revealed anatomical changes occurred in all planes. However, the only consistent alteration was a decrease in patellar height by an average of 8.16mm (1.79–13.17). Additionally, there was a consistent increase in patellar tendon length by 5.30mm (2.38–7.34).

Conclusions: Using RSA in MOWHTO for the first time, we were able to demonstrate a useful and accurate measurement tool for this procedure. We found there were many immediate anatomical changes following MOWHTO that are inconsistent and not well understood. There were, however, several anatomical changes that remained consistent among all subjects. Patellar height decreased, patellar tendon length increased, and posterior tibial slope demonstrated an average increase.


M. Forsythe L. Geller M. Burman R. Marien E. Lenczner

Purpose: There is increasing evidence that surgical reconstruction of the ACL deficient knee in active patients over the age of 40 is the treatment of choice. The purpose of this study was to compare the objective and subjective outcomes of patients over 40 years old with those of a group of younger patients, all of whom underwent arthroscopic ACL reconstruction with quadruple hamstring autograft.

Methods: Forty patients were enrolled in this retrospective case-control study. Twenty patients over 40 years of age were compared to twenty patients under the age of 40 from our database. Both groups underwent single incision ACL reconstruction using hamstrings autograft and had a minimum of one year followup. Each patient underwent subjective questioning, radiographic and physical examination by 2 independent clinical reviewers. Subjectively, the groups were then compared using the IKDC (International Knee Documentation Committee) subjective questionnaire, Lysholm Knee score, Tegner activity level, and SF-36 general health survey. Objectively, they were compared using the IKDC objective questionnaire and KT-1000 arthrometry.

Results: The average age of the older group was 50 while the younger group age was 28. The two groups were also similar in terms of sex distribution, follow-up, and meniscal injury at reconstruction. Two patients in the over 40 group had postoperative infection. One patient in the under 40 group suffered a deep abrasion secondary to the tourniquet.|We found no significant difference between the 2 groups in regards to IKDC Subjective score, Lysholm Knee Score, Tegner Activity Level, and SF-36 General Health Survey. Also we found no significant difference between the groups objectively with IKDC scores, KT-1000 measurement and complication rates.

Conclusions: These results indicate that ACL reconstruction using hamstrings tendon autograft in patients older than 40 years old is comparable with that of a younger cohort. Age alone should not be used to determine whether surgical management of patients with ACL deficiency is necessary.


M. Tanzer N. Noiseux

Purpose: Acetabular labral tears are most commonly associated with minor or atraumatic events. As a result, it is likely that these tears occur in the presence of an abnormal hip joint. The purpose of this investigation was to establish whether anterior hip impingement, secondary to an anterior femoral offset deficiency from a pistol grip deformity, was a common and poorly recognized cause of acetabular labral tears.

Methods: Sixty-five consecutive patients who underwent a hip arthroscopy and were found to have a labral tear were evaluated. Preoperative hip radiographs were evaluated for abnormalities of the femur and /or acetabulum. The patient’s outcome with respect to resolution to pain and mechanical symptoms was assessed.

Results: All labral tears identified at the time of hip arthroscopy were found to be located anteriorly. A pistol grip deformity of the proximal femur was identified on the preoperative radiographs in 92% of the patients. Labral excision resulted in complete resolution of hip pain in only 8 (28%). With the remaining 72% experiencing mild or moderate pain.

Conclusions: Acetabular labral tears are the result of repetitive femoral-acetabular impingement, from a pistol grip deformity, with eventual tearing of the labrum from a relatively minor trauma. This is analogous to a rotator cuff repair in the shoulder that is secondary to repetitive impingement by the acromium. Decompression or correction of the anterior hip impingement should routinely be considered at the time of labral surgery to provide complete relief of symptoms and diminish the risk of future joint degeneration.


J. Cameron

Purpose: Mal-tracking or dislocation of the patella is often the result of abnormal anatomy. Understanding the abnormal anatomy will clarify the treatment options available. The common anatomical causes of dislocation range from the valgus knee with an elevated ‘Q’ angle to patella alta with a hypo-plastic trochlea, to external tibial torsion, resulting in an excessive ‘Q’ angle. External tibial torsion results in symptoms ranging from patello-femoral pain to subluxation or dislocation. Many patients are asymptomatic prior to an injury. The decision to correct the underlying anatomical abnormality is often a difficult one.

Methods: A retrospective study of 232 rotational HTO’s in 221 patients operated on between 1990 and 2003 was conducted. The pre-operative degree of external tibial torsion and ‘Q’ angle was noted as well as the degree of rotation. The extent, if any patello-femoral pathology, was noted. Assessment was carried out using the HSS scoring system and Lysholm score.|Notation was made of prior surgery to the knee ranging from arthroscopy to patella tendon transfer to patellectomy.

Results: Of the 232 cases 80% were good to excellent with resolution of patello-femoral pain and instability. 10% had residual pain but no instability and 20 cases had to proceed to total knee replacement.|The best results were seen in cases with pain and instability but minimal patello-femoral pathology. Even cases with end-stage patello-femoral osteoarthritis were improved by maximizing the function of the extensor mechanism.

Conclusions: Rotational osteotomy of the proximal tibia for symptoms of patello-femoral instability secondary to significant external tibia torsion provided much better results than isolated patella tendon transfer.


T. Whitehead R. Giffin J. Dasilva P. Fowler D. Bryant

Purpose: To clinically and radiologically evaluate medium term outcome of a patient cohort age 55 years or older at the time of medial opening wedge high tibial osteotomy (MOWHTO).

Methods: Between January 1997 and January 2003, 60 patients (52 males) underwent 66 MOWHTOs. Following a systematic chart review 56 returned for follow up. Outcomes measures were KOOS, LEFS, SF-12, Cincinnati, Tegner scores, a new activity score and physical examination. Routine knee and long leg standing radiographs were compared to pre and early postoperative radiographs.

Results: Thirteen patients were not assessed further, 6 (7 MOWHTOs) had undergone total knee arthroplasty (TKA), 3 had passed away and 4 were lost to follow up. Thus the probability of survival (not converting MOWHTO to TKA) was 0.966 at 3 years, 0.927 at 4 years and 0.878 at 5 years. Quality of life, functional status and general health of the remaining 47 patients (52 HTOs) with a mean age of 62 years (55–75) at the time of surgery were assessed. At a mean follow up of 62 months (26–98), on the author’s activity score, 83% performed at least one high impact activity at moderate to high intensity an average of 4–7 times weekly and 6% did not participate in any sport. Average participation in activities/sports was 3 per person at a participation level of 4.6 (Tegner). The mean Cincinnati score was 75% (SD=23, 14–95%). Mean scores for the KOOS and LEFS were 66% (SD=22,7–99%) and 49 (SD=18, 5–80) respectively. The mean physical component score of the SF-12 was 42 (SD=11, 21.7–60.4) and the mean mental component score, 54 (SD=11, 26–68). Seventy–two percent were fully weight bearing by 3 months. There were 6 revisions performed for a combination of delayed and non-unions.

Conclusions: MOWHTO remains a viable alternative for patients over the age of 55 with knee osteoarthritis and varus malalignment who would otherwise be candidates for arthroplasty and particularly for those wishing to maintain or regain a high level of activity.


R.S.J. Burnett G.J. Dellarocca H. Prather M. Curry W.J. Maloney

Purpose: A prospective investigation to define the syndrome associated with symptomatic labral tears definitively diagnosed at hip arthroscopy.

Methods: 66 consecutive patients that had an arthroscopically documented labral tear were evaluated. Demographics, symptomatology, examination, previous treatments, functional limitations, were assessed prospectively. Onset/duration of symptoms to diagnosis of tears, other diagnoses offered by healthcare providers, and non-labral procedures that patients had undergone for the symptoms were analyzed. Radiographic abnormalities and MR arthrography findings were recorded.

Results: There were 47 female and 19 male patients with a mean age of 38 years. Initial presentation: insidious in 61%, acute injury in 30%, and trauma in 9% hips. Moderate to severe pain occurred in 86% of patients, with groin pain predominating (92%). Fifty three percent had true mechanical symptoms - catching/locking. Walking, pivoting, impact activity aggravated patient symptoms (p< 0.05). Pain was characterized as a combination of dull aching pain with intermittent episodes of sharp pain in 70%(p=0.001). Pain was frequently activity related (p< 0.05) and night pain occurred in 71% of patients (p=0.0006). The majority of patients (98%) with a labral tear reported being active/athletic. On examination 39% patients had a limp, 38% a positive Trendelenburg sign, and 95% a positive impingement sign. The mean time to diagnosis of labral tear from the onset of symptoms was 21 months. A mean of 3.3 healthcare providers were seen prior to a definitive diagnosis. Surgery on another anatomic site was recommended in 11 patients and 4 of these underwent an unsuccessful surgery prior to diagnosis of the labral tear. Radiographic data indicated that 38% of hips had an underlying structural abnormality consistent with mild development dysplasia or anterior femoroacetabular impingement. Preoperative MRA detected 73% of the labral tears.

Conclusions: The clinical presentation of a labral tear may vary, with duration of symptoms often greater than 12 months prior to diagnosis. In young, active patients with a predominant complaint of groin pain with or without a history of trauma, the diagnosis of a labral tear should be suspected, and investigated, as radiographs and history may be nonspecific for this diagnosis.


J. Cameron

Purpose: This study documents the short term follow-up of a group of patients with unicompartmental osteoarthritis with associated collateral ligament laxity. there are currently few studies documenting the indication and results of open wedge high tibial osteotomy.

Methods: A retrospective assessment of 52 cases of open wedge high tibial osteotomy ws carried out of cases performed between 1999–2003. The average follow-up was 4.5 years and the mean age was 38 years. We selected cases with varus alignment and laxity of the medial collateral ligament. Clinical evaluation was carried out using the HSS knee rating score. Clinical laxity pre and post-op was noted, as well as range of motion, quads bulk and swelling. Pre and post-op 3 foot standing x-rays were carried out to assess alignment.|The Puddu open wedge osteotomy was used in all cases with autogenous bone from the iliac crest. Supplemental fixation of the opposite side of the tibia was used if there was any tendency to open.

Results: Open wedge high tibial osteotomy for unicompartmental osteoarthritis with ligament laxity treats both problems. The change in alignment deals with the arthritic symptoms and the opening wedge tensions the collateral ligament.|Of the 52 cases, 44 are good to excellent with 2 non-unions and 3 cases converted to total knee replacement.

Conclusions: Open wedge high tibial osteotomy can deal effectively with selected cases of unicompartmental osteoarthritis with secondary collateral ligament laxity.


M.E Forsythe E. Lenczner E. Nilssen M. Burman R. Marien M. Schweitzer D. Chatha

Purpose: Despite a number of recently published reports on the success of meniscal repair devices, there are no anatomic studies documenting their safety. The purpose of this cadaveric and radiographic study was to anatomically determine the proximity of a common commercially available meniscal repair device to the popliteal neurovascular structures

Methods: Five human cadaveric knees were obtained and procured from the medical school anatomy lab. Two Biostingers (Linvatec) measuring 16mm in length were placed in the posterior one third of the medial meniscus. Each specimen was then placed prone with the knee extended to expose the posterior aspect of the knee. The distance to the neurovascular bundle for each device was then measured with a ruler calibrated to the nearest 0.1cm. To validate our anatomic dissection results, fifty calibrated human knee MRI scans were reviewed by two independent radiologists. The distances measured were from the popliteal artery to the closest point at the lateral meniscus periphery/capsule and the medial meniscus periphery/capsule. The average distance as measured by the two radiologists was calculated as was the average for the entire population of fifty subjects

Results: The mean distance in the cadaveric study was 15.6mm (14.0–18.0mm) between the tip of the repair device needle and the neurovascular bundle. The mean distance on MRI from the popliteal neurovascular bundle to the closest point in the posterior medial meniscus was 20.0 mm (13.0 mm–28.7 mm). The mean distance from the popliteal structures to the posterior lateral meniscus was 9.4 mm (3.2 mm–16.5 mm).

Conclusions: Considering the potential for significant morbidity, we recommend medial meniscal repair should be performed carefully with repair devices. Specifically, one should limit posterior capsule penetrations to less than 15 mm based on these findings.


P. MacDonald K. Rodwan A. Dion

Purpose: To describe functional results following revision ACL reconstruction surgery.

Methods: Patients more than 2 years post-operative from revision ACL surgery by the same surgeon were asked to participate. Patient-based evaluation was determined by ACL Quality of Life(QOL) and Lysholm scores while clinical evaluation was based on IKDC and KT1000 Arthrometer scoring. Surgical information and radiographs were reviewed to identify associated pathologies and surgical technique.

Results: Of 18 eligible patients, 15 were available for review(10 male, 5 female). Average age was 29 years(24–52); average follow-up time was 45.6 months(24–120). Primary ACL reconstructions failed due to surgical technique in 3 patients(20%), while trauma led to failure in 11 patients (73%). One patient failed due to previously unrecognized posterolateral instability and required an osteotomy at revision surgery. During revision surgery, 12 patients received a hamstring graft (10 contralateral, 2 ipsilateral) and 3 patients received a tibial posterior allograft. The most frequent concomitant procedures were a partial medial meniscectomy(3) and chondroplasty (5). Based on latest follow-ups, 7 patients had +2 grade on Lachman’s test, 4 patients had +1 grade and 4 patients had a negative grade. IKDC evaluation classified 3 patients as ‘normal’, 4 as ‘nearly normal’, 3 as ‘abnormal’ and 1 as ‘severely abnormal’. Autograft patients had a mean side-to-side difference of 2.8mm while allograft patients had a mean difference of 4.5 mm. Patient-rated Lysholm scores indicated that 4 patients received a ‘good’ score (84–94), 5 patients a ‘fair’ score (65–83) and 3 patients a ‘poor’ score (0–64). The average QOL score was 58.2%(12–96%). Patients characterized as having poor clinical and patient-rated results also had significant articular lesions identified during surgery.

Conclusions: Results of revision surgery do not appear to be as good as previously published reports of primary reconstructions. Consideration must be given to the status of the articular cartilage, as it appears to be an important factor in determining the overall functional result.


Arild Aamodt Per O. Østbyhaug Jomar Klaksvik P̊l Benum

In the past it has been widely accepted that bone remodelling of the proximal femur after cementless total hip replacement is a result of the altered mechanical environment. Usually, there is are distribution of the stresses in the bone, and subsequently bone mass, from the metaphysis to the proximal part of the diaphysis. The design rationale for some cementless stems is to transmit load to the proximal femur and thus to preserve the bone mineral content in this area. The aim of the present study was to investigate the relationship between postoperative strain shielding of the proximal femur and the bone remodelling after insertion of two different cementless femoral stems.

Experimental study: Twelve pairs of human cadaveric femurs were instrumented with strain gauge rosettes in Gruen zones2 to 7 and the cortical strains were measured during simulation of one leg stance before and after insertion of a custom stem (Unique, SCP) or an anatomic stem (ABG, Stryker-Howmedica).

Clinical study: In a prospective, randomized study including 80 patients, the same types of stems were inserted and the bone mineral density (BMD) was measured during the first two years postoperatively using DEXA. Then, the pattern of remodelling was compared with the gradient of strain shielding in each of the Gruen zones in the frontal plane.

In Gruen zone 7 the relative cortical strain shielding was45% in the femurs with a custom stem and 87% in the femurs with an anatomic stem. In zone 6 the corresponding figures were 2% and 38%, in zone 5 0% and15% and in zone 3 0% and 20%. The DEXA measurements showed a decrease in BMD in zone 7 of 22% and 23% for the two stems, respectively. In the other zones the bone loss was smaller and there was no difference between the stems.

In the proximal zones there was a highly significant difference in strain shielding between femurs receiving a customor an anatomic stem. However, there was no difference in the pattern of bone remodelling. The bone remodelling around these two stems does not seem to mirror the gradient of strain shielding.


R. Aldegheri A. Berizzi

The mean way to fill bone loss, to fix loss of continuity or to correct severe dysplasia in pelvis and in the femur during replacement or revision arthroplasty is the augmentation of the bone stock by mean of bulky or morcellized bone allograft. In order to treat these problems, limiting the possible complications connected to the use of massive bone allograft (bulky or morcellized), and to simplify the surgical procedure we thought to apply in selected cases the platelet’s derived autologous growth factors (AGF), alone or added to Granular Hydroxyapatite.

From january 2001 to june 2003 we have applied-autologous growth factors in 10 cases. The diagnosis was: 5 acetabula in primary THR, 2 acetabular and 1 femoral revision after THR, 1 femoral and 1tibial revision after TKR. We applied the pure AGF in 2 cases and AGF plus Granular Hydroxyapatite in 8 cases. We used emispherical, HA coated, uncemented acetabular cup plus screws (6 cases), uncemented revision cup plus screws (1 case), straight HA coated uncemented femoral stem (1 cases), semi-constrained cemented TKR prosthesis (1 cases). The mean age atoperation was 45 years (21–69). The mean follow-up time was 12,5 months (28–6).

At the last follow up in all the implants there were no signs of loosening; all the graft seems to be well osteo integrated except in 1 case in which we have had fracture and partial reabsorption of the granular HA, without failure of the implant. We haven’t had any inflammatory reaction or signs of intollerance to the graft.

The short term results of our experience seems to be encouraging. If these results will be confirmed in the future the application of AGF should reduce the utilization of massive bone allograft.


P.R. Aldinger H.S. Gill C. Rumolo M. Schneider D.W. Murray S.J. Breusch

Objectives : To determine the change in passive knee kinematics after Oxford Unicompartment Arthoplasty (UKA) (Biomet, Uk); and to compare the change in kinematics post-operatively between image guided and the normal surgical procedure.

Background: In anteromedial osteoarthritis, only the medial compartment of the knee is affected and the collateral ligaments as well as the cruciate mechanism are intact. These preconditions make the knee suitable for UKA. The operative technique of the Oxford UKA theoretically allows the surge on to replicate the natural kinematics of the knee, due to accurate ligament balancing and fully congruent meniscal bearing design of the prosthesis. Our hypothesis was that no difference in tibiofemoral kinematics is observed after UKA. In addition we also hypothesised that the results of the image guided surgery would be the same as the normal surgical procedure.

Design/Methods: To test this hypothesis, we conducted a study using 13 normal human cadaveric knees. For kinematic analysis, the Surgetics TM surgical navigation system (Praxim, France), equipped with custom written tracking software, was used. Reference markers were mounted to the proximal tibia and the distal femur. In a standardized set-up, the knee was positioned in a leg holder and preoperative kinematics of the normal knee was recorded after a para-patellar mini-incision (70–90 mm). Joint kinematics were recorded during passive knee flexion and plotted against flexion angle. Oxford UKA was performed; the standard Phase III instrumentation was used for six knees and the image guided procedure was used for seven knees. The main difference between the standard and image guided procedures was that the inter-medullary rod was not used for the image guided surgery. After the operation postoperative kinematics were recorded using the same measurement protocol. All data were processed using Matlab 6.1 analysis software (The Math Works Inc., MA, USA). Preoperative and postoperative tibiofemoral kinematics were determined and compared. The mechanical axes of the tibia and femur were determined and kinematics represented as functions of knee flexion range. Over both the flexing and extending cycles of the knee the changes in tibiofemoral rotation (& #916;ROT), tibiofemoral ab/adduction (& #916;ABD), and distances between the origins of the mechanical axes (& #916;X, & #916;Y, & #916;Z) were calculated between pre and post-operative states.

Design/Methods: To test this hypothesis, we conducted a study using 13 normal human cadaveric knees. For kinematic analysis, the Surgetics TM surgical navigation system (Praxim, France), equipped with custom written tracking software, was used. Reference markers were mounted to the proximal tibia and the distal femur. In a standardized set-up, the knee was positioned in a leg holder and preoperative kinematics of the normal knee was recorded after a para-patellar mini-incision (70–90 mm). Joint kinematics were recorded during passive knee flexion and plotted against flexion angle. Oxford UKA was performed; the standard Phase III instrumentation was used for six knees and the image guided procedure was used for seven knees. The main difference between the standard and image guided procedures was that the inter-medullary rod was not used for the image guided surgery. After the operation postoperative kinematics were recorded using the same measurement protocol. All data were processed using Matlab 6.1 analysis software (The Math Works Inc., MA, USA). Preoperative and postoperative tibiofemoral kinematics were determined and compared. The mechanical axes of the tibia and femur were determined and kinematics represented as functions of knee flexion range. Over both the flexing and extending cycles of the knee the changes in tibiofemoral rotation (& #916;ROT), tibiofemoral ab/adduction (& #916;ABD), and distances between the origins of the mechanical axes (& #916;X, & #916;Y, & #916;Z) were calculated between pre and post-operative states.

Conclusions: The image guidance system used in our study is a valuable tool for assessing pre- and postoperative knee kinematics. Oxford Unicompartmental Knee Arthroplasty with the Phase III instrumentation in the presence of the cruciate mechanism reproduces the normal kinematics of the knee very accurately. The image guided procedure, performed without the inter-medullary rod, produced similar results to the standard surgery. Image guidance has a great potential for the assessment of pre- and post-replacement kinematics of the knee joint during surgery.


R. Aldegheri A. Berizzi

The durable fixation of an uncemented cup is due to two major factors: the primary stability obtained by the design of the cup and the secondary fixation obtained by the features of the surface of the cup. The CSF (cancellous screws fixation) cup is an emispheric press-fit Hydroxyapatite coated cup that has 5 holes for screws. This permit to insert screws not only in the superior part of the acetabulum but also in the inferior and supero-medial. This theoretically guarantee, also in those cases in which a perfect press-fit was non achievable, a good primary fixation. This primary fixation permit the osteo-conductive function of the HA coating in order to gain secondary e more stable fixation.

From january 1999 to september 2003 we per-formed130 uncemented THR with the CSF cup and the Furlong stem. In the first 100we always insert three screws. In the next 30 only in case of a non perfect-press-fit (10). The mean age was 65 years (14–80). The follow-up varying from 5 years to 6 months. The study is retrospective.

At the last follow-up all implants resulted well integrated.. The formation of new trabecular bone bonding the cup was noted on the X-ray since the third month’s control. There was no complication due to the position of the screws. All patients regained full authonomy.

Primary stability is mandatory in order to obtain a good secondary fixation by osteointegration. The possibility to insert additional screws in a triaxial fashion permit to obtain good primary stability. in all the cases. The screws must be inserted carefully under X-ray in order to avoid complications. Hydroxyapatite, guiding the growth of new trabecular bone bonding the cup to the pelvic bone, guarantee a good secondary fixation.


C Harlan Amstuts Michel J. Le Duff Patricia A. Campbell Frederick J. Dorey Paul E. Beaule’ Tom A. Gruen

The purpose of the present study was to analyze the-clinical and radiographic factors which determine the enduring fixation of metal on metal hybrid surface arthroplasty.

The first 500 hips (in 436 patients) of a consecutive series of over 700 Conserve® plus were reviewed clinically and radiographically. The patients were 48.6 years-old in average, 74% were male and the dominant etiology was idiopathic osteoarthritis (64.6%). All femoral components were cemented but the femoral metaphyseal stem was cemented in 112 hips and press-fit in the remaining 388.

Average follow-up was 4.8 years (range, 2.7 to 7.8 years). Eighteen hips were converted to a THR, 11 of them for aseptic loosening of the femoral component at an average follow-up of 40.5 months. Put in positives mention fx and loose incidence, survor ship details of loose and fx for other At last review, 14 hips presented metaphyseal stem radiolucencies and 16 hips (3.2%) showed a narrowing of the neck of 10% or more at the interface with the femoral component. None of the components with cemented stems showed femoral radiolucencies, neck narrowing, or were revised for aseptic loosening. Cementing the femoral stem significantly (p = 0.013) reduces the chances of early femoral failure or appearance of a metaphyseal stem radiolucency.

Risk factors for loosening or radioluciences included cysts > 1 cm, small femoral head size, female gender, early cases (before improved acrylic fixation including femoral suctioning measures were instituted) and reduced stem shaft angle. Metal-on-metal surface arthroplasty provides a stable, bone conserving, low morbidity and wear resistant prosthetic solution well suited for young and highly active patients.


Amit Amin Anish Sanghrajka Gordon Blunn Tim Briggs Paul Unwin Steve Cannon

The purpose of this study was to evaluate the results of custom-made endoprosthetic reconstruction for both tumourous and non-tumourous conditions around the elbow joint.

28 consecutive cases of endoprosthetic elbow reconstruction, performed between 1989 and 2003, were identified using the unit database. There were 12 males and 16 females, with a mean age 48.9 years, (range 14–84). There were 16 cases of malignant tumour (10 primary, 6 secondary), 3 cases of benign tumour (one each of giant cell tumour, osteoblastoma and pigmented villonodular synovitis) and 10 non-oncological cases, (5 cases of fracture, 3 failed total elbow replacements and 1 infected synostosis). A distal humeral prosthesis was used in 16 patients, distal humeral and proximal ulna in 10 patients, proximal ulna with a humeral component in one patient and proximal radial replacement in one patient. Clinical and radiographic review of all available patients, including a functional assessment with The Toronto Extremity Salvage score (TESS) was undertaken.

28 consecutive cases of endoprosthetic elbow reconstruction, performed between 1989 and 2003, were identified using the unit database. There were 12 males and 16 females, with a mean age 48.9 years, (range 14–84). There were 16 cases of malignant tumour (10 primary, 6 secondary), 3 cases of benign tumour (one each of giant cell tumour, osteoblastoma and pigmented villonodular synovitis) and 10 non-oncological cases, (5 cases of fracture, 3 failed total elbow replacements and 1 infected synostosis). A distal humeral prosthesis was used in 16 patients, distal humeral and proximal ulna in 10 patients, proximal ulna with a humeral component in one patient and proximal radial replacement in one patient. Clinical and radiographic review of all available patients, including a functional assessment with The Toronto Extremity Salvage score (TESS) was undertaken.

Endoprosthetic reconstruction around the elbow joint is effective in a wide range of pathologies, allowing in most cases a reasonable level of function, even following two-stage revision for infection.


Katie S. Alford Richard D. Komistek Douglas A. Dennis

Polyethylene debris can cause patient osteolysis, patient pain and discomfort, and implant revision. Previous fluoroscopic studies have determined the incidence of femoral head separation from the acetabular cup, but clinical significance of this phenomenon has not been established. It has been hypothesized that hip separation may lead to polyethylene wear, while others hypothesize that hip separation may be occurring due to wear. Therefore, the purpose of the study is to conduct an in vivo kinematic analysis to determine if there is a correlation between-femoral head separation and wear and to utilize a mathematical modeling to determine the clinical significance of these variables.

Twenty subjects were strategically selected to participate in this study. Ten subjects were determined to have at least1.0 mm of polyethylene wear, while ten subjects had less than 0.1 mm of polyethylene wear. All 20 patients were asked to perform gait on a treadmill while under fluoroscopic surveillance. The incidence of femoral head separation was determined for each subject. Then, a three-dimensional mathematical model of the hip joint was used to determine bearing surface conditions for each subject.

Fifty-five percent of the subjects evaluated demonstrated femoral head separation. Subjects deemed to have greater than 1.0 mm of wear experienced less separation, on average and overall magnitude than subjects without wear. In this study, only 10% of the subjects tested-demonstrated no wear and no separation. The derived force profiles in this study were greater for both groups, compared with the non-implanted hips, previously evaluated. The forces in the hip joint ranged from 2.0 to 3.0times body weight.

Although it was expected that subjects having more wear would have greater magnitudes of femoral head separation, the opposite was true. Further kinetic analysis determined that the subjects having wear also experienced greater force profiles through gait. Therefore, it is assumed that the subjects having wear may have been-implanted with a tighter socket, thus leading to greater shear forces.


Harlan C. Amstutz Patricia A Campbell Paul E. Beaulé

The purpose of the present study was to identify risk factors for femoral loosening and neck fracture for Conserve+ metal-on-metal hybrid surface atrhroplasty.

The first 500 hips (of over 700 implanted by the senior author) in 436 patients were reviewed. Mean age was 48.6 with 74% of males patients.

16 hips were converted to THR secondary to aseptic failure on the femoral side (11 femoral component loosenings and 5 femoral neck fractures). 14 hips showed radiolucencies around the short metaphyseal stem at last follow-up. A retrieval analysis was performed and analyzed specimens compared with the intra operative photos of the prepared femoral head and the post-op X-rays. The cause of neck fractures is multifactorial. Risk factors include: uncovered reamed bone, leaving the component proud, notching the neck, impingement, osteopenia and cysts, and trauma. Avoidance of technical deficiencies and proper patient selection can eliminate neck fractures. Loosening is also multifactorial. Risk factors for loosening included: cysts > 1 cm, small femoral head size, female gender, early cases (before improved acrylic fixation including femoral suctioning measures were instituted) and reduced stem shaft angle.

Meticulous initial preparation of the femoral bone surfaces, drying with suctioning, and maximizing the fixation area are critical when the fixation area is small, especially with osteopenia and cystic degeneration. These techniques have dramatically diminished the incidence of loosening and radiolucencies. Cementing the femoral metaphyseal stem is a meaningful technical improvement towards the prevention of early femoral failure in patients with risk factors.


Sonny Bal Len Rahaman Scott Miller Aldo Toni

Alumina bearings are an available option in total hip replacements in the United States. Alumina has high strength and low friction and wear as an articulating surface. To determine the potential damage that can occur to alumina surfaces during implantation and dislocation of such bearings, we examined several explanted bearins at a microscopic and microchemical level.

Alumina femoral heads and acetabular liners that-were rejected during surgery because of metal staining, or removed from patients after known times of implantation were examined in the scanning electron microscope to observe the extent of surface degradation. 13 samples were examined. Four samples consisted of a femoral heads that had come in to contact with the metal acetabular shell during implantation, and therefore had metal staining on the surface. Nine femoral heads and a cetabular linerpairs were removed from patients with a history of recurrent dislocations of the prosthetic hip. Of these 5 pairs had grossly visible surface damage, and four did not. These latter four pairs, and the four femoral heads with surface staining were each coated with carbon and observed in a scanning electron microscope fitted with an energy dispersive X-ray analysis (EDAX) attachment for microchemical analysis.

Alumina heads that had inadvertently rubbed against the metalacetabular shell during surgery demonstrated dark metallic staining on the surface. EDAX analysis indicated that the stain had a composition very close to a Ti-6Al-4V alloy. Closer examination in the SEM revealed that the metal stain has a particulate structure, with the size of the particles ranging from sub-micron to several tens of microns. These titanium stains could be removed by a benign chemical etch, leaving no corrosion of the a lumina bearing surface. In contrast, alumina heads and liners removed after various times of implantation show significant surface deterioration. A wide range of features were observed, including uneven wear, cracks, embedded particles, deep groves and pits.

Considerable surface staining of aluminafemoral heads can occur during surgery if they come into contact with metal. This staining occurs due to surface deposition of metal particles which can be easily removed by wiping the surface with a benign etchant. If not removed, the presence of metal reduces the smoothness of the alumina, and may contribute to three-body wear. In contrast, alumina bearings removed from patients with multiple hip dislocations show significant, non-uniform-surface degradation. The observed features, such as embedded particles, cracks, and pits can contribute significantly to surface wear, which was grossly evident in 5 alumina head/liner pairs retrieved for this study. These data suggest that multiple dislocations in total hips with alumina bearings may need earlier surgical intervention because of the surface damage to the bearings, and potential for catastrophic wear.


Giles R. Scuderi Jean Noel Argenson Richard D Komistek Mohamed R. Mahfouz

Previously, fluoroscopy has been used to determine the in vivo kinematics during gait, step-up maneuvers and flexion to nine tydegrees. Recently, TKAs have been designed for deep flexion maneuvers. Therefore, the objective of this study is to determine the in vivo kinematics for subjects implanted with either a fixed or mobile bearing deep flexion TKA from full extension to maximum knee flexion

Three-dimensional femorotibial contact positions for thirty-nine subjects, implanted by two surgeons, were evaluated using fluoroscopy into deep flexion. Nineteen subjects had a fixed bearing PS deep flexion TKA and 20 subjects were implanted with a mobile bearing deep flexion TKA. Both TKA designs have similar design features, including condylar geometries.

Seventeen of nineteen subjects implanted with a fixed bearing deep flexion TKA experienced posterior femoral rollback, while all 20subjects having a mobile bearing deep flexion TKA experienced poster iorfemoral rollback. On average, subjects experienced -5.1 and -8.1 mm of posterior femoral rollback, for the fixed and mobile bearing TKA, respectively. The maximum amount of posterior femoral rollback was -11.8 and -12.4 mm for subjects having a fixed and mobile bearing TKA, respectively. On average, subjects experienced 6.5 and 5.4 degrees of normal axial rotation for a fixed and mobile bearing TKA, respectively. The average amount of weight-bearing range of motion was 116 and 125 degrees for a fixed and mobile bearing TKA, respectively. Also, subjects having both TKA types evaluated in this study experienced excellent patellofemoral kinematics

This is the first study to evaluate femorotibial and patellofemoral knee kinematics into deep flexion for a fixed and mobile bearing TKA, designed for deep flex-ion activities. Both groups in this study experienced, on average and subject-to-subject comparison, excellent kinematic patterns. Also, both TKA types evaluated in this study achieved excellent weight-bearing range-of-motion, supporting the design goal for these TKA.


Harlan C. Amstutz John Antoniades Michel J. Le Duff Paul E. Beaulé

Obtaining fixation in DDH with Surface arthroplasty (SA) with a two part polyethylene (PE ) socket was technically challenging. Although dislocation was rare there was a high loosening rate secondary to polyethylene wear. The purpose of this study was to evaluate the results of Conserve Plus metal-on-metal SA in Crowe class I and II Developmental Dysplasia of the Hip patients.

54 patients (59 hips), 72% females, average age43.7 years (15 to 63.8) met these inclusion creteria with 2 years of follow-up minimum. Seven hips were Crowe type II and fifty-two were type I.

Harlan C. Amstutz, John Antoniades, Michel J. Le Duff, Paul E. Beaulé

The results of MMSA are much improved over those of prior generations of SA and socket fixation is stable even in Crowe type II with the porous coated acetabular components without adjuvant fixation despite incomplete acetabular coverage of the socket. The hips have-been stable even with important range of motion. Recent short term failure and radiolucencies have been eliminated by improved technique despite a high incidence of femoral cysts and reduced area of fixation.


V. Shim I. Anderson M. Rossaak R. Streicher R. Pitto

In recent years, some attempts have been made to develop a method that generates finite element (FE) models of the femur and pelvis using CT. However, due to the complex bone geometry, most of these methods require an excessive amount of CT radiation dosage. Here we describe a method for generating accurate patient-specific FE models of the total hip using a small number of CT scans in order to reduce radiation exposure.

A previously reported method for autogenerating patient-specific FE models of the femur was extended to include the pelvis. CT osteodensitometry was performed on 3 patients who had hip replacement surgery and patient-specific FE models of the total hip were generated. The pelvis was generated with a new technique that incorporated a mesh morphing method called ‘host mesh fitting’. It used an existing generic mesh and then morphed it to reflect the patient specific geometry. This can be used to morph the whole pelvis, but our patient dataset was limited to the acetabulum. An algorithm was developed that automated all the procedures involved in the fitting process.

Average error between the fitted mesh and patient specific data sets for the femur was less than 1mm. The error for the pelvis was about 2.5mm. This was when a total 18 CT scans with 10mm gap were used – 12 of the femur, and 6 of the pelvis. There was no element distortion and a smooth element surface was achieved.

Previously, we reported a new method for automatically generating a FE model of the femur with as few CT scans as possible. Here we describe a technique that customizes a generic pelvis mesh to patient-specific data sets. Thus we have developed a novel hybrid technique which can generate an accurate FE model of the total hip using significantly less CT scans.

An automated method of generating FE models for the total hip with reduced CT radiation exposure will be a valuable clinical tool for surgeons.


Harlan C. Amstutz Michel J. Le Duff

The purpose of this study was to review our entire primary THR experience using large diameter femoral heads in order to prevent dislocation.

83 hips in 77 patients (average age 61years) had a total hip replacement using femoral heads at least 36 mm in diameter. Average follow-up was 4.4 years (range 1 to 17). 22% of the bearings used were conventional UHMWPE, 25% Metal on Metal (two thirds of which were one-piece sockets), and 53% cross-linked polyethylene.

UCLA hip scores improved significantly (p< 0.001) to 9.4, 8.4, 7.5, and 5.2, for pain, walking, function and activity respectively. All of the hips were stable at last follow-up although 3 hips had to be revised: 2 for instability in the early post-op period for poorly positioned socket and one for acetabular component aseptic loosening, which was rectified by revision surgery. Two out of these 3 hips had an etiology of DDH. The dislocations occurred in hips reconstructed with a head size less of 36mm only and none of the hips that dislocated had to be revised with a constrained acetabular liner.

As the safety of new wear-resistant joint bearings has improved, an increase of femoral head size leads to a lower prevalence of dislocation in THR potentially without adverse wear consequences. However, adequate positioning of the acetabular component remains a key factor in the success of this type of hip arthroplasty. Metal-on-metal, which provides the largest ball size for a given socket diameter, especially with a one-piece socket, best addresses component-to-component impingement by increasing the range of motion. Bone-to-bone impingement risks are also minimized as the travel distance to dislocation is increased by maximizing the head diameter and minimizing the socket shell thickness.


V. Shim I. Anderson M. Rossaak R. Streicher R. Pitto

In recent years, some attempts have been made to develop a method that generates finite element (FE) models of the femur and pelvis using CT. However, due to the complex bone geometry, most of these methods require an excessive amount of CT radiation dosage. Here we describe a method for generating accurate patient-specific FE models of the total hip using a small number of CT scans in order to reduce radiation exposure.

A previously reported method for autogenerating patient-specific FE models of the femur was extended to include the pelvis. CT osteodensitometry was performed on 3 patients who had hip replacement surgery and patient-specific FE models of the total hip were generated. The pelvis was generated with a new technique that incorporated a mesh morphing method called ‘host mesh fitting’. It used an existing generic mesh and then morphed it to reflect the patient specific geometry. This can be used to morph the whole pelvis, but our patient dataset was limited to the acetabulum. An algorithm was developed that automated all the procedures involved in the fitting process.

Average error between the fitted mesh and patient specific data sets for the femur was less than 1mm. The error for the pelvis was about 2.5mm. This was when a total 18 CT scans with 10mm gap were used – 12 of the femur, and 6 of the pelvis. There was no element distortion and a smooth element surface was achieved.

Previously, we reported a new method for automatically generating a FE model of the femur with as few CT scans as possible. Here we describe a technique that customizes a generic pelvis mesh to patient-specific data sets. Thus we have developed a novel hybrid technique which can generate an accurate FE model of the total hip using significantly less CT scans.


Sonny Bal Doug Haltom Matthew Barrett

Primary hip replacement using separate incisions to install the femoral and acetabular components can minimize surgical trauma, and expedite patient recovery. We examined the acute complications in a consecutive series of 54 primary total hip replacements performed with this technique.

The series included all patients undergoing a primary total hip replacement for degenerative arthritis. Un cemented components were implanted in each case; with the first 23 hips done with a proximally coated femoral implant; the next 15 with a fully coated femoral implant and the remaining 16 receiving a proximally coated wedge-shaped implant that relied on mediolateral press fit in the metaphyseal femur. Identical rehabilitation protocols were used in all cases. No particular attempt was made to discharge any patient early from the hospital. Results were reviewed at 3 months after surgery.

Sonny Bal MD, Doug Haltom MD, Matthew Barrett MD

The two-incision hip replacement is a technically demanding procedure. Significant complications can occur with this approach. Attention to several technical details, experience, and choice of implant affected the incidence of complications in our series. These data will be of interest to anyone contemplating adoption of this technique.


Andrea Baldini_ Paolo Aglietti Monica Carfagni Lapo Governi Yari Volpe Pierluigi Cuomo

Static finite-element (FE) analysis has been extensively used to examine polyethylene stresses in Total Knee Arthroplasty (TKA). The aim of this study was to use an explicit-dynamic FE approach with force driven models to simulate both the kinematics and the internal stresses within a single analysis of the Meniscal Bearing Knee (MBK, Zimmer, Warsaw, IN) prosthesis

The MBK is a mobile-bearing prosthesis (rotating and AP-gliding) with complete femorotibial conformity throughout motion owing to spherical femoral condyles. The FE meshes of the MBK were created from data obtained from the manufacturer as Initial Graphics Exchange Specification (IGES) files. Three-dimensional FE models of the original MBK design and of two modified versions (MBK-Flex and MBK-PS) were generated in Hypermesh 5.1 software. The tibial insert was modeled as a flexible body with 82212 noded solid tetrahedral elements (Poisson ratio: 0.46). The femoral and tibial components were modeled as rigid bodies. No abnormal alignment or soft tissue imbalance were assumed. Linear soft tissue constraints (30 N/mm AP and 0.6 N-m/degree rotational displacements) were included. Axial load was 4.9mm medially displaced to achieve amedially-biased (60–40) condylar load allocation. Waveforms to simulate gait, stair-climbing and deep-knee-bending with the FE models were obtained from the proposed International Standards Organization 14243–1 and from literature data.

Peak contact stresses for each activity evaluated were below 11 MPa for both the original and modified MBK versions. Kinematics analysis showed similar amount of displacements (average rotations: 3.7°: average AP-glide: 2.5mm) for the various design during gait. In simulated stair-climbing and deep-knee-bending the PS version showed a more reproducible pattern of posterior rollback in flexion without increasing contact stresses.

Explicit FE analysis is an efficient screening tool before in-vivo or in-vitro testing. It provides a means of testing the effect of variables such as change in prosthetic design, surgical techniques and applied loads on knee forces and kinematics.


M Barink N Verdonschot M De Waal Malefijt A Van Kampen

It is impossible to determine the effect of a single parameter in clinical or in-vitro knee research. There are also parameters which can not or hardly be determined. These disadvantages can be overcome with a model. The objective of this study was to create a dynamic FE model of a human knee joint after TKA which is applicable to a variety of research question.

The knee model consisted of a femur, tibia and patella, collateral ligaments and a PCL, combined with a CKS cruciate retaining total knee prosthesis. The patella was not resurfaced. An axialload of 150 N and a quadriceps-force of 81N was applied. The model was validated by the model prediction of joint laxities at different flexion-angles and the calculation of the knee kinematics during flexion-extension.

The predicted varus-valgus laxity at different flexion angles was in between 0 and 6.3 degrees. Laxity values decreased towards extension and towards 90 degrees of flexion. The AP test at 20, 30 and 90 degrees of flexion showed a anterior laxity of 3.1, 4.3 and 2 mm, respectively. The posterior laxity was 5.7 mm, but could only be determined at 90 degrees. The model predicted reasonable kinematics, which were identical for two consecutive flexion-extension movements.

The model predictions were well in agreement with reported values, which were measured experimentally. Differences could be well explained by ligament structures which were (still) omitted with in the model. This dynamic model, in which ligaments were actually modelled as bands, combined all major structures within the knee joint. It was well able to predict laxities and kinematics and turned out to be very stable, mathematically. With this model we will be able to address effects of prosthetic and surgical parameters on the stability and kinematics of the knee joint.


SA Banks B Ginsel K Mitchell N Verdonschot WA Hodge

Contemporary knee implants use a variety of methods to control tibiofemoral motions. Posterior stabilized implants have a post and cam to force the femur posterior with flexion. Most posterior cruciate retaining designs rely solely on this ligament and symmetric tibial surfaces to control tibiofemoral translations. However, many studies have demonstrated poor control of tibiofemoral motion in PCL retaining knees. One strategy to augmenting PCL function is to provide a gait-congruent lateral articulation providing definitive stability in extension while allowing lateral condylar translation in deep flexion. It is unknown whether this design strategy, essentially substituting for the ACL, allows the PCL to function more normally.

Fifteen knees in ten patients with a fixed-bearing, PCL retaining, lateral pivot arthroplasty were observed during maximum flexion kneeling and lunging using fluoroscopy. The tibial insert provides a fully conforming lateral articulation from 0°–70° flexion, allowing lateral AP translation at greater flexion. Recruited on the basis of combined KSS scores > 180 points, patients averaged 72 years, 27.5 BMI, and 12 months post-op. Shape matching techniques were used to determine the 3D pose of the implant components.

Skeletal flexion during kneeling averaged 134° (117°–156°) with 11° tibial internal rotation. Medial condylar contact was 3mm posterior, and lateral contact was 11 mm posterior to the tibial AP midpoint. Skeletal flexion during lunging averaged 122° (106°–146°) with 11° tibialinternal rotation. Medial condylar contact was 1mm posterior, and lateral condylar contact was 9mm posterior to the tibial AP midpoint.

Knees with lateral pivot arthroplasty exhibited flexion comparable to the best reported results in North American patients. Tibial rotation was statistically greater than has been reported for symmetric posterior stabilized or PCL retaining implants for the same activities. Posterior translation of the condyles with flexion beyond the range of full articular congruity is consistent with relatively normal PCL function.


JV Baré S Dixon DJ Beard HS Gill G McEachen DW Murray

The long-term survival of total knee arthroplasty (TKA) has been well established; however, functional outcome remains inconsistent. More normal postoperative TKA kinematics have been shown to produce better knee function. Improved kinematics can be obtained by using implants with optimised surface geometry. Hence a TKA with an appropriate surface geometryis likely to provide superior long-term functional outcome. The Advance-Medial Pivot TKA (Wright Medical) is a fixed bearing prosthesis with a conforming medial compartment and a non-conforming (flat on flat) lateral compartment. This surface geometry is designed with the intention of replicating the normal knee motion of sliding or pivoting medially and rolling back laterally.

Aim: To investigate the sagittal plane kinematics of Advanced Medial Pivot Knee and compare with those of “flat on flat” fixed bearing TKA and normal knees

18 patients who had undergone primary TKA for osteoarthritis were recruited at an average of 18 months post operation. These patients performed flexion and extension exercises against gravity and a step up exercise. Video fluoroscopy of these activities was used to obtain the patellar tendon angle (PTA). This is a previously validated method for assessing sagittal plane kinematics of a knee joint. The kinematic profile of the Advance Medial Pivot Knee was compared to the profile of 14 normal knees and 30 flat on flat, fixed bearing TKA’s.

The sagittal plane kinematics of the Advance TKA differed from the normal knees. However, similarly to normal knees, a linear relationship was observed between PTA and knee flexion angle throughout knee flexion range. The kinematics of the Medial Pivot Knee were similar to normal when the knee was in a highly flexed position.

Functional plane kinematics of the Advance Medial Pivot TKA appear to meet the design criteria in that a linear relationship between PTA and flexion angle is maintained. Further work is required to establish if these improved sagittal plane kinematics translate into improved functional outcome.


Pal Benum Olav Foss Kristin Haugan

Computer-assisted techniques are developed to optimise the positioning of acetabular cups in total hip replacement. However, ordinary guiding devices are still most commonly used. The aim of this study was to evaluate the accuracy when using a simple mechanical guiding device.

30 patients were operated by an experienced hip surgeon. A lateral position and a lateral approach were used. An un cemented press fit cup (Trilogy AB) was inserted using the guiding device for this type of pros-thesis, aiming 45 degrees abduction and 20 degrees ante-version. Radiological investigations were performed one week and three months postoperatively. Frontal views of the pelvis and of the operated hip were obtained. After scanning the contour of the opening of the acetabular prosthesis was identified and digitised using an edge detecting technique. The axes of the ellipsis of the acetabular opening served for calculation of the version of the cup. A lateral view clarified whether the cup was ante- or retroverted. The abduction related to the teardrop-line was measured on the scanned pelvic radiograph.

One week postoperatively mean abduction was 50 degrees (37–62), SD 5 degrees. Mean anteversion measured on the pelvic view was 9 degrees (2–23), SD 5 degrees, compared to 11 degrees (4–24), SD 5 degrees, on the frontal view of the hip joint 50 per cent of the cups showed a deviation of more than 10 degrees from the aimed anteversion.. At average the anteversion was 2 degrees lower when measured on the pelvic view compared to that measured on the AP-view of the hip. There were no significant differences between the measurements at one week and three months.

The anteversion of uncemented press fit acetabular components tends to be lower than intended when using a simple guiding device. The risk of an unacceptable abduction seems negligible. The inaccuracy in acetabular positioning may be due to inadequate positioning of the pelvis or inaccurate insertion technique.


K Barker SM Isaac I Danial D Beard HS Gill CLM Gibbons CAF Dodd DW Murray

Proprioception protects joints against injurious movements and is critical for joint stability maintenance under dynamic conditions. Knee replacement effect on proprioception in general remains elusive. This study aimed to evaluate the changes in proprioceptive performance after knee replacement; comparing Total (TKA) to Unicompartmental Knee Arthroplasty (UKA).

Thirty-four patients with osteoarthritis were recruited; 15 patients underwent TKA using the AGC prosthesis and 19patients underwent UKA using the Oxford prosthesis. Both cruciate ligaments were preserved in the UKA group, while only the PCL was preserved in TKA patients. Patients’ age was similar in both groups.> Joint Position Sense (JPS) and postural sway were used as measures of proprioception. Both groups were assessed pre- and 6 months post-operatively in both limbs. JPS was measured as the error in actively and passively reproducing five randomly ordered knee flexion angles between 30 and 70°using an isokinetic dynamometer. Postural sway (area and path) was measured during single leg stance using a Balance Performance Monitor. Functional outcome was assessed using the Oxford Knee Score (OKS).

Pre-operatively, no differences in JPS or sway were found between limbs in either group. No differences existed between the two groups. Post-operatively, both groups had significant improvement of JPS in the operated limb (UKA mean4.64°, SD1.44° and TKA mean5.18°, SD1.35°). No changes in JPS were seen in the control side. A significant improvement (P< 0.0001) in sway area and path was found in the UKA group only in both limbs. No significant changes in sway occurred in either limb of TKA patients. The OKS improved from 21.4 to 35.5 for TKA patients and from 23.9 to 38for UKA patients.

Both UKA and TKA improve proprioception as assessed by JPS. However, UKA alone improves postural sway in both limbs. This may impart explain why UKA patients function better than TKA patients


Antonio Berizzi-Roberto Aldegheri

On a theorethical basis a larger head diameter permit ewider range of motion and enhance the stability of the implant, reducing the risk of dislocation but increasing the level of friction and the production of debris. The need for a small head diameter (22 or 28 mm) was thus storically connected to the behaviour of the metal-polyethilene interface and the problem of PE debris. After the introduction of ceramics the production of debris diminished but the technology didn’t permit diameter-wider than 28 – 32 mm. The development of new ceramics with improved mechanical properties permit now to obtain thinner acetabular inserts and thus a larger head diameter, without increases the production of debris.

From september 2003 to jenuary 2004 we have implanted 20 uncemented alumina on alumina THR with an head diameter of 36mm. The diagnosis was: hip fracture (14 cases) and hip osteoarthritis in 6cases. The mean age at operation was 73 years (52–88).. The mean follow-uptime was 5 months (3–8) The study is focused on preliminary observation about early complication.

All the patients at the last follow-up have regained complete authonomy during the normal day life activity We have had only one early dislocation, occurred in the 5th post-op day, with the patient in sitting position. After reduction (under anesthesia) and partial immobilization for3 weeks in hip-spica cast there was not recurrence of the dislocation. No other complications were noted.

One of the major problem regarding theutilization af alumina in hip arthroplasty is an higher risk of dislocation of the implant. The introduction of a new ceramic with improved mechanical properties that permit larger head size should minimize this risk. This fact, associated to the low production of debris of the alumina bearing-surfaces open new prospective in performing THR.


Benjamin E. Bierbaum James D’Antonio William Capello Michael Manley Rahul Deshmukh

A major challenge for total hip arthroplasty is to minimize wear and osteolysis in young, active patients. Alumina ceramic bearings have shown superior wear resistance and lubrication and do not carry the risk of ion release.

In a prospective randomized study (ABC), 514 hips were implanted. All patients (average age, 53 years) received the same press-fit hydroxyapatite coated femoral stem; two thirds (345 hips) received alumina ceramic bearings, and one third (169 hips) received a cobalt-chrome-on-polyethylene bearing. A fourth arm (Trident) was included involving use of a metal-backed acetabular component implanted in 209 patients.

At a mean follow-up of 35.2 months (range, 24–48 months), there was no significant difference in clinical performance between the patient cohorts. The cohort of patients included in the ABC, Trident, and extended access portion of the study represents a population of 2313 patients with no device related failures attributable to the ceramic on ceramic articulation used in these patients

This new experience involves the use of improved ceramic materials and new design considerations that eliminate the risks and complications of past experiences with ceramic implants and provides a safe bearing option for young patients.


L. Fassina L. Visai G. Magenes F. Benazzo

The skeleton is tuned for sensing and responding to mechanical forces: a global bone strain moves the extra-cellular fluid through the lacunocanalicular network of compact bone, so gene expression of osteocytes is mechanically modulated by extra cellular fluid flow shear stress. Several studies showed that shear stress modulates bone cells gene expression: in vitro mechanical stimulation impacts the levels of alkaline phosphatase, cAMP, intracellular calcium, NO, prostaglandin E2, c-fos, COX-2, osteopontin and osteocalcin. Aim of this study is to investigate the effect of shear stress on SAOS-2 human osteoblasts proliferation, bone matrix production and mineralization, using a biostable polyurethane as scaffold and a perfusion bioreactor.

Polyurethane scaffolds with an average porediameter of 624 micron were utilized. Scaffolds were sterilized and placed in to standard well-plates (condition A) and into a bioreactor with forced perfusion at a rate of 3 ml/min (condition B). Human osteosarcoma cell lineSAOS-2 was obtained from the ATCC and cultured in McCoy’s 5A modified medium. A suspension of 7′105 osteoblasts was added onto the top of each scaffold. Medium was changed every 3 days and sampled for osteopontin and-osteocalcin ELISA kits. After 16 days culture DNA and calcium contents were measured, light microscopy and SEM analysis were performed.

In condition B, in comparison to A, we observed 33% higher cells proliferation, 12.6-fold higher osteopontin secretion, 99.6-foldhigher osteocalcin secretion and 8-fold higher calcium deposition. Microscopy observations revealed that in condition A osteoblasts were few with thin discontinuous extracellular matrix; in contrast shear stress induced 3D modeling of cells and matrix organization, so several cells were in multilayer with highly developed matrix and no surfaces were cell free.

Statically cultured osteoblasts showed normal proliferation, but a very low matrix synthesis. Into bioreactor, which provides physiological levels of shear stress, the osteoblasts proliferated and showed increased metabolic activity.


Dr. Jens Boldt Peter Thumler

Malpositioning of prosthetic components in TKA may cause clinical relevant complications. This study focuses on a variety of TKA problems that were related to femoral component internal malrotation.

Inclusion criteria in this study were all TKA seen at one-year follow-up with a moderate or poor clinical outcome using the Knee Society Score. Reduced mobility, pain, and patella problems were most frequent in this group. Infection, trauma, or wound problems were exclusion criteria. Two different mobile bearing knee systems were utilised in one large centre; LCS (DePuy Int, Leeds, UK) and MBK (Zimmer, Warsaw, USA). From more than 200 LCS and 70 MBK prostheses 27 cases entered the study, all of which underwent spiral CT investigation for evaluation of femoral component rotational alignment.

There was an increased incidence of femoral component internal rotation in this group with poor outcome. Mean internal rotation was 4.2 degrees (0 to 8) in relation to the transepicondylar axis.

Evaluation of femoral component rotational alignment in TKA has recently gained increased attention. Particularly internal malrotation does often lead to flexion instability, poor biomechanics, and patellofemoral tracking problems with lateral subluxation. It is also associated with painful and stiff knees as recently reported (AAOS 2002, Dallas, USA). In this study early postoperative complications in TKA were also associated with femoral component internal malrotation. We, therefore, recommend CT evaluation of component alignment in clinically doubtful knees. Cases that present with internal malrotation should be considered for revision surgery with the view to revise the femoral and/or tibial component.


Dr. Jens Boldt Peter Keblish Urs Munzinger

Patellectomized knees often perform poorly with respect to extensor mechanism function. Reconstruction options and literature reports are limited. The purpose of this study was to describe and review bone graft patella reconstruction in TKA.

Material_e_Methods: Since 1990 nine previously patel-lectomized patients underwent cementless Low-Contact-Stress TKA with autologous patella reconstruction. One patient died 5 years post surgery. Mean follow-up was 8.0 years (6 to 12). Autologous bonegraft was taken in five cases from the iliac crest, in two cases from the posterior femoral condyle and in two cases from the opposite patella at time of simultaneous bilateral TKA. Postoperative evaluation included clinical and radiographic analysis and bilateral comparative isokinetic strength measurement at 60 degrees per second (Biodex).

Clinical scores had a mean of 27 points (max: 30) and mean isokinetic extension strength of 71Nm (81 percent) compared with the opposite healthy patella site. One patient with bilateral patellectomy and unilateral patella reconstruction showed a 50 percent increase of strength on the grafted side. Radiographs showed minor signs of neopatella bone resorption, but a maintained leaver arm.

Reconstruction of a neo-patella in TKA with autograft provides marked improvement of isokinetic extensor strength, little evidence of autograft resorption, excellent or good clinical outcome and high patients satisfaction after a mean of 8 years. The results of this study indicate encouraging data for reconstructing a new patella and lever arm in patellectomized knees during primary or revision TKA. Cosmetic improvement in females is another subjective advantage.


Dr. Jens Boldt Peter Keblish Urs Munzinger

The purpose of this prospective and randomized study was to objectively evaluate isokinetic strength, clinical, and radiographical outcome in bilateral TKA using the same prosthesis with and without patella resurfacing.

Bilateral TKA, one with, one without patella resurfacing was performed in 22 osteoarthritic patients, mean age was 68 years using the Low-Contact-Stress prosthesis. Minimum Follow-up was one year. Evaluation included clinical investigation, specific patella scores, radiographic analysis and isokinetic strength measurement of both knee flexion and extension at 60 degrees per second (Biodex). surement at 60 degrees per second (Biodex).

There was no significant clinical score difference, but mean isokinetic strength of knee extension was significantly (p< .0001) stronger in the non-resurfaced patella TKA (40.5 Nm) compared with the resurfaced TKA (38,5 Nm). Flexion was also significantly stronger in the patella non-resurfaced group with 22.4 Nm versus 19.5 Nm in the resurfaced group. Mean lateral deviation was significantly (p< .001) less ideal in the resurfaced group as was postoperative patellofemoral congruent contact (p< .001). However, there was no correlation between lateral patella deviation or congruent contact and iso-kinetic strength.

The results of this study indicate that mean isokinetic strength of both knee flexion and extension was significantly stronger in the non-resurfaced patella TKA. This study provides encouraging data for patella non-resurfacing. However, clinical scores or patient’s preference did not show any difference.


Dr. Jens Boldt Peter Keblish Urs Munzinger

The purpose of this study was to determine whether internal mal-rotation of the femoral component is associated with arthrofibrosis in TKA. Multiple etiological factors have been suggested, but specific causes have not been identified. We hypothesized arthrofibrosis may be triggered by a combination of non-physiological kinematics (femoral component internal rotation) and a tight medial compartment.

From a consecutive cohort of 3058 mobile bearing TKA forty-four (1.4%) cases were diagnosed as having arthrofibrosis, of which thirty-eight (86%) cases could be recruited. Thirty-eight patients with a well functioning TKA served as matched controls. Evaluation included CT investigation to determine femoral component rotation with reference to the transepicondylar axis (TEA).

Results: Femoral components in the AF group were significantly (p< 0.00001) internally mal-rotated by a mean of 4.7 degrees ranging from ten degrees internal rotation (IR) to one degree external rotation (ER). Mean femoral rotational in the control group was parallel (0.3 degrees IR) to the TEA (six degrees IR to four degrees ER). Arthrofibrosis was not associated with age, gender, body-mass-index, or preoperative diagnosis

There is a highly significant association between arthrofibrosis in TKA and internal mal-rotation of the femoral component. On the base of these results it was hypothesized that non-physiological kinematics in TKA with mal-aligned femoral components influence and/or trigger arthrofibrosis in TKA.


A. Croce D. BRIOSCHI B. Grisone

The use of metal-on-metal THA has taken origin from the use of Mc Kee prostheses in our Institute in 1967. In 3rd Division of “Istituto Gaetano Pini” in Milan have been performed more than 1300 implants of these prostheses between 1967 and 1983. The analyses of implant surfaces after removal have demonstrated an almost null debris and good liability regarding implant stability. Even if someone assumed, in the past, the carcinogenic effects induced by metal debris, recent publications showed no statistically significant differences in the incidence of cancer between patients treated with metal-on-metal prostheses and normal population. The very good results in follow-up and the evidence of limited debris of metallic contact surfaces have encouraged us to continue with this experience using large head prostheses with metal-on-metal interface.

We implanted 73 Artek cup in 1997–2000 years, an uncemented pre-assembled cup, fixed by pure press fit. The advantages with this cup derived from his low profile (1/3rd of sphere) and contemporary use of large diameter heads (38 mm), similar to McKee’s model (35–41.5 mm). This design allowed us not only to preserve bone-stock, but even to reduce displacement risk. These advantages were increased by the absence of interposed PE surfaces, which inevitably suffer from time-related degeneration. In the last years we increase the use of hard surface THA, usually performing the implant of pressfit cups with metallic liner and large diameter heads (32 and 36 mm) or ceramic-ceramic interface. We believe in better indication (null-wear) of ceramic-ceramic THA in < 60 years patients (even in older ones high functional requests). Usually > 60 years we implant metal-on metal THA: we think that can guarantee very low debris rates and, if used in association with modular components and large diameter heads, a sensibly increased ROM and lower displacement rate.

We implanted 73 Artek cup in 1997–2000 years, an uncemented pre-assembled cup, fixed by pure pressfit. The advantages with this cup derived from his low profile (1/3rd of sphere) and contemporary use of large diameter heads (38 mm), similar to McKee’s model (35–41.5 mm). This design allowed us not only to preserve bone-stock, but even to reduce displacement risk. These advantages were increased by the absence of interposed PE surfaces, which inevitably suffer from time-related degeneration. In the last years we increase the use of hard surface THA, usually performing the implant of pressfit cups with metallic liner and large diameter heads (32 and 36 mm) or ceramic-ceramic interface. We believe in better indication (null-wear) of ceramic-ceramic THA in < 60 years patients (even in older ones high functional requests). Usually > 60 years we implant metal-on metal THA: we think that can guarantee very low debris rates and, if used in association with modular components and large diameter heads, a sensibly increased ROM and lower displacement rate.

The common use of hard surface THA has to be considered “gold standard” even in the elderly, in a constantly increasing mean-life era with corresponding better quality of life: we believe that is mandatory to offer, even to these patients, a long-lasting and high result hip arthroplasty.


Jens Boldt Peter Thumler Urs Munzinger Peter Keblish

Patella management in total knee arthroplasty remains controversial. Minimizing patella related problems is the main goal in any type of knee arthroplasty. This can be achieved with and without resurfacing. However, patella resurfacing resulted in, at times, catastrophic failures, which increased the popularity of patella non resurfacing, particularly with anatomical femoral groove designs. If patella non resurfacing is to be recommended, clinical outcomes must be equal or better than those of routine patella resurfacing in the specific prosthesis utilized.

From a large cohort of over 6000 TKA five studies were conducted to analyze isokinetic strength, subjective, clinical, and radiographic outcomes as well as histopathological data.

Isokinetic strength, subjective, clinical, and radiographic outcomes favor nonresurfacing in TKA with proper femoral component rotation and conforming patellar groove. Our data indicate that patella subluxation and femoral component malrotation is significantly associated with development of arthrofibrosis.

On the base of our studies we propose specific surgical techniques for optimal patella treatment (patelloplasty) in TKA.


M Bruzzone F Castoldi R Rossi A Marmotti P Rossi

The ABG total hip prosthesis had been studied to prevent any kind of stress shielding and to allow the localization of the loads in the metaphiseal region of the femur. The aim of this study was to analize the effective behaviour of the loads in long-term implants and the possible correlations of those findings with the clinical situation of the patients.

We considered 87 total hip arthroplasty implants executed from 1989 to 1995 and performed by using Anatomique Benoist Girard I uncemented prosthesis. The radiographical findings have been classified observing Engh’s stability criteria according to Gruen’s subdivision of the periprosthetic femoral zones.

The radiographical analysis shows a higher presence of can cellous densification in Gruen’s zones 3 and 5 than the one found in zones 2 and 6. Furthermore the presence of a cortical reaction is more relevant in the distal zones.> Radiolucent lines are present in 16% of the cases in zone 4; their percentage in zones 3 and 5 decreases to 7.14% and 10.71%.

Our study shows the certain presence of the stress shielding mechanism in long-term analysis and documents that the main region of late anchorage is the distal, not hydroxyapatite-coated, one.> The comparison with other similar studies shows the decrease of the presence of radiolucent lines in proximal femoral zones with the rise of the follow-up: it can be interpreted as the lesser presence of micro movements of the tip of the prosthesis due to the distalization of the anchorage.


Sharon S. Brown Ian C. Clarke

Zirconia (ZrO2) on Polyethylene (PE) has been used for18 years. However, a majority of clinical results expressed caution, citing surprisingly high wear and osteolysis. The most recent clinical study (Walters 2004) reports 20% higher wear with ZrO2/PE compared to CoCr/PE The PE wear may be the result of increased surface roughness of the ball, due to zirconia transformation from tetragonal to monoclinic phase. Impingement of metal cup backing on zirconia may result in high stress that drives the transformation. Our objective was to simulate the conditions most likely to transform the zirconia ball surface.

In phase one, the rim of a titanium cup was loaded against a zirconia ball with a static load range of 0.01kN to 10kN to simulate impingement-dislocation stress. The ball was cleaned with acid, ultrasonic cleaning, and then observed under SEM. Ball sections were made for XRD study. In phase two, the zirconia balls were pressure stressed in a hip simulator (static load range of 1kN to 4kN) for 600 cycles. Wear studies follow.

In phase one, the rim of a titanium cup was loaded against a zirconia ball with a static load range of 0.01kN to 10kN to simulate impingement-dislocation stress. The ball was cleaned with acid, ultrasonic cleaning, and then observed under SEM. Ball sections were made for XRD study. In phase two, the zirconia balls were pressure stressed in a hip simulator (static load range of 1kN to 4kN) for 600 cycles. Wear studies follow.

Pressure alone does not appear to transform zirconia in the articular surface. The phase two simulator studies include combinations of mechanical stress, environmental aging (autoclave) and lubricants (air, water, serum). The role of the heavy metal transfer may actually protect the zirconia surface from transformation phenomena.


C. Castelli F. Barbieri V. Gotti

To obtain a good outcome in TKA is mandatory to reach a balanced flexion-extension gap. That requires, during surgery, to choose the amount of bone resection and the position of the prosthetic component, mainly the femoral one. These choices are based upon some bone landmarks, but overall could be based upon a proper ligament’s tension, as a preview of ideal kinematics.> About this topic several Authors published in the last decade, but the determination of a value of ligament’s tension still remains a big issue.

So we made an hydraulic knee analyzer (HKA® ) computer integrated and we tested and validated by a cadaveric study. Aims of this study are: to validate the reproducibility, in vivo, of the results of the cadaveric study, and subsequently to evaluate the outcome between two groups of patients undergone to surgery, one by conventional technique and the other by C.A.S. The previous cadaveric study, that was done on ten fresh knees by HKA®, highlighted a relation between ligament’s tension in flexion and in extension, 4 bar vs 6 bar. Twenty patients were operated by C.A.S. (Navitrack® Centerpulse-Zimmer) and HKA®, Twenty patients were operated conventionally, by the same surgeon and utilizing the same prosthesis (Innex® Centerpulse-Zimmer). Preoperative and postoperative study was performed by: long lenghth lower limb x-ray, IKSS score and SF 36 score.

In all the C.A.S. patients it’s got a rectangular and balanced gap, both in flexion and extension, utilizing a 4 bar in flexion and 6 bar in extension, as shown in the cadaveric study.

The comparison between two groups of patients has underlined a better functional outcome in the C.A.S. group.


F Castoldi F Dettoni M Girardo GL Collo R Rossi P Rossi

The failure rate of peritrochanteric fracture implants ranges from 5 to 20 % The aim of the present preliminary study is to evaluate the relationship between Singh index (SI), and failure of internal fixation (cut-out), examining bone mechanical properties from ex-vivo human femoral heads.

The failure rate of peritrochanteric fracture implants ranges from 5 to 20 % The aim of the present preliminary study is to evaluate the relationship between Singh index (SI), and failure of internal fixation (cut-out), examining bone mechanical properties from ex-vivo human femoral heads.

From a methodological point of view we decided to use SI on the basis of previous literature,, our data seems not to be influenced by the use of this methodological approach. > Three load speeds were set: 3, 10, 500 mm/min resulting values of BW/s were compared with Davy and Bergmann ones (obtained with instrumented prosthesis), and test validity was confirmed. In conclusion our data demonstrated that: cut out phenomenon occurs for lower mechanical load in femoral heads of patients with lower SI.


G. Cerulli A. Caraffa P. Antinolfi

The Arthrotic knee is frequently associated with several-pain and loosening of joint function often so important to need a total knee arthroplasty (TKA). Obviously, the aims of a TKA is to obtain no pain and restore a good joint function so to contribute to a good health and a better quality life. To realize ends like these it’s necessary a good selection of the patients first, an adequate preparation for the surgery, correct surgery technique and a specific post-operative rehabilitation until achieving the normal daily activities. In this way clinical biomechanical evaluations can contribute to quantify the achievement of the ends and they can get influence to modulate the “ways” used. Actually the dynamic evaluation more useful and reproducible in the gonartrhosis is the gait analysis.

Patients were selected from a group of subjects suffering from advanced gonartrhosis. Exclusion criteria from the study were: bilateral advanced arthrosis; previous surgery at the lower limbs or other disease that could influence the gait pattern. With these criteria a group of 7 males and 2 females, mean age 67,7 years old, participated at the study (after a known consensus). All subjects had clinical evaluation. For the dynamic analysis The knee society evaluation system for arthroplasty was used. The knee stability was evaluated on the frontal and mediolateralaxis. For evaluating the pain entity we used the V.A.S. score at rest and during gait, before and after taking the analgesic drug. In addition standard X-ray of the knees were evaluated. Gait Analysis was performed at the biomechanical laboratory “Let people move” of Perugia (Italy). Subjects walked on a track of 12,5 m., a 3Dcinematic evaluation was performed using the APAS system (ARIEL Dynamics, USA) with 4 high speed video cameras. 15 auto reflexed markers were applied on both lower limbs. The ground reaction forces during the gait were recorded at 500 Hz with Bertec platform placed at the centre of there cording area. At the subjects was asked to make 10 valid trials (5 for right and 5 for left knee). During gait was evaluated the range of motion of ankle and foot too.

The mean score obtained with the V.A.S. score for the pain during the first section was 3.3 (range 0–7). After taking the analgesic drug and 20 minutes of rest the range was 0–4 at the sequent trial. The results so obtained said that there’s no difference between the range of motion of the knee after taking the drug on the sagittal plane. In addition, no difference neither between the range of motion of the hip and the ankle, on the sagittal plane after the drug.

The mean score obtained with the V.A.S. score for the pain during the first section was 3.3 (range 0–7). After taking the analgesic drug and 20 minutes of rest the range was 0–4 at the sequent trial. The results so obtained said that there’s no difference between the range of motion of the knee after taking the drug on the sagittal plane. In addition, no difference neither between the range of motion of the hip and the ankle, on the sagittal plane after the drug.


A Causero A Beltrame E Paschina E Campailla

The success of total knee replacement depends on several factors, however, surgical technique is particularly important. In fact mistakes in alignment of prosthtic components are common causes of aseptic loosening.

Serious improper alignment (more than 3°) was found out, according to several papers, in about 10% of the implants; this appears not correlated with surgeon’s experience when they use mechanical alignment devices either extra medullary or intra medullary. The development of computer-based systems to achieve correct prosthetic components alignement has the purpose to solve the problems of traditional mechanical alignement systems. At present computer-assisted navigation systems, either they areimage-free or imege-based, are widely empolied while robotic systems are not so commonly used. The Authors describe in this paper the features of the computer-assisted navigation system they at present employ. They moreover emphasize its precision and the reproducibility of the results they can achive. The features of this system (it is based on an image-free navigation method; it allows quantification of the kinematics of the knee; it allows the use of either specially designed cutting bolcks or standar instruments), are an intresting evolution of computer-assisted navigation systems for knee replacement.


R. Chiesa C. Piconi L. Chiusoli L Vandini

Design and materials selection and optimisation are the-factors affecting the performance of the modern TKR. In this study new surface treatments were performed and investigated on CoCrMo with the goal to minimize the wear in a new total knee prosthesis design.

Three surface finishing treatments were considered and applied to cast CoCrMo alloy specimens. A surface polishing treatment performed by mass finishing technique was applied on machined CoCrMo. ACoCrMo coating, obtained by Magnetron Sputtering Physical Vapour Deposition (PVD) technique, was applied on mass finished CoCrMo specimens. Conventional hand polishing performed by silicon carbide papers followed by a final diamond past polishing was considered as reference material. For this study not cross-linked not sterilized UHMWPE was used. Surface morphology obtained by the surface treatments was investigated by SEM, Atomic Force Microscopy, and non contact laser profilometry. The microstructure and micro-hardness of CoCrMo alloy was investigated as well. Wear tests were performed in bovine serum using two screening wear test machines. A final wear test was performed on the new knee pros-thesis design using a knee wear simulator, up to five millions cycles.

CoCrMo PVD coating performed on CoCrMo substrate was capable to eliminate and to fill all the surface defects originated by the casting process of the CoCrMo alloy. Such surface defects could not be eliminated by hand polishing or mass finishing process alone. Vickers micro-hardness was improved by the mass finishing treatment. Although the roughness measured on the mass finished specimens was not the lowest, screening wear test produced for them the best results. Wear simulator test performed on the mass finished knee femoral prostheses sliding against UHMWPE, confirmed very low UHMWPE wear generation.

The mass finishing surface treatment applied to cast CoCrMo alloy specimens and femoral components is capable to polish the surface to the level required by standards. The PVD coating investigated was capable to improve the surface morphology of the alloy and to eliminate all the surface micro defects. Nevertheless, the screening wear tests indicated that the mass finishing treatment generate the lowest wear. The results were confirmed by wear simulator test. This study indicated that the mass finishing surface treatment can be effectively applied for the polishing of the femoral components of knee prosthesis.


Dr Christopher J Wilson Mr Gavin Tait

Aims: In this study we present the outcome for patients with the Rotaglide mobile meniscal knee prosthesis implanted for osteoarthritis. All patients reviewed had this prosthesis implanted as a primary total knee Arthroplasty in Cross house Hospital. The minimum follow up period was 2 years (range 2–8.2).

Patients were assessed clinically by the junior author (CW) and results were standardised using the Hospital for Specialist Surgery (HSS) knee score. Complications were quantified from patient history and examination of the case notes.

Results: Results: Two hundred and two knees were reviewed. The results were then consolidated into groups with a minimum follow up of 2,3,4 and 5 years. The average HSS score was consistent at 91 for all four groups. Complications were also consistent ranging between 10 and 11% in all groups. These are summarised in Tables 1–4 below. The commonest complication was superficial wound infection (4.95%). There were also three deep infections (1.49%) and two revisions due to meniscal failure (0.99%).

These results suggest the Rotaglide total knee Arthroplasty offers safe and effective treatment for osteoarthritis with constantly good clinical results at 2–5 years follow up. The complication rate was also consistent over this period with a low incidence of meniscal failure and deep infection. There have been no failures due to aseptic loosening in this group to date.


N. Confalonieri A. Manzotti K. Motavalli

Nowadays unicompartimental knee replacement (UKR) is a valuable solution for the treatment of knee osteoarthritis. Likewise in selected cases bicompartimental arthritis of the knee in patient younger than sixty still remains a challenge for the orthopaedic surgeon. In this selected cases, the Authors present their experience in performing a mini-invasive bi-unicompartimental knee replacement assisted by a computer navigation system trying to obtain both a correct alignment and a soft tissue balancing.

From January to December 2003, the Authors treated 5 patients (5 knees) with bicompartimental arthritis of the knee. The mean age was 66 and in all the cases there was a arthritis deformity with intact both ACL and PCL without any pain at the femur-patella joint. All the patients had previously undergone to multiple surgical procedures. Orhophilot (4.0 version) navigation system (Aesculap, Tuttlingen, Germany) was used during the surgery to assist prosthesis placement. In all the cases a minimal surgical approach was used (7 to 9 cm skin cut). The patients were assessed using a UKR dedicated outcome score, Italian UKR User’s Group (G.I.U.M.) score, pre-operatively and at the latest follow-up. Pre-operatively the mean GIUM score was 49.1 (range 26–63) At the lastest follow-up the mean GIUM score was 80.2 (range :75–94). The average femoral-tibial angle was 179° (range 177° −181°). All the patients had a good ligament balancing with computer assisted spreader device. All the patients were satisfied and had returned to their previous occupation soon.

According to their previous experience performing bi-unicompartimental prosthesis, the Authors underline how the computer navigation system support ligaments balancing and a correct prostheses alignment. They emphasize this real mini-invasive surgical approach to the cure of the knee arthritis, above all in young patients with post traumatic deformities.


A Manzotti N Confalonieri

Drainage of the surgical wound following major surgical procedures is advocated to avoid haematoma formation. Recently the need for of wound drainage in joint arthroplasty has been questioned. The aim of this prospective randomised study is to determine the benefits of a postoperative closed-suction drain after UKR.

In a prospective randomised trial we evaluated the use of a postoperative closed-suction drain in unicompartmental knee replacement. Seventy-eight patients were divided into two groups: one without a postoperative closed-suction drain (Group A) and one with a drain (Group B). Both groups were matched for age, sex, and pre-operative haemoglobin.

In group A we observed a lower day one post-operative analgesic requirement, smaller knee circumference 3 days postoperatively and less local wound complications. No deep infections occurred in either group during the follow-up period. Drain usage in UKR resulted in no significant advantage in postoperative pain, range of motion, and hospital stay. Post-operative drainage does however increase the cost of the procedure both in labour and equipment expenditure.

We conclude that avoiding postoperative closed-suction drainage in UKR does not influence the final outcome.


V Consoli M Scaglione S Marchetti

Recently it has been increasing the interest of theorthopaedic surgeon about those tools o devices to optimize the results of the replacement surgery. In fact in the last few years the incidence of operations executed in order to treat patients affected by osteoarthritis of the hip with THR is increased, and so the need ness of giving back more long-lived implants.

For this reason new navigation systems, based CT have been developed, which, during surgey, can make the positioning hip and knee prosthesis easier. A pool of international workers (surgeon, engineers, etc.) has developed recently an articular navigation system based on surgery reliefs, using tools gauged and provided with visible markers detected by a computerized system which uses infrared cameras.

For this reason new navigation systems, based CT have been developed, which, during surgey, can make the positioning hip and knee prosthesis easier. A pool of international workers (surgeon, engineers, etc.) has developed recently an articular navigation system based on surgery reliefs, using tools gauged and provided with visible markers detected by a computerized system which uses infrared cameras.

In fact it is not based on CT images of thehip, but on direct data (kept during the operation) analysis, and for this reason the procedure should be more accurate.


Full Access
Antonio Murcia MA Suárez L. Rodríguez G. Acebal A. Murcia

Tantalum is a pure metallic element and is attractive for use in orthopaedic implants because it is one of the most biocompatible metals available for implant fabrication. The potential advantages for the use of porous tantalum in total hip arthroplasty include:

excellent bone and tissue in growth observed histologically;

direct polyethylene intrusion into the metal substrate. This allows the elimination of any potential backside wear in the monoblock cup;

The two-piece design consist of a tantalum shell with screw holes for fixation into the dome of the ilium and posterior column.

A polyethylene liner is cemented into the tantalum shell to eliminates backside motion. In addition, acetabular augments of porous tantalum have been developed for use in restoration of major bone deficiencies. Prospective study on a case serie of 113 THA’s performed by two surgeons in a single institution.

From 2000 to December 2003, 113 hips have undergone arthroplasty using porous tantalum implants consisting of 54 primary hip arthroplasties and 59 revision THA’s. The patients where evaluated clinical and radiographically every 3 month during the first year, and after yearly. Mean patient age was 64,2 years, (range 44–87); with 59% males and 41% females.

No patients died or lost to follow-up. No further surgeries of the involved hip. No radiographic signs of loosening of the acetabular component according to the criteria of Hodgkinson et al. No problems specifically from the use of acetabular augments or extra screws has been noted. Of the revision series, a total of 16 cases have received acetabular augments. Complications included 1 superficial infection, 2 dislocations. No vasculo-nervous complication; and in 2 cases technical difficulties to achieve good fixation due to ethiology of the THA (desarthrodesis). The average Harris hip score improved from 48 to 89 following primary surgery.

Tantalum acetabular components for primary and revision hip surgery have performed well for up to 3 years, and have excellent stability. The two-piece acetabular shell and augments permits the reconstruction of every acetabular bone defect.


A. CROCE D. Brioschi B. Grisone

The constant increase in number of hip revisions during last years has lead to a consequent increase even in fracturative events of the femoral shaft. The treatment of these kind of fractures have to be considered like the one for « pathologic fractures », due to periprosthetic or pericemental osteolysis that occurs in prosthesis’ mobilization, reducing drastically the bone resistance.

We use to divide these fractures primarily in two groups:

Pathologic Fractures, occurring before revision surgery.

Fractures occurring during revision surgery.

Surgical solutions are different, according to fracture’s level and severity. TYPE 1 Fracture limited to trochanteric region TYPE 2 Fracture not exceeding stem length TYPE 3 Fracture line from shaft to distal part of the stem TYPE 4 Fracture line completely under femoral stem TYPE 5 Plurifragmentary fracture

For 1st group, surgical solution is to stabilize trochanteric region with dynamic wiring. For 2nd group, plate with both screws and dynamic wires are indicated. The fractures of last three groups are successfully treated with cementless long stem prosthesese, eventually associated with plate. In summary, the modern techniques of revision surgery associated with systems of cement removal (ultra-sounds and re-cementing procedures) have permitted to decrease the number of periprosthetic fractures. We think that the use of last generation models of cementless modular stem for revision, associated with dynamometric wiring, always allows brilliantly solving this complex surgical problem.


A. CROCE D. Brioschi B. Grisone

Great diffusion of hip prosthetic surgery, in relatively-young patients too, generates as consequence an increase in prosthesis failures associated with limited or massive bone losses, making revision surgery mandatory, even in most advanced degrees of osteolysis.

In best surgery strategy planning are essential: - evaluation of osteolysis degree with standard x-Rays; - evaluation of periprosthetic bone turn-over with scintigraphy (both a specific as they give merely qualitative evaluations of bone remodeling); – quantitative evaluation of periprosthetic bone mineral density with periprosthetic mineralometry (D.E.X.A.). Data obtained with these methods allow more accurate decisions, during the pre-operative phase, regarding the most indicated implant for revision surgery: mid or long-stem, with or without omoplastic transplants, with or without materials promoting bone rehabitation. In any case, the surgeon must have all possible solutions in order to eventually change the operative plan during surgical act.

Following qualitative and quantitative periprosthetic bone evaluations, we use to classify stem and cup mobilizations with Italian Group for Revision (GIR) classification. According to GIR classification, our actual trends in the choice of revision prostheses, in the most advanced degrees of complex mobilizations of stem and cup, are the following: - GIR 3 (Enlargement of the femoral shaft with thinning of cortical bone and loosing of 2 or more walls; loosening and acetabular deformation with losing of one ore more columns and the bottom). In this degree we prefer a long-stem concept straight prosthesis; this prosthesis allows an immediately more stable implant, due to optimized length, in opposition to rotation forces and assuring force transfer in both proximal and distal direction. When osteolysis is wider, it was necessary a strategy change, searching a more distal locking of the implant, according to Wagner’s criteria. The SL Wagner’s prosthesis restores cohesion with the reabsorbed bone surface, generating a relative stability in the immediate post-op period; in the following 2 months, an intense bone apposition, which brings to a progressive filling of bone losses, takes place. For this purpose, it is not indicated, apart from surgical way used, cutting the muscle insertions around the thinned wall. This revision prosthesis is fixed without the use of cement due to the distal blocking, guaranteed by his conical shape; the stem is straight and it is not fit to the natural front-bending of femoral shaft. For this last explained reason, we follow these guidelines, improving our results, using a cementless anatomic modular stem: with this kind of implant design, that preserves cortical bone of femoral shaft from stress shielding, and the extremely wide (XX combination) choice of head and neck components, we are now able to regain as well as possible, the correct offset and center of rotation. For the acetabular loosening, we use to implant oval cups, that naturally fit the acetabular lesion, with or without bone grafts impaction in bone loss areas.- GIR 4 (Massive proximal bone loss all around the shaft; massive peri-acetabular loss). In the past we implanted wide-resection cemented (Muller) or non cemented (Kotz) prosthesis, originally designed for onchologic patients, to treat complete femoral osteolysis. The wide resection uncemented prosthesis, after follow up, supports the Wagner’s theory of distal support, because in spite of an almost complete bone sacrifice, there is an attempt of periprosthetic corticalization by the femoral bone. Since some years we implant even in this cases a modular distally-anatomic revision prosthesis, this type of prosthesis, thanks to his proximal component, provides a relative primary metaphyseal support, that improves global stability of implant. In massive peri-acetabular loss we prefer the use of oval components with peripheral supports and obturatory hook, with bone graft impaction. Only as “extrema ratio” we choose for the implant a McMinn stemmed cup.

From these guidelines, integrated with clinical observation at mid range follow-up, appears clerarly that cementless prosthesis in hip revision surgery, even in most advanced degrees of osteolysis, are really able to guarantee good results for the patient. These patients, previously implanted with hip prosthesis, have intrinsic limitations of hip joint ROM, sometimes associated with muscular impairments; therefore it’s rarely possible to bring back the hip to an optimal degree of function, especially if compared with a normal joint. The goodness of long-term results must be therefore evaluated in relation to patient’s conditions before the operation itself, especially according to bone conditions regarding osteointegration of prosthesis. If follow up of patient is constant, allowing to program with good timing the revision surgery, if necessary, the use of cementless prostheses is a very powerful (nevertheless conservative) instrument for good functional recovery of these patients.


D Crottet T Maeder D Fritschy H Bleuler LP Nolte IP Pappas

Ligament balancing in total knee arthroplasty is believed to have an important influence on the joint stability and prosthesis lifetime. In order to provide quantitative information and assistance during the ligament balancing phase, a device that intra operatively measures knee joint forces and moments has been developed.

Thanks to its small thickness (6mm), the developed device fits after a tibial precut entirely in the tibio-femoral gap with thepatella in its anatomical place. The device measures the tibio-femoral contact force amplitude and location, thus allowing the computation of the net varus-valgus moment, which characterizes the ligamentous balance. Following an accuracy study, the device was validated with a plastic knee joint model equipped with spring-ligaments, which allowed the application of various degrees of ligamentous imbalance. Finally, the device was tested ina cadaver experiment by an experienced surgeon.

During the accuracy study, the absolute force amplitude and location error were respectively 1.4 N and 0.6 mm, which corresponds to a 3%relative error on the active measurement range. The expected linear relationship between the varus-valgus moments and the spring forces in the plastic bone experiment was experimentally verified and the slope corresponded effectively to the lever arm within 12%, which attests the device’s suitability for the purpose of ligament balancing. The cadaver experiment demonstrated the adequacy of the measurement scale (0–500N) as well as the consistency between the acquired data and the surgeon’s perception.

The design and first prototype of the proposed device has been experimentally validated. In a near future, the benefit of using such a device will be examined by a series of cadaver experiments.


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Dante Dallari Marco Fravisini Cesare Stagni Marco Veronesi Armando Giunti

Replacing a fused or ankylosed hip with a prosthesis has several advantages. It reduces the pain in the lumbar-sacral spine and the ipsilateral knee. It gives a better range of movement and leg length is restored.

In this study we present our experience of 50 cases of total hip arthroplasty in fused or ankylosed hips. Aetio-pathogenesis was rhizomelic spondylitis in 35 cases, sequelae of cox it is in 2, posttraumatic in 4, Ankylosis in 6, and fusion in 3. For clinical assessment we used the Merle D’Aubignè score, and for radiographic evaluation we used the Gruen method of area subdivision

Of the 50 prosthesis implanted, 3 were removed due to aseptic loosening. The other were the radiographically stable after an average follow-up of 12 years. Preoperative clinical scores were: pain (2.9), range of motion (2.5), and walking (2.1). At the latest exam the scores were: pain (5.5), motion (4.6), walking (4.5). Preoperative leg shortening was 3.5 cm, whereas at the latest exam it was 0.9 cm. Lumbalgia decreased notably in 62%.

Total hip arthroplasty may have advantages over fusion on one hand, but on the other it is technically more difficult and gives results that are inferior to common indications. It is therefore important to assess patients (time of fusion, age of patient, residual muscular function) preoperatively to obtain good results.


O. Della Gaspera G. Pezzotti F. Variola G. Falcone O. Sbaizero V. De Santis I.C. Clarke L. Proietti

The experimental determination of residual stress fields on the surface of retrieved femoral heads represents a fundamental step in understanding their wear degradation behavior and the tribological mechanisms, which are operative on the femoral joint during its working life time. In this work, the surface of retrieved alumina and zirconia (Al2O3 and ZrO2) femoral heads were investigated by piezo-spectroscopic tecniques based both on photoluminescence and Raman effects. The high spatial resolution of the laser, impinging on the investigated surface (typically about 1 micron of lateral resolution), enabled us estimating patterns and magnitude of residual stress in extremely narrow zones, comparable with the grain size of the material.

Four retrieved ceramic femoral heads were analyzed. Two balls were made of alumina with a typical grain size of from 4 to 10 microns. Both alumina balls were retrieved after only few years from implantation, due to septic and aspetic loosening. The remaining two femoral heads were made of zirconia with a typical grain size of 1 micron. These latter balls were retrieved after 2 and 13 years, respectively (both for loosening problems). With a systematic collection of a large number of data on a microscopic level it was possible to assess the retrieved femoral heads in to to, thus extending the microscopic analysis to the entire joint.

In allumina balls retrieved after short time implantation, a macroscopic stress field was found, which arose from manufacturing, loading history, and the displacements acting on the femoral head during its lifetime. This stress field was completely overcome by a microscopic residual stress field due to local contacts (e.g., local shocks owing to microseparation, impinging and wear contacts). On the other hand, in zirconia femural heads, the major amount of surface deterioration after long-term exposure arose from tetragonal-to-monoclinic transformation in biological environment. These data allowed us to draw interesting considerations about the role of the material microstructure and the peculiar kinematic mechanisms involved with the use of femoral heads made of different materials.

Spectroscopic techniques, which are complementary to in vitro testing procedures and stress analyses based on finite-element methods, can be very useful for improving the design of the femoral head and for optimizing the microstructural characteristics of the ceramic materials employed. Based on this and previous fluorescence and Raman spectroscopic studies, we also propose that a systematic screening of the ceramic implants before implantation can strongly reduce the probability of failure of the implant.


Darryl D. D’Lima Shantanu Patil Nikolai Steklov John Slamin Clifford Colwell

The knee is a complex joint that is difficult to model accurately. Although significant advances have been made in mathematical modeling, these have yet to be validated successfully in vivo. Direct measurement of knee forces should lead to a better understanding of the stresses seen in total knee arthroplasty. An instrumented knee prosthesis was developed to measure forces in vivo after total knee arthroplasty.

An instrumented tibial prosthesis was implanted in an 80-year-old male weighing 66 kg. The prosthesis measured forces at the four corners of the tibial tray. The patient walked approximately 1.6million steps per year before surgery (ankle accelerometer measurements). Knee forces were measured postoperatively during passive and active knee flexion, rehabilitation, rising from a chair, standing, walking, and climbing stairs.

The patient was walking with the help of a walker by postoperative day 3. Peak tibial forces were 1.2 times body weight (BW). By the sixth postoperative day the tibial forces during gait were 1.7 times BW. At six weeks the peak tibial forces during walking had risen to 2.4time BW. Stair climbing increased from 1.9 times BW on day 6 to 3.3 times BW at six weeks.

This represents the first direct in vivo measurement of tibial forces. In vivo tibiofemoral force data will be used to develop better biomechanical knee models and in vitro wear tests and will be used to evaluate the effect of improvements in implant design and bearing surfaces, rehabilitation protocols, and orthotics. This should lead to refining surgical techniques and to enhancing prosthetic designs that will improve function, quality of life, and longevity of total knee arthroplasty. This information is vital given the current trend in the increase of older population groups that are at higher risk for chronic musculoskeletal disorders.


C. PATTYN K.A. De Smet

Postoperative dislocations are known to be a big problem in revision surgery. In literature dislocation rates vary from 4.8% to 33% after previous surgery. In revision surgery, impingement of the implant components, the capsular and soft tissue release, muscular weakness and greater trochanter problems can give additional instability. The reason for revision is important, where instability, infection and tumour cases will lead to a higher percentage of dislocations. The use of big metal heads on polyethylene should be avoided because of the higher volumetric wear. With the new developments of metal-on-metal hip resurfacing and the production of big modular metal heads, the metal-on-metal bearing should guarantee a low-wear result without osteolysis.

Between November 2000 and December 2003 45 patients requiring a revision were treated with a Birmingham Hip Resurfacing cup (MMT, UK) and a big metal-on-metal modular head. All surgery was done with a posterolateral approach. Cup sizes range from 44 to 66 mm, head sizes range from 38 to 58 mm. The head sizes most often used were 58 mm, 54 mm and 50 mm. All patients were prospective followed using the Orthowave software (CRDA France).

In this series of 45 revisions (mean age 56.17) with large modular heads we encountered 2 dislocations, which give us a dislocation rate of 4.4%. One of these dislocations became recurrent and was revised to a full-constrained acetabular component.

Our own dislocation rate in revision hip surgery is 13% (21/159) in the anterolateral approach. Dislocations using the posterolateral approach increased this percentage to 14.8% (21/141). Taking in account that 31% of the causes of revision were infection and recurrent dislocation, this trial demonstrates that large diameter ball heads give beside a better range of movement also a statistically proven reduction in the dislocation rate in revision hip surgery.


Darryl D’Lima Juan Hermida Clifford Colwell

Highly cross linked polyethylenes have been shown to be substantially wear resistant. Typically, crosslinking is achieved by radiation in a low oxygen environment. While the early wear-simulation data is encouraging, concerns remain about the potential for aging and oxidative damage on exposure to oxygen during storage or in the body. This study measured wear rates in highly crosslinked liners that had been exposed to room air for up to 4 years.

Polyethylene liners were divided into four groups: two groups of highly crosslinked liners, XL (freshly opened) and XL-Aged (aged); and two groups of nominally crosslinked liners, N (freshly opened) and N-Aged (aged). The highly crosslinked liners were crosslinked with 9.5 Mrad of warm electron-beam irradiation, treated to a post-cross linking heat treatment to quench free radicals (WIAM), followed by ethylene oxide sterilization. The nominally cross linked liners were sterilized with 2.5 Mrad. The aged liners (XL-Aged and N-Aged) were stored in saline (at 37°C) exposed to room air for 4 years. Three liners from each group were tested in a hip-wear simulator (90% bovine serum) for 5 million cycles. Gravimetric wear measurements were made at 500,000 cycle intervals.

The N and N-Aged groups wore at rates of 14.76 ±3.1 and 15.58 ±1.21 mg/million cycles, respectively. The wear in both XL and XL-Aged groups was not measurable, resulting in weight gains of 2.73±0.5 and 2.17 ±1.1 mg/million cycles, respectively.

WIAM cross linked polyethylene has been reported to generate the least free radicals and has the least potential for oxidative damage. There have been concerns regarding the validity of artificial aging by the high-temperature oxidation. Aging in saline at body temperature while exposed to room air is more representative of in vivo aging. This data supports the results of artificial aging and the long-term durability of WIAM polyethylene.


R D’anchise M Andreata C Balbino

minimally invasive surgery is a concept well known in medicine – In orhotpedic surgery the advent of arthroscopic techniques has given a dramatic change in clinical and surgical approach. Total knee replacement (TKR) is a well established procedure. Good result have been widely documented. Nevertheless wide surgical approach, the post op. pain, the lenght of hospitalization, the rehabilitation program are still long and heavy for the patient.

Minimally invasive procedure consist in a new way of approaching the surgical intervention in TKR, riducing the lenght of the incision, minimizing the soft tissue thrauma, sparing as much as possible the extensor mechanism. This new approach has brougt to a change also in instruments design.

This is a new technique and we don’t have statistically significative data. We rely upon data from authors like Tria and the clinic results of our cases

We can affirm that minimally invasive techniques in TKR permits a lower level of post op. pain and bleeding, shorter lenght of hospital admission time, faster rehabilitation


Darryl D. D’Lima Shantanu Patil Nikolai Steklov Clifford W. Colwell

Complications after total knee arthroplasty (TKR) such as malalignment, instability, subluxation, excessive wear, and loosening have been attributed to poor soft-tissue balance. Traditional approaches for soft-tissue balance involve static measurements in full extension and at 90° flexion. A trial prosthesis instrumented with force transducers was used to measure soft-tissue balance through the entire range of flexion.

The trial prosthesis was instrumented with four force transducers, one at each corner of the tibial tray, and was implanted in four cadaver knees and four patients intra-operatively. Tibial forces were recorded during passive knee flexion after the tibial and femoral bone cuts were made and again after soft-tissue balance was achieved using standard techniques.

In all eight knees measurable imbalance was initially recorded. The differences in forces were a mean of 18 N (range, 6 to 72) mediolateral and a mean of 26 N (range, 13 to 108) anteroposterior. After a routine procedure of soft-tissue balancing, the mean imbalance between the transducers was reduced by 62 % to 87 % (p < 0.05). However, even the knees that appeared perfectly balanced at 0° and 90° flexion, some imbalance occurred [mean 22 N (range, 2 to 34)] at flexion angles other than 0° and 90°.

Soft-tissue balance in TKR remains a complex concept. Even after accurate static balancing was achieved in extension and 90° flexion, dynamic measurements revealed discrepancies in mid flexion, which may explain the wide variation in knee kinematics reported after TKR and in the reported incidences of mid-flexion knee instability. Computer-aided surgical navigation systems can increase the precision and accuracy of component alignment. However, these systems cannot directly address soft-tissue balance and knee tightness. An instrumented tibial prosthesis could be a useful adjunct to enhance the value of these navigation tools.


A. Wang S-S Yau A. Essner M. Manley J. Dumbleton

Remelted highly cross linked UHMWPEs have no detectable free radicals but the mechanical and fatigue properties are reduced because remelting changes the microstructure. Annealed highly cross linked UHMWPEs maintain the microstructure and mechanical properties but contain free radicals. A novel sequential irradiation and annealing process preserves the microstructure while providing enhanced oxidation resistance.

6_B_Material_e_Methods: GUR 1020 polyethylene was sequentially cross linked using three separate gamma radiation doses of 3 Mrad with an annealing step at 130 degrees C after each irradiation (SXL). Density was measured according to ASTM D1505. Crystallinity and thermal properties were determined according to ASTM D3417. Crystallite size/lamellar structure was determined by small angle x-ray scattering. Accelerated aging was carried out in an oxygen bomb under 5 atmospheres of oxygen at 70 degrees C for 14 days.

SXL density was 939.2 kg/cubic meter, identical to that for unirradiated UHMWPE and UHMWPE irradiated in nitrogen to 3 Mrad (gamma-N2). SXL crystallinity was 61.7%, compared to 61.3% and 59.2% for gamma-N2 and virgin UHMWPE, respectively. The long period spacing, crystal thickness and amorphous thickness were 38.2, 23.6 and 14.6 nm respectively for SXL and 38.9, 23.0 and 15.9 for gamma-N2. There was no statistical difference. Accelerated aging resulted in a white band for gamma-N2 with an oxidation index of 1.27. The response of SXL was the same as virgin UHMWPE e.g. crystallinity and density were unchanged with no white band formation and an oxidation index of 0.09.

By avoiding remelting, sequential irradiation and annealing preserves polyethylene microstructure. The sequential process allows more efficient cross linking of free radicals resulting in an oxidation resistance equivalent to that of virgin UHMWPE.


C. Doria P. Lisai C. Fabbriciani

To evaluate the findings of fusion of titanium interbody cages in a sheep lumbar interbody fusion model.

Six sheep underwent lumbar discectomy and fusion at L3-L4 throught transperitoneal approach. An cervical threaded expanding and cylindrical cage packed with bone autografts was placed into intervertebral disc space. The sheeps were killed at 9, 12 and 18 months after surgery. The lumbar spines were excised, trimmed of residual musculature and underwent to plain radiographs and CT scans. The spines were dissected and sectioned using the EXAKT microgrinding device creating parasagittal and coronal sections.

Plain radiographs demonstrated no lucent lines around the implants and no change in disc height. CT scans showed mineralized bone within the cages and bone in growth wit anterior bony bridging outside of the cages. Histologic characterizations indicated the presence of mature lamellar bone with osteonic systems filling the central area of the cage. Bone in growth on the surface of the implant is present near the fenestrations alone. A membrane of fibrous tissue layer is present on the external surface of any cage separating bone from the implant.

Expanding titanium cages have shown mechanical and biological validity to achieve an optimal interbody fusion. Design of the cage showed a decisive role to provide superior endplate-to-endplate contact for unsurpassed strenght and stability and to agree the achievement of the interbody fusion across its fenestrations.


Dufek Pavel

We performed in 1998–2003 in our Orthopedic clinic-nearly 3800 hip arthroplasties, nearly 650 of them S-ROM System (includingrevision surgery). The aim of these paper is to introduce our experience inhip arthroplasty in specific anatomic conditions with Modular S-ROM System.

We examined in a retrospective study 42 patients, operated in 1998/1999, with follow up of 37 months. It was by all of these patients because of specific anatomic conditions (CDH, M. Perthes, Coxaplana, St. p. osteotomy of proximal femur...) not possible or reliable to implant our standard implant and we had implanted Modular S-ROM System.

We had seen intra operatively 3 femur infractions and postoperatively 1 partially is chiadicus palsy after leg lengthening of 3,5cm. The Harris hip score is in all patient improved (preoperatively on average 41,7 pts., postoperatively 85,2 pts.). We habe seen no thigh pain in our group of patients and no loosening of prothesis.

We use, due to our increased positive experience in primary and also revision hip surgery in last years with-Modular S-ROM System (modularity, variability, rotational stability, good osteointegration, no fretting, no thigh pain), this System in specific anatomic conditions and in most cases of revision hip surgery, with good and reliable aerly and mid term results.


A. Wang S-S Yau A. Essner M. Manley J. Dumbleton

Highly cross linked polyethylenes fall into two classes depending on whether annealing or remelting are used in processing. Annealed polyethylenes contain free radicals. Remelted polyethylenes have reduced mechanical properties but no free radicals. Research has now produced a highly cross linked polyethylene (SXL) that combines the advantages of each class.

GUR 1020 polyethylene was sequentially cross linked using three separate gamma radiation doses of 3 Mrad with an annealing step at 130 degrees C after each irradiation (Mrad total). Free radical concentration was measured by electron spin resonance. Accelerated aging was carried out in an oxygen bomb under 5 atmospheres of oxygen at 70 degrees C for 14 days. Tensile properties were determined according to ASTM D638. Wear measurements to 5 million cycles were made on an MTS hip joint simulator at 1 Hz using the Paul load curve with maximum load of 2450 N with alpha fraction bovine calf serum.

Free radical concentration was 14 x 10(14) spins/g for SXL compared to 1550 x 10(14)spins/g for GUR 1020 irradiated to 3 Mrad in nitrogen (gamma-N2). The maximum oxidation index was 0.09 for SXL, 0.09 for unirradiated UHMWPE, and 1.27 for gamma-N2 respectively. Mechanical properties exceeded the ASTM F648 specification and were unchanged by oxidative challenge. Wear rates were 1.35 cubic mm per million cycles for SXL and 46 cubic mm per million cycles for gamma-N2 respectively. Wear particle sizes were similar for the two materials

Sequential irradiation and annealing provides more complete cross linking of free radicals with a consequent reduction in free radical level. SXL has the same resistance to oxidative challenge as unirradiated polyethylene. Mechanical properties exceed the ASTM F648 values. Wear is reduced by 97% compared to that of gamma-N2. Sequential irradiation and annealing preserves the microstructure by avoidance of melting yet minimizes free radicals.


Gregory Y. Lee Ajay Srivastava Pam Pulido Darryl D. D’Lima Clifford W. Colwell

The Omnifit-HA femoral component has shown excellent results in early and mid-term industry sponsored multi-center clinical trials. To validate these results, an independent cohort of patients was followed prospectively for an average of ten years.

The senior author performed 103 consecutiveuncemented primary total hip arthroplasties in 89 patients from July 1991 to December 1996. The components implanted were the Omnifit-HA femoral stem and the Omnifit PSL porous coated acetabular shell. The cohort, with a mean ageat the time of the index procedure of 52 ± 9 years, was comprised of 45females and 58 males. The mean follow up was 10.3 years (range 7.3 – 12.7years). Two independent observers who were not part of the surgical team performed clinical and radiographic evaluations.

The senior author performed 103 consecutiveuncemented primary total hip arthroplasties in 89 patients from July 1991 to December 1996. The components implanted were the Omnifit-HA femoral stem and the Omnifit PSL porous coated acetabular shell. The cohort, with a mean ageat the time of the index procedure of 52 ± 9 years, was comprised of 45females and 58 males. The mean follow up was 10.3 years (range 7.3 – 12.7years). Two independent observers who were not part of the surgical team performed clinical and radiographic evaluations.

The Omnifit-HA femoral component continues to show excellent clinical results as indicated by the multi-center trials. This is the first study to report 10-year follow up by an independent surgeon. Despite the younger mean age, relatively high polyethylene wear, and 10% rate of lysis in the acetabulum, the femoral stem had a 100%survivorship. This supports the theory that proximal circumferential bone in growth affords protection against the migration of wear debris along the femoral stem.


C. Doria P. Lisai

Traditionally, spinal fusion has been the treatment of choice for individuals who have not found pain relief for chronic back pain through conservative treatment. Premature degeneration at adjacent levels of the spine remains one of the more vexing problems facing spinal surgeons when advising relatively young people to consider lumbar fusion surgery. The use of an artificial disc to replace a damaged intervertebral disc that is generating chronic back pain is currently in various phases of development.

Patients with a primary diagnosis of degenerative lumbar disc disease accompained by low back pain and unilateral leg pain, having failed conservative treatment, were considered for the surgical procedure. Twenty-eight patients were randomized into two groups of 15 and 13, respectively, using a random numbar table. Group 1 had two threaded titanium expanding fusion cages inserted posterior with bilateral medial facetectomy. Group 2 had a disc nucleus replacement device inserted posterior with unilateral medial facetectomy and hemilaminectomy

The artificial disc offers several theoretical benefits over the spinal fusion for chronic back pain including potentially enhanced clinical success rates as pain reduction and potential to avoid premature degeneration at adjacent levels of the spine by maintaining normal spinal motion.


Boyd M. Evans Joel T. Outten Douglas A. Dennis Richard D. Komistek

Numerous dynamic studies have evaluated the tibiofemoral contact pressures that follow total knee arthroplasty (TKA), and several static studies utilizing finite elements and pressure sensitive film have evaluated malalignment. The objective of this study was to compute the in vivo dynamic tibiofemoral contact forces for normal alignment and evaluate the change in contact pressure with increasing malalignment of the femoral component.

A three-dimensional computational model of the lower limb during deep flexion was created using Kane’s method of dynamics. A hybrid approach was used to determine the boundary conditions of the model. The motions of a total knee arthroplasty patient were measured using fluoroscopy. The motions of the patient were varied from the normal motions to simulate malalignment of the femoral component. The change in forces with malalignments of up to 10° valgus, 10° varus, 10° internal rotation, and 10° internal rotation were determined.

An increase in the axial tibiofemoral contact force from 2.44 times body weight (BW) to 2.62 BW and a decrease in the quadriceps force from 6.8 to 5.65 BW were observed with varus malalignment. The medial-lateral patellofemoral contact force decreased from 0.95 BW to 0.1 BW with 10° varus positioning of the femur and increased to 2.2 BW with 10° valgus positioning of the femur and a decrease in the patellar ligament forces from 1.70 to 1.63 BW was observed.

Changes in the tibiofemoral and patellofemoral forces of 1–2 BW were observed as the femur was malaligned with respect to the tibia. The most significant of these changes was the medial-lateral patellofemoral contact force. The implications of these findings are that malalignment could result in increased patellar subluxation or increased wear of the polyethylene component. Concerns were raised that this initial subject evaluated may not have had optimum alignment, thus leading to more optimal bearing surface stress conditions with varus malalignment. Future studies will be evaluated for subjects having the joint line restored to conditions for non-implanted knees.


E Fawzy H Pandit P McLardysmith C Dodd D Murray

The purpose of the study: to determine if Patient height-and gender could be used to predict component size With a minimally invasiveapproach for unicompartmental knee replacement.

Material and methods: One hundred x-rays of patients (44 men, 56 women), who had undergone Oxford UKR, were reviewed. The preoperative radiographs were assessed for component size using the standard template. The postoperative x-rays were reviewed to determine-whether the ideal component size had been used or if not what could be the most appropriate. Patient’s height was recorded. The proportion of patients for whom an appropriate size could be selected by either template or height measurements was calculated.

Current templating system accurately predicted the ideal size in 67%. In no case was the size incorrect by more than one size. The following size bands were set according to height. For men: size small in patients less than160 cm, medium less than 170 cm and large less than 180cm. For women: size small in patients less than 165 cm, medium less than 175cm and large less than 185 cm. Height accurately predicted the ideal size in75%. In no case was the assessment of component size incorrect by more than one size.

As the Oxford femoral component is spherical, its size is not critical and it is acceptable to use one size too large or too small. Both height and templating safely predicted an acceptable size in all cases and predicted the ideal size in about 70% > Conclusion: Gender specific height should be used to predict the component size in situations were templating is difficult as in digital x-rays orsuperimposition of the two femoral condyles, and non-standardised x-raymagnification.


C. Eingartner U. Ochs D. Egetemeyr K. Weise C. Eingartner U. Ochs D. Egetemeyr K. Weise C. Eingartner U. Ochs D. Egetemeyr K. Weise

The major challenges in an increasing number of periprosthetic femoral fractures are pre-existent aseptic loosening and femoral bone loss. The successful concept of interlocked intra medullarynailing of multi fragmentary femoral fractures has been applicated onperiprosthetic fractures. A specially designed revision stem combines the features of an intramedullary nail in its distal part and of an uncemented coated prosthesis in the proximal part. This prosthesis has been used successfully in elective revision surgery for aseptic loosening.

Thirty-nine patients with periprosthetic fractures have been operated between 1994 and 2000. Eleven patients were male, the mean age was 70,3 years. The series includes three intra operative fractures of the femoral shaft, in which a revision stem was applied, in the other cases the primary intervention was 10.9 years before the periprosthetic fracture. In 16 cases the shaft was loose prior to the fractures, and in 13 cases the cup was loose as well.> A modified transfemoral approach was done in any case, and long revision stem with distal interlocking was applied. The fragments were adapted to the shaft by cerclage wires, and bone grafting was done in 14 selected cases.

All patients could be followed up. In all but 4 cases the fracture was healed and the revision stem was well osteointegrated. Radiologically, the bone stock of the proximal femur was restored by means of bone grafting and fracture healing in this cases. A recurrent revisionhad to be undertaken in four cases due to lack of osteointegration and subsidence of the stem. In 5 cases the cerclage wires had to be removed due to local irritation. 3 patients had a recurrent trauma and a new periprosthetic fracture distal to the tip of the revision stem; plating had to be performed in this cases.

We conclude that interlocked intramedullary stabilisation of periprosthetic fractures with a revision stem can be a option especially in those challenging cases with pre-existent shaft loosening and bone loss.


CC Castelli R* Ferrari IA Spika RP Pitto

Two-stage exchange technique is currently considered the standard treatment for the infected total knee arthroplasty, but the clinical outcomes associated with the use of articulating bone cementspacers are not well established. Spacer-K is a pre-formed articulatingspacer made of genta-micin-impregnated acrylic cement. The aim of this prospective study was to assess safety and effectiveness of Spacer-K for the management of the infected total knee arthroplasty.

Twenty-two consecutive patients were operated on in two centres. Infection was caused by Coagulase neg. Staphylococcus (11cases), Staphylococcus aureus (3), and others (5). In 3 cases microorganisms were not identified. The mean implantation time of the spacer was 11 weeks(range, 7 to 28 weeks). The rehabilitation program between stages consistedin early range of motion exercises and partial weight-bearing. In one patient removal of the spacer and insertion of a molded cement block with vancomycin was necessary because of insurgence of MRSA.

The mean follow-up of 21 knees after removal of the spacer and insertion of the new prosthesis was 28 months (6 to 45 months). In one patient removal of the spacer and insertion of a molded cement block with vancomycin was necessary following insurgence of methi-cillin-resistant Staphylococcus aureus isolated between stages. No patient had recurrence of infection at latest follow-up. The mean Knee Society functional score during spacer management was rated 76 points (range 55 to 80 points) and was rated 86 points (range, 76 to 90 points) at latest follow-up. Preoperative range of motion improved markedly after removal of the infected pros-thesis and insertion of the spacer. Neither breakage, nor clinically relevant wear of the spacer were detected, and no complications related to the device were observed

The Spacer-K is safe and effective for the management of the infected total knee arthroplasty.


Marco Fravisini Andrea Pellacani Cesare Stagni Marco Veronesi Dante Dallari Armando Giunti

Girdlestone’s arthroplasty is often used to treat septic loosening of hip prostheses. Although this operation provides goodresults with regards to pain and loosening, it causes instability and in the hip and limb shortening that force the patient to use walking aids.

From 1990 to 1999 we treated ten cases of revisionhip arthroplasty after Girdlestone’s arthroplasty. Girdleston e’sarthroplasty was carried out in all cases due to sepsis in the previousimplant. Preoperatively all patients underwent granulocyte-labeledscintigraphy. For clinical evaluation we used the Merle D’Aubignè score.

From 1990 to 1999 we treated ten cases of revisionhip arthroplasty after Girdlestone’s arthroplasty. Girdleston e’sarthroplasty was carried out in all cases due to sepsis in the previousimplant. Preoperatively all patients underwent granulocyte-labeledscintigraphy. For clinical evaluation we used the Merle D’Aubignè score.

Girdlestone’s arthroplasty is very effective for treating septic loosening of hip prostheses, but it causes severe walking impediment. Revision surgery restores limb length and walking. Patients that undergo this treatment should be checked for residual sepsis, which may jeopardize the operation. Currently we are experimenting with spacers with antibiotics and our initial results are promising.


A. Gonzalez Della Valle A. Zoppi M.G.E. Peterson E.A. Salvati

The role of surface finish on the survivorship of cemented stems is controversial. The purpose of this study is to prospectively evaluate the mid-term clinical and radiographic performance of a cohort of patients who underwent total hip replacement with two identical cemented femoral stems differing only in surface finish (VerSys, Zimmer, Warsaw, IN).

64 total hip replacements with a rough stem (Ra: 70–100 micro inches) and 138 total hip replacements with a satin finish stem (Ra: 20–25 micro inches) were followed clinically and radio graphically for 4 to 7 years. All surgeries were performed by one surgeon, during a period of 1 year, utilizing the same surgical approach and technique, ace tabular cup, cement type and cementing technique. The groups had similar demographics, diagnosis, preoperative clinical score, cement mantle quality, alignment, and length of follow up.

The preoperative and postoperative Hospital for Special Surgery Hip Score at last follow up of the patients with a successful operation was not significantly different among the two groups. Five hips in the rough group and none in the satin group developed aseptic loosening and required revision (p=0.0009). The femoral bone-cement interface revealed progressive radiolucent lines or osteolysis in 8 out of 64 rough stems and in 3 out of 138 satin stems (p=0.01). There were progressive radiolucenciesor osteolysis in 44 out of possible 448 Gruen zones in the rough surface group and in 8 out of possible 966 Gruen zones in the satin finish group(p< 0.001).

A rough, textured stem is more likely to fail at intermediate follow-up than a satin surface stem. We recommend that the surface of cemented stems should be satin or polished, with a Ra of less than 20 micro inches.


Alejandro González Della Valle Adam Rana Bridgette Furman Thomas P. Sculco Eduardo A. Salvati

Backside wear is generated at the non-articulating surfaces of modular acetabular cups. We compared the backside wear of retrieved liners from cementless non-modular and modular cups of first and second generation designs. We match paired for time in situ, patient age and weight, 9 retrieved Harris Galante type 1 liners, 9 Harris Galante type 2, 9 Trilogy, and 9 liners from a modern two-piece preassembled cup (Implex). The average time in situ was 2.5 years (1 to 7). The backside was divided in quadrants and each one examined under a 10x binocular loupe and rated with a score from 0 (absence of wear) to 3 (severe backside wear) for a total ranging from 0 to 12. Among 36 quadrants in the HG1 group there were 3 rated 1, 23 rated 2, and 10 rated 3. In the HG2 group, there was 1 quadrant rated 0, 16 rated 1, 14 rated 2, and 5 rated 3. In the Trilogy group, there were 6 quadrants rated 0, 27 rated 1, and 3 rated 2. In the Implex group, there were 15 quadrants rated 0, 21 rated 1. The average total backside wear score was 8.4; 7.3; 3.7; and 2.3 respectively. The HG cups demonstrated more severe backside wear than the Trilogy and Implex (HG1 vs Trilogy and HG1 vs Implex: p< 0.001; HG2 vs Trilogy and HG2 vs Implex: p< 0.02). There was a tendency towards less backside wear in the Implex cup when compared to the Trilogy (p=0.04). The difference between the HG1 and HG2 was not significant. Despite the limitations imposed by the small sample studied, the presence of multiple screw holes in the Harris-Galante retrievals, and sub-optimal matching for sex, height, and varied indication for revision, we detected significant reduction in the backside wear of modern modular and non-modular acetabular cups when compared to first generation modular designs.


Alejandro González Della Valle Adriana Zoppi Margaret Paterson Eduardo A. Salvati

The role of surface finish on the survivorship of cemented stems is controversial. The purpose of this study is to prospectively evaluate the mid-term clinical and radiographic performance of a cohort of patients who underwent total hip replacement with two identical cemented femoral stems differing only in surface finish (VerSys, Zimmer, Warsaw, IN). 64 total hip replacements with a rough stem and 138 total hip replacements with a satin finish stem were followed clinically and radiographically for 4 to 7 years. All surgeries were performed by one surgeon. The groups had similar demographics, diagnosis, length of follow up, cement mantle quality and alignment. The preoperative and postoperative Hospital for Special Surgery Hip Score at last follow up was not significantly different among the two groups. Five hips in the rough group and none in the satin group developed aseptic loosening (p=0.0009). The femoral bone-cement interface revealed progressive radiolucent lines or osteolysis in 8 out of 64 rough stems and in 3 out of 138 satin stems (p=0.01). There were progressive radiolucencies or osteolysis in 44 out of possible 448 Gruen zones in the rough surface group and in 8 out of possible 966 Gruen zones in the satin finish group (p< 0.001). A rough, textured stem is more likely to fail at intermediate follow-up than a satin surface stem. We recommend that the surface of cemented stems should be satin or polished, with a Ra of less than 20 microinches.


A. Gonzalez Della Valle A. Rana B. Furman T.P. Sculco E.A. Salvati

Particles generated at the non articulating surface (backside) of modular acetabular components have been implicated in the development of periprosthetic osteolysis after total hip arthroplasty. Several design changes have been introduced in modern uncemented acetabular cups in an attempt to reduce backside wear, including the use of so called “non-modular cups”. We compared the backside wear of retrieved cementless non-modular cups, with modular cups of first and second generation designs.

Nine retrieved non-modular cups (Implex) were match paired for time in situ, patient age and weight, with 9 retrieved Trilogy cups, 9 Harris-Galante 1, and 9 Harris-Galante 2. The average time in situ was 2.5 years (1 to 7). The backside was divided in quadrants and each rated utilizing a score with a value from 0 (absence of wear) to 3 (severe backside wear) for a total ranging from 0 to 12. The score was validated for intra and inter observer reproducibility.

Among 36 quadrants in the HG1 group there were 3 rated 1, 23 rated 2, and 10 rated 3. In the HG2 group, there was 1 quadrant rated 0, 16 rated 1, 14 rated 2, and 5 rated 3. In the Trilogy group, there were 6 quadrants rated 0, 27 rated 1, and 3 rated 2. In the Implex group, there were 15 quadrants rated 0, 21 rated 1. The average total backside wear score and 95%CI were 8.4 (7.6–9.3); 7.3 (5.5–9.1); 3.7 (3.2–4.1); and 2.3 (1.3–3.4) respectively. The HG1 and HG2 groups demonstrated similar backside wear scores (p=0.3). The HG1 and HG2 designs demonstrated significantly more backside wear than the Trilogy and Implex (p< 0.01). The differences between the Trilogy and the Implex were not significant in this cohort.

A comparison of the “in vivo” backside wear of first generation and modern acetabular cups has not been published to date. Despite the limitations imposed by the small sample studied, the presence of multiple screw holes in the HG retrievals, and sub-optimal matching for sex, height, and varied indication for revision, we detected significant reduction in the backside wear of modern modular and non-modular acetabular cups when compared to first generation modular designs.


A. Gonzalez Della Valle A. Zoppi M.G.E. Peterson E.A. Salvati

First generation uncemented modular cups reproduciblyfixed to bone but they were associated with unacceptable rates of pelvicosteolysis and mechanical failure. Consequently, second generation cups weredeveloped with shells having a limited number of holes or no holes, and improved conformity and locking mechanisms with the liner. The purpose of this study is to report the clinical and radiographic results of a second generation acetabular component for primary total hip arthroplasty.

297 patients who underwent 335 consecutive primary total hip arthroplasties by a single surgeon with the Trilogy modular acetabular component were followed clinically with the Hospital for Special Surgery Hip Scoring System and radiographs, for 4 to 7 years. All cups were implanted with a press-fit technique.

This second generation acetabular cup design achieved predictable fixation and was associated with a low prevalence of revision for loosening and low prevalence of osteolysis at an intermediate follow up.


E.H. Garling W. Barendregt B.L. Kaptein R.G.H.H. Nelissen E.R. Valstar

The most widely accepted method to measure kneekinematics is using external movement registration with the aid of skin-mounted markers. However, a large error component appears due to skin movement relative to the underlying bone. The goal of this study is to use fluoroscopy to quantify skin movement artefacts in patients with a total knee prosthesis during a step-up task.

The most widely accepted method to measure knee kinematics is using external movement registration with the aid of skin-mounted markers. However, a large error component appears due to skin movement relative to the underlying bone. The goal of this study is to use fluoroscopy to quantify skin movement artefacts in patients with a total knee prosthesis during a step-up task.

Translational and rotational errors attributed to soft tissue movement were three times larger for the femur than for the tibia about allaxes. The mean of the absolute rotational differences for the femur were2.6, 3.3 and 1.7 degrees about the X, Y and Z axes respectively. Absolute peak differences for individual subjects were 9.1, 12.9 and 10.5 mm along the X, Y and Z axes respectively.

This is the first study examining the 3D relative motion between surface-mounted and bone-anchored markers without the use of cortical pins anchored to the tibia and/or the femur. The results revealed no regular pattern of soft tissue error between subjects indicating the unlikely success of numerical methods for modeling and removing soft tissue motion artifacts when using standard motion capture methods.


Andrew Graydon Sharif Malek Iain Anderson Rocco Pitto

The correct positioning of implant components in total knee replacement (TKR) is important for a successful long-term outcome. In order to address the problems inherent with conventional alignment methods, several computer-assisted navigation systems (CAS) have been developed. Despite numerous reports of clinical outcomes and system reliability, there is a lack of studies independently evaluating the precision and accuracy of such systems. We report on the design and development of a method and device to evaluate the accuracy of such a computer-assisted navigation system in two situations; 1) Normal or near-normal lower limb mechanical axis, and 2)Simulated femoral and/or tibial extra-articular deformity in either varus/valgus (x), internal/external rotation (y) or flexion/extension (z) planes.

The system assessed was the Ci Knee-CAS navigation system (BrainLab/De Puy). This image-free system requires the registration of specific anatomical points to identify the mechanical axis of the lower limb and therefore provide information on resection level and alignment. In order to precisely measure and accurately reproduce these points we constructed a phantom device along anatomical guidelines, with lockable joints located at the mid-shaft of both femur and tibia. We then identified geometric CAS data; 1) Tibial resection height, and 2) Tibial resection plane, and using specially written software compared this against validated co-ordinate measurements independently obtained by a FaroArm co-ordinate measurement system (FARO Technologies, USA). This enabled data from the navigation system to be directly compared against highly accurate reference measurements.

Accuracy of the system was then assessed with both normal mechanical alignment of the lower limbs and simulated extra-articular deformity.


Melinda Harman Sabine Schmitt Sven Roessing Scott Banks Hanns-Peter Scharf W. Andrew Hodge

There is renewed interest in unicondylar knee replacements (UKR) to meet the increasing demand for less invasive surgical procedures for knee arthroplasty. UKR survivorship exceeds 85% at 10 years, with unconstrained (round-on-flat) designs showing significantly better survivorship than conforming designs. However, round-on-flat articulation shave the potential for poor wear performance and more conforming, mobile-bearing UKR designs have been advocated. The purpose of this study was to evaluate the wear performance of unconstrained UKR polyethylene bearings retrieved at revision knee arthroplasty.

Forty-two UKR (eight designs) were retrieved from 26 female and 16 male patients. Patient age averaged 73+10 (45–89) years and time in-situ averaged 7+4 (1–19) years. Revision reasons included loosening (45%), progressive osteoarthritis (17%), polyethylene wear (14%), instability (5%), and other (19%). Retrospective radiographic review of radiolucent lines and component alignment was completed. Polyethylene damage (severity score, 0–3) and location were measured using optical microscopy and digital image analysis.

81% of the polyethylene inserts had a concave deformation located on the central or posterior third of the articular surface, consistent with damage due to femoral component articulation. Abrasive damage on 29 (69%) inserts was consistent with impingement between the polyethylene and extra-articular cement or bone. There was delamination in the central region of 7 (17%) inserts and on the extreme posterior rim of 3 (7%) inserts. Severity score averaged 2.0+1.2 for abrasion and 0.5+1.0 for delamination. Radiographic component position was correlated with abrasive polyethylene damage.

Despite initial tibiofemoral incongruity and concerns of high contact stress, round-on-flat UKR offers a durable knee arthroplasty. Delamination was infrequent and did not correlate with time in-situ. Rather, polyethylene cold flow increased the contact area during in-vivo function. Rigorous attention to cement technique and component position may reduce the incidence of abrasive damage on UKR polyethylene inserts.


Bernd Heinlein Antonius Rohlmann Georg Bergmann

Instrumented joint prostheses offer the possibility of measuring in vivo loads during activities of daily living. To analyze the complex kinetic situation in the knee joint, a six degree-of-freedom measurement is essential. A tray-in-a-tray tibial baseplate design was developed to measure the resultant forces and moments. The strain distribution within the double wall central stem of the baseplate is measured by means of strain gages. In combination with a pre-operative calibration procedure the forces and moments in the knee joint are subsequently calculated. Unfortunately, the same resultant force may deform the baseplate and subsequently the hollow stem differently, depending on the medial/lateralload distribution and the corresponding lever arms. Thus, the resulting measuring error depending on different implant geometries should be analyzed by means of a finite-element-analysis (FEA).

Different baseplates were designed using a 3D CAD-software (Unigraphics V18, EDS). These models were imported into the finite-element package (Patran 2001r3, MSC; Abaqus, HKS). The tibial baseplate was meshed automatically using tetraeder elements. The refinement of the mesh was controlled by means of mesh seeds for the central hollow stem. A 2 mm thick ring of bone, simulating the cortical shell, supported the tibial base-plate. No trabecular support was modeled to create a worst-case scenario for the implant. Tibiofemoral forces were applied in 3 directions on two contact areas, representing the femoral condyles. In the transversal plane the location of these contact areas was varied, simulating ML-movement and axial rotation. The resultant forces and moments were kept constant.

The proposed design shows an influence of the load transfer mode on the strain distribution in the stem, which is below 2%.

The accuracy of the proposed design is further encouraging the development of an instrumented knee prosthesis.


O. Andres Barrera Hani Haider Peter S. Walker Todd D. Sekundiak Kevin L. Garvin

Most navigation systems for TKR help in the alignment of bulky cutting jigs. We hypothesized that TKR bone cutting could be done free hand without cutting jigs, by navigating a bone saw directly. This would allow smaller incisions, faster recovery time and simpler procedures. The goal of this study was to evaluate the results of free-hand cutting by using in-house developed CAOS software against cuts with traditional jigs.

Experiments were carried out on the five planar cuts of the TKR distal femur, using first the conventional cutting jig and then freehand. The Freehand cutting system navigated and displayed 3D realistic models of the saw, the bone and the planes along which the blade should be orientated. Two experienced arthroplasty surgeons and one engineer performed the experiments on 18 identical synthetic femurs. Each performed one using jigs and five freehand. The experiments were timed and > 50 direct measurements were made for each (cut) bone with a computer digitizer, digital caliper and protractor to assess their quality.

Surgeon’s comments, qualitative and quantitative assessments of the cuts proved the concept’s feasibility and its encouraging potential. The engineer’s time improvement with freehand navigation has implications for easier TKR for trainee surgeons.


JT Hauptfleisch S Glyn-Jones HS Gill P McLardy-Smith DW Murray

The Charnley Elite femoral component was first introduced in 1992 as a new design variant of the original Charnley femoral component (De Puy, Leeds, UK) with modified neck and stem geometry. The original component had undergone few changes in nearly forty years and has excellent long-term results. Early migration of the new stem design was determined by Roentgen Stereophotogrammetric Analysis (RSA)1. Rapid early migration of a component relative to the bone, measured by RSA, is predictive of subsequent aseptic loosening for a number of femoral stems. As there was rapid early migration and rotation of the Charnley Elite stem, we predicted that the long-term results would be poor. An outcome assessment is indicated as stems of this type are still being implanted.

One hundred Charnley Elite stems, implanted in our centre between 1994 and 1997 were included in a prospective, cross-sectional follow-up study. Outcome measures include validated clinical scores (Charnley hip score, Harris hip score and Oxford hip score) and radiological scores (Gruen classification) as well as revision rates over the past 10 years.

The clinical follow-up supports the RSA predictions of early failure of the Charnley Elite femoral stem.


Samih Tarabichi Marwan Hawari

The majority of papers covering MIS total knee describe a surgical approach where the quads tendon is violated. This presentation describes a modified subvastus approach using MIS technique. The results are compared to the regular subvastus approach.

Material and methods: 423 total knee replacements were performed through MIS subvastus approach from November 2002 to February 2004. All cases were performed by the same surgeon. The subvastus approach was modified to allow more quads excursion so the surgery can be performed without dislocating the patella. The data was processed at University of Dundee. The results were compared to the results of 361 cases of standard subvastus approach performed by the same surgeon.

Kanasaki et al. (ISTA 2002) has shown that patients who had subvastus approach were able to regain the ability to do a straight leg raising faster than the standard parapateller incision. The results in this paper confirm the same showing that the ability of patients to rehabilitate is not related only to the size of the incision. Having relatively small incisions help in shorten hospital stay but did not make any difference in blood loss. The subvastus approach the only true quad sparing approach and it can be performed through 10 cm incision safely even in heavy patients with severe knee deformity.


Geoffrey Horne Peter Devane Douglas McInnis

To document the medium term results of the use of a fluted tapered titanium femoral stem in revision total hip arthroplasty.

70 patients undergoing total hip revision using a tapered grit blasted titanium modular stem were reviewed at a mean follow up time of 47 months. No bone graqfts were used. Femoral defects were classified according to Pak and Paprosky and the femoral bone quality was assessed with the Bohm and Bischel system. Clinical function was assessed by the Oxford Hip Score. Radiographic analysis was performed in all cases.

The results of the use of this prosthesis compares favourably with other revision stems. The Oxford Hip Scores compare favourably with the results for revisions recorded in the New Zealand National Joint Register (24.3) Although technically demanding this stem offers a very satisfactory solution for revision of total hips in most circumstances.


D Hollinghurst H Pandit DJ Beard S Ostlere CAF Dodd DW Murray

The indications for unicompartmental knee arthroplasty (UKA) remain controversial; in particular the threshold of disease in the patellofemoral compartment is debated. Whilst some authorities ignore the condition of the patellofemoral joint, others consider pre-existing patellofemoral osteoarthritis (PFOA) a contra-indication to UKA. The aim of this study was to determine the influence of PFOA on the outcome of medial UKA.

This prospective study involved one hundred consecutive patients who had undergone cemented medial Oxford UKA (phase 3), via a minimally invasive approach, at least one year previously. Patients were divided into two groups according to the presence or absence of full thickness cartilage loss (FTCL) on the patella or trochlea at operation. A pre-operative skyline radiograph was graded using the Altman score, by an independent Musculoskeletal Radiologist. Outcome was evaluated with the Knee Society Score (AKSS) and the Oxford Knee Score (OKS, maximum 48). Groups were compared for differences in knee score and Altman grade using a one way ANOVA. Repeat analysis was performed using the presence of anterior knee pain (AKP) as the group defining variable.

There were 28 patients with FTCL, and both groups were well matched for age, gender and activity levels. Analysis showed no significant difference in post operative knee scores between groups with either the presence of FTCL or the presence of AKP pre-operatively as a factor. There was no significant difference in Altman grade between groups.

Intra-operative evidence of PFOA in patients with medial compartment osteoarthritis does not prejudice the outcome of UKA. Even the inclusion of patients with symptomatic AKP, without necessarily having PFOA, does not affect the outcome after UKA. These short results are encouraging, but longer follow up is required.


D. Hollinghurst J. Stoney T. Ward H.S. Gill D.J. Beard C.E. Ackroyd D.W. Murray

Functional outcome after patellofemoral joint replacement (PFA) for osteoarthritis remains inconsistent. It is believed that functional outcome for joint replacement is dependent upon postoperative joint kinematics. Minimal disruption of the native joint, as in PFA, should produce more normal kinematics and improved outcome. No previous studies have examined joint kinematics after isolated PFA.

Aim: To investigate the sagittal plane kinematics of patellofemoral replacement and compare with the normal knee.

Twelve patients who had undergone successful PFA at least two years previously were recruited. Patients performed flexion/extension against gravity, and a step up. Video fluoroscopy of these activities was used to obtain the Patellar Tendon Angle (PTA), the angle between the long axis of the tibia and the patella tendon, as a function of knee flexion. This is a previously validated method of assessing sagittal plane kinematics of a knee joint. The kinematic profile of the PFA joints was compared to the profiles for fourteen normal knees.

Overall, the kinematic plot obtained for PFA reflected similar trends to that for normal knees; but the PTA was slightly but significantly increased throughout the entire range of flexion (two degrees). This is equivalent to an average displacement of the lower pole of the patella of 1.5mm.

Sagittal plane knee kinematics after PFA are much more normal than after TKR and this should give improved functional outcome. The observed increase in PTA through range may result from increased patella thickness or a shallow trochlear groove and may influence patellofemoral contact forces.


Hiraku Hotta Yuri Yabuki Toshie Sasaki Kenji Yamaguchi Shigeru Yanagimoto

Since the autumn of 2003, a computer-assisted system (VectorVision® Hip, version 2.1, Brain LAB, Germany) has been used to perform total hip arthroplasty (THA) operations in our hospital. In the present study, the postoperative acetabular cup position was evaluated using the records of the system and the data measured from postoperative radiographs.

To date, 18 patients have been treated using this-system. We studied the cup inclination and anteversion records in this system recorded in the THA procedures. We also measured the cup inclination and anteversion using postoperative radiographs, according to the method described by Pradhan. The inclination and ante-version were the ‘operative’angles for this system and were the ‘radio graphical’ ones for measuring from the radiographs according to the definition described by Murray.

The initial planning of the acetabular cup position was 45° ‘operative’ inclination and 20° ‘operative’ ante-version. From the system records, the average ‘operative’ inclination was 46.5°± 3.9° and the average ‘operative’ anteversion was 25.5°± 6.0°. The average ‘radio graphical’ inclination measured from the postoperative radiographs was 49.0°± 6.0°, and the average ‘radio graphical’ anteversion was 10.6°± 5.8°.

Between the ‘operative’ angles from this system and the ‘radio graphical’ angles from the postoperative radiographs, the inclination was approximately the same, while the anteversion was different. When the ‘radio graphical’ anteversion was corrected for X-ray beam spreading and then converted to the ‘operative’ anteversion, the resulting ‘operative’ anteversion was 21.1°± 7.8°. And when the ‘operative’ anteversion recorded by this system was corrected for the pelvic tilt, the corrected ‘operative’ anteversion was 22.1°± 6.5°. The average difference between these corrected ‘operative’ anteversion in each case was 5.8°± 3.8°. Especially in 10 of the 18 cases, each difference was within 5°. The accuracy of the cup position using this computer-assisted system was shown by this study.


Hirotsugu Ohashi Hiroyoshi Iwaki Akio Kobayashi Kunio Takaoka Yuji Tanabe

Highly crosslinked polyethylene has been developed to reduce polyethylene wear and to expect the longevity of THA. In daily activity of patients, total hip prostheses repeatedly suffer impact loading. However, the mechanical properties, especially impact load transmission, are not well investigated and the viscoelasticity might influence the loosening of cemented all-polyethylene cup. In this study, the impact load transmission through the complex of polyethylene cup, ceramic ball and metallic femoral stem was investigated.

Impact compressive tests on the complex were performed using Hopkinson pressure bar apparatus. Conventional and highly crosslinked polyethylene cups of three different sizes (40mm, 50mm, 56mm) were compared. The impact load was applied either from the cup or from the stem. The impact load transmission ratio (ILTR) i.e. the ratio of the magnitude of transmitted load to that of incident one was investigated. The loading pulse profiles were theoretically calculated based on the one dimensional elastic wave propagation theory and were compared with experimental results.

The ILTR was independent of the cup size in all experimental conditions. When the impact load was applied from the cup, the ILTR was not different between two types of polyethylene. On the other hand, when the impact load was applied from the stem, the ratio was greater than the previous loading condition, while the ratio of crosslinked polyethylene was significantly lower than that of conventional one (p < 0.05). The theoretically predicted stress pulse profiles were well correlated to the experimental ones.

The lower ILTR in highly cross linked polyethylene is considered to be due to lower stiffness. These mechanical properties increase the deformity of the cup and may cause the loosening of the cup. These results indicated that the ILTR was not different among cup sizes, while the ratio was significantly affected by the loading conditions and the type of polyethylene.


D. Hollinghurst J. Stoney T. Ward H.S. Gill D.J. Beard J.H. Newman D.W. Murray

Medial unicompartmental replacement (UKR) has been shown to have superior functional results to total knee replacement (TKR) in appropriately selected patients, and this has been associated with a resurgence of interest in the procedure. This may relate to evidence showing that the kinematic profile of UKR is similar to the normal knee, in comparison to TKR, which has abnormal kinematics. Concerns remain over the survivorship of UKR and work has suggested the anterior cruciate ligament (ACL) may become dysfunctional over time. Cruciate mechanism dysfunction would produce poor kinematics and instability providing a potential mechanism of failure for the UKR.

Aim: To test the hypothesis that the sagittal plane kinematics (and cruciate mechanism) of a fixed bearing medial UKR deteriorate over time (short to long term).

A cross sectional study was designed in which 24 patients who had undergone successful UKR were recruited and divided into early (2–5 years) and late (> 9 years) groups according to time since surgery. Patients performed flexion/extension against gravity, and a step up. Video fluoroscopy of these activities was used to obtain the Patellar Tendon Angle (PTA), the angle between the long axis of the tibia and the patella tendon, as a function of knee flexion. This is a previously validated method of assessing sagittal plane kinematics of a knee joint.

This work suggests the sagittal plane kinematics of a fixed bearing UKR is maintained in the long term. There is no evidence that the cruciate mechanism has failed at ten years. However, increased tibial bearing conformity from ‘dishing’, and adequate muscle control, cannot be ruled out as possible mechanisms for the satisfactory kinematics observed in the long term for this UKA.


Geoffrey Horne Peter Devane Robert Rowan

The purpose of this paper was to assess the incidence of pelvic osteolysis following the use of a one piece all polyethylene titanium plasma spray backed acetabular component a mean of 9.6 years following implantation.

The radiographs of 86 hips followed for a mean of 9.6 years were reviewed. All had primary total hips using a titanium plasma spray backed all polyethylene uncemented acetabular component. Radiographs were assessed for osteolysis in the three zones described by DeLee and Charnley.

There was no osteolysis seen in any cup in any of the zones. There were no loose cups and no obvious cup migration.

This acetabular component shows superior performance compared with all two piece cups in terms of the development of periacetabular osteolysis. The use of two piece cups should be reconsidered.


S M Isaac J Hauptfleisch E Fawzy C Kellett R Gundle D Murray P McLardy-Smith

Bone stock loss secondary to debris and mechanic alin-stability presents a challenge in revision hip arthroplasty. The aim of our study is to evaluate the clinical outcome of revision hip arthroplasty using the Oxford hip prosthesis combined with impaction allografting.

Between 1999 and 2002, we revised 72 hips in 69 patients using this technique (mean age 65years). Indications were aseptic loosening (56), infection (8), peri-prosthetic fracture (7) and a broken stem (1). The mean time to revision was 8.5 years (1–21years). Patients were assessed clinically and with the Oxford Hip Score (OHS) pre- and post-operatively. Fifty-seven patients also had acetabular revision. Four patients required femoral osteotomy to remove the old prosthesis. We used a mean of 1.8 (1–4) femoral heads per operation.

Patients were mobilised partially weight bearing (8weeks) followed by a gradual return to full loading. Complications included peri-operative femoral fracture (6), infection (6), dislocation (10), DVT (1)and PE (2). The average blood transfusion was 1.8 units (0–9). The OHS improved from 45 (26–58) pre-operatively to 24.3 post-operatively (12–43). No hip has been re-revised for aseptic loosening at a mean follow-up of 32.7months (16–51).

The Oxford hip is a trimodular prosthesis with a polished tapered metaphyseal section that is free to slide and rotate on the stem. The stem is first inserted uncemented into the diaphysis. Bone graft is impacted proximally, with mesh if necessary, and then the proximal wedge is cemented in. The wedge allows for some subsidence in the cement and creates optimal radial force transmission, which is essential for bone-remodelling stimulation and preventing proximal stress shielding. Although this is a short-term experience, we believe that the use of the tri-modular Oxford stem combined with minimal proximal impaction allografting is a reliable method of dealing with difficult revision femoral surgery. The results were comparable with a primary arthroplasty in terms of pain relief and functional results.


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Ishida Toshimasa Nishimura Ikuya Tanino Hiromasa Ito Hiroshi Matsuno Takeo Mitamura Yoshinori

The main reasons of aseptic loosening of the cemented hip stem are three: Bone cement fracture, bone cement debonding, and rupture of cement/bone interface. These are caused by normal/shear stress in the cement mantle. In past studies, there are introduced some optimum design of the hip prosthesis. But all there are not considered enough design objectives. The purpose of this study is to design the optimum stem geometry, which reduces the many stress in the cement mantle at the same time. We reserched the relationship between stem design and cement mantle stresses for this purpose.

The cemented THA proximal femur FEM model was created on CAD and FEM software. Harris Precoat Design was used for stem model. Seven design parameters were defined on this model. Optimization calculation was performed by changing the design parameters. Four objective functions were defined; largest maximum principal stress in the cement mantle, stem/cement interface shear stress, bone/cement interface shear stress, and tensile stress between stem and cement mantle on proximal lateral section. Genetic algorithm was used to change the design parameters. Pareto map was created from results of calculation to reserach the realtionship of each objective functions.

From Pareto maps, we can know that Principal stress and Tensile stress are trade-off relation; the geometry decreasing Princpal stress is increasing Tensile stress. However, stem/cement shear and bone/cement shear are similar. Principal stress and shear stress are also similar.

Multicriteria design optimization of the hip prosthes is was performed based on the HARRIS Precoat stem. In the results, we got many Pareto solutions and relationship between each objective function. And with general methods of development, analysis of trade-off relationship is very useful method for Hip prosthesis development.


Geoffrey Horne Peter Devane Robert Rowan

The management of periprosthetic femoral fractures associated with a total hip arthroplasty remains controversial. The 2003 AAOS Instructional Course Lecture states “Regardless of the method of fixation, the fracture site should be bone grafted with morcellised allograft.” We do not believe bone grafting is necessary to obtain union .

Forty six periprosthetic femoral fractures associated with a total hip were reviewed retrospectively. Follow up included chart and radiographic review, Oxford Hip Score, and SF-12. All fractures were classified acording to the Vancouver classification.

There were 31 type B fractures and 15 type C fractures. All fractures healed. The mean healing time was 15 weeks. No allograft was used. The mean Oxford Hip Score was 26, and the SF-12 33. There were a number of complications, primarily dislocation in the more severe fractures.

The results of this series indicate that bone graft is not necessary to obtain union in periprosthetic femoral fractures. The use of allograft is associated with possible disease and infection transmission and increased cost, risks that we do not believe are justified.


I. Iavicoli G. Falcone M. Alessandrelli S. Salvatori R. Cresti V. De Santis S. Caroli G. Carelli

During the past fifty years metal hip implants have been used in orthopaedics. While these implants are considered biologically inert, several studies indicated that prosthetic implants could release metal ions following wear. The aim of this study was to evaluate serum and urine concentrations of metal ions in patients treated with hybrid surface replacement of the hip.

Co, Cr, Mn, Mo, and Ni in the serum and urine of 14 patients and 19 controls were quantified by Sector Field Inductively Coupled Plasma Mass Spectrometry (SF-ICP-MS). A Spectrometer ELEMENT (Finnigan MAT, Bremen, Germany) was used at the following resolution: 98Mo, 100Mo, (m/D;m = 300); 52Cr, 53Cr, 55Mn, 59Co, 60Ni, (m/D;m = 3000). The internal standard method (In) was applied to correct the random fluctuations of the signal. Indium was added to the sample solutions so as to reach a final concentration of 1 ng mL-1. Limits of Detection were calculated on the basis of the 3=555; criterion for 10 replicate measurements of solutions containing dilute pooled blood serum and dilute pooled urine, and recovery was obtained by quantifying the analytes of interest in spiked serum and urine. Recoveries of the elements ranged between 94.6% (serum Cr) and 118% (urine Ni).

Data support the assumption that the concentrations of Co and Cr (the major components of the alloy) are substantially higher in serum and urine of patients than in those of controls while for the other elements no specific trend could be observed.

Actually there isn’t any explanation on the possible biological consequences related to the increase of the metal ions levels although many hypothesis have been made. Further studies are thus mandatory to clarify this pattern.


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Geoffrey Horne Peter Devane Kathryn Adams

Single stage bilateral total knee replacement is an uncommon and often controversial procedure. Some authors have reported significant complications. We have reviewed our experience with the procedure in 40 cases.

Forty patients undergoing simultaneous bilateral total knee replacement with a minimum follow up of two years were reviewed. Thirty of the patients completed an Oxford Knee score and an EQ-5D. Eight patients were lost to follow up. Two were deceased.

The age at the time of surgery ranged from 25–87 years – mean 68yrs. 8o% were done under general anaesthetic. 50% required blood transfusion in the post operative period, the average volume being 4 units. 50% had physiotherapy following discharge. There were 4 patients with delay in wound healing and 1 patient who had an infection requiring wound debridement. There were no other significant complications. The mean Oxford Knee score was 21.6, the mean score for primary unilateral knee arthroplasty for patients on the National Joint Register is 23.5. The EQ-5D scores were very satisfactory.

This study demonstrates that in our unit this procedure can be performed with minimum complications and the expectation of an excellent outcome.


Ikuya Nishimura Yasuharu Izumisawa Yoshinori Mitamura

To overcome the controversial points of present porous surfaces structure for cementless artificial hip joint, the new porous surface structure was developed. This new porous surface structure is made on base metal directly, therefore it has no interface between base metal and porous seen in the usual porous structure. The new porous surface structure was manufactured by making holes in base metal using laser beam machining. Diameter, pitch and depth of holes were 0.3mm, 1mm and 1mm, respectively. These values were decided referring to other porous structures like bead porous or fiber mesh porous. The aim of this study is to make an investigation into effectiveness of new porous surface structure by animal experiments.

In order to evaluate the bone in growth ability of the new porous surface structure, experiments on animals were carried out. The cylindrical samples those had new porous surface structure were implanted into lateral femora of dogs. At the same time, samples those had usual porous surface structure (bead porous) were implanted into opposite femora as control. The diameter of samples were 4.5mm, and length of samples were 15mm. The implants were retrieved at either 6 or 12 weeks after operations and push out tests were carried out immediately.

New porous surface structure showed high bonding strengths (13–15MPa) equal to the bead porous, and the bone ingrowth ability higher than the usual porous surface structure.

New porous surface structure has bone-in growth ability on an equlity with usual porous surface structure. The structural merits of the direct porous is it has no boundary surface between base metal and porous structure. The unification of the materials which has different function will solve the issue of the stability between porous structure and base metal interface.


J. Miyagi M. Suzuki N. Funabashi T. Tsuneizumi T. Tsukeoka N. Yanagawa H. Moriya

Combined multi-detector row CT (MD-CT) pulmonary angiography (CTPA) and lower extremity venography (CTV) is an effective method for detection of pulmonary embolism (PE) and deep vein thrombosis (DVT). However, the usefulness of this method after total knee arthroplasty (TKA) has not been reported. The aim of this study is to evaluate our screening program in the management of thromboembolism.

Over a 1.5-year period, 30 patients with primary TKA were examined using an MD-CT (Lightspeed ultra 16.GE) before and 7th day after operation. 25 seconds after intravenous administration of 320ml of contrast material, CTPA was performed with 1.25-mm collimation and CTV from the iliac crest to the ankles was done with 0.625-mm collimation 165 seconds after contrastmaterial injection. The mean age of the patients was 72.2 (53–80). Twenty patients had osteoarthritis, nine had rheumatoid arthritis and one osteonecrosis. All patients were received 4 weeks of warfarin therapy and prophylaxis.

PE was observed in A1+2, A3, A6, A9, A10 area. PE was most frequently detected in A10 area of pulmonary artery (6/30). While, DVT was detected in only popliteal vein (6/30). The incidence of PE was 30% (9/30)and DVT 20% (6/30). Both PE and DVT were observed in 3 patients, the incidence was 10% (3/30).

Combined CTPA and CTV is a safe and accurate diagnotic method for detecting PE and DVT after TKA, and the ability to directly visualize emboli of this system is effective as therapeutic tool.


Jean-Yves JENNY Cyril BOERI

Introduction: The accuracy of implantation is an accepted prognostic factor for the long term survival of a unicompartmental knee prosthesis (UKP). Minimal invasive technique is recommended for faster post-operative recovery. We developed an adaptation of a non image based system for either conventional or minimal invasive UKP implantation. We hypothesized that the used non image based navigation system will allow to place a UKP in the same position for both conventional and minimal-invasive approach.

Methods: 20 patients were operated on with this experimental minimal invasive navigated technique (group A) and compared to a group of 20 cases operated with the conventional navigated technique (group B), matched to the study group according to age, gender andseverity of the coronal deformation. Coronal mechanical femorotibial angle and coronal and sagittal orientation of the components were measured on post-operative antero-posterior and lateral long leg X-rays. The rate of satisfactory implanted prostheses was compared in both groups with a Chi-square test with a 0.05 limit of significance.

There was no significant difference in the pre-operative data between both groups. The post-operative coronal group A and 17 cases in group B. The prosthesis was optimally implanted in 17 cases in group A and 18 cases in group B. No difference was statistically significant.

Discussion-Conclusion: The used navigation system allowed a very precise implantation of a UKP for both conventional and minimal invasive navigated technique.


H Iwaki A Kobayashi K Iwakiri K Takaoka H Kagiyama

Acetabular revision in patients with bone deficiency is often difficult because of the poor quality and quantity of the acetabular bone stock. The purpose of this study was to evaluate the midterm clinical and radiographic outcomes of acetabular revision with use of an impaction bone-grafting technique and a cemented polyethylene cup.

Results: thirty consecutive acetabular revisions were performed with impaction bone-grafting and use of a cemented cup in twenty-eight patients with bone deficiency. The average age at the revision was sixty-eight years. The minimum duration of follow-up of all reconstructions that were still functioning or that were followed until the time of death was three years (mean, 8.1 years; range, three to fifteen years). The acetabular bone defects were classified as cavitary in fifteen hips and as combined segmental-cavitary in fifteen hips according to AAOS classification.

One hip had a repeat revision. Radiographic analysis that had not been revised showed loosening in four hips. All these four hips were treated by bulk bone graft covering more than 50% of cups. Kaplan-Meier analysis demonstrated a prosthetic survival rate, with aseptic loosening as the end point, of 72% at fourteen years and, with revision as the endpoint, of 100% at ten years and 83% at fourteen years.

Impaction bone-grafting was an excellent option to manage acetabular revision surgery. However, excessive bulk bonegraft should not be used.


Louise M. Jennings Carol J. Bell Eileen Ingham Richard Komistek Martin H. Stone John Fisher

Considerable differences in kinematics between different designs of knee prostheses and compared to the natural knee have been seen in vivo. Most noticeably, lift off of the femoral condyles from the tibial insert has been observed in many patients. The aim of this study was to simulate lateral femoral condylar lift off in vitro and to compare the wear of fixed bearing knee prostheses with and without lift off.

Twelve PFC Sigma cruciate retaining fixed bearing knees (DePuy, Leeds, UK) were tested using six station simulators (Prosim, Manchester, UK). The kinematic input conditions were femoral axis loading (maximum 2.6 kN), flexion-extension (0–58°), internal/external rotation (±5°) and anterior/posterior displacement (0–5 mm). Six knees were tested under these standard conditions for 4 million cycles. Six knees were tested under these conditions with the addition of lateral femoral condylar lift off, for 5 million cycles. The lubricant used was 25% newborn calf serum. Wear of the inserts was determined gravimetrically.

Under the standard kinematic conditions the mean wear rate with 95% confidence limits was 8.8 ± 4.8 mm 3/million cycles. When femoral condylar lift off was simulated the mean wear rate increased to 16.4 ± 2.9mm 3/million cycles, which was statistically significantly higher (p < 0.01, Students t-test). The wear patterns on the femoral articulating surface of all the inserts showed more burnishing wear on the medial condyle than the lateral. However, in the simulation of lift off the medial condyle was more aggressively worn with evidence of adhesion and surface defects.

The presence of lateral femoral condylar lift off accelerated the wear of PFC Sigma cruciate retaining fixed bearing knees. The lateral lift off produced uneven loading of the bearing, resulting in elevated contact stresses and hence more wear damage to the medial side of the insert. The implications of condylar lift off include increased wear of the polyethylene and possible osteolysis.


Hiroshi Ito Takeo Matsuno Toshiki Nakamura Akio Minami

We evaluated intermediate-term results of primary cementless Omniflex prostheses.

Forty-nine patients (57 hips) with a mean age of 44 years were observed for an average of 8.6 years.

These results were inferior to those using other recent cementless total hip systems. The increasing prevalence of loosening and osteolysis with time are problems related to this Omniflex femoral component. Although the implant design is unique, the authors no longer use this system.


B.M. Jolles K. Aminian H. Dejnabadi C. Voracek P.-F. Leyvraz

Background: Mobile-bearing knee replacements have some theoretical advantages over fixed-bearing devices. However, very few randomized controlled clinical trials have been published to date, and studies showed little clinical and subjective advantages for the mobile-bearing using traditional systems of scoring. The choice of the ideal outcome measure to assess total joint replacement remains a complex issue. However, gait analysis provides objective and quantifying evidences of treatment evaluation. Significant methodological advances are currently made in gait analysis laboratories and ambulatory gait devices are now available. The goal of this study was to provide gait parameters as a new objective method to assess total knee arthroplasty outcome between patients with fixed- and mobile-bearing, using an ambulatory device with minimal sensor configuration.

This randomized controlled double-blind study included to date 14 patients: the gait signatures of four patients with mobile-bearing were compared to the gait signatures of nine patients with fixed-bearing pre-operatively and post-operatively at 6 weeks, 3 months and 6 months. Each participant was asked to perform two walking trials of 30m long at his/her preferred speed and to complete a EQ-5D questionnaire, a WOMAC and Knee Society Score (KSS). Lower limbs rotations were measured by four miniature angular rate sensors mounted respectively, on each shank and thigh.

A new method for a portable system for gait analysis has been developed with very encouraging results regarding the objective outcome of total knee arthroplasty using mobile- and fixed-bearings.


B.L. Kaptein E.R. Valstar B.C. Stoel R.G.H.H. Nelissen J.H.C. Reiber

Model-based Roentgen Stereophotogrammetric Analysis (RSA) measures micromotion of an orthopaedic implant with respect to its surrounding bone, without the use of markers on the implant. In previous studies with a total knee prosthesis, Model-based RSA showed to be very accurate. In this study, Model-based RSA is validated in a phantom experiment of a total hip prosthesis.

A metal backed, elliptical shaped EP-FIT PLUS ®cup was used in combination with a SL-PLUS ® hip-stem from PLUS Endoprothetik AG. In vivo conditions were simulated by using sawbones and perspex plates to mimic the bones and soft tissue. Virtual projections of the CAD models of the implant were fitted on the automatically detected contours in nine RSA radiographs and the error inmigration calculation was determined.

The standard deviations of the error in translation for the cup were: 0.03, 0.05, and 0.21 mm. (x, y, z-direction) The standard deviations of the error in orientation were respectively 0.56, 0.48, and 0.18 degrees (n = 10). For the stem, the standard deviations of the error in translation are: 0.09, 0.11, and 0.29 mm and for the orientation: 0.63, 2.03, and 0.24 degrees (n = 0).

The results for the cup are satisfactory, and make Model-based RSA a good alternative for conventional RSA. Especially for this type of metal backed, non hemispherical cup for which no markerless alternative is available. The error in orientation around the y-axis of the stem is of concern. Experiments with models from Reversed Engineering had similar low accuracy. We expect that the cause of these inaccuracies is the rectangular cross sectional shape of this specific hip stem, and we expect better results from experiments with differently shaped stems. The results of this study make very clear that Model-based RSA is avaluable and accurate technique, but phantom studies are always necessary to validate the accuracy for a specific implant shape.


Keisuke Hagio Nobuhiko Sugano Takashi Nishii Hidenobu Miki Yoshito Otake Asaki Hattori Naoki Suzuki Kazuo Yonenobu Hideki Yoshikawa Takahiro Ochi

We have developed a novel system of 4-dimensional motion analysis after total hip arthroplasty (THA) that can aid in preventing dislocation by assessing safe range of motion for patients in several daily activities.

This system uses skeletal structure data from CT and motion capture data from an infrared position sensor. A 3-D model reconstructed from CT data is combined with the motion capture data. Using this system, we analyzed hip motion when getting up from and sitting down in a chair or picking up an object while sitting in a chair in 17 patients (26 hips) who underwent THA. To assess the accuracy of this system’s measurements, open MRI was used to evaluate positions of skin markers against bones in 5 healthy volunteers in various postures.

No impingement between bones and/or implants was found in any subjects during any activities. However, mean angle at the point of maximum hip flexion was different for each patient. The open MRI results indicated that average error in hip angle of the present system was within 5 degrees for each static posture.

The functional position of the pelvis during daily activities must be taken into account when assessing the real risk of dislocation. The present system enables dynamic analysis involving not only alignment of components and bones of each patient, but also individual differences in characteristics of daily motions. Further investigation using this system can help determine safe ranges of motion for preventing hip dislocation, improving the accuracy of individualized guidance for patients regarding postoperative activities.


Ayumi Kaneuji Tanzo Sugimori Masataka Ogawara Kiyokazu Fukui Kengo Yamada

Studies have reported stem subsidence without loosening in cemented polished tapered stems. And also, the initial radiolucency seen immediately after surgery at the bone-cement interface has decreased in some cases with polished tapered stem as time passed. The etiologies of these phenomena are not still elucidated. We made a comparative study on the relation between stem subsidence and the initial radiolucency in polished and rough surface stems.

Subjects were 42 hips of 38 cases and 36 hips of 31 cases received primary THA using a Collarless Polished Tapered (CPT) stem and a polymethylmethacrylate pre-coated (VerSys Cemented Plus) stem respectively. Three x-ray films taken within 2 months, at 6 months and a year after surgery were reviewed.

Stem subsidence was seen in 34 hips of 31 cases (81.0%) in the CPT group and averaged 0.72mm (range, 0–2.52mm) at a year after surgery. Decrease in the initial radiolucency was seen in 15 hips (35.7%) in the CPTgroup. Stem subsidence averaged 1.12mm (range, 0.46–2.52mm) and 0.48 mm(range, 0.00–1.91mm) in the cases with decrease in the initial radiolucency and in those without any change respectively. Stem subsidence was significantly greater in the cases with decrease in the initial radiolucency(P< 0.005). In the VerSys group, no stem subsidence was seen except in 1 case of mechanical failure with 0.65mm of subsidence. No decrease in the initial radiolucency was seen, either.

It has been reported that the decrease in the radiolucency as we showed was thought a dense appearance of cancellous bone by load transfer in other polished tapered stem. In this study, stem subsidence may have caused decrease in the initial radiolucency. It has a possibility that not only a dense appearance of cancellous bone but also cement creep caused decrease in the initial radiolucency.


Oliver Kessler Scott Banks Henrich Mannel Lutz Claes Robert Streicher Lutz Dürselen

Kinematic evaluation of the knee after total joint arthroplasty plays an important role to analyze and understand the post operative outcome of the surgical procedure. The objective of the study was to quantify in vivo kinematics of two different knee designs (dual radius, single radius) by combining video fluoroscopy and helical axis of motion analysis.

3D position of the finite helical axis (FHA) of the displacement of the tibial component of the prosthesis relative the femoral component during a knee extension from 55° to 20° flexion underweight bearing conditions was computed. The motion data were extracted from in vivo fluoroscopy measurement. Angular deviations as angles between each FHA and the mediolateral axis of the femoral component of the prosthesis, and the localization deviation as the distance between each FHA and the center of the femoral component of the prosthesis were calculated. The median and the interquartile range (IQR) of the angular deviation and the localization deviation were computed. Non-parametric Wilcoxon test compared the values of the two designs.

The angular and localization deviations of the dual radius design were bigger than of the single radius design. Median localization deviation, IQR Angle deviation, IQR localization deviation showed highly significant differences between the two designs (p< 0.01).

Compared to the dual radius design the single radius design modified the knee kinematics in vivo. Since it is asingle axis design FHA is therefore concentrated near this unique single axis. On the contrary the dual radius design has two axes, and the FHA floated between these two axes.


Kazuhisa Aikawa Nobuhiko Sugano Hidenobu Miki Keisuke Hagio Nobuo Nakamura Yoshito Otake Asaki Hattori Naoki Suzuki Hideki Yoshikawa

While numerous studies have examined dislocation caused by basic everyday movements, no objective studies have investigated body positions to minimize risk of dislocation during intercourse. We therefore used a four-dimensional motion analysis system to assess sexual activities in patients who had undergone total hip arthroplasty (THA), to identify body positions displaying less risk of dislocation.

Five body-surface infrared sensors were placed on five healthy female volunteers, and maximum hip joint angle was measured. Subjects were asked to take the following three body positions: supine (missionary); top (woman on top); and kneeling (doggy-style). Angle data obtained using body surface markers were combined with three-dimensional skeletal models extracted using CT images obtained from the 24 joints of 16 patients who had undergone THA, to ascertain angles at which collision with the artificial joint or skeleton would occur.

Collision angle for: supine position at maximum abduction in flexion was 77±16° in flexion and 82±57° in medial rotation; top position at maximum extension was 36±16° in flexion and 68±53° in medial rotation; top position at maximum flexion was 12±9° in flexion and 14±11° in medial rotation; kneeling position at maximum extension was 115±1° in flexion and 127±44° in medial rotation; and kneeling position at maximum flex-ion was 14±8° in flexion and 17±11° in medial rotation.

The present study only assessed risk for dislocation caused by collision with the artificial joint or skeleton, and did not take into account the effects of soft tissue. However, we were able to quantitatively assess angle of the hip joint for some leg positions involved with various common coital positions. The results showed that the supine position at maximum abduction in flexion is relatively safe, since the range of motion before collision would occur was relatively wide. In addition, top and kneeling positions at maximum extension were relatively safe, but caution must be exercised at maximum flexion, as not much extra angle was available in flexion and medial rotation.


Kenjiro Hasegawa Masae Shimizu Akihiko Inuhusa Takehide Chujo Yoshihiro Mikawa

We report an artificial elbow joint with a novel type radial component that we have designed that is now at the stage of trial production.

The humeral component is a trochlea capitulum replacement type with a stem. The ulnar component with a stem has an articular surface distributed not only on the trochlea surface but also on the capitulum surface of the humeral component, and has another concave articular surface toward the radial component. The radial component also has a stem and has a spherical convex articular surface. This surface of the radial component does not assume the conventional anatomical morphology, but the convexity is designed to fit the concave articular surface of the ulnar component. In other words, the new artificial elbow joint is a functionally dissociated type, in which flexion-extension is achieved by the humeroulnar joint while rotation is done via the radioulnar joint. The newly designed artificial joint was used to replace the cadaveric elbow joint. Radiographic studies were conducted to observe the compatibility of each component during extension-flexion and rotationmovements.

By replacing the cadaveric elbow joint with the newly designed artificial elbow joint and performing manual extension-flexion simultaneous with pronation-supination, the flexion positions of the humeral component and ulnar component were not affected, and stable compatibility was obtained for the radial component and ulnar component.

Artificial elbow joints with a radial component have been reported by various authors. However, since the humeroradial joint possesses two movement axes for both flexion-extension and rotation, good compatibility with the humeroulnar joint is necessary. Aradial component that simply adopts the anatomical morphology does no tachieve good humeroradial joint compatibility. The functionally dissociated artificial elbow joint that we have designed is expected to offer a clue to solve these problems.


Byung-Hoon Ko Suk-Hoon Park Yong-San Yoon Young Yong Kim

The purpose of this research is to propose CT-free cup orientator using tilt sensors without expensive point tracking devices in total hip replacement. In the case of using a mechanical guide, the accuracy of cup orientation can be sacrificed because of change of the patient’s posture during procedure. Several navigation systems have been introduced to secure an accurate position and orientation of the implant in THR. These systems are expensive and have some weakness due to possible interference inoptical measurement. Our orientator employs a T-bar shaped gauge and economic tilt sensors to secure a fairly orientation of acetabular cup inTHR.

The T-bar gauge having three feet with adjustable distance is designed to obtain the anatomical landmarks concurrently. Each foot is placed on the anatomical landamark of the sawbone. The gauge has its own tilt sensor to identifiy the tilt angle of the guage using AD input board. Similary, the cup positioning tool and dynamic reference base (DRB) have their own tilt sensors. The experimental procedures of CT-free cup orientator are done as follows:

Place the T-bar gauge in right place on the pelvis by setting three feet on the ASIS and pubic.

Attach DRB to pelvis and align its orientation parallel to the T-bargauge.

Align the tilt sensor of the cup positioner parallel to DRB.

We define errors as difference between experimental data and ground truth obtained by Micro-Scribe (Immersion Inc.) Errors of the cup in abduction and anteversion were 1.2 and 1.0 degrees respectively when the test is performed on a sawbone.

We analyzed the causes of error to improve the accuracy of our cup orientator. Measuring landmarks and aligning three tilt sensors seemed to cause some errors. Base on this study, we expect to make an experiment on cadaver.


Kang-Jung Kim Kenji Kaneko Miho Iwase Taiki

Osteoprotegerin (OPG) has been reported to be a novel protein that can suppress osteoclast differentiation and activation. This study examined the therapeutic effects of OPG on established periprosthetic osteolysis in a rat model.

A bone cement prosthesis was inserted into the rat femur and polyethylene particles were continuously infused into the knee joint using an osmotic pump. After osteolysis was established in four weeks, rats were intravenously injected with vehicle (control group) or 1 mg/kg of OPG (OPG-1 group) or 10 mg/kg of OPG (OPG-10 group) every week until they were sacrificed at 8 weeks. Effects of direct injections of OPG into the knee joint were also investigated. Periprosthetic bone resorption was evaluated with bone mineral density and histomorphometric analysis of membranes composed of total area of interface membrane and inflammatory grading. Radiographs were evaluated for focal osteolysis with a blind manner.

Periprosthetic bone resorption was significantly suppressed in OPG-10 group compared to the other groups (p < 0.05). Histomorphometric analyses showed less total area as well as less inflammatory grading of the interface membrane in OPG-10 group compared to other groups (p < 0.01). Radiographic osteolysis appeared to decrease in number in OPG-10 group. Direct injections of OPG into the knee joint appeared to be more effective compared to intravenous injections.

The present study demonstrates that OPG has significantly restored the established periprosthetic osteolysis in our animal model. OPG may be a possible agent to retain the bone stock before revision surgery for failed prostheses. Conclusion: This study demonstrates that osteoprotegerin suppresses the progression of periprosthetic osteolysis and restores bone stock in a rat model.


Oliver Kessler Kurt Bormann Savas E. Lacatusu Tanja Augustin Mark B. Sommers Michael Bottlang

Menisci contribute to load distribution, damping and stabilization of the knee. Meniscal tears are a common injury in the young and active population during combined axial loading and twisting of the knee. The in situ effect of combined axial loading and knee rotation on hoop strain in the medial meniscus of human cadaveric specimens was examined.

Four fresh-frozen human cadaver knees were rigidly potted in base fixtures. Muscle tissue was removed, and the joint capsule and ligamentous structures were preserved. Through two arthrotomies, strain sensors (DVRTs) were placed in the peripheral border into the mid-substance of the medial meniscus. These DVRTs captured circumferential hoop strains e;AM, e;PM in the anteromedial and posteromedial medial meniscus. Each specimen was mounted in a knee loading simulator, driven by a biaxialmaterial test system and were axial loaded with 1,4 kN. While maintaining axial load, ± 10° tibial rotation (IR, ER) was subsequently applied at 1°/s. Tests were conducted for knees flexion between 10° and 60° in 10° intervals.

Strain reports e;AM and e;PM were highly similar for any given test. Therefore, they were averaged to express meniscal hoopstrain as e;AVG. At 30° flexion, 1.4 kN axial load yielded e;AVG =0.9%±0.4%. ER resulted in a significant strain increase (2.1%±0.8%) (p=0.003). IR caused a decrease (0.2%±0.7). At 60° knee flexion, 10° ER induced significantly less strain (1.3%±0.9%) as compared to the 10° flexed knee(2.8%±1.3). For knee flexion from 10° to 50°, combined ER and axial loading-caused significantly higher strain as compared to axial loading alone.

This study documents for the first time strain in the medial meniscus under combined axial and torsional loading. The finding that meniscal strain can increase over two-fold during 10°external rotation has implications for injury biomechanics and meniscal repair strategies.


Shunji Kishida Yoshitada Harada Chikashi Shirai Yoko Miura Takeshi Miyasaka Noriyuki Yanagawa Hideshige Moriya

We usually plan surgery for total hip arthroplasty (THA)using pre-operative X-ray templates. However, the technique provides only two dimensional (2D) images and therefore has limitations for planning three-dimensional (3D) objects. Recently it has become possible to describe 3D images using computer programs that use free down loaded computer software (Hip-op) that enable comparison between 3D templates obtained by computed tomography (CT) and 2D conventional X-ray templates.

Six hip joints in 6 patients (1 male, 5 females; age range at the time of operation, 49–77 years) were evaluated. Five of the patients suffered from secondary osteoarthritis of the hip (secondary OA), while the remaining patient suffered from osteonecrosis of the femoral head (ONFH). All the patients underwent THA using a cement less femoral stem (ANCA-FIT Wright Medical Technology, Arlington, Tennessee, USA). Pre-operative planning was performed using Hip-op software (Rizzoli Institute, Bologna, Italy). After the THA surgery, we carried out a repeat CT scan that was used to analyze stem fitting in the femur.

In all the patients it proved easy to obtain the pre-operative template. In 4 patients, the correct stem size was selected pre-operatively, while in the other 2 patients, the planned stem size was one size smaller than that actually implanted. In the 4 patients in whom the correct stem was selected, 2 had their template correctly assessed by conventional 2D images, 1 patient’s template was one size smaller than the implant, while the remaining patient’s template was two sizes smaller than the implant. In the 2 patients who received implants one size smaller than the CT template, 1 patient had the stem inserted in the virus position while in the other patient a fracture occurred during implantation

Preoperative planning for THA using a CT-based computer templating system proved to be a useful technique for the orthopedic surgeons.


O. Kessler E. Lacatusu O. Vande Erne C. Zandschulp C. Engel A. Spriggins M Bottlang

This study investigated the difference in proximal tibial cortical strain distribution using a fixed or mobile bearing design for TKA.

Eight fresh frozen human cadaver tibias were used. The strain magnitude and distribution on the anterior cortex of the proximal tibia during axial and rotational loading of the knee were measured with a quantitative full-field strain measurement technique (Electronic Speckle Pattern Interferometry). First, strain distributions of the intact knee were acquired. Subsequently, strain distributions after implantation of conventional and mobile bearing PCL retaining total knee implants (Scorpio®) were measured

Under each loading condition, the minimum principal strain was greater in magnitude as compared to the maximum principal strain. Under 1,500 N axial loading, the resulting minimum principal strain magnitude and orientation was nearly identical between the mobile bearing configuration(500 ± 287m;e;), and the fixed bearing configuration (500 ± 286m;e;). In response to 10° internal rotation, this strain increased to 782 ± 371m;e; and 1000± 389m;e; for the mobile and fixed tibial component, respectively. In 10° external rotation, minimal principal strain decreased to 421 ± 233m;e; for the mobile bearing, but increased to 632 ± 293m;e; for the fixed bearing. These differences between mobile and fixed bearing scenarios were highly statistically significant.

For this in-vitro study under exact controlled loading conditions the mobile bearing design induced less strain in the proximal tibia than the fixed bearing tibial component. The difference in strain levels may be of importance for bone remodeling and osseointegration.


Richard D. Komistek Douglas A. Dennis Mohamed R. Mahfouz Joel T. Outten

The objective was to assess and compare polyethylene-bearing mobility patterns and magnitudes in various total knee arthroplasty(TKA) types of mobile bearing TKA.

In vivo kinematics were determined for 38 subjects implanted with either a PCL-retaining (PCR) mobile bearing TKA, which allows both rotation and antero-posterior (AP) translation (n=20), aposterior stabilized rotating platform (PS) TKA (n=9) or a PCL-sacrificing (PCS) rotating platform TKA (n=9) using video fluoroscopy. Using a 3D model-fitting technique, kinematics were determined during a weight-bearing deep knee bend. The femoral and tibial components and mobile bearing polyethylene insert (implanted with four tantalum beads) were overlaid onto the fluoroscopic images to determine bearing mobility. AP bearing translation was determined for subjects implanted with a PCR mobile bearing TKA. Subjects implanted with PCR and PCS TKA were evaluated at a single interval. Those with a PS TKA were evaluated at two postoperative intervals, (12 months apart) to assess changes in bearing mobility over time.

All subjects experienced polyethylene bearing rotation relative to the tibial tray and minimal rotation relative to the femoral component. The average maximum amount of bearing rotation was 10.3o (3.0o to 20.8o), 8.9o (5.3o to 14.1o), and 8.5o (3.3o to 12.9o) for subjects implanted with a PCR, PS, and PCS mobile bearing TKA, respectively. For subjects implanted with a PS mobile bearing TKA, bearing mobility increased to 9.8o (4.8o to 14.1o) one year later post-operatively. All subject shaving a PCR mobile bearing TKA experienced AP bearing translation, averaging 5.6 mm (1.0 mm to 12.5 mm).

These results demonstrate that the polyethylene bearing is rotating and translating relative to the tibial tray in all subjects. Minimal motion occurred between the femoral component and the polyethylene insert. Magnitude and direction of bearing motion varied among subjects. Paradoxical anterior translation of the bearing during deep flexion was observed in the PCR TKA group. The presence of bearing mobility should result in lower contact stresses, reducing the potential for polyethylene wear.


K Yagihashi I Nishimura T Ishida H Ito H Tanino T Nakamura T Matsuno Y Mitamura

Prosthetic impingement after THA is to different for the angle and shape of the implant. Purpose of this study is examine the range of motion(ROM) on a computer when angle and shape of the implant are changed.

The 3D implant models were created on a computer. The angle was measured in the flexion, extension, adduction direction byevery 0.1 degrees. There are three kinds of acetabular abduction angle, two kinds of acetabular anteversion angle and two kinds of femoral anteversion angle. There are three kinds of the radius of neck and the neck shaft angle. All 324 patterns of the above model were measured.

When the radius of neck decreased, the ROM increased in all cases. When the neck shaft angle decreased, the ROM increased by almost all cases. When the acetabular anteversion angle increased, the ROM of flexion direction increased and adduction direction decreased, and as for the extension direction, all the factors had influenced the change in the ROM. When the acetabular angle increased, the ROM of the extension direction increased and the flexion directions decreased. As for adduction direction, femoral anteversion angle, acetabular anteversion angles, and the radius of neck had influenced the ROM. When the femoral anteversion angle increased, the ROM of flexion direction increased and extension, adduction direction decreased.

The clinical ROM is affected by the impingement of non-implant and the strain of the soft tissue. Therefore, It’ s considered that the clinical ROM is smaller than the ROM which was investigated in this study in many cases. When the radius of neck and the neck shaft angle decrease, the increase of the ROM expected. However the radius of the neck should not be decreased too much to avoid the decrease of the neck strength.


Adrija Sharma Matthew B-K. Kubo Richard D. Komistek

The objective of this study was to determine the location of polyethylene post position and/or axis of polyethylene (PE) bearing rotation in order to maximize the rotational freedom of the PE bearing in a posterior-stabilized mobile-bearing TKA.

Kinematic data obtained in a previous study involving subjects implanted with the PFC Sigma RP (PS) was used in two mathematical models to determine the optimal configuration of the implant’s features. An inverse dynamics mathematical model used the kinematic input to calculate interactive forces between the implant components. The second mathematical model used the femur-polyethylene and polyethylene-tibial plate interactive forces in a forward solution giving the amount of polyethylene bearing rotation. Researchers altered the location of cam/post interaction and/or bearing rotation to determine the criteria for optimal bearing rotation.

During flexion, the maximum femur-polyethylene contact force calculated by the inverse model was 1.9 x BW, at maximum flexion. Maximum quadriceps, patello-femoral, and patellar ligament forces were approx. 2.9 x BW, 2.8 x BW, and 1.5 x BW at maximum flexion, respectively. We determined that the sample group experienced an average maximum bearing rotation of approximately 3.5°. Maximum bearing rotation reached approx 12.5° (10°–15°) with a 5mm lateral shift in cam/post engagement. Bearing rotation reached approximately 17.5° (15°–20°) by shifting the bearing axis 5mm posterior to that of the current design. Shifting the cam/post mechanism or bearing axis by greater than 5mm in any direction produced undesirable results.

The mathematical models used in this study were verified by comparing kinematic results obtained from a 3-D model-fitting program whereby models are matched to their respective silhouettes in a 2-D fluoroscopic image. Results from this study show that the rotational freedom of the PE bearing can be optimized by shifting its axis of rotation posterior to its present location.


Kim Bertin William Kennedy Aaron Rosenberg Richard D. Komistek Mohamed R. Mahfouz

Previously, we conducted a single surgeon in vivo kinematic study that revealed subjects having a PCR TKA with asymmetrical condyles experienced a high incidence of posterior femoral rollback. Therefore, the objective of this follow-up study was to determine if posterior femoral rollback from our single surgeon series can be attributed to the implant design, surgical technique, or the presence of a well functioning PCL.

Three-dimensional femorotibial contact positions for eighty subjects, implanted by three surgeons, were evaluated using fluoroscopy during a deep knee bend. Twenty subjects had a PCR TKA without a PCL, while the other 60 subjects were deemed to have a functional PCL. All subjects were implanted with a PCR TKA having a larger lateral radius of curvature compared to the medial condyle.

Fifty-four of sixty subjects in this study having a functional PCL experienced posterior femoral rollback of the lateral condyle, while 13/20 subjects not having a PCL experienced posterior femoral rollback. Also, 48/60 subjects having a well functional PCL and 10/20 subjects without a PCL experienced a normal axial rotation pattern. The incidence for condylar lift-off was low, and only 6/80 subjects in this study experienced greater than 2.0 mm of condylar lift-off. Forty of sixty subjects having a well-functional PCL experienced greater than 100 degrees of weight-bearing range-of-motion and the maximum weight-bearing range-of-motion was 144o.

The subjects in this study experienced excellent kinematic patterns, consistent to the normal knee, although less in magnitude than the normal knee. Surprisingly, on average, subjects in this study without a PCL experienced posterior femoral rollback of the lateral condyle leading to the assumption that the PCL did not play a significant role in the excellent kinematic patterns achieved by subjects in this study. The results from this study do support the hypothesis derived from our single surgeon series that asymmetric condylar geometry may lead to better kinematic patters for subjects implanted with a fixed bearing PCRTKA, as it appears implant design is the most influencing factor that lead to normal kinematic patterns.


Kosmas S. Stafilas Panayiotis S. Koulouvaris Alexandros N. Mavrodontidis Grigoris I. Mitsionis Theodore A. Xenakis

The purpose of this study was to analyse the complications of THAs in CDH. 418 THAs were performed in 356 patients, with a mean follow-up 108 (7–237) months. The mean age was 53.3 (24–79) years. 83 patients had CDH in high position. 40 stems were custom made. Complications included seven intraoperative fractures of the femur, 12 dislocations, four peroneal nerve palsies that recovered, 25 heterotopic ossifications, seven deep vein thromboses, three pulmonary embolisms, early mechanical loosening in four cemented and ten cementless cups and three infections. Complications were diminished dramatically last years due to improved surgical technique, new available implants and preoperative evaluation of the hip with CT and CAD-CAM-CAE study.


Alejandro Leali Joseph Fetto Harvey Insler

Background: Over the past decade, several modifications have been introduced to uncemented femoral stems. The design of the stems, however, still classically fall under two categories: anatomical and straight. The purpose of this paper is to report the first clinical, radiographic and periprosthetic densitometry results of a cementless total hip arthroplasty performed with an off-the-shelf extended metaphyseal loading device

Fifty-eight consecutive patients who received aproximally loading non-cemented hip prosthesis were followed for an average of 4.4 years. Patients were clinically and radiographically followed at 3 weeks, 3 months, 6 months, 1 year and yearly thereafter. In addition, a group of 8 consecutive patients were studied with Dual X-Ray Absorptiometry Scans(DEXA) at the same intervals during the first year and at 18 months after surgery.

The extended proximal geometry of the device allowed for initial and secondary stability reflected by the low subsidence values over time. The maintenance of periprosthetic bone stock over time and the absence of stress shielding can be explained by the proximal loading pattern of the stem.


Alejandro Leali Joseph Fetto

Thromboembolism following total hip arthroplasty is a common complication that may result in significant morbidity and mortality. Despite this, optimal prophylactic regimen is controversial. According to the literature, the prevalence of deep venous thrombosis during the early post-operative period ranges from 13% in patients utilizing low molecular weight heparin to 18% in patients treated with sequential compression devices alone.

We investigated the efficacy of a comprehensive approach encompassing the use of aspirin, intermittent compression devices (‘foot pumps’), and early mobilization in a cohort of 290 consecutive patients after non-cemented total hip replacements. The surgical procedures were carried out under epidural anesthesia in most cases (91%). All patients were allowed full weight bearing and received ambulation training starting on the first post-operative day. Ankle-high pneumatic boots (‘foot pumps’) were used early immediately surgery. Aspirin (325 mg po/qd) was used as a pharmacological measure to prevent thromboembolism. The presence of deep vein thrombosis was determined with the routine use of venous duplex scans on post-operative day number 5 to 10 (mean 6.8). The duration of the follow-up was 3 months. No patients were lost to follow-up.

Four distal DVT and two proximal DVT were detected in five patients (3%). None of the patients developed symptomatic pulmonary embolism during the follow-up period. There were no major wound complications.

Venous thromboembolic disease after hip replacement surgery is largely associated with postoperative immobilization and venous stasis. It is the authors’ opinion that a prevention strategy should include mechanical as well as pharmacological measures. The concomitant use of epidural anesthesia, “foot pumps”, aspirin and early full weight bearing ambulation may be effective in further reducing the incidence of DVT after surgery.


Fabrizio Macchi

Volumetric wear study in metal-polyethylene bearing couple, has demonstrated that the wear rate is reduced by the decrease of the diameter of the ball-heads. On the other hand, small ball-heads introduce some limitations: the stability, the subluxation and the dislocation of the prostheses are directly correlated with the diameter and are often cause of failure.

The crosslinked polyethylene, promising lower wear rates, seems to have higher Function Biological Activity (FBA) because of its smaller but more aggressive particles[1]. In ‘70s, the alumina ceramics has been introduced in the hip prostheses due to its high wear resistance and its bulk material and debris biocompatibility. Laboratory test and long terms clinical experience confirmed that the BIOLOX®forte/BIOLOX®forte bearing couple offers a reduction of two orders of magnitude of the linear wear rate (in vivo results 0.005 mm/year) if compared with metal-polyethylene (0,2 mm/year), it does not produce reaction[2] and it has a high reliability (fracture rate = 0,01% )[3]. Moreover, it has been noticed that for each mm of linear wear of the liner, the correspondent penetration of the head reduces the Range Of Motion (ROM) of approximately 7°.

The low friction coefficient of the alumina, reduces the friction torque and the stresses between the bone and the cup[4]. Greater diameters (32 mm and 36 mm) offer different advantages. The ceramic ball-heads of greater dimensions have better mechanical characteristics. The minimal fracture load of BIOLOX®forte ball-heads (L neck) increases from 55 KN of the 28mm ball-heads to 65 KN of the 32 mm until to 90 KN of the 36 mm ones[5]. This superior characteristics allows to increase reliability (fracture rate of 32 mm ball-heads is 0,004%)[3]. The luxation risk is one of the most important parameter for the reliability of prostheses. Bigger diameter increases the luxation distance and consequently decreases the risk of subluxation and dislocation of the prostheses. The ROM is directly correlated to the diameter of the head. With ball-heads of 36 mm it can be caught up a ROM of approximately 136°. This is an advantage for the reliability of the system because it reduces the risk of impingement that is often cause of failure[6,7]. The lengths of the neck (+/− 3,5 mm for 28 mm ball-heads) can be increased. With 32 mm ball-heads there is an excursion of +/− 4 and the increase of the diameter reduces the necessity of a XL neck.

Due to its biocopatibility, low wear characterisitcs and mechanical aspect, ceramic on ceramic bearing couple of bigger diameter seems to be the right solution for long terms results for active and young patients.


Yukihiko Kudo Hiroyuki Nozaki Scott A. Banks Toru Suguro

Medial pivot total knee arthroplasty is designed to permit posterior rolling and sliding of the lateral femoral condyle around a stable medial femoral condyle. The purpose of the current study was to analyze the weight-bearing kinematics of medial pivot TKA’s with three different treatments of the posterior cruciate ligament: PCL resected, PCL partially released and PCL retained, to determine if the PCL status had a significant effect on tibiofemoral translations or rotations in a medial pivot TKA design.

In vivo kinematics were determined for 17 clinically successful total knee arthroplasties during a stair-climbing activity using lateral fluoroscopy and shape matching techniques.

All three groups showed similar medial pivot motions. PCL retained knees showed significantly greater tibial internal rotation than PCL resected knees for flexion of 30° and greater. Rotation of the PCL released knees was midway between PCL resected and PCL retained knees

Regardless of PCL treatment, patients with medial pivot total knee arthroplasties had medial pivot motion patterns during stair climbing activities. This study showed a clear and intuitive trend in motions with PCL-treatment, such that knees with partially released PCL’s had kinematics midway between those where the PCL was either fully maintained or fully resected.


Alejandro Leali Joseph Fetto

Uncemented porous coated femoral implants rely on bone in growth to achieve stable, long lasting fixation. The loss of proximal femoral bone mass around hip stems has been traditionally termed ‘stress shielding’ and has been linked to the transfer of loads to the diaphysis and the relative unloading of the proximal femur. Proximally loading devices should then minimize or avert stress shielding altogether. We prospectively evaluated the changes in the periprosthetic bone mass density after insertion of an off-the-shelf non-cemented stem designed to engage both cortices at the metaphyseal level.

A total of 10 total hip arthroplasties with a proximally coated lateral flare device were evaluated with dual-energy x-ray absorptiometry and qualitative radiographic changes 3 weeks after surgery and at 12, 24 and 52 weeks thereafter. The regions of interest (ROI) used in this study corresponded to the zones described by Gruen.

All hips were radiologically stable. The DEXA measurements revealed an overall increase in the BMD at 52 weeks of 4%. Greater gains were observed at or below the lateral flare of the stem in the metaphyseal femur.

The use of an extended proximally loading device proved to have a beneficial effect in the periprosthetic bone mass density due to its geometry and inherent primary stability evidenced by the DEXA and subsidence values.


Prof. W. Thomas Dr. L. Lucente Dr. N. Mantegna

The pathologies of the hip (epiphisiolysis, Perthes, congenital dysplasia) cause invalidating outcomes in young patients. In the years many authors searched for the golden standard if total hip arthroplasty is necessary. From Smith-Petersen to McKee, to Amstutz the saving of the femoral neck has been the main objective, with the longevity of the system. Therefore the combination metal-metal has been used for articular components, because the friction of metallic components creates sub-micron metallic particles causing only minimal foreign body reactions andvery low wear rates.

Our study group (Arthro Surgery Group) has implanted, from April 2003, 28 cementless resurfacing hip prosthesis with metal-metal articular components.

The average follow-up has been of 6 months (from 3 months to 1 year). In all cases, the Harris Hip Score has been good or excellent (from 77 to 100), and radiographic exams didn’t show signs of radiolucence or resorption.

This type of prosthesis allows moreover an minimum-invasive approach to the hip and a second line of defense in case of revision.


J Hauptfleisch P McLardy-Smith

Significant proximal femoral bone deficiency in revision hip surgery poses a considerable challenge, especially as revision hip surgery is increasing in prevalence. Many femoral prosthetic devices, which compensate for this bone loss, are available to surgeons but ideally one wants to restore viable proximal bone stock. The Oxford Universal Hip (OUH) has been designed and modified with these challenges in mind. This is atrimodular, non-locking device that allows for some rotation and subsidence in the cement. Load transfer occurs at the proximal wedge, thus avoiding proximal stress shielding. The OUH has been used extensively in both primary and revision hip surgery and is particularly useful when used in conjunction with proximal impaction bone grafting. The main aim of this study was to determine the clinical outcome of the patients. The viability and survivorship of the impacted bone graft was assessed in order to give some indication of adequate perfusion of the incorporated bone grafting.

Between 1999 and 2002 the OUH, in combination with proximal impaction bone grafting, was implanted in 72 hip revisions in 69 patients. All patients were clinically evaluated using the Oxford Hip score. Histological samples of impacted bone grafting were analysed by a pathologist 2 years after implantation to assess viability and perfusion of the impacted bone graft.

The Oxford Hip Score improved from a pre-operative to a post-operative score of 45 (26–58) to 24.3 (12–43) respectively (p< 0.001). The mean follow up time was 32.7 months and in that time there were no re-revisions for aseptic loosening. Histology demonstrated viable bone stock in the proximal femur where bone grafting had been impacted 2 years previously.

The OUH is a versatile hip prosthesis for use in revision hip arthroplasty and is especially well suited to proximal impaction bone grafting where it is possible to restore viable bone stock


M. Manili R. Sgrambiglia P.F. Nardis

Near 70% of failures of knee arthroplastys due to septic or aseptic mobilization are complicated because of massive loss of bone stock. In these cases surgeon have to perform a salvage procedure to restore legamentous balance, articular plane direction and axes of lower limb, finally to fill bone defects. Today intrinsic biomechanical stability of revision implant is entrust to sophisticated design and materials of custom made and modular implants. Endomedullary stem has to assolve specific functions: mechanical stability contrasting stress due to the boneloss, offering support for omoplastic or spongious bone innests in femoralor tibial defects. There are paucity of study in literature about dimension and morphology of endomedullary canal, probably because of variability between periostal andendostal anatomy in each patients, specially age related. This date has conditioned production of several number of revision stem size for all population. This anthropometric study verify presence of a particular regionin femoral and tibial endomidullar canal not dependent from sex, height, morphotype, important for a good press-fit of revision stem.

Morphological date of midfemoral and tibial geometry was assessed in 50 subjects using Axial Computerized Tomography. Eleven (22%) were in men, thirty nine (78%) were in woman, with avarage of 73 years old (from 57 to 85). Exclusion criteria were previous operation at the same limb, deformity, pathology of bone metabolism. The level of sections were at 20, 18, 16 and 12 centimiters from articular plane for femur and at 8, 10, 13, 16 cm for tibia. Preliminar Ct scan with hight resolution program with bone alghoritm was performed. Axial view of any section was visualized at real dimension and maximal and minimal diameter of sections e were measured in millimiters.

Areas of any section is different in each patient; this variability is greater near articular plane. Infact in our sample SD (Standard Deviation) of diameters of proximal femoral and distal tibialsections was lesser than SD of the other measurements. No difference of results about sex was noted. On base of these measuremts more proximal two femoral sections and two more distal tibial sections were considered to elaborate an ideal area for anchorage zone of anatomical revision stem. We subdivided all sample in five groups with homogeneous value of diameter in selected sections. For any groups tangent & #945; of an ideal trunk of cone including maximum and minimum value of diameter considered was computed, and the relative inclination angle. In our sample the greatest diameter in proximal femoral section was 20 mm and the lowest 10 mm; for tibial measuremnts the greatest value in distal tibial level was 18 mm and the lowest was 10 mm. Inclination angle was ever around 2° in all groups. Moreover we have calculated the presumable length of an ideal trunk of cone that includes the minimum and maximum value of femural and tibial diameter measured.

About 5% of knee arthroplastys is destinated to an unsuccessfull. In many cases loosing of bone stock is huge and localized near articular plane. Afterward it’s important to restore biomechanical stability through endomedullary stem of revision implant. There are not many reports about morphology and anatomical study of femoral and tibial endomedullary canal. Many authors focus the attention on bone density or functional axes of the lower limb. Some authors studied remodelling process age-related about periostal ad endostal bone; cortical area undergoing thinning specially over fourthy years old. Our sample had mean of 73 years old: remodelling process is almost complete and then it is a good referenceto extrapolate real data about endomedullary morphology and width. Variability of data in all population about diameter of endomedullarycanal is lesser near femoral and tibial istmo, in particular around 18–20 cm from articular plane for femur and at 13–16 cm for tibia In our opinion short stem can’t guarantee good press-fit because of extreme variability of diameters in the population near knee. This anthropometric study confirm presence of anatomical area of the midfemural and tibial canal with common geometric characteristic in allpatient; it can be used to realize an anatomical stem that guarantees a good contact bone/prosthesis and then an optimal bone integration. On base of our results it is possibile realize few revision stem because in all groups of patients studied at 18–20 cm from knee for femur and at 13–16 cm for tibia, angle of inclination was ever 2°.


M. Manili N. Fredella A. Moriconi R. Sgrambiglia

Asepting loosening by polyethylen wears is on of the main problems in total knee replacement. In the last years, the major improvement is about matherials. The polyethylene remains the major problems for long term results of total knee replacement despite new types of polyethylenes like cross linked or high reticulation. From to 2 years a new matherial (Oxinium) for femoral component has been avaluated; Oxinium is an high temperature and oxidation procedure to trasform the articular surface like a ceramic. In this paper early results with this total knee replacement are reported and the advantages of this new matherial are discussed.

110 primary Oxinium-Profix were evaluated. Mean follow up is 18 months ( min2 max 26). Mean age is 67 years (53 yrs– 74yrs). Both components were cemented. In all cases PCL was retained. Never patella was replaced. Lateral release with out-in technique was performed in all cases. The Knee Society scoring system was used to assess patients both clinically and radiografically.

Clinical and radiographic results are promising despite the short follow-up. Oxiunium seems to be a safe matherial, especially for young patients because of low rate of wear. However, only a long term follow up could confirm the intial promising results


K Mannan W Hoo SL Burtt A Kumar

Midline skin incision and medial arthrotomy for knee arthroplasty may be preformed in flexion or extension. Anatomical studies have revealed a risk to the infra patellar branch of the saphenous nerve. This study addresses

whether sensory loss is greater following skin incision in flexion or extension.

The area of sensory loss six months following knee arthroplasty.

Null hypothesis- there is no detectable difference in sensation before and after knee arthroplasty. Pilot study- light touch, sharp touch and two point discrimination were evaluated pre-operatively, at one week, six weeks and six months postoperatively in twelve patients recruited prospectively. Randomization was achieved using an envelope system. Six patients underwent approach and closure in flexion and six in extension. Prospective cohort study – 50 patients underwent sensory mapping for light touch and sharp touch pre-operatively. These control results were compared with the post-operative findings at six months. All measurements were standardised to anatomical landmarks with the knee in 90 degrees flexion.

There is a constant area of sensory loss lateral to the midline scar, which shows some recovery with time. The sensory loss affects both light and sharp touch. Initially, this is in a similar distribution anteriorly and laterally extending from the superior pole of the patella to the tibial tubercle, approximately 2cm lateral to the midline. The loss is most marked immediately after surgery. There is a noticeable recovery in sharp touch by six weeks. The recovery in light touch is slower and less complete at the six month review. There is no demonstratable difference in sensory loss regardless of whether the incision is made in flexion or extension, (p=0.1)

Lateral sensory loss is a constant feature in this series six months following knee arthroplasty. Patients may benefit from pre-operative counselling regarding the likelihood of lateral cutaneous sensory deficit following knee arthroplasty.


Dr. S. Mai

There exists a lot literature referring to the cementing technique of hip replacements, but when talking about longevity of knee prostheses only seldom the cementing technique is mentioned even though 90% of the knees are cemented. Especially the tibial component, that has to cope with different forces such as pressure, rotation, tilt and sliding, is said to last longer when cemented.

Cementing Technique: There are many aspects that need to be thought of when cementing knee prostheses:

The preparation of the bone: The preparation of the surface of the bone is of great importance, as the-bond of the cement with the bone is by the shape of the surfaces and not by a chemical reaction. A good penetration of the cement into the cancellous-bone enlarges the connecting surface and optimizes the power transmission. The pulse-lavage is the most effective to open the spongy bone. Sclerotic bone needs to be penetrated.

Selection of cement: PMMA-cement (Polymeth-ylmetacrylat) is used with proven effectiveness since 1958 (Charnley). Very Similar to the well known cement Palacos (BiometMerck) is the new SmartSet GHV (DePuy) but it provides a longer time for processing, which is useful when cementing all components in one go. Mixing and hardening time are therefore shorter.

Mixing of the cement: Mixing is mostly done manually even though it is known that the quality of the cement is minor than with a vacuum system. The advances of such a system are better microporosity, no air bubbles, and safety for the staff, who breathe less fumes.

Application of cement – viscosity: The cement can be applied to the prosthesis or directly onto the bone. If the implant is precoated, the viscosity of the cement should be low to achieve better joint. The bone should in any case be dry to avoid mixing with blood.

Pressure: During implantation a short high pressure is of importance for the depth of penetration. Some implants have an edge to guarantee better distribution of the pressure. During the hardening of the cement the pressure has to b ekept at a certain level as the volume of the cement changes a bit during the polimerisation.

Hardening: The pressure needs to be controlled avoiding small movements. When cementing all components at once the ligaments have to be balanced, otherwise unnoticed deviations might occur. The leg should not be hyperextended to avoid tilting of the components.

Temperature of polimerisation: The temperature can be reduced in vivo by cooling of the bone or the cement and by good spongy bone that transports the temperature away. If the cement penetrates more than 5 mm or its homogeneous thickness is more than 3mm osteonecrosis is likely to occur.

Thickness of cement layer: Several authors and the finite element measurements found out, that acement layer from 2–5 mm ensures good stability for the tibial component. Cementing the shaft does not lead to significant better results but may lead to atrophy of the bone underneath the tibial plateau. Femoral components show good results also uncemented.

Excess of cement: Cement that juts out must be removed especially in the dorsal parts, where an impingement can be produced. Bits in the soft tissue must also be removed with care. Cement should not touch the polyethylene during the whole procedure.

Antibiotics: The quality and longevity of the cement is reduced by adding antibiotics because of resulting higher porosity. A special management for risk patientsis necessary.

When cementing knee prostheses one should give high attention to the cementing technique as especially a good anchorage of the tibial component will lead to longevity of the implant.


A. Manunta M. Fadda A. Fiore F. Zirattu

Metallosis is a combined chemical and toxic reaction which, if the wear of a metal implant is large, may cause extensive reaction of synovial membrane and thus triggering the loosening.

We present a case of a 72 year-old man, who underwent to a cemented unicompartimental porous metal coated knee implant because affected by rheumatoid arthritis complicated by osteonecrosis of medial femoral condyle of the knee. Four years after replacement, the patient presented symptoms included moderate swelling, pain, synovitis inability to bear full weight as well as grinding; plain radiographs shows well fixed implant and not finding of loosening of prosthesis; arthroscopy revealed the diagnosis of metallosis. The specimens of synovial tissue were prepared to observation to light and electron microscopy. Total synovialectomy and revison with total knee replacement were successful in relieving the symptoms.

Arthroscopy examination revealed a posterior break of tibial component, source of the release of multiple metal beads; we observe alsogray black discoloration of hypertofic and hyperplastic synovium pannus like; metal beads were detected in the joint space soft tissue and were also embedded in the articulating surface of the tibia component. Microscopic examination shows metal debris as black aggregates and a diffuse sheet like proliferation inside histiocytes of villous membrane. Ultrastructural study demonstrate that the presence of metallic fragments, measuring less than 0.3 micron in diameter is predominantly concentrated inside the macrophage’s phagolisosomes.

Delivery of large number of metal beads from implant and the release of smallest size metal debris play a pivotal role in the development of a foreign body granulomatous reaction. The failure of unicompartimental prosthesis has been accellerated by unperformed sinoviectomy during the first implant; the cells of synovial membrane are continuosly activated, by wear of implant material, to phagocitate and to secrete inflammatory response.


Stephen Mendelson Mark Yudelev Aiguo Wang Gregg Schmidig Mark Kester David Markel

Neutron beam irradiation is currently being explored as an alternative modality to improve local control of sarcomas. The purpose of this study was to investigate the effects of a sarcoma-dose fast neutron therapy on the wear properties of standard and highly cross-linked polyethylene total hip arthroplasty liners

Two groups of 28 mm I.D. polyethylene liners were used in this study – conventional polyethylene liners (N2vac: 3Mrads innitrogen, Howmedica Osteonic, Allendale, NJ), and highly cross-linked liners (Crossfire: 10.5MRads total radiation dose, Howmedica Osteonics, Allendale, NJ). All liners were sterilized in a oxygen free environment and stored in inert nitrogen packages. The plastic cups were sandwiched between two tissue-equivalent blocks to simulate the human hip region and brought to the fast neutron therapy unit. The neutron beam is produced in a super conducting cyclotron by bombarding an internal beryllium target with 48.5 MeV deuterons [d(48.5)+BE]. The cups were exposed to a dose of 15 Gy represented a typical neutron-dose given to a sarcoma patient. Wear testing was then performed utilizing a hip simulator (MTS, EdenPrairie, MN) with matched 28 mm diameter CoCr femoral heads. Physiologic loading was simulated with biaxial cross-path motion and peak loads of 2450 N. All tests were performed in 50 percent diluted alpha-calf serum(Hyclone Laboratories, Logan, UT) to simulate human serum exposure. Every 250,000 cycles the serum was changed and samples were removed from the machine, cleaned and weighed. The volume loss measurement shown below used the weight loss to calculate the wear rate. The wear rate was converted to volume loss by dividing by the density. The value is given as millimeter scubed per million cycles (mm3/mc). Phase one cups were tested within one month of radiation. Phase two cups served as soaked controls, and spent 7months in calf serum prior to wear testing. A total of five million wear cycles were performed for each cup to simulate five years worth of use.

The Averaged volumetric wear loss data demonstrated significantly less wear in CrossfireÒ compared to N2vac in both neutron irradiated and non-irradiated samples. This suggests that in sarcoma cases of the hip involving adjuvant fast neutron therapy, highly crosslinked poly-ethylene should be utilized. Averaging all data there was no statistically significant difference between the neutron radiation and non-treated components for both material conditions (N2VacÒ and CrossfireÒ). A trend towards decreasing wear in phase two samples was noted which may represent a material change in the liners exposed to serum over time. In addition, larger than normal variability in wear rates was seen within each group. Further testing of these liners is planned to elucidate these phenomenon. Table 1: – Volumetric wear loss per group. UHMWPE Material Volumetric wear Loss (mm3/mc) Standard Deviation N2VacÒ Phase 1 29.6 1.6 N2VacÒ Phase 2 14.0 N/a Neutron treated N2VacÒ Phase 1 52.2 18.1 Neutron treated N2VacÒ Phase 2 20.9 0.8 CrossfireÒ Phase 1 3.0 0.9 CrossfireÒ Phase 2 2.0 0.6 Neutron treated CrossfireÒ Phase 1 2.5 0.5 Neutron treated CrossfireÒ Phase 2 1.9 0.03 Graph 1– Averaged volumetric wear loss values

Sarcoma-dose (15Gy) fast neutron therapy adversely affects the wear of standard polyethylene acetabular cups. The wear rate of the conventional gamma-inert sterilized polyethylene increased by more than 50% following a 15Gy fast neutron treatment. The highly cross-linked polyethylene (Crossfire), on the other hand, was immune to the effect of neutron treatment at the same dose. The mechanisms responsible forth is difference are unclear and warrant further investigation. The clinical implication of this study is that for sarcoma patient receiving total hip replacement, highly crosslinked poly-ethylene rather than standard polyethylene should be used for the acetabular cup.


Prof. W. Thomas Dr. L. Lucente Dr. N. Mantegna

The improvement of the anchorage surfaces of the total hip arthroplasty (THA) has allowed a better bone integration of the stem and of the cup more durable in the time and often more advanced to the duration of those articular components subject to wear.

In case of lesion of one of these components, our study group (Arthro Surgery Group) has created a standard protocol for the revisions of total hip arthroplasty with well fixed stems and shells (PIT-STOP). We operated 22 patients with THA more than 10 years ago after the first implantation.

The average HARRIS HIP SCORE post-op is 92 in 1 year follow-up. The X-rays exams are excellent.

In case of wear of the polyethylene liner or of the head, we proceed to the substitution of the components if available and if the fixation mechanism is not damaged. In case of old designed THA, with articular components not available (polyethylene liner for the cup and ceramic or metal head), we use the liner fixation by cementation into the well fixed original metal back and a new head. If an alteration or an anomalous size of the neck is evidenced, we put on a metallic special device of measure adapted (taper case) on which we put a new ceramic head. In case of fracture of a ceramic head, we remove all the fragments and put on the prosthetic neck a new ceramic head with the metallic special device (taper case), after many washing and radical sinoviectomy.


Ken Mannan Amit Amin Gordon Blunn Tim Briggs Stephen Cannon Paul Unwin

Endoprosthetic reconstruction as a form of limb salvage in the management of malignant disease is common. We present our experience with custom-made distal femoral replacement as a form of limb salvage in the absence of malignancy.

49 cases of distal femoral replacement were identified using the unit database. There were 18 males and 31 females, with a mean age at operation of 62.3 years (range 26–86). There were 29 cases of failed total knee replacements, 8 cases of fracture associated with bone loss, non-union or deformity, 7 periprosthetic fractures, 3 aneurysmal bone cysts, and one case each of avascular necrosis and Gorham’s disease. Clinical and radiographic review of all available patients, including a functional assessment with the Musculoskeletal Tumour Society (MSTS) Score and Toronto Extremity Salvage (TES) score was undertaken.

The average follow-up was 5.4 years (range 1 to 29 years). Three types of endoprosthesis were used, rotating hinge, fixed hinge and arthrodesis prosthesis. One patient required amputation at 2 months following post-operative wound infection with methicillin-resistant staphylococcus aureus and subsequent inability to provide adequate soft tissue coverage. There was one revision at 16 months for deep prosthetic infection. 21 patients were available for functional follow-up. The mean MSTS score was 63.7 (range 16.0–86.7) and the mean TES score was 59.4 (range 9.4–87.5).

Custom-made distal femoral replacements have an established role in limb-salvage surgery for malignant disease. This series demonstrates the reconstructive capability of custom prostheses in non-malignant disease, where deformity causes functional embarrassment or when massive bone loss would normally lead to amputation.


Merkert Patricie

The choice to use alumina in the manufacture of a low-wear THR bearing made by Boutin and its co-workers has proven its effectiveness in almost 35 years of clinical use. A continuous development process aimed to improve mechanical properties led to today’s materials that exhibit extreme high reliability. The recent introduction in clinical use of an alumina matrix composite developed by CeramTec and available under the trade name Biolox®Delta represents the latest evolution of alumina. This material allow new design in ceramic components thanks to its equilibrium among high hardness, high toughness, and high bending strength.

Composites obtained introducing zirconia in the alumina matrix, known as Zirconia Toughened Alumina (ZTA) are candidate for use in THA bearings from a long time. A real breakthrough was represented by alumina ceramics toughened both by phase transformation both by platelets nucleated in-situ during sintering. Optimised processing and quality control led to optimised material behaviour.

The chemical composition and the microstructure of Biolox®Delta were optimised to achieve a ceramic material joining strength of more than 1200 MPa, Vickers hardness 1975, fracture toughness of 6,5 MPam-1/2, and extremely low wear also in the most severe simulator tests performed in microseparation mode.

The paper reviews the improvements introduced in the technology of ceramic for arthoplasty, and their effects on the microstructural properties and on the performances of the past and actual generation of ceramic for THR bearings, and summarise the results obtained in the development of alumina matrix composite Biolox® Delta.


JM Meswania S Taylor GB Blunn

For the treatment of malignant bone tumours in immature patients, extending prostheses are used to maintain growth in the affected limb. This new prosthesis allows the implant to be lengthened by using electromagnetic coupling that is simple and easy to use.

Because of bone tumour, fourteen patients between the age of 8 and 15 years underwent bone replacement treatment and a further two patients, both male 18 and 61 years, received the same treatment to restore limb length discrepancy. These implants consisted of a telescoping shaft where the expansion is done by a power screw driven by a gearbox connected to a NdFeB magnet. This prosthesis is capable of being extended under an axial load of up to 1350N. This is in line with 76 distraction force measurements taken in 43 patients with growing prosthesis where extension was achieved by invasive procedure and where a force of up to 1513N for an extension of 6mm was recorded. Once implanted, the non-invasive prosthesis is extended by placing the limb through an external drive unit. As the drive unit is turned on, it produces a rotating magnetic field capturing the implant magnet causing it to rotate in synchronisation. At full speed, the implant grows at a rate of 0.23mm per minute.

Of the sixteen patients, seven have been extended with one to its full capacity of 63mm. During extension, the patients have no sensations of vibration, heat, stretching or any other kind although the faint vibrations could be heard by placing a stethoscope on bony protrusions such as greater trochanter. At each sitting, the patients were extended by approximately 4mm during normal outpatient clinics and were able to walk as before immediately after the treatment. Patients with knee joint were functionally assessed before and after the treatment and showed approximately 10° to 15° of reduction in knee flexion/extension.

This new extending mechanism in these prostheses has provided the patients a treatment, which reduces trauma infection and discomfort. The mechanism of extension is reliable and effective.


Hiromasa Miura Shuichi Matsuda Ken Okazaki Yukihide Iwamoto

Minimally invasive surgery (MIS) for unicompartmental knee arthroplasty (UKA) has become increasingly popular. However, wound problems may be encountered with longitudinal skin incisions. This probably occurs because the skin is under excessively high tension during MIS. We have been using transverse incisions for MIS-UKA. We describe the surgical technique and an experimental study for assessing blood flow in the skin around the knee.

A 5–7 cm transverse skin incision was made from the medial edge of the patella at the level of 1–2 cm proximal to the joint line. The capsule was incised along the medial parapatellar up to the proximal two-thirds of the patella, and a few cm were also cut along the distal end of the vastus medialis. Because skin on the anterior aspect of the knee is more flexible in the longitudinal direction, exposure is easy even with a small incision.

Experimental study: We measured the direction of blood flow on the anterior aspect of the knee using laser flowmetry. Nine normal subjects were examined. A probe was attached to the skin on the medial parapatellar region, and two 7 cm long parallel depressors were applied bilaterally on the sides of the probe. The depressors were placed longitudinally or transversely under 30N of compression force, and then blood flow was recorded.

Blood flow was markedly increased due to congestion when the depressor was placed longitudinally. On the contrary, changes in blood flow were significantly lower when the depressor was placed transversely.

Transverse incision can lead to better exposure and permit an smaller incision. Moreover, transverse incisions are less invasive to the skin’s circulation and leave less distinctive scars than longitudinal incisions.


Hiromasa Miura Shuichi Matsuda Ken Okazaki Hidehiko Higaki Yukihide Iwamoto

Kinematics of mobile bearing TKA has been evaluated by fluoroscopic studies. However, these studies focused on the relative motion between the femoral component and the tibial tray. The purpose of this study was to investigate the kinematics of the polyethylene insert in mobile bearing TKA under dynamic conditions using a custom-made 6-DOF kneesimulator.

The mobile bearing TKA used in this study had a ågstopåh on the tibial tray, allowing rotation and translation. The implants were mounted on the knee simulator. Vertical load and 5-DOF motions were regulated according to the kinematic data from the literature. The knee simulating test was conducted under three different conditions including a static condition and dynamic conditions of 0.5 Hz and 1.0 Hz. Four metal balls mounted on the insert were observed with two cameras, and position of the insert was calculated. Contact pressure on the insert was also measured using a tactile sensor.

Under the static condition, the femoral component kept almostfull contact with the insert. However, the insert shifted posteriorly with impingement to the stop under the 0.5 Hz condition. Under the 1.0 Hzcondition, antero-posterior translation of the insert was larger with impingement to the stop in both directions and contact pressure was greater.

To our knowledge, no study on the motion of the insert of the mobile bearing TKA has been reported. In the present study, the insert showed different motion and contact stress according to the given condition, in spite of the same relative motion between the femoral component and the tibial tray.


M. Marek V. Pawar S. Tsai R. Thomas J. Sprague G. Hunter A. Salehi

Due to their superior wear characteristics, oxidized Zr-2.5Nb heads are used with hip stems made of conventional orthopaedic alloys. Galvanic interactions between Zr-2.5Nb (Zr) and Ti-6Al-4V (Ti), cobalt-chromium (CoCr), and 316L stainless steel (SS) alloys were evaluated.

Galvanic current density was measured for Zr/Ti,Zr/CoCr, Zr/SS, CoCr/Ti, and CoCr/SS couples under static conditions in aneutral Ringer’s solution and in an acidic (1.7 pH) solution. To simulate fretting, one or both coupled alloys in the neutral solution subsequently were abraded by a bone cement pin (82 MPa Hertzian stress). An extended(7-day) static test in the acidic solution was performed for Zr/SS and CoCr/Ti to simulate crevice conditions. The dissolved metal ion concentration was determined using direct coupled plasma emission spectrometry.

Mean initial current densities of the Zr/SS, SS/CoCr,Zr/CoCr, CoCr/Ti, and Zr/Ti couples were 3.0, 0.36, 0.16, 0.05, and 0.04μA/cm2, respectively, in the neutral solution, and 0.57, −0.29, 0.04, 0.02, and 0.03 μA/cm2, respectively, in the acidic solution (positive when first alloy was anode). Within 30 minutes, all values decreased below 0.02μA/cm2. The current densities increased by orders of magnitude under fretting conditions. When both alloys were abraded, the highest values were minus;677 and 464 μA/cm2 for CoCr/Ti and Zr/SS, respectively. In the extended static test of Zr/SS, the mean total metal ion concentration decreased from 8.15 mg/L when the alloys were uncoupled to 4.50 mg/L(p=0.007) when they were coupled. For CoCr/Ti, the change from 1.28 to 1.72mg/L when the alloys were coupled was not statistically significant(p=0.22).

With its strong tendency to passivate, the Zr alloy produced galvanic interactions within the range observed with conventional alloy couples. Its anodic characteristic helped protect SS in a galvanic couple.


K. Mitchell S. Banks W.A. Hodge

Achieving normal strength after total knee arthroplasty (TKA) remains a major challenge, with recent reports suggesting strength following TKA averages 65% of normal. Gait lab studies have reported the greatest strength (80%–84% of normal) in knees with intrinsic stability, i.e. knees where the implant surfaces or retained ligaments provide definitive control of tibiofemoral motions such that dynamic muscle stabilization is not required. Superior results have been reported for bicruciate retaining arthroplasty, posterior-stabilized arthroplasty with early-engaging cams, and single radius highly congruent posterior-stabilized arthroplasty. The goal of this study was to determine if knees with an intrinsically stable posterior cruciate ligament (PCL) retaining implant design showed strength comparable to these other intrinsically stable types of arthroplasty.

Ten patients with unilateral intrinsically stable PCL-retaining knee arthroplasty were studied using full-body motion capture, force platforms and electro myography while they stepped onto and over a 20cm box. The implant design includes an asymmetric tibial bearing surface with a fully congruent lateral articulation (0°–70° flexion). Subjects were recruited on the basis of combined KSS scores greater than 180 one year after surgery. Peak knee flexion torques, normalized by body weight and height, are used as a measure of functional strength.

Knees with posterior cruciate retaining, intrinsically stable TKA exhibit functional strength comparable to other intrinsically stable TKA designs and superior to strength in less stable TKA designs. These knees show some reduction of knee flexor activation, indicating that antagonist coactivation is not required for joint stability. Stable joints permit more optimal muscle activation, making patients effectively stronger while reducing loads at the joint.


M. E. Murphy O. Clarkin G. M. Insley

The recent development and use of Calcium Phosphate (CaP) based products as orthopaedic implants has increased the need for the development of a greater understanding of the starting materials inherent properties. Chemical composition and crystal phase greatly influence the final product’s behaviour in the body. By gaining a deeper understanding of these properties, greater control in making tailor-made products can be achieved.

Calcium Phosphate based powders of varying CaO: P2O5 ratios were prepared by cold isostatic pressing into compact discs (13 mm diameter x 3.6 mm height) and subsequently sintered at temperatures ranging between 200 to 1140 degrees Celsius for a period of 8 hours. The starting powders had CaO:P2O5 ratios ranging from 1.165 to 1.22. Each composition was analysed for microstructural and associated crystal phase modifications with varying sintering temperatures, by scanning electron microscopy (SEM) and X-ray diffraction (XRD).

All compositions were shown by XRD to have an initial starting composition of Hydroxyapatite (HA) and Dicalcium Phosphate Anhydrous (DCPA). With increasing sintering temperatures, it was found that the initial composition readily transformed to beta-tricalcium phosphate(B-TCP) for all of the CaO:P2O5 ratios. However, it was found that the higher CaO:P2O5 ratio materials tended to retain residual HA. Sintering of all powders was found to have a densification effect on the microstructure of these compositions.

The sintering behaviour of calcium phosphates is extremely dependent on the CaO:P2O5 ratio of the material, influencing both the crystal as well as microstructural properties of the sintered components. This in-turn will have a strong influence on the behaviour of this biomaterial when placed in-vivo.


Takashi Nakamura Bojian Liang Daizabro Ohnish Kentaro Ise Keiichi Kawanabe

Zirconia ceramic femoral head has better mechanical properties than those alumina head has. However, it is concerning whether the wear of UHMWPE against zirconia head is as low as that of alumina head. We compared polyethylene wears against 22.225mm alumina and zirconia heads in total hip arthroplasties (THA) occupied in our hospital.

Kobelco hip prostheses (Kobelco, Kobe, Japan) were used. Titanium alloy stem was cement-fixed and all-polyethylene acetabular components were articulated with alumina or zirconia femoral heads. In the cases from February 1996 to December 1998, 96 primary cemented total hip arthroplasties (THA) in 87 patients of osteoarthritis were observed with a minimum follow-up of five years. The clinical results were evaluated using JOA hip score (100 in normal hip). There were 46 hips with alumina heads and mean follow-up of 6.2 years, and 51 hips with zirconiaheads and mean follow-up of 5.2 years. Mean ages at operation were 58 years. For each patient, the initial postoperative and the latest anterior-posterior radiographs of the pelvis were selected. With the custom software Image-Pro Plus version 4.0, linear wear and volumetric wear were measured.

Clinical results of both heads showed no difference. Linear wear rate of alumina is 0.080±0.047mm/year, while it is 0.147±0.069mm/year for zirconia, significantly higher than alumina (p?0.0001). Volumetric wear rate of zirconia (42.499±20.233mm3/year) is also significantly higher than alumina (27.049±17.216mm3/year) (p?0.0001).

The low thermal conductivity of zirconia is thought to cause local high temperature, leading to the phase transformation and lower-temperature aging degeneration (LTAD) of zirconia head surface. In order to solve this problem, alumina-adding zirconia compound ceramics with lower phase transformation were developed. Hip simulator test revealed much lower wear rate of improved zirconia. This will be discussed.


T Moro Y Takatori K Ishihara T Konnno Y Takigawa H Takadama K Nakamura H Kawaguchi

Despite improvements in techniques and materials, aseptic loosening of artificial hip joints remains as the most serious problem. This study investigated mechanical and biological effects of biocompatible 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer on prevention of aseptic loosening.

To examine mechanical effects of MPC grafting, we performed hip simulator tests (3million cycles) using cross-linked polyethylene (CL-PE) liners with or without nano-grafting of MPC onto articulating surface (MPC liner/CL-PE liner) and PE liner against CoCrMo heads. To examine biological responses of macrophages and osteoblasts, we prepared MPC nanoparticles (500nm). Using in vitro/vivo murine particle-induced osteolysis model, we examined biological effects of MPC nanoparticles on osteoclastogenesis.

The friction torque was about 90% lower in MPC liners than control liners. Total amounts of wear produced from MPC liner was about 1/5and 1/30 of those from CL-PE and PE liners, respectively. Three-dimensional analysis and SEM analysis of MPC liners revealed no or little wear. The effect of MPC nanografting was maintained even after the test, because XPS analysis confirmed the remainder of specific spectra of MPC on the liner surface. When nanoparticles were exposed to cultured mouse macrophages, MPC nano particles were hardly phagocytosed by macrophages and did not enhance the concentration of bone resorptive cytokines and PGE2. Furthermore, culture medium of macrophages exposed to MPC nanoparticles did not induce RANKL expression in osteoblasts and osteoclastogenesis from bone marrow cells. In vivo murine osteolysis model, particle-induced bone resorption was hardly observed in mice implanted MPC nanoparticles.

Some medical devices grafted MPC onto itssurface have been already used under authorization of the FDA. This study demonstrated that MPC grafting markedly decreases wear production. In addition, even if wear particles are produced, they are biologically inert in respect to phagocytosis by macrophages and subsequent resorptive actions, suggesting an epochal improvement of artificial hip joints preventing aseptic loosening.


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Antonio Murcia MA Suárez L. Rodríguez G. Acebal

Tantalum is a pure metallic element and is attractive for use in orthopaedic implants because it is one of the most biocompatible metals available for implant fabrication. The potential advantages for the use of porous tantalum in total hip arthroplasty include:

excellent bone and tissue ingrowth observed histologically;

direct polyethylene intrusion into the metal substrate. This allows the elimination of any potential backside wear in the monoblock cup;

The two-piece design consist of a tantalum shell with screw holes for fixation into the dome of the ilium and posterior column.

A polyethylene liner is cemented into the tantalum shell to eliminates backside motion. In addition, acetabular augments of porous tantalum have been developed for use in restoration of major bone deficiencies. Prospective study on a case serie of 113 THA’s performed by two surgeons in a single institution.

From 2000 to December 2003, 113 hips have undergone arthroplasty using porous tantalum implants consisting of 54 primary hip arthroplasties and 59 revision THA’s. The patients where evaluated clinical and radiographically every 3 month during the first year, and after yearly. Mean patient age was 64,2 years, (range 44–87); with 59% males and 41% females.

No patients died or lost to follow-up. No further surgeries of the involved hip. No radiographic signs of loosening of the acetabular component according to the criteria of Hodgkinson et al. No problems specifically from the use of acetabular augments or extra screws has been noted. Of the revision series, a total of 16 cases have received acetabular augments. Complications included 1 superficial infection, 2 dislocations. No vasculonervous complication; and in 2 cases technical difficulties to achieve good fixation due to ethiology of the THA (desarthrodesis). The average Harris hip score improved from 48 to 89 following primary surgery.

Tantalum acetabular components for primary and revision hip surgery have performed well for up to 3 years, and have excellent stability. The two-piece acetabular shell and augments permits the reconstruction of every acetabular bone defect.


O. Moreschini M. S. Boccanera F. Pulcini A. Nocca

Conservative hip arthroplasty with resurfacing of the acetabulum and the femoral head is an attractive concept particularly in young and active patients. The principal advantages are less femoral bone destruction and resection, avoidance of stress shielding in the proximal femoral shaft; however this technique don’t permit a same preservation of acetabular bone stock and a mini invasive surgical approach.

From January 2003 the Authors have performed 5 metal-on-metal Birmingham hip resurfacings in patient under the age of 58 with avascular necrosis of the femoral head (without a wide necrosis) or primary osteoarthritis. In all cases was performed a posterior approach slightly more extended to permit the release of the gluteus maximus tendon; the rehabilitation program involve immediate full weight bearing one day postoperatively. Data were collected intraoperatively and postoperatively in a prospective way.

The early clinical and radiological results are very satisfactory: resurfacing hip arthroplasty appears to be a good alternative for the treatment of young patients, permitting a preservation of femoral bone stock and early functional recovery. In our opinion the key factors for a good result is a meticulous technique and a good bone quality.


Jacob Munro Melissa Rossaak Rocco Pitto

Considerable advances have recently been made in improving cementing techniques in THA. It has been proposed that certain benefits in terms in reduction of curing time and increased bonding at the cement-stem interface, can be attained by the preheating of the femoral component prior to insertion. The aim of this study was to assess the clinical and radiological 5 year follow-up results of the preheating technique used for fixation of the femoral stem (Lubinus, Link, Germany).

100 consecutive patients (100 hips) with OA and an average age of 72 years (65–85) were operated on by a single surgeon in a single institution. two cohorts of 50 hips were randomised to either conventional cementing techniques, or with a preheated femoral component (40–50 degrees). The same cement was used in both cohorts (Cemex, Tecres, Italy). Follow up was clinical (Harris Hip Score) and radiological.

A reduction in curing time provides significant time savings without compromising implant performance. We recommend preheating of the femoral component for suregons experienecd in joint replacement and with a skilled surgical team.


SATYA NAMBU MICHAEL CARROLL STEVE SEYER IRINA TIMMERMAN

Large diameter metal-metal bearings possess several clinical advantages over small bearings including greater joint stability, improved range of motion, and lower wear due to improved lubrication. Simulator wear tests were conducted to assess the effects of thermal processing on the wear behavior of large diameter metal-metal hip bearings.

Three groups of high carbon, cast 54 mm hip bearings with different thermal processing histories were tested. Two groups of bearings were manufactured to identical specifications and subjected to either no heat treatment(as-cast) or to typicall thermal processing prior to testing. The third group was comprised of commercially available as castbearing systems. Wear tests were performed on a Shore Western orbital bearing wear test machine. A simulated gait profile (triple-peak Paulprofile) with a maximum force of 2000N was applied to the bearings at a frequency of 1 Hz. The bearings were tested in the inverted position (headabove, shell below).

The general wear behavior of all three groups of bearing couples was similar to that previously reported for metal-metal bearings. All couples exhibited a run-in wear phase followed by a low-wear steady-state phase. For all bearing couples tested the heads demonstrated more wear than the shells. The appearance of the worn surfaces of all the bearing couples tested in this study were consistent with that of previously reported in-vitro wear testing as well as metal-metal hip bearing retrieval studies. There was no statistical difference among the three groups tested in the run-in or steady-state wear rates, although the heat treated bearings tended to wear less on average.

The results of this study indicate that thermal processing has no adverse effect on the wear of large diameter metal-metal hip bearings.


Sam Nasser

Hypersensitivity to metal alloy orthopaedic implants has become identified increasingly as a cause of implant failure. Because of their hypoallergenic properties, ceramic materials have been recommended as an alternative to metals. Unfortunately, the cost of ceramics and limitations imposed by their material properties has restricted these applications. The metalloceramic composite Oxinium® has been suggested as asubstitute. This is the first study to prospectively compare these materials in patients with documented cobalt-chrome hypersensitivity.

Over a period of ten years, preoperative screening using skin patch testing and in vitro leukocyte stimulation testing of patients with gonarthrosis and a history of metal hypersensitivity identified sixteen patients with allergy to cobalt-chrome alloy. Twelve (all& ) underwent primary, and four underwent revision (3& , 1%) knee replacement surgery using either alumina ceramic femoral components (3 primary, 2 revisions) or Oxinium® femoral components (9 primary, 2 revisions) All implants were fixed with acrylic cement, and all-polyethylenetibial implants were used in each procedure.

None of the patients in the primary groups developed symptoms of allergic reaction at a minimum of one year following surgery. Serial serum antibody and leukocyte stimulation studies have shown no reaction following placement of either type of prosthetic knee. Those undergoing revision surgeries had rapid resolution of preoperative symptoms of pain, effusion and eczematous rash. Serum studies showed a concomitant fall inantibody levels. The two patients undergoing revision surgery with alumina femoral implants subsequently underwent second revisions (both at 8 years) using Oxinium® femoral implants. Neither developed clinical symptoms orchanges in antibody profile.

While the number of patients in the present study is relatively small, it is the only independent, prospective, clinical comparison of these materials. The uniformly good results suggest implants of Oxinium® offer the hypoallergenic properties of alumina without adverse-material properties and at a lower cost.


Sam Nasser Robert Poggie

Revision TKA patients who have severe patellar bone loss or undergo patellectomy often have inferior clinical results. Current treatments are limited and often unsatisfactory. This study reports the surgical technique and clinical follow-up (4-year minimum) for 10 patients who underwent revision or salvage TKA and received a porous tantalum implant for replacement of their patella.

The prosthesis is comprised of two parts, a poroustantalum base and titanium suture ring for initial fixation, and a polyethylene surface that is cemented to the base. The surgical technique evolved over the course of the first three cases, during which the suture technique and size (non-absorbable number 2) and bone preparation were defined.

The results of this study indicate that this porous tantalum patella is an effective prosthetic option that is capable of improving function and reducing pain for patients with severe patellar boneloss and complicating factors.


Takashi Nishii Nobuhiko Sugano Hidenobu Miki Masaki Takao Tsuyoshi Koyama Hideki Yoshikawa

Alendronate is a potent inhibitor of bone resorptive activity, and has been shown to prevent and restore periprosthetic osteolysis in experimental models. A preliminary study was conducted to examine clinical usefulness of a lendronate treatment.

Twenty-five patients (27 hips) with radiological evidence of osteolysis after cemented total hip arthroplasty were included. Of these, 14 patients (15 hips) were administered 5 mg of alendronate daily (alendronate group), and 11 patients (12 hips) did not receive alendronate treatment (control group). The subjects were followed up for 12 months, using radiological examinations and biochemical markers. The radiological analysis was evaluated blindly by 2 joint arthroplasty experts, each with more than 10 years of experience, without knowledge of alendronate administration.

In the alendronate group, average serum bone alkaline phosphatase and urinary excretion of the N-telopep-tide of type I collagen values decreased from the baseline values after administration of alendronate, to 71% and 76% of baseline at the 3-month examination, and 57% and 62% at the 1-year examination, respectively. In the control group, expansion of osteolysis was found in 5 hips (42%) and no hip showed restoration of osteolysis. In the alendronate group, expansion of osteolysiswas found in 2 hips (13%), and restoration of osteolysis was found in 5 hips (33%). There was a statistically significant difference in ratio of hips with osteolysis restoration between the 2 groups (p< 0.05). In the alendronate group, there was no significant difference in age, average linear wear rate of polyethylene, and the biochemical markers, between the hips with and without diminishment of osteolysis.

Conclusions: The present results indicate that clinicala-lendronate treatment can prevent and restore periprosthetic osteolysis, which is generally thought to require surgical intervention. These findings warrant further study of the effects of duration and dose of alendronate treatment, component materials, and component fixation methods.


T Nakamura H Ito Y Atsuta H Tanino I Nishimura R Shimizu T Ishida Y Mitamura T Matsuno

Thigh pain appears often after THA used of the cement-less femoral components, but the appearance mechanism of thigh pain does not have been elucidated. As one factor of manifestation of thigh pain, it has been guessed that the pressure from the inside of medullary cavity of bone by the stem. The purpose of this study is confirming whether the flexor reflex is caused, by using the femur of a rabbit that applied the pressure from the inside of medullary cavity of bone.

Japanese white rabbits with weight of about 3kg were used. Evaluation of the appearance of the pain by the pressure was performed by measurement of the hind leg flexor activity produced by the flexor reflex. After confirming that appearance of the muscles activity by the pain reflex from adding the pain stimulus to the hind leg skin of rabbits, we loaded of the pressure into the inside of medullary cavity of bone and observed whether the muscles activity appears. As the laboratory animals model, we prepared two kinds of rabbits by the difference in the amount of reaming. And we tested how the differences show up between these two kinds of rabbits.

In the rabbits with few amounts of reaming, the flexor reflex appeared in low pressure. But, in the rabbits with many amounts of reaming, the flexor reflex did not appear in high pressure, either.

It is known that the somatic sensory nerves are distributed in the bone, and it is known that the sensory nerve ends exist in the medullary cavity of bone. It was suggested that the pain is induced, when the sensory nerve ends remained in the inside of medullary cavity of bone and the pressure in whicha reaction is possible was carried out there.


Hirotsugu Ohashi Hiroyoshi Iwaki Akio Kobayashi Kunio Takaoka Yuji Tanabe

Highly closslinked polyethylene has been developed to reduce polyethylene wear and to expect the longevity of THA. In daily activity of patients, total hip prostheses repeatedly suffer impact loading. However, the mechanical properties, especially impact load transmission, are not well investigated and the viscoelasticity might influence the loosening of cemented all-polyethylene cup. In this study, the impact load transmission through the complex of polyethylene cup, ceramic ball and metallic femoral stem was investigated.

Impact compressive tests on the complex were performed using Hopkinson pressure bar apparatus. Conventional and highly crosslinked polyethylene cups of three different sizes (40mm, 50mm, 56mm)were compared. The impact load was applied either from the cup or from the stem. The impact load transmission ratio (ILTR) i.e. the ratio of the magnitude of transmitted load to that of incident one was investigated. The loading pulse profiles were theoretically calculated based on the one dimensional elastic wave propagation theory and were compared with experimental results.

The ILTR was independent of the cup size in all experimental conditions. When the impact load was applied from the cup, the ILTR was not different between two types of polyethylene. On the other hand, when the impact load was applied from the stem, the ratio was greater than the previous loading condition, while the ratio of crosslinked polyethylene was significantly lower than that of conventional one (p < 0.05). The theoretically predicted stress pulse profiles were well correlated to the experimental ones.

The lower ILTR in highly crosslinked polyethylene is considered to be due to lower stiffness. These mechanical properties increase the deformity of the cup and may cause the loosening of the cup. These results indicated that the ILTR was not different among cup sizes, while the ratio was significantly affected by the loading conditions and the type of polyethylene.


Ken Okazaki Hiromasa Miura Shuichi Matsuda Taro Mawatari Naohide Takeuchi Yukihide Iwamoto

It is recommended in the TKA operation to balance the tension of soft tissues to make the rectangular gap in both flexion and extension because significant imbalance may result in eccentric stress on the polyethylene insert. However, no intensive research has been done on the medial and lateral laxity of the normal knee

X-ray of 50 normal knees were taken under the varus or valgus stress in both extension and flexion at 80 degrees. The angle of lines on the femoral condyles and tibia plateau was measured. The same methods were also done for the 20 osteoarthritis knees.

In extension of the normal knees, the mean angle was 5.06 degrees in varus stress and was 2.46 degrees in valgus stress. In flexion of the normal knees, the mean angle was 5.04 degrees in varus stress and was 1.82 degrees in valgus stress. Therefore, the lateral laxity was significantly larger than the medial laxity in both extension and flexion (p< 0.0001). The lateral laxity was significantly larger also in osteoarthritis knees (p< 0.0001).

There are some arguments about the priority to make the perfect rectangular gaps. The methods to measure the tension of soft tissues during the operation are not accurate and does not always reflect the post-operative tensions. Furthermore, the tension during the operation may be different from dynamic phase such as walking and standing. The present study showed that the mediolateral laxity was asymmetrical in the normal knees. This imbalance may be necessary for the medial pivot movement of the normal knee. These results suggest that a slight lateral laxity is acceptable during TKA operation and may be beneficial to achieve the normal kinematics especially for the cruciate retaining prosthesis.


M. Oransky M. Cianfanelli G. Montanari

Reconstruction and revision of the acetabulum component in loose hip implants may be conducted with several techniques, depending on the entity of the defects and of the surgeon’s experience. Impaction grafting with cemented cups or associated to rings or non cemented cups with flanges are some of the options. Rings or cages may have a containment effect but usually do not osteo-integrate.

Since 2001 we performed 28 acetabular revisionswith trabecular tantalum metal cups (Zimmer) for Paprosky type II and IIId efects. All the patients but three needed fresh frozen morcellized allograft. Eight patients had less than 50 years; twelve had a previous acetabular fracture that ended in an improper reduction or an infection.Three had a previous infected joint implant, one an infected non-union; this group before the definitive reconstruction had one to three débridement procedures. Six patients without infection had three to six previous surgeries including hip reconstruction. Medial containment disks were used in six patients, to contain bone defects. All patients had a trabecular metal cup fixed with screws or stabilized with press fit alone , associated to a cemented poly cup.

Dislocations were not observed. The cemented cup was oriented to overcorrect the head coverage only in four cases. Three patients had a high hip center, but only one has shorter limb. At short follow up no lyseswere observed with adequate osteointegration. Infection did not recurred in any patient.

TMT cups simplify complex reconstructive procedures, and in spite of cementing a poly cup, osteointegration occurred in all patients. Lysis was readable in three patients but it was marginal and restricted. Great attention should be kept when an additional hole is done in the cup to confine metal dissemination to the soft tissues.


Hironobu Oonishi Sok Chol Kim Masaru Ueno Ryota Aoki Masayuki Kyomoto

Different studies have shown that gamma-irradiated polyethylene generally results in degradation by oxidation. On the other hand, we clinically used ultra-high molecular weight polyethylene sterilized by gamma-irradiation of 1,000kGy dose in the air (100Mrad cross-link polyethylene) for total hip prostheses from 1970 to 1978, and excellent clinical results extending for 30 years were shown. In the present study, the wear characteristics were evaluated by hip simulator on 100Mrad cross-link polyethylene cups which were available after shelf-aging for extremely long term (about 30 years). The results are compared with those ofthe explanted cup after 30 years of clinical use as well as the cups aged by acceleration in order to review the influence of aging environments and themechanism of degradation.

The 100Mrad polyethylene cups were manufactured by Mizuho Medical Instruments in the 1970s and they have been in stock on the shelf in air-containing package or without being packed for 30 years. These cups were tested with alumina heads (36mm in diameter) by the AMTI hip-joint simulator.

The 100Mrad polyethylene cup aged for 30 years without a package showed considerable initial wear. In case of the same cup aged in an air-containing package, however, a significant reduction of wear was observed even with the presence of the oxidized surface layer. This observation agreed with the low wear of explanted 100Mrad polyethylene after 30 years of clinical use. These results suggest that wear properties of this gamma-irradiated polyethylene are significantly affected by the environmental conditions it was kept for long period of time.


Joel T. Outten Boyd M. Evans Richard D. Komistek Douglas A. Dennis

The objective of this study was to compute the in vivo dynamic tibiofemoral contact forces for normal alignment, and then evaluate the change in contact forces and pressures with increasing varus-valgus and internal-external rotational malalignment of the femoral component. A three-dimensional computational model of the lower limb during deep knee bend was created using Kane’s method of dynamics. The change in forces from normal with malalignment of up to 10° valgus, 10° varus, 10° internal axial femoral rotation, and 10° internal axial femoral rotation were determined. In this study, varus-valgus malalignment had the greatest effect on medial-lateral pattelofemoral contact forces, with a maximum increase of 2.25 times body weight for 10° valgus malalignment. Axial malalignment had the greatest influence on tibiofemoral contact forces.


Joel T. Outten Richard D. Komistek Mohamed R. Mahfouz Daniel D. Auger

At present, computational modeling has not been utilized as a design tool for total knee replacement (TKR). Also, classifying a new design as successful usually requires many years of long-term clinical follow-up studies. Computational modeling presents an opportunity to contribute to implant design evaluations and prediction of long-term success, during the early stages of the implant design process. The purpose of this study was to construct a computational model that will determine and compare in vivo dynamic forces and torques of the non implanted and implanted knees. It is hypothesized that this model will provide valuable information pertaining to post-implantation boundary conditions during the design phase.

A three-dimensional (3-D), inverse dynamics model of the human lower limb was created. System differential equations were derived for the human lower extremity using Kane’s theory of dynamics.Input kinematics were obtained for five normal knees and five posterior stabilized TKR, determined while subjects performed deep knee bend while under fluoroscopic surveillance. Musculo tendinous units were assumed to act along straight line segments, and ligamentous units were represented by nonlinear elastic elements. Knee kinetics were calculated and compared fo reach group and a comparison was conducted.

Kinetics were much more variable for the TKR group, and tibiofemoral contact forces were on average higher than the normal group: 2.47 times body weight (BW) and 2.21 BW, respectively. Increased posterior femoral rollback lead to lower axial contact forces and lower quadriceps forces in both groups. Force patterns were very sensitive to input patient specific kinematics.

The predicted tibio femoral forces were higher in TKR subjects, which is consistent with current clinical knowledge. Force patterns for the normal subjects were more consistent than those forthe TKR subjects, which was primarily attributed to the greater variance in kinematics for the TKR subjects. This study represents a first step in constructing a design facilitation tool for TKR technology. Successful designs will be determined by producing kinetic patterns most similar to normal knee patterns.


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C Piconi G Maccauro F Muratori G Gasparini

The choice to use alumina in the manufacture of a low-wear THR bearing made by Boutin and its co-workers has proven its effectiveness in almost 35 years of clinical use. A continuous development process aimed to improve mechanical properties led to today’s materials that exhibit extreme high reliability.

The recent introduction in clinical use of alumina matrix composites represents the latest evolution of alumina that thanks to high hardness, toughness, and bending strength allow to manufacture new design of ceramic components. Composites obtained introducing zirconia in the alumina matrix, known as Zirconia Toughened Alumina (ZTA) are candidate for use in THA bearings from a long time. A real breakthrough was represented by alumina ceramics toughened both by zirconia both by platelets nucleated in-situ during sintering (Zirconia-Platelet Toughened Alumina - ZPTA).

The chemical composition and the microstructure of ZPTA were optimised to achieve a ceramic material joining strength of more than 1200MPa, Vickers hardness 1975, fracture toughness of 6,5 MPa m-1/2, andextremely low wear also in the most severe simulator tests performed in microseparation mode The paper reviews the improvements introduced in the technology of ceramic for arthoplasty, and their effects on the microstructural properties and on the performances of the past and actual generation of ceramic for THR bearings, and summarise the results obtained in the development of alumina matrix composites.


G Pignatti C Stagni V Bochicchio G Dolci A Giunti

The vast majority of total-joint-replacement components utilized are modular to some degree. Modularity increases the surgeon’s options in both primary and revision THA. Modular prostheses allow the surgeon intra-operative versatility, allowing adjustment of leg length, offset, neck length, and version. This is particularly helpful in CHD, posttraumatic arthritis and in hip revision. Modularity may be applied also to the neck, enlarging the range of choice for difficult cases. Howeverusing of a modular interface increases risk of fretting, wear debris, and dissociation and mismatching of components.

A series of 87 revision THA performed between 1997 and 2003 using modular neck was reviewed. The pros-theses are AnCA-Fit with a cementless titanium anatomical stem and Profemur with a tapered revision titanium stem. Both provided with a modular neck inserted by morse taper and a hemispheric press-fitted cup. All the implants have a ceramic-ceramic coupling. Four cases were performed due to recurrent dislocation and 83 for implant loosening. Retrieved necks were studied searching for corrosion.

No cases of disassembly or fracture of the neck were observed. Two cases of dislocation were treated with brace. Analysis of retrieved necks confirmed the absence of corrosion. Leg length discrepancy decreased from 57.7% to 22%. One post-operative infection was successfully treated with debridment.

Modular neck system allows to correct intraoperatively leg length and offset, choosing between five interchangeable necks available in two lengths: straight, varus-valgus, ante-retroverted. Restoration of hip biomechanics prevents instability. Removal of the neck allows a better surgical exposure when femoral stem is retained. Moreover it allows to maintain ceramic-ceramic coupling. Modular prosthesis has some problems related to risk of corrosion, fretting, fracture or dislocation of components. We observed no cases of disassembly of components or fracture and comparative analysis between retrieved necks and those experimentally studied confirmed absence of corrosion.


H Pandit C. Jenkins D. Beard H S Gill P McLardy-Smith CAF Dodd DW Murray

Oxford Unicompartmental knee arthroplasty (UKA) is now performed using a minimally invasive surgical (MIS) technique. Although early results are encouraging, the studies assessing outcome could be criticised for the restricted number of patients and limited follow-up. Aim of this study was to assess clinical outcome and prosthetic survival rate inpatients with minimally invasive Oxford medial UKA.

This prospective study assessed 500 consecutive patients, who underwent cemented Oxford UKA for medial OA using MIS technique. Patients were assessed using objective and functional Knee Society Score (KSS).

This study has confirmed preliminary findings that Oxford UKA using a minimally invasive approach is safe, reliable and effective.


C. Pattyn K.A. De Smet

The difference in outcome after uncemented ceramic-on-ceramic total hip and metal-on-metal resurfacing is looked at in comparable patient groups. Theoretical advantages in resurfacing are less bone resection, normal femoral loading, avoidance of stress shielding and restoration of normal anatomy. In addition, reduced risk of dislocation, less leg lengthening and easier revision should convince us to perform metal-on-metal resurfacing. These advantages of resurfacing, the subjective “better feeling” and having a more “normal” joint is illustrated by objective proof with functional scores and activity.

The first 250 cases of 1067 (September 1998 –March 2004) performed Birmingham Hip resurfacings (MMT, UK) (follow up 2–5 years, mean age 49.54) were scored clinically and functionally. In the same period (July 1996 – September 2003) 164 ceramic-on-ceramic Ancafit total uncemented prostheses (Wright Medical, US) were implanted inthe same age and activity group as the resurfacings. The first group of 126 patients (follow up 2 – 6 years, mean age 46.76) was compared with the resurfacing group. All the data were collected intra operatively and postoperatively, mostly in a prospective way.

At the most recent follow-up there was a significant statistical difference in Harris Hip Scores (global and total), and activity function between the 2 types of pros-theses. Resurfacing scored a Harris Hip Total of 97.9 (ceramic THA 92.1). Of the resurfacing patients 60.71 had a strenuous activity (ceramic THA 30.43). Dislocation rate in resurfacing group was 0.4% (ceramic THA 3%).

The early clinical results in the group of metal-on-metal resurfacing are very satisfactory with Harris and PMA scores indicating early clinical success. The high percentage of strenuous activity in this young patient group satisfies the expectations of the resurfacing. The difference with a normal uncemented hip is stated with a better outcome in Harris Hip Scores and a better activity level.


E Paschina A Causero E Cautero E Campailla

The degenerative processes of the glenohumeral joint can be derived from primitive glenohumeral arethrosis, post traumatic arthrosis, neurogenic arthropaty and rotator-cuff arthropaty with inveterate cuff tears. These conditions have shared characteristics but the arthropaty from an inveterate tear of the rotator cuff estabilishes a characteristic connected to the distinctive lesions that culminate in the well-known radiologic imaging of ace-tabularization.

Our experience of prothesization of the shoulder referring to this final result, with wich we previously tented toward using a bipolar endoprothesis, often with comforting but at time also decidedly disappointing results. Overall, our dissatifaction was attributed to the insufficient mobility regained with modest remaining muscle-tendons available, and to the anterior instability of the implant if not contained in a valid coracoacromiale arch. For this reason we are tending toward ageo-metric inverse prothesis with the supposition of intrinsic stability and a lever arm favorable to the contraction of slight muscolar recruitment. The inverse Delta prothesis provide an innovative therapeutic option for many patients with serious glenohumerale arthrosis associated with massive tear of the rotator cuff with the rising up of the humeral head. Our work intends to show which are the advantages and the limits, including surgical ones, of using the result of the prothesization of eight specially selected patients treated with the Delta prothesis. Without doubt the innovative architecture and the recent modification ofthe prothesis become clear; it becomes possible to do certain manouvers very easily which in the past were more complicated; also highlighted is the immediate symptomatic benefit that the patient obtain from the joint-substitution operation with this type of prothesis. On the other hand, it is therefore fundamental to select the patients in a very precise way who can undergo this operation, to have a notable improvement in their lifestyle. The modest but significant esperience derived from these first cases treated with the geometri inverse prothesis have introduced us to a relative simple prosthetic system, but just a bit more invasive than the endoprosthetic surgery; it is stable and well-tolerated, able to adequately satisfy the modest functional request permitted by the residual anatomic substratum. The autors, based on this limited but significant experience, intented tomention same technological problems inherent to the various od the implantation including the dif-ficulties occasionally met and resolved.


C. Pattyn A. Kloeck K.A. De Smet

Dislocation rates after total hip arthroplasty vary from 1% to 8% and approximately 1% will require revision surgery to treat hip instability. From these revisions only 60% is successful with redislocation frequencies from 8.2% to 39%. A full-constrained acetabular cup can be used by hip surgeons as a measure of salvage. The purpose of this paper is to describe the complications the authors have encountered in a short postoperative period with the use of three different types of full-constrained acetabular cups.

Over a period of three years, between January 1999 and December 2001, 25 full-constrained acetabular components were implanted. Three different types of full-constrained prostheses were used: the Osteonics Bipolar Constrained Insert (Osteonics Corp., Allendale, NJ), the Ringloc Constrained Liner (Biomet Inc., Warsaw, IN) and the Trilogy Constrained Liner (Zimmer Inc., Warsaw, IN). In 14 cases the full-constrained cups were used in revision hip arthroplasty and in 4 cases as revision for failed full-constrained implants. Seven patients received a primary constrained acetabular prosthesis.

Of the 23 patients one woman died after a follow-up period of 25.5 months. The other 22 patients had an average clinical follow-up of 22.5 months, ranging from 16 to 47.5 months. In 8 prostheses 6 different postoperative problems were encounterd, resulting in a total of 32 % failures. Seven of the complications were different types of constrained acetabular cup disassembly and one complication was due to a failure at the interface between bone and the porous-metal surface. As alternative treatment option, the authors have used the Birmingham Hip Resurfacing (Midland Medical Technologies, Birmingham) Dysplasia cup with modular head in seven patients who sustained recurrent dislocations after multiple revision surgery, with only one failure (1/7 - recurrent dislocation) after a mean follow-up of two years.

In view of the high short-term complication rate (32%) in a follow-up period of three years, the authors strongly recommend judicious use of the constrained acetabular prosthesis. The component should only be applied as a salvage tool in selected patients in whom no other treatment options would be successful. In these cases the use of a constrained acetabular prosthesis might solve the problems encountered in the majority of patients, but it can never guarantee a problem-free course of this cup. Alternative options such as the use of large diameter femoral heads with a resurfacing cup, using a metal-on-metal friction couple should be considered as a worthwhile alternative in those cases.


O. MORESCHINI F. PULCINI M.S. BOCCANERA

Periprosthetic fractures certainly are one of the most dreadful complication in THA operated patients. Risk factors are both pre-operatory (age, bone quality, morphology offemoral canal) and post-operatory (periprosthetic osteolysis, trauma). There are many classifications about periprosthetic fractures, but, in ouropinion, the most complete is the Vancouver’s classification of 1994. Osteolysis main cause for sure is the presence of wear debris, fragments created by friction of the different surfaces of prosthetic components. These particles, delivered inside joint space, spread into the bone-prosthesis joint and then activate the immunity system, promoting the relief of many mediators, both infiammatory and osteolytic. The most important mediators for sure are cytochines (IL-1, IL-6 and TNF), prostaglandins (PG-E2) and some digestive enzymes. These can get to the development of osteolytic areas with direct enzymaticdigestion and osteoclastic activation. Inexorable conseguence is periprosthetic bone fragility and high risk of fracture. Between 1997 and 2003 we observed 18 perprosthetic fractures in our department, all overhauled.

We studied 22 THA patients (25 hips, 7 male, 15 female, average age 70 yy) for 11 years of follow-up. Wear rate has been calculated by the computerized Liver-more technique, using the AutoCad program. By this program we can work out a bidimensional reconstitution of the prosthesis, using a simple A-P Rx of the hip.

We calculated that average wear is 0,153 mm/y (range 0,054 −0,329 mm/y) and average total wear is 1,624 mm. 6_D_Discussion_e_Conclusions: Computerized analysis of wear rate andosteolysis rate of polyethylene, in our opinion, is an efficent way to prevent periprosthetic fractures, programing a prosthesis revision, before the periprosthetic bone-stock is too poor. More and more importance have studies about alternative coupling (reticular polyethylene, new generation ceramics, metal-to-metal). If the clinical results will confirm the literature’s encouraging datas, this materials coupling will guarantee a bone-loss reduction, increasing prosthesis longevity.

Computerized analysis of wear rate andosteolysis rate of polyethylene, in our opinion, is an efficent way to prevent periprosthetic fractures, programing a pros-thesis revision, before the periprosthetic bone-stock is too poor. More and more importance have studies about alternative coupling (reticular polyethylene, new generation ceramics, metal-to-metal). If the clinical results will confirm the literature’s encouraging datas, this materials coupling will guarantee a bone-loss reduction, increasing prosthesis longevity.


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P Kumar K Mannan AM Chowdhury KC Kong J Pati

Acute urinary retention (AUR) is a common complication following arthroplasty of the major joints and may lead to a delayed discharge with financial considerations not to mention the risks of sepsis – in the urinary tract and also rarely but very significantly in the joint itself. Our aim was to study the various factors associated with risk of AUR following arthroplasty.

We conducted a retrospective review of all available casenotes of patients undergoing total hip (THR) and knee arthroplasty (TKR) in a consecutive three year period. Variables noted included rate of AUR, catheterisation, urinary tract infection (UTI), urinanalysis, joint sepsis, anaesthetic type, use of patient controlled analgesia, postoperative morphine requirement, alpha blockade, past medical and urological history.

100 patients underwent THR. AUR occurred in 22%. Deep joint sepsis occurred in 1% – this patient had not been catheterised. 3% had positive urine analysis but were asymptomatic. No patients had a symptomatic postoperative UTI. 117 patients underwent TKR. AUR occurred in 19%. The rate of deep joint sepsis was 0.85%. There was one case of superficial infection. Neither of these cases was catheterised. There were no cases of postoperative UTI. There was correlation between previous AUR and incidence of AUR (p=0.95).

There was no significant correlation between past medical history and AUR contrary to reports by previous authors. The correlation between previous AUR with risk of AUR in the TKR group warrants further investigation. Catheterisation has been previously thought to be associated with infection. In our study with cefuroxime at induction and two doses postoperatively and gentamicin for catheter insertion and removal there were no cases of postoperative UTI and although deep sepsis was seen it was not associated with catheterisation either pre-operatively, perioperatively or postoperatively in AUR.


R Poggie M Tanzer J Krieger D Lewallen A Hanssen R Lewis A Unger T Okeefe M Christie S Nasser J Wood SD Stulberg JD Bobyn

There has been a longstanding need for a structural biomaterial that can serve as a bone graft substitute or implant construct and is effective for fixation by bone ingrowth. A porous tantalum material was developed to address these issues. The purpose of this paper and presnetation is to describe the properties and 2 to 5 year clinical results of porous tantalum in various reconstructive orthopaedic procedures.

Porous tantalum has been used to manufacture primary and revision acetabular cups, acetabular augments, tibial and patella implants, patellar augments, structural devices for the treatment of osteonecrosis, and spinal fusion implants. Clinical follow-up includes: 2–5 year clinical and radiographic evaluation of: 414 monoblock cups in primary THA, 36 monoblock cups and 587 revision hemispheres used in revision THR, 16 hips revised with acetabular augments and revision hemispheres; 2 to 4 years for 101 tibial implants used in primary TKR and 69 patellas used in cementless TKR; 2–4 years for 11 patellar augments in salvage TKR, 1–5 years for 53 revision TKRs using knee spacers; 1–4 years for 91 osteone-crosis hip implants; and for 15 cervical fusion cases.

This innovative tantalum implant material with trabecular architecture possesses advantages in stiffness, friction coefficient, porosity, rate and extent of tissue ingrowth, and versatility in manufacturing of structural devices. It has been clinically validated in numerous and diverse reconstructive procedures.


K Polgár HS Gill DW Murray JJ O’Connor

The design philosophy of polished tapered total hip replacements (THR), such as the Exeter, intends for them to migrate distally within the cement mantle. As well as migration, dynamically induced micromotion (DIMM) occurs as a result of functional activity between the implant and the cement. The aim of the current study was to develop and validate a finite element (FE) model of the Exeter/cement/bone system which can be used to predict DIMM and investigate the stresses induced in the cement mantle during functional activity.

In the context of the current study, DIMM is defined as the displacement of the implant component relative to the bone when moving from double leg stance to single leg stance on the operated limb. Using Roentgen Stereo-photogrammetric Analysis (RSA), DIMM was measured in 21 patients implanted with Exeter stems 3 months post-operatively. A previous study, using a reduced FE model of the Exeter stem and the surrounding cement mantle focused on the solution of the contact problem at the stem-cement interface. It was demonstrated that sliding contact combined with Coulomb friction and an appropriate parameter setting could be used to predict DIMM of a polished tapered stem. For the purposes of the current study, the previous simple model was incorporated into the FE model of the Muscle Standardised Femur and validated against the RSA measurements for DIMM. For the current extended model, loading included muscle forces representing all active muscles acting on the femur. The effect of initial cement stresses and interdigitation was also considered.

The Exeter stem demonstrated significant DIMM (p< 0.017). The FE model, accounting for sliding contact at the cement–implant interface was able to predict similar distal migration of the head and the tip. The results of both the calculations and the measurements showed that the femoral head moves medially, distally and posteriorly relative to the bone. In the cement mantle, maximum principal stresses were oriented circumferentially, minimum principal stresses were oriented radially. When the taper got engaged, submicroscopic movements which did not recover following unloading still took place and accumulated.

The results of the present study showed that it is possible to measure DIMM in the Exeter stem and combine this with FE modelling of the contact mechanism. Future studies will include various activities, such as walking or stair climbing. Based on accumulated submicroscopic movements, short-, mid- or long-term migration patterns will be predicted.


Robert Poggie Michael Christie Vincent Eilers Arlen Hanssen David Lewallen Randall Lewis Thomas O’Keefe David Stulberg Charles Sutherland Anthony Unger Thomas Gruen

Press-fit acetabular reconstructions have become the standard THA; however, controversies remain. The purpose of this study was to critically evaluate serial radiographs for initial cup stability, i.e. gaps and signs of periacetabular interface changes for a porous tantalum monoblock socket.

A multicenter study evaluating 574 primary THRs (542 patients) performed by 9 surgeons at 7 hospitals, all with a monoblock cup without screws. Analyses included clinical outcomes and detailed 2-year minimum radiographic evaluation by one independent observer (mean follow-up, 33 months).

Complications included 9 intra-operative acetabular fractures. Among the 123 cases excluded from radiographic evaluations: deceased (19), lost-to-follow-up (8), 7 early revisions (recurrent dislocations (6) and one trauma-related loosening), and sepsis (3). Patient demographics (414 hips): mean age 65 years (19–93); 58 percent females. Baseline radiographs revealed 113 zones in 85 hips (21 percent) with acetabular gaps; 36 in zone I, 72 in zone II, and 5 in zone III. Of these radiolucencies, 57 zones were 1 mm or less and 56 zones ranged from 2 to 5 mm. At last follow-up, 64 hips (75 percent) had complete gap fill-in, including 100 percent of gaps greater than 3 mm.

There were no socket migrations, no evidence of lysis, no revisions for loosening, and no complete periacetabular interface radiolucencies. The fill-in of preexisting OA cysts and gaps is attributed to adequate initial stability and osteointegration into the porous tantalum. These results suggest that a monoblock cup without screws is an attractive option in THA.


Marc-Antoine Rousseau Stéphane Le Mouel Daniel Goutallier

Mechanical failure in total hip arthroplasty is usually due to aseptic loosening related to wear particles as seen with polyethylene bearing. Alumina has been proposed for avoiding wear problems. In vitro and mid-term clinical studies showed tribological advantages but early acetabular fixation issues. Since alumina on alumina bearing is currently used with new fixation techniques, updated evaluations of the ancient series are informative regarding the long-term tolerance of alumina in vivo.

In this paper, we investigated 104 consecutive lumina on alumina cemented total hip arthroplasties (CER-VAER-OSTEAL, Roissy, France) implanted 20 years ago in 81 patients (from 1979 to 1983). Alumina femoral head was 32 mm in diameter. Alumina acetabular socket and titanium femoral stem were cemented. The clinical evaluation used Postel Merle d’Aubigné score. Radiological wear and appearance of osteolysis or loosening were noted for establishing actuarial curves. When accessible, histological samples from revision procedures were analyzed.

Six infected cases were not taken into account later. The average follow-up was 11 years, reaching 18 years in 38 cases. Twenty-three hip were revised for changing 23 acetabular sockets, 12 femoral heads, and 1 femoral stem. We noted 1 femoral head fracture, 24 definite ace-tabular loosenings, 12 probable acetabular loosenings, and 3 definite femoral loosenings. Radiological acetabular osteolysis was present in 4 cases, always limited to De Lee zone 1, and associated with loosening. Radiological wear was below eye detection. Peri-prosthetic tissue showed non-specific histological reaction to cement particles. Survival rate at 20 years was 61.4% in term of revision (57.1% and 95.2% concerning acetabular and femoral defininte loosening).

Beside the high rate of cemented fixation failure of the socket, loosened and non loosend cases showed an excellent tolerance of alumina on alumina bearing in the long-term, with minimal wear and osteolysis. This may also have protected the femoral component from complications.


L. Quagliarella N. Sasanelli B. Moretti V. Patella

Clinical follow-up of hip and knee arthroplasty is not related to objective functional parameters while this is one of the main goal of evidence based medicine. Therefore a functional test was defined in order to correlate clinical and biomechanical data.

The experimental set-up has been presented [1] as well as the test protocol [2]. Three parameters have been analyzed: reaction time (Tr), flight time (Tf) and maximum force (Fmax). The data refer to 21 subjects with hip joint replacement (HRG) and 22 subjects with knee joint replacement (KRG). Tests, were performed before surgery and after one, three and six months. The results were compared with values obtained from a control group of 402 normal subjects.

One months after surgery the performance is lower respect to normal data, both for HRG and KRG. Three months later, there is a partial recover expecially for HRG. At six months follow-up, also the KRG reach better performance. While the performance starting point is higher in the HRG, the percentage recovery is equal in both the groups. During the follow-up also the non operated leg, both for HRG and KRG, shows a progressive changing in its performances, which can increase or decrease, but always it brings at the same level of ability for both legs.

The data suggest that there are different performance and time recover related to the replaced joint (hip or knee) while the total amount of recover is not joint related and there are no differences for laterality. Experimental data correlate with clinical observation; therefore the proposed protocoll seems to be usefull for objective evaluation of joint replacement follow-up. The re-equilibration of the kinematic abilities between the limbs, which cannot be detected by clinical observation, requires further investigation and could be related to neurological integration and less algia limitation.


M. Manunta A. Fadda G. RINONAPOLI

An animal study was performed to assess whether hydroxyapatite could induce bone ingrowth to close gaps at the bone – implant junction in a weight-bearing model.

14 titanium alloy plates, 2 x 0,5 X 0,1 cm, sprayed on one flat side with HA and left as bare metal on the other, concave surface, were inserted into the distal metaphysis of the femur of 14New Zealand adult rabbits, perpen-diculary to the diaphyseal long axis . The sections of the femur were performed through the plate and were observed by S.E.M.

During the first week, we found medullary hyper-plasia and differentiation of osteogenic cells producing osteoid. By the 2nd-3rd week, immature bone formed from the endosteum towards the plate, leading to the filling of the gap with the HA – coated surface of the plate. Between the 4th and the 8th week the remodeling process occurred with formation of lamellar bone. At 12 weeks bone – ingrowth appeared to be greater in areas of proximity to the endosteal wall, especially when the plate was oriented in such a way that acute angles with the endosteum were present. Ha –coatings were degraded by a process of creeping substitution. The gap between bone and non-coated surface was not filled at the end of the experiment. At six months the crystalline part of the coating appeared as separated grains (for dissolution of the amorphous phase). This degradation is responsible for the release of calcium-phosphate debris.

The present study shows great evidence of HA osteo-conductivity. The physico-chemical similarity between artificial HA and mineralized bone probably explains that the mechanism of HA resorption is similar to that of bone resorption. The remodeling cycles of resorption and new formation give as a final result the deposition of bone tissue onto the metallic alloy.


Amar S. Ranawat Chitranjan S. Ranawat Jose

Intro: There are few modern reports which document the results of all-polyethylene tibial components in younger, more active patients. The potential benefits of this design are the elimination of backside wear and lower implant cost than modular, metal-backed components.

From January 1992 to the present, 56 TKRs were implanted in 41 patients less than 60 years of age at the time of index surgery using a cemented all-poly tibial component with a PS design. Indications included all patients with osteoarthritis or post-traumatic arthritis without significant tibial bone loss. All patientswere followed prospectively with clinical and radiographic criteria asdefined by the Knee Society. Patient Assessment Questionnaires were used to quantify patient satisfaction, pain, and activity levels.

From January 1992 to the present, 56 TKRs were implanted in 41 patients less than 60 years of age at the time of index surgery using a cemented all-poly tibial component with a PS design. Indications included all patients with osteoarthritis or post-traumatic arthritis without significant tibial bone loss. All patientswere followed prospectively with clinical and radiographic criteria asdefined by the Knee Society. Patient Assessment Questionnaires were used to quantify patient satisfaction, pain, and activity levels.

Discussion: Since the mid 1980s, modular, metal-backed tibial trays have dominated the TKR market based on finite-element analysis studies which demonstrated superior force distribution compared to conventional all-poly components. As a result, backside wear has become an emerging problem and refocused design efforts on unitized components. Our clinical experience indicates an all-poly tibial component fixed with cement provides excellent performance and survivorship even in younger, more active patients.


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S. Romagnoli E. Bibbiani N. Castelnuovo G. Cusmà F. Verde

In last ten years U.K.R. number increased due to diffusion of M.I.S. concepts, new indications/tecniques and durable prosthetic models. Also the amount of revisions, performed for different reasons, has increased. Failures relate to planning and surgical errors, aseptic loosening, non treated or femoro patellar compartment degeneration, ligaments instability, P.E. wear, components ruptures, infections.

In our division in 1990–2003 we performed 136 U.K.R. revisions on 13 different implants with a prevalence of “fixed bearing” (79,40%) on “meniscal bearing” (20,60%). A classification withprevalence of failure causes, different from T.K.R.’s, is proposed. Revision procedure strongly depends on causes: “Uni”, “BiUni” or “Total” approach is possible. We present our experience and derived indications.

Aseptic loosening were treated differently depending on bone stock and on failure risk factors (ligament laxity, surgical osteotomic or axial errors, fixation defects) with a “Uni” revision or with a “Total”. Unicompartimental degeneration with a previous medial or lateral U.K.R. in good conditions may undergoes “BiUni” instead of “Total” only in absence of ligament laxity and femo-ropatellar symptomatic degeneration. Femoro-patellar degeneration needs a T.K.R. implant. We managed cases with macroscopic surgical errors (ostheotomy or component alignment) by using T.K.R. (stemmed and with auto-graft if needed) and U.K.R. revision. Failures due to varus-valgus instability were normally treated with T.K.R. (standard or stemmed) and with constrained T.K.R. (1 Reumatoid Arthritis case). We resolve P.E. debris failures in fixed bearing implants simply with a component change as we do in stress fractures (femur or “full poly” tibia). We treat infections with a 2 step procedure; for 2°step we used T.K.R. (standard or stemmed).

In conclusion U.K.R. revision is technically easier than TKR’s, bone stock defect may be fighted with auto graft and/or stems and in a selected amount of cases it’s possible to use U.K.R. orstandard T.K.R. with very similar long term results of first implants.


A. Saleh S. Tarabichi S. larsen

In living normal knee the lateral femoral condyle rolls posteriorly more than the medial side to the extent that in deep flexion the lateral femoral condyle sublux from the tibial surface (Nakagawa et al). The purpose of this presentation is to study the tibiofemoral movement in patients who had full flexion after total knee replacements and to compare it with that of normal knee.

23 knees were scanned using SIEMENS SIREMOBILE Iso-C with 3D Extension C-arm. The system is able reconstruct 3D images that can be viewed from deferent angle and precise measurements of distances between the deferent components of the implant can be made. The knee was scanned while the patient is sitting in kneeling position with the calf touching the thigh (flexion of over 150degree

All the cases studied showed a variable roll back between the medial and lateral femoral condyle. In all cases the lateral roll back was much more than the medial. In 14 cases we confirmed lateral condyle subluxation similar to what is seen in normal knee. The position of the foot (internal or external rotation) during scanning did not affect the lateral femoral condyle role back.

Although previous studies have shown paradoxical types of tibiofemoral movement in patients who have total knee replacements throughout the range of movement, the knees in patients who had full flexion after TKA tend to have the same tibiofemoral movement as the normal knee in deep flexion. The lateral femoral condyles spin off or subluxation could adversely affect the implant components especially if the design does not accommodate this movement. The lateral femoral condyle may sublux from the tibia during kneeling inpatients who had full flexion after TKA. These findings should call for changes in the implant design to accommodate the lateral condyle roll back.


Toshie Sasaki Yuri Yabuki Hiraku Hotta Shigeru Yanagimoto

Dislocation after total hip arthroplasty (THA) remains a significant clinical problem. The acetabular cup position is one of the main factors in the incidence of dislocation after THA. We reviewed dislocation cases in 247 primary THA

Between 1997 and 2001, 247 patients underwent a primary THA procedure. The original diagnoses in these patients were as follows: osteoarthritis (OA, n = 190), osteonecrosis (ION, n=28), rheumatiod arthritis (RA, n=16), and rapidly destructive coxarthropathy (RDC, n=13). A posterolateral approach was used in all cases. We examined mainly the acetabular cup position (ante-version and inclination angle) using anteroposterior radiographs

Six dislocations (2.4%) occurred : three anterior dislocations and three posterior dislocations. Dislocation rate according to the original diagnoses were as follows, 2 dislocations in OA (1.1%), 2 dislocations in RA(12.5%), 2 dislocations in RDC(15.4%) and no dislocation in ION. All cases were treated with close reduction and no component revision was needed. On X-P measurement of setting the acetabular cup in all cases, the mean ante-version angle was 16.3617;6.8 degrees and inclination angle was 43.3& #61617;7.3 degrees. In comparison with these measurement values, there was no statistical difference between the dislocation groups and no-dislocation groups. The number of the cases within Lewinnek’s safe zone in acetabular cup was 178 (72%). The dislocation rate in these 178 cases was low (1.1%).

Setting the acetabular cup in adequate position is one of the major factors avoiding dislocation after THA. We have been performimg computer - assisted THA since 2003. Computer - assisted surgery enables the acetabular cup position to be precisely planned before surgery and allows superior positioning during surgery.


Tomotaro Sato Hitoshi Umeda Naoto Kuno Naohiro Ono

One of major problems in Total Hip Arthroplasty is thigh pain. We have examined the effect of femoral canal injection of Calcium Phosphate Paste (CPP) for cementless THA. CPP is a mixture of alpha Tri-Calcium Phosphate, Tetra-Calcium Phosphate, Calcium Hydrogen Phosphate and Hydroxyapatite. This paste harden in 10 minutes and its stiffness increases to 80Mpa in 3days.

Cementless THA were performed in 45 osteoarthritic hips from 1999 to 2002. Eight of 40 patients were male and 32 were female, average age were 62.4 years old ranged 43 to 81. In 11 hips, CPP (10–12g) were filled as a femoral canal filler around the distal end of stem. In 34 hips, as a control, no CPP were filled in the canal. Proximal part of the stem was HA coated on rough metal surface.

No thigh pain were observed in CPP group patients. In control group, five hips (14.7%) showed thigh pain (p< 0.05), but walking disability and pain were mild in the first year and improved by the next year. CPP filled in the canal were absorbed slowly on X-ray film, but prevention of thigh pain lasts for long time maximum 3 years. No infections and pulmonary embolism were observed in both series.

Filling CPP into the gap between stem tip and femoral canal is useful technique to prevent thigh pain after cementless THA.


R Rossi F Castoldi M La Russa M Germano P Rossi

The ABG stem (Anatomique Benoist Girard, How-medica) was realized of titanium alloy (TA6V) and it was designed to provide anchoring only at the femour’s metaphyseal portion. The long-term stability is achived by osteointegration of the implant at the metaphyseal region, which is coated with hydroxyapatite (HA) crystals. The plasma-sprayed HA coating has a tickness of 60 μm for the stem.

The current study presents radiographic outcomes of more than one hundred primary uncemented HA stems with a long-term follow-up. One hundred and eleven ABG hip arthroplasties were evaluated with a mean follow-up of 9.8 years. The radiographical findings have been classified observing Engh’s stability criteria according to Gruen’s subdivision of the periprosthetic femoral zones.

Dividing the hips into two different groups (in the first one the prosthesis implanted 11, 12 or 13 years ago and in the second one the prosthesis with a maximum age of 10 years) it’s possible to see as in the first group the radiolucent lines are quite reduced. Among the older prosthesis the percentage of radiolucent lines is 3.1% in zones 3 and 5 and 18.8% in zone 4. For what concerns the younger ones the percentage are 10.1% (zone 3), 21.5% (zone 4) and 15.2% (zone 5).

We believe that there is a load transfer from the metaphyseal to the metadiaphyseal portion of the femur without a worsening of the clinical outcomes. The absence of reactive lines and lucencies around the proximal HA-coated portion of the stem supports an excellent circumferential bony ingrowth in the metaphyseal area of the proximal femur. According to these percentages we can say that there’s less presence of radiolucency in the oldest prosthesis and it could be possible to argue that radiolucent lines tend to reduce along the time. This is probably due to the increase of the strength of the stem anchorage.


AP Sanghrajka A Amin TWRB Briggs SR Cannon G Blunn P Unwin

The purpose of this study was to determine whether the low rate of mechanical loosening of the SMILES rotating hinge distal femoral endoprosthesis relates to the hydroxyapatite (HA)-coated, grooved collar of the femoral component.

A database was used to identify two groups of cases of primary distal femoral replacement with a custom-designed and manufactured SMILES endoprosthesis at our unit; those with the collared femoral component (“collar group”), and those without a collar (“non-collargroup”). From these two groups, patients were pair-matched for age and length of bone resection. A retrospective review of serial biplanar pairs of radiographs of each patient, assessing radiolucent lines and extracortical bone pedicle.

11 matched pairs were identified, (14 females, 8 males), with a mean age of 36 years, (range 16–66). The pathology was primary bone tumour in 20 cases, (17 malignant, 3 benign), and metastatic disease in 2 cases. Mean length of follow-up was 85 months, (range 27–122). Radiolucent line score (RLS) progression over time was significantly lower in the collar group, (0.01 vs 0.73, p=0.001) (fig. 1 & 2), as was the mean final RLS, (2.72 vs 7.81, p=0.02). Mean RLS per radiographic quadrant was 0.56 in cases in which a bony pedicle was ingrown onto the prosthesis, (exclusively in the collared-group), 2.41 in cases in which the pedicle was not ingrown, (most prevalent in the non-collared group), and 1.02 in those cases without any pedicle formation, (ANOVA analysis, p=0.0002).

This study demonstrates that the HA-coated, grooved collar significantly reduces the progression of radiolucent lines, and consequently the overall RLS, explaining the reduced rate of mechanical loosening of the collared endoprosthesis. A bony pedicle that does not incorporate onto the prosthesis surface may be associated with an increase in radiographic loosening.


M. Salvi G. Piu F. Caputo M. Conte

The pourpose of this study was to investigate the variability of the posterior condylar angle and the whiteside’s angle to establish if three degrees of external rotation of the femoral component produce the correct rotational alignment, in varus knee

33 patients (33 knee) affected by varus osteoarthritic knee (5°–30°)underwent a preoperative CT scan examination of the knee and the hip. On the axial views, we have evaluated the femoral anteversion, the posterior condylar angle and the whitesiede’s angle.

The mean femoral anteversion angle was 5.5°±13.7° (−24°;33°). The mean posterior condylar angle was 6.1°±2.5° (1°;14°). The mean intraobserver error was 0.9°. In 60.6% of the cases the angle was greater than 5°. The mean Witheside’s angle was 6°±3.5° (1°;16.5°). The mean intraobserver error was 0.8°. In 51.5% of the cases the angle was greater than 5°.

Both the posterior condylar angle and the Whiteside’s angle showed values almost double than three degrees proposed as standard rotation for the femoral component. The method of three degrees standard of external rotation lead to relative internal rotation of the femoral component in TKR also for varus knee.


Adrija Sharma Richard D. Komistek Chitranjan S. Ranawat Mohamed R. Mahfouz Douglas A. Dennis

At present, contact stress analyses of TKA involve in vitro experimental testing. The objective of this project was to develop a parametric mathematical model that determines in vivo contact stresses for subjects implanted with a TKA, under in vivo, dynamic conditions. It is hypothesized that the results from this model will be more representative of in vivo conditions, thus leading to more accurate prediction of TKA bearing surface stresses.

In vivo kinematics were determined for ten subjects implanted with a posterior stabilized TKA during gait and a deep knee bend under fluoroscopic surveillance. Three-dimensional contact positions, determined between the femoral component and the polyethylene insert, were entered into a complicated mathematical model to determine bearing surface forces. In vivo kinematics and kinetics were entered into a deformation model to predict in vivo contact areas between the medial and lateral condyles and tibial insert. The orientation of the femoral and tibial components, the predicted in vivo contact areas, and vectoral information of soft-tissue derived from MRI images were then entered into a mathematical model that predicted in vivo contact stresses between the femoral component and the tibial insert.

This is the first computational model that utilizes fluoroscopy, MRI, deformation characteristics and Kane’s theory of Dynamics to predict in vivo contact stresses. Although previous models have not been validated, this model was validated by comparing the predicted foot/ ground force with the experimentally derived force. This study demonstrates that patellar motion influences forces throughout the lower extremity. The in vivo contact stress values predicted in this initial study were less than the yield strength of polyethylene.


H.C. Shin Y.S. Yoon

Heat generation during bone cutting operations inorthopaedics may cause thermal damage to the bone. During the bone cutting, the maximum temperature occurs on the contact surface between the bone and tool. Because of the low thermal conductivity and diffusivity, the temperature gradient of the bone interior is very high around the cutting site and the measurement of maximum temperature is difficult at the contact surface. While many researchers tried to measure the temperatures, they may have underestimated the temperatures of bone on account of measurement limitations. To solve this problem, we investigated the temperature distribution model of the bone interior during the milling operation and verified the model with a cutting experiment.

During the bone milling, most of the cutting energy is converted into the heat energy near the contact surface between the bone and tool. If the cutting tool moves on the bone surface, we can assume that a heat source moves on the bone surface at the speed of the feed rate. To predict the maximum temperature, we performed a milling experiment with fresh bovine cortical femurs. The feed rate were 2~9.8mm/s, the cutting depth were 0.3~1mm and the rotational speed were 30,000~50,000RPM. No irrigation solutions were applied. To measure the local temperatures around the tool, two infrared thermometers were attached behind the bur at 10mmintervals from the bur center. We calculated the maximum temperatures and errors from the measured temperatures.

The predicted maximum temperature increment was 55~131& #8451; as the cutting conditions change. The mean errors and standard deviation errors were several degrees. The increased feed rate and decreased cutting-depth reduced the maximum temperature.

Our observed temperature is quite higher than those in the previous studies. Because of the high temperature-gradient(57& #8451;/mm), the thermocouple alone will likely yield large errors and generally underestimate the temperatures of the bone interior. With a thermal damage criterion of 50& #8451;(& #916; T=13& #8451;), thermal damage may reach 1mm in depth. To reduce the thermal damage, it is recommended to increase feed rate and decrease cutting depth.


Raj K. Sinha Deidre Braun Robert Murphy

Adequate pain control is important in allowing early participation in physical therapy after total joint replacement. Opioidanalgesics often cause side effects that limit physical therapy. Therefore, adequate pain relief with reduced narcotics opioids should speed recovery.

Purpose: To determine whether postoperative acupuncture would reduce narcotic usage and improve physical therapy after total joint replacement.

Total knee (TKR) and total hip replacement (THR)patients who received acupuncture on POD 1–3 or did not receive acupuncture were prospectively followed. Postoperative usage of patient controlled analgesia (PCA, normalized to intravenous morphine) and oral and parenteral opioids (normalized to oral immediate release morphine) were measured. Verbal analog pain scores, performance in physical therapy, length of stay(LOS) and location of discharge were recorded.

After TKR, there was no difference in pain scores in either group (acupuncture n=23, non-acupuncture n=25). PCA usage was 58% less in the acupuncture group for the entire hospital stay (p< 0.05). 74% of acupuncture patients and 36% of non-acupuncture patients did not require PCA after POD 2 (p< 0.05). The amount of additional narcotics was 58% less(p< 0.05) for the acupuncture group. Walking distance was greater in the acupuncture group by greater than 40% (p< 0.05) on any day after surgery.43% of the acupuncture patients and 24% of the non-acupuncture patients went home. There was no significant difference in knee flexion or LOS. After THA, the acupuncture group (n=7) used 54% less PCA (p< 0.05), used 96% less additional narcotic, and had 36–83% greater walking distance on any POD than-non-acupuncture group (n=7). Location of discharge and LOS was the same in both groups. There were no complications related to acupuncture in any patient.

Acupuncture is a safe and effective adjunct to traditional methods of postoperative pain management after total hip and total knee replacement.


J. Scholz U. Böhling

The last years showed an increasing demand especially of younger patients for bone protecting total hip arthroplasty. Apart from the well known cemented versions a cementless implant with a variable short stem has been developed. It also consists on a metal backed metal inlay.

The femoral component of the Eska Hip Resurfacing System is surfaced on the bone side with the well experienced metal-spongiosa II three dimensional structure. The femoral component can be combined with a short stem either of 30 or 50 mm of length. The diameter increases in two millimeter steps. The socket component is also covered with the metal-spongiosa II structure. The cup inlay is secured by conical fixation and can be changed.

We think the implant offers a very helpful new development in the cementless hip resurfacing arthroplasty. First technical problems have been solved.


G. Saxler G. Bontemps

Increasing experiences in determining the indication for UKA and improvements in design and materials of the prosthesis led to better results. The AMC-Uniglide has an unconstrained mobile bearing with congruent area contact. This ensures complete freedom to rotate and slide upon one other with physiologic kinematic and low intrinsic stability

Minimal-invasive technique 30 patients with minimal-invasive AMC-Uniglide implantation technique were compared with 30 conventional implanted AMC’s and 30 total knee replacements in regard to rehabilitation and accuracy of implantation. 361 AMC-Uniglides 361 consecutive patients were investigated after AMC-Uniglide implantation. The mean duration of follow-up was 5.5 (2.3–12.5) years. Patients were reviewed using the American Knee Society Rating System. The roent-geno graphic analyses were performed with the American Knee Society Evaluation System.

The clinical results of the investigated patients demonstrate that the AMC-Uniglide is a successful concept with a safe anchorage of the prosthesis and a good durability of the mobile bearings. An advantage of minimal invasive technique with regard to a reduced time of rehabilitation was found. The accuracy of implantation was comparable between the conventional and the minimal-invasive technique


Vincenzo Sessa Sandro Rossetti

Since wear debris is recognised as a major cause of hip prosthesis loosening in the last decade, research was aimed to lower the coefficient of friction. Polyethylene revealed to be the principal source of debris so new bearing materials were introduced in the effort to increase implant longevity.

In 1965 Mc Keee Farrar introduced metal on metal bearings, in 1970 Boutin ceramic on ceramic. Both of them demonstrated the capability to reduce wear debris more than 97% as compared to PE-metal coupling but have possible risks. Ceramic heads are scratch resistant but they can fracture, then they offer limited options as lenght and diameter. Metal on metal bearing couples give all the options but can determine high blood metal ions level, potentially dangerous. To avoid these risks new coupling materials were introduced: oxinium and cross-linked polyethylene.

Cross-linked ultra-high molecular weight polyethylene was first employed for liners more than 30 years ago with excellent results. On the other hand oxinium is a metal compound of 97,5% zirconium and 2,5% niobium, whose surface is transformed into a smooth ceramic with a coefficient of friction that is half that of cobalt-chrome, and same wettability and hardness of ceramic. Oxinium-cross-linked polyethylene produce nearly undetectable wear even if subjected to abrasive conditions.

Oxinium femoral heads offer the option of different neck lenght and head diameter. Laboratory testing demonstrated that rough oxinium heads provided 61% less polyethylene wear than did the rough metal heads. Clinical results have a too short follow-up to be reported but are promising.


SD Stulberg VA Brander AD Adams SJ Austin O Woods

The most reported benefit of TKA navigation technologies has been the reduction in limb and component alignment outliers. This improvement has not been shown to effect clinical outcomes. This study was designed to compare the functional outcomes between computer assisted techniques and manual techniques.

Each group had 60 patients with similar demographics. The average functional outcomes (SF-36, WOMAC, range of motion, pain relief, and knee society score) were the same.

The average scores of the SF-36, Knee Society Score, WOMAC were similar for the two groups. However, fewer patients in Group II reported visual analog pain scores greater than 40 at 6 wks, 3 mos and 6 mos. At 1 yr, the pain scores of the two groups were similar. Fewer patients in Group II had KSS scores less than 70 at 3 months, 80 at 6 months, and 90 at one year, than those in Group I. The average range of motion in Group II was greater by 8 degrees at 4 wks and 3 mos, but equal to the average ROM in Group I at 6 and 12 mos. However, the number of patients with less than 90 degrees of motion at each follow-up period was less in Group II than in Group I at each follow-up period. There were fewer superficial wound infections in Group II than in Group I.

The average functional outcomes were similar; the results indicate a consistent reduction in outliers in most measured parameters of functional outcomes. In particular, the guidelines for administering pain medication and providing physical therapy were similar for the two groups. The results of this study are parallel to the radiographic results comparing TKA’s performed with manual and computer assisted instrumentation. In those studies, a reduction in outliers was consistently associated with the use of computer assisted techniques.


Michael L. Swank

Minimally invasive total hip replacement surgery not only decreases the number of visual cues necessary for proper acetabular component position, the small incision makes it technically more difficult to use traditional mechanical alignment guides. Furthermore, traditional mechanical guides have been shown to be unable to accurately predict component position as determined by intraoperative computer measurements.[ 1,2 ] Computer assisted intraoperative navigation can enable minimally invasive surgery by giving the surgeon immediate intra-operative feedback of actual component position. We wished to compare the intraoperative computer determined measurement of acetabular inclination with the postoperative radiographic measurement of inclination in order to validate the results of the computer assisted measurements in the clinical setting. To determine whether computer assisted navigation of the acetabular component allows the surgeon to accurately place the prosthesis in minimally invasive hip replacement and to compare the results of intraoperative navigation with the postoperative radiograph.

42 consecutive patients underwent a minimally invasive posterior approach for total hip arthroplasty with the assistance of CT based intraoperative navigation with the BrainLAB VectorVision software. Preoperative surgical planning was performed after acquisition of a CT scan. All components were templated to be placed in 45 degrees of inclination and 25 degrees of anteversion. Intraoperatively, cementless acetabular components were aligned with the computer navigation at these values prior to implant impaction. Because of the press fit nature and limited soft tissue exposure, many components would shift during impaction. Final component position was then verified and values recorded by detecting points on the acetabular surface. If the prosthesis was felt to be in an acceptable position, no attempt was made to modify component position to the predetermined values in order to avoid potentially compromising component fixation. Postoperative supine AP pelvis radiography was then used to determine final inclination. Measurements were made by drawing a line perpendicular to the acetabular teardrop and parallel to the acetabular component and measured with a standard goniometer. These data were then placed in an SPSS database and analyzed by an independent statistician.

Assessing acetabular component position in routine total hip arthroplasty has been shown to be unreliable even with experienced surgeons with mechanical alignment guides. [1,3] In minimally invasive total hip arthroplasty, routine visual cues are limited and mechanical instruments are difficult to place in the small operative wounds making an already difficult task even more difficult. CT based image guided surgery can has been shown to improve the acetabular component position intraoperatively 2. However, postoperative validation studies comparing the intraoperative computer assessment with the postoperative radiographic measurement are scarce. [ 2 ] In this consecutive series, which represents the author’s first experience with this technology, several conclusions can be made. First, the act of impacting a solid, porous coated, hemispherical cementless acetabular component in minimally invasive hip surgery often leads to a final component position different from the intended position. Second, computer generated determination of implant position is reliable but care must be taken to make sure the reference arrays do not lose fixation during the procedure or spurious results can occur. Third, routine AP pelvis radiographic measurements are not accurate enough to determine whether the computer determined values are accurate. In spite of these measurement inaccuracies, the computer determined results and the radiographic results were within 10 degress 95 % of the time which is far more accurate than results obtained with mechanical alignment tools 3. Finally, further validation studies need to be done with postoperative CT scanning to determine the accuracy of the intraoperative computerized measurements and determine the measurement errors inherent in the clinical setting. Given these limitations, computer assisted navigation improves the accuracy and reliability of acetabular component position over traditional mechanical instruments and can be utilized in minimally invasive hip surgery to assist in the appropriate placement of the acetabular prosthesis.


SD Stulberg VA Brander AD Adams SJ Austin O Woods

Customization makes it possible to fulfill design requirements during MIS-THA procedures, and has helped define the parameters of fit and fill. This study describes the results of using customization techniques to develop a femoral implant for utilization.

CT-based design criteria for femoral implants has-been developed and used for primary, cement-less, non-minimally invasive THA surgery. Over 1000 procedures performed with these devices have been associated with displaced femoral fractures, and have been revised for septic loosening. This study has 2 parts:

20 implants were designed and implanted with CT-based criteria that utilized the identical fit and fill standards of the custom implants previously established, but had short (< 115 mm), tapered stems;

20 patients underwent primary, cement-less THR wherein an off-the-shelf femoral implant system was determined to fulfill fit and fill requirements of custom implants.

The stem of these implants was shortened (95–115 mm) and tapered. Implants in both groups were inserted using a single incision, posterior-lateral MIS approach. Patients were followed clinically and radiographically for six months. Immediate full weightbearing and use of a single cane were encouraged.

The use of CT-based customization techniques is helpful for defining design criteria of femoral implants, but the instrumentation for inserting these implants must be adapted to the specific surgery. Customization also facilitates the design and evaluation of CAOS applications for inserting these MIS implants.


C Stagni Marco Fravisini Marco Veronesi Dallari Dante Giunti Armando

Aim: to assess the effect of lyophilized bone grafts, autologous platelet gel and autologous medullary cells on bone repair processes after tibial osteotomy for genu varum

Preliminary results confirmed that the use of platelet gel and packed medullary cells as adjuvant for the lyophilized bone aid bone repair and graft integration. Morphological and morphometric tests showed that at six week the newly formed bone of group 3 had better mechanical properties.

This study shows that the use of platelet gel and packed autologous medullary cells combined with lyophilized bone chips produces a faster and mechanically stronger recovery of bone stock in the treatment of bone defects.


Fei Liu Shaun Stinton Richard D. Komistek

Previous studies of cervical fusion have noted the appearance of new degeneration at levels adjacent to fused segments. The cause of this degeneration has not been accurately determined. The objective of this project is to determine the forces in normal and fused spines in vivo and compare the results to see if the forces in the fused spine are increased enough to cause degeneration in adjacent levels.

A normal and a fused patient (one level fused in C5-C6) have been chosen to perform a full flexion and extension motion experiments. Kinematic functions were obtained from the images. Data was input into the mathematical model and the kinetic results have been decided.

The result can help us understand in vivo kinematical and kinetic characteristics of cervical spine fusion and develop further studies in 3D models. The calculated forces will be compared to previously reported data to determine if the expected increased forces in the fused spinal are great enough to cause degeneration of adjacent levels. A better understanding will help in better treatment of cervical spine disorders.


Tanzo Sugimori Ayumi Kaneuji Tadami Matsumoto

In this study, bone ingrowth was investigated in three-different cementless acetabular cups, titanium fiber mesh cup (non-HA), hydroxyapatite tricalcium phosphate sprayed cup (HA/TCP), alkali- and heat-treated titanium porous cup (AH). “Gap filling” was evaluated as the finding of the bone ingrowth on X-ray. The phenomenon is that slight gap between acetabulum and the cup observed after total hip arthroplasty (THA) disappear gradually.

One hundred and thirty-seven consecutive primary THAs using cementless cups were evaluated for the rate of bone ingrowth. Patients were divided into three groups based on the different types of cups, 51 non-HA cups, 51 HA/TCP cups and 35 AH cups. The groups were similar with regards to age, sex, body mass index, original diagnosis, surgical technique and post operative rehabilitation. Average follow up period was35months, 33 month and 32 months respectively.

Initial gap between acetabulum and the cup after operation was observed in 44 hips of non HA group, 39 hips of HA/TCP group and 33 hips of AH group. Rate of the gap filling at the last follow up was 2 hips (4.5%) in non-HA, 31 hips (79.5%) in HA/TCP and 33 hips (100%) in AH. Early gap filling that occurred for less than three months was 17.9% (7 of 39) in HA/TCP and 72.7% (24 of 33) in AH.

The HA/TCP coated cup and the alkali- and heat-treated cup had the high frequency which gap filling occurred compared with the cup of only titanium fiber mesh processing. Additionally, in the AH cup more gap filling for less than three months had occurred compared with the HA/TCP cup, so AH cup is the most effective implant to obtain the bone ingrowth at an early stage and it is expected to acquire the better results.


Kosmas Stafilas Panayiotis Koulouvaris Alexandros Mavrodontidis Grigoris Mitsionis Theodore Xenakis

Total hip arthroplasty (THA) in neglected congenital dislocation of the hip (CDH) constitutes a challenging procedure, with surgical difficulties and complications. The purpose of this study was to analyse the complications of THAs in CDH.

Between June 1983 and September 2002, 418 THAs-were performed in 356 patients with CDH, with a mean follow-up 108 (7–237)months. The mean age at surgery was 53.3 (24–79) years with 325 females and31 males. 83 patients had CDH in high position. 307 arthroplasties were cementless, 39 cemented and 72 hybrids. 40 stems were custom made. The cup always was positioned at the true acetabulum. 24 shortening osteotomies of the femur, 8 corrective supracondylar and 6 trochanteric osteotomies were performed.

Preoperatively the average Merle d’Aubigne-Postel hip score was 1.1 for pain, 4.8 for range of motion and 3.1 for walking ability. Postoperatively the average hip score was 5.2, 4.7 and 5.3 respectively. The average length discrepancy was 8 cm (3–12) preoperatively and 1.5 cm remained in 8 patients. Complications included 7 intraoperative fractures of the femur, 12 dislocations, 4 peroneal nerve palsies that recovered, 25heterotopic ossifications, 7 deep vein thromboses, 3 pulmonary embolisms, early mechanical loosening in 4 cemented and 10 cementless cups and 3infections.

Complications were diminished dramatically last years due to improved surgical technique, new available implants and preoperative evaluation of the hip with CT and CAD-CAM-CAE study that allowed better surgical planning with trial stem implantation from a series of stem designs and custom made femoral components manufacturing


S Bignozzi JL Briard M Marcacci M Swank

The Vector Vision CT free navigation system of Brain-Lab (Heimstetten, Germany) for total knee arthroplasty incorporates a ligament balancing feature which allows recording of flexion extension gaps and clinical alignment [3]. Since routine spacer blocks do not necessarily load the joint space symmetrically, if either the bone cuts are asymmetric or the ligaments are not evenly balanced, a tensioning device that applies a constant load to the medial and lateral joint space separately and which can collapse or expand on each side independently should be able to provide a better evaluation of ligament tension and allow the computer software to better plan the appropriate bone cuts or ligament release. The tensioning device comprises 2 linked plates contacting the femur and tibia separated by two independent springs in the medial and lateral compartments. It can be positioned precisely in the joint with the navigation system and, with respect to spacer blocks, this device was designed in order to allow a dynamic evaluation of joint stiffness during all range of motion and, thanks to it’s reduced dimensions, with patella in situ. The springs apply a consistent known force on the compartments, while at the same time the gap produced by the applied forces is measured by the navigation. This study integrates previous article [1] on the validation of the tensioning device and reports the first phase of the clinical validation of the tensioning device, including first qualitative comparison with standard navigated technique and consideration on the use of the device.

A spring loaded mechanical device was designed with a constant 6kg load in the springs for each compartment. For the clinical evaluation, the device was inserted into flexion and extension spaces after the tibial cut was performed in routine computer assisted total knee arthroplasty. The gap produced by the applied forces is measured, by the navigation system, as the distance between tibial cut and most distal points on condyles in extension or most posterior points on condyles in flexion. Under the same conditions a set of solid spacer blocks were inserted to obtain a gap able to balance the knee according to surgeon’s sensitivity. This gap was used as reference and compared with the gap obtained with the spring device. The clinical evaluation was performed in order to determine whether there was a difference between the gaps as indicated by both the tensioning device and the spacer blocks. Five experienced orthopaedic surgeons were involved in a randomized study producing 58 complete data sets. Eight measurements (medial and lateral gap, in flexion and extension for tensioning device and spacer blocks) were taken intra-operatively using the ligament balancing features of the VectorVision system. Because many of the measurements were not normally distributed, nonparametric statistical tests (Mann-Whitney and Wilcoxon) were chosen to look for statistical differences, looking for differences in medians and ranking of data instead of differences in averages and distributions. Repeatability of measurements performed with the spring device was defined as the occurrence of same values obtained with the device and by surgeons with spacer blocks. Since the uncertainty in the measurements, due to optical navigation system is near, differences within a range of ±1mm were considered the same value, moreover data within a range of ±2mm were considered a positive result. This data was analyzed with Minitab software version 13.31.

Results are reported in Tab.1.

Results: extension Flexion compartment Medial lateral medial lateral average difference 0.2 (±2.5 mm) 0.0 (±3.6 mm) 1.3 (±2.1 mm) 1.4 (±2.5 mm) number of cases 57 100 57 100 57 100 57 100 median ±1mm 30 52.6 24 42.1 34 59.6 23 40.4 median ±2mm 43 75.4 36 63.2 47 82.5 36 63.2 Table.1. Average difference between gaps obtained with tensioning device and spacer blocks, and related occurrences in medial\lateral compartments inflexion and extension. Difference between the tensioning device and the spacer blocks in flexion is 0.2mm medially and 0.0mm laterally, while in flexion it is 1.3mm medially and 1.6mm laterally, moreover the alignments of resulting femoral cuts obtained with spring device can be considered the same of the alignments obtained with spacer blocks (difference is < 1°). Data, summarized in Tab.1, highlight that knee has a different behaviour in flexion and extension. Applying the same force with the tensioning device the resulting gap in extension (10mm medial, 10.5mm lateral) is lower than the one flexion (10.5mm medial, 12.5 lateral). The percentage of values around the average in the range of 1mm is 52.6% – 59.6% medially and 40.4% – 42.1% laterally, showing a higher variability on lateral compartment, while the percentage of values in a range of 2mm is75.4% – 82.5% medially and 63.2% laterally, confirming the variability.

Determining the soft tissue balance in total knee replacement is important to proper reconstruction. Traditional spacer blocks are unable to load the medial and lateral joint space independently which may compromise the surgical plan. A tensioning device which loads the-joint space independently with a constant load should theoretically allow proper planning of the bone resections and ligament releases during reconstructive surgery. The spring loaded tensor device coupled with image navigation and compared to independent spacer blocks performed by different surgeons revealed that there is no statistical difference between the gaps obtained with spacer blocks and tensioning device in extension, while in flexion there is an average difference 1.4mm, it revealed also that there was greater surgeon variability in the use of spacer blocks compared to the tensioning device. Furthermore, the device produced results that were similar to the results obtained by the spacer blocks especially when surgeon’s variation in technique was taken into account. The use of a joint tensioning device, coupled with computer assisted surgery, allows planning appropriate bone resection and ligament releases to produce matched medial and lateral joint spaces in flexion and extension. There were no reports, either inter-operatively or post-operatively, of any complications or adverse events nor any malfunctions of the device. On a number of occasions it was felt necessary to perform additional bone resections to allow the insertion of the spring device. However this should be considered as a normal part of TKA and of the inter-operative decision making process. This data also revealed, as would be expected clinically that the joint space is less in extension than in flexion after the tibial cut is performed [3]; surgeons with the help of spacer blocks apply less force in flexion in order to obtain the same gap during range of motion, the spring device, applying always the same force, is opening the joint more in flexion. Furthermore, when evaluating the lateral joint space, the tensioning device has a greater variability than the spacer blocks [4]. In this series of patients, a spring loaded tension device decreased surgeon variability in the assessment of ligament tension and, when coupled with computer navigation, allowed the surgeons to appropriately plan the femoral resection to create balanced flexion and extension spaces.


Takashi Sato Yoshio Koga Ten Sobue Go Omori Yuji Tanabe

Change in the joint line in TKA has been recognized as an important parameter in association with post-operative soft tissue tension, range of motion, and knee kinematics. In general, the joint line has been assessed only in tibial side based on the bony reference point of tibia. However, the joint line should also be assessed in the femoral side. This is because a replaced femoral condyle often does not accurately restore the geometry of the original condyle, depending on the alignment, the size, or the design of the component. This discrepancy, especially in the geometry of the distal and posterior condyle will greatly affect the knee kinetics in association with the soft tissue tension. Objective of this study was to investigate how joint line was changed in femoral and tibial condyle by TKA.

We have developed a method to assess the femoral-joint line and the tibial joint line three-dimensionally and quantitatively by the 3D model image matching to biplanar computed radiography. Twenty-knees underwent TKA and 3D joint line examination.

Most of the knees demonstrated the significant proximal movement of the medial joint line in tibia, while the lateral joint line was restored. The significant distal movement of the distal femoral joint line was demonstrated in most of the knees, and it was demonstrated more frequently in medial condyle. Most of the knees demonstrated the significant anterior movement of posterior femoral joint line while no knee demonstrated the significant posterior movement.

From the results of this report, it was proved that the joint line can be changed by TKA procedure not only in tibial condyle but also in distal and posterior femoral condyles with considerable variations. In addition, it was also proved that there can be a difference in the change in the joint line between medial and lateral condyle.

Award for the best student biomaterials paper (US$ 2,000); a proper certificate


Takashi Sato Yoshio Koga Ten Sobue Go Omori Yuji Tanabe

Single plane 2D-3D image matching procedure using fluoroscopic images with CAD data of components has been a gold standard of the in-vivo knee kinematics analysis after total knee arthroplasty (TKA). Numerous literatures have highlighted the “Condylar lift-off” (CLO) phenomenon that is thought to be the cause of eccentric polyethylene wear. However, these reports have not taken account of the 3D geometry of tibial polyethylene insert (TPI).

We have developed a system for analyzing static 3D relationship between femoral and tibial component after TKA accurately utilizing the biplanar computed radiography. By applying this system to fluoroscopic knee motion analysis, it has been possible to analyze the 3Dbehavior of femoral component on the TPI by reducing the error in determining the out of plane translation and rotation. Four knees underwent TKA and postoperative knee motion analysis. Knee kinematics was analyzed by translation of medial and lateral estimated contact points of femoral component on TPI. CLO was defined as the separation of femoral component from TPI by more than 1 mm.

All 4 knees showed the “tilting” of femoral condyle relativeto tibial base plate in coronal plane (this phenomenon has been generally recognized as CLO) resulted from that one femoral condyle contacted with the lower potion in convex geometry of the TPI while the other contacted with the higher potion. This was occurred by a rotation of femoral condyle. However, no CLO was demonstrated in this series. This might be because that recorded knee motions were relatively slow and supported by examiners.

From the results of this report, it was proved that a tilting of femoral component relative to tibial base plate in coronal plane not always indicates CLO. For detailed analysis of knee kinematics after TKA, it was thought to be necessary to take account of the geometry of TPI.


Jiro Tamura Keiichi Kawanabe Motoyuki Shimizu Eijiro Ohnishi Takashi Nakamura

We have developed bioactive bone cements manufactured from bioactive glass-ceramic powder and BIS-GMA resin, which has the bone-bonding ability. In the present clinical trial, this bioactive bone cement was used for fixation of total hip arthroplasty (THA) and the clinical results were investigated

Two types of bioactive bone cements (high- and low- viscosity type cements) were prepared (Nippon Electric Glass Co. Ltd.). Inorganic filler contained 72.0 wt% AW-GC (apatite and wollastonite containing glass-ceramic) and 27.0 wt% SiO2 powder. All surgery was performed at Kyoto University Hospital between February and October 1996. 20primary THA (20 patients) were performed using bioactive bone cement as a clinical trial. The average age of the patients was 58 years. The average follow-up period was 6 years, 9 months. The diagnosis for 18 hips at the operation was osteoarthritis and 2 hips were rheumatoid arthritis. All sockets and one stem were fixed by bioactive cement, and all but one stem were fixed by PMMA cement. In all cases all polyethylene socket and titanium stem were used (14 KC type THA and 8 KMAX type THA). For the femoral head 22 mm diameter alumina head was used in all cases.

If the bone cement is bioactive and shows direct bonding with the bone, wear particles can’t enter the interface and thus prevention of loosening due to bone resorption would be expected. This cement demonstrated satisfactory clinical results, proving to be a promising material for implant fixation.


T D Stewart N Flemming M Wroblewski J Fisher

The product recall of Desmarquest Zirconia heads in 2001 was associated with specified batches of material. Despite of this fact, concerns raised over the stability of Zirconia led to a vast decrease in the use of Zirconia for hip prostheses. While there is evidence in the literature suggesting that Zirconia may become unstable, there remain many prostheses with Zirconia heads in use today. The purpose of this study was to report the condition observed in retrieved Zirconia heads not included in the product recall.

The bearing surfaces of seven retrieved 22mm diameter Zirconia on UHMWPE hip prostheses were investigated to determine whether any degradation of the Zirconia occurred in-vivo. All seven of the Zirconia heads were manufactured by Saint-Gobain Cerammiques Avancees Desmarquest and implantation time varied from 1 to 10 years. Components were analysed by Talysurf, Interferometer, SEM and XRD and compared to new components.

Talysurf of the components revealed an average surface roughness ranging from 0.004 to 0.007 micrometers Ra. This was only slightly rougher than new ceramic components which generally have an Ra of 0.003 micrometers. SEM of the surfaces did not reveal any difference between the retrieved components and new components. Further surface XRD of 4 of the 7 heads, as shown in Figure 1, showed very small percentages of monoclinic phase (28 degrees 2 theta) with predominantly tetragonal phase (30 degrees 2theta), similar to what is observed in new components. Figure 1: XRD of typical retrieved ZR head surface.

All seven retrieved heads demonstrated no evidence suggesting that degradation of the Zirconia had occurred in-vivo.


D. Tigani P. Trentani F. Trentani C. Leonida A. Giunti

The Gpsystem Medacta vision system is composed of an infrared camera that produces and receives infrared rays reflected by almost 3 reflectors mounted on different rigid body devices (F=femoral, T=tibial, G=guide), in order to determine its position with an error lower than 0.35mm. Data received from this vision system are than elaborated by the Cinetique Gpsystem Version 1.0 system in order to determine the correct cutting guide positioning both for the femur and the tibia. The cutting guide is moved on different planes by 5 electric engines applied on 5 no ending screws.

The first step of this system is determining, with the F and the T rigid bodies, patient’s lower limb kinematic in order to evaluate its mechanical axis, its flexion-extension range of movement and its pathological deviations. The second step is evaluating anatomical landmarks to find out the correct degrees of tibial and femoral cuts: these landmarks are the medial and lateral tibial glena, the distal femoral condyles, the posterior femoral condyles, the anterior femoral cortex, the tibial tuberosity, the Whiteside line and the epycondilar axis (each anatomical landmark is identified by multiple points in order to decrease possible errors). The third step is applying the cutting guide and the Grigid body on the femoral clamp in order to estimate the correct level for the tibial cut than, once the tibial osteotomy is done the vision system controls its correct execution and the soft tissue balancing of the knee. The fourth step is calculating with the Gpsystem the correct orientation of the femoral cutting guide and checking its positioning and cutting execution. The last step is applying the test-prosthesis verifying the mechanical axis of the knee and than assembling the definitive prosthesis.

Since now we have applied 10 Cinetique knee prosthesis with the Medacta computer navigation system with good results and good positioning of the prosthesis

Medacta computer navigation system for Cinetique knee arthroplasty is innovative for its simple cutting guide and movement device both in their hardware than in their way of using and for a simpler software interface; these characteristics allows faster surgeon technique learning, shortening of surgical time and a better prosthesis positioning.


Yasir Tarabichi Samih Tarabichi

At our institution significant number of patients were able to have full movement after TKA; however the concern is whether deep flexion after TKA will increase certain complications or whether it will cause early damage to the knee components.

384 Total knee replacements were performed from January 97 to January2002. Three deferent knee systems were used (IB2, NEXGEN and LPS Flex). Preoperative and post operative range of motion was document on lateral x-ray. Knee score was documented and data was processed at major university in Scotland. All surgeries were performed by a single surgeon. Patient was considered to have full flexion if he is able to flex the knee over 140 and able to kneel with the calf touching the thigh for at least one minute. Post operative x-ray was reviewed at 1 and 2 years.3D images were obtained on selected cases.

216 Cases had full flexion as per above definition and 168 cases failed to achieve full flexion. There was no significant deference in complication rate between patients who had full flexion and those who did not. The complication rates were similar to that reported in other series. X ray review did not show any component damage in the full the flexion group; however two phenomenons were documented in some patient who had full movement: dig in phenomenon and lateral femoral condyle spin off (confirmed on 3D images).

Full flexion after TKA did not increase complication rates. The significance of dig in and spin off phenomenon needs further investigation


Amih Tarabichi Marwan Hawari Yasir Tarabichi

The majority of implants available in the market today were designed to allow for a flexion up to 130 degree angle. The LPS Mobile Flex was designed to accommodate deep flexion, up to 160 degree angle. The purpose of this study is to evaluate the clinical result of the LPS Mobile Flex knee.

From January 1999 to February 2004, 635 surgeries were performed on patients treated for advance osteoporosis. All the surgeries were carried out by the same surgeon. The majority of the patients had bilateral total knee replacements simultaneously. Pre-operative ranges of motion were documented on lateral x-ray. Patients were considered to have full flexion if they were able to fix the knee to at least 140 degree angle sit on the ground with calf touching thigh for at least one minute.

68% obtained full flexion as defined above. The majority of the cases with full flexion had full movement pre-operatively, except for 26 cases. Some omplications were reported. There were 2 cases of personal nerve palsy, three of dislocation, and one of infection. There was also a case of rupture of MCL ligament, a case of intra-operative tibial plateau fracture and one of upra-condyler femur fracture. No revision was performed. There were no patella complications

The LPS Flex Implant had a similar complication rate to those reported by other series. There was no complication that could be specifically attributed to deep flexion. Surprisingly, there were no patella complications and the implant, in general, had an excellent clinical outcome as far as mobility. However, it should be stressed that this exceptional result has to do mainly with careful patient selection.


Tosihiko okubo

Though THA against the perfect dislocation coxarthropathy is a rare operation, you should defend the shortening bone cutting of the femoral bone along with the position of establishment of the implant, the bone graft method and the amount of lower extremity extension and neuroparalysis perioperative treatment degree operation. We report it because we put 23 cases of postoperative results which passed for more than postoperative 28 months together.

Material is The coxarthrosis of the congenital dislocated 23 hip cases. An age was an average 56.4 years old to 67 years old more than 51 years old at the time of the operation. A follow-up period was an average 77 months from 28 months until 142 months. JOA score was used as the clinical evaluation. thigh pain was investigated again, too. Subsidence and Spot Welds were investigated as an X-rays evaluation.

When it is left, a congenital dislocated hip case causes the trouble of the spine and the knee opposite. THA that it faces a congenital dislocated hip case with the sufficient preoperative plan by the accurate operating technique can be said as the effective means by this investigation when both of the clinical evaluation and the X-rays evaluation consider that it was a good results, too.


P Trentani D Tigani F Trentani I Andreoli A Giunti

Compromised patellar bone stock poses significant the chnical problems in primary and revision knee arthroplasty. In these situations, traditional approaches have included: non resurfacing, patellectomy, patellar bone grafting, ‘Gull-Wing’ osteotomy. A new material (Trabecular Metal) fabricated using a tantalum metal and vapor deposition techhnique that create a metallic strut configuration with 80%porosity, and physical and mechanical properties similar to bone has been introduced. The authors studied the short-term results following patellar resurfacing using trabecular metal patella in primary and revision total knee arhroplasty (TKA).

Nine patients undergoing primary (2 cases) or revision (7 cases) TKA with the use of a trabecular metal patella were evaluated at a mean of 16 months follow-up. All patients had marked patellar bone deficiency precluding resurfacing with a standard cemented patellar button. The all polyethylene patela was cemented into the trabecular metal base and the remaining patella bone stock; additional fixation was provided by # 2 non absorbable sutures through the peripheral holes on the metal shell.

Revision TKA may be complicated by severe patellar bone loss that preclude implantantion of a standard cemented patellar component. Several options including patellectomy, non resurfacing and osteotomy or grafting of remaining bony shell have been proposed. It is rare in primary knee arthroplasty that the patella has been so eroded that resurfacing is not feasible. Trabecular metall patella may be indicate in the complex revision or even primary knee arthroplasty in which all that remains of the patella is a thin shell of anterior cortical. The short-term results of patellar resurfacing with trabecular metal have demonstrated favorable results.


N Verdonschot M MM Willems B Stungo M Slomsikowsky P Gibbons HR Kriek I Revie

Most minimal invasive surgical (MIS) systems use traditional implant systems combined with new instrumentation. In this study we analyzed a THR system that basically implies that all components are implanted through the femoral neck. The cemented femoral component consists of a highly polished tapered design. The acetabular component is made of Alumina and has an outside diameter of 20 mm. The purpose of this study was to investigate the range of motion, the wear characteristics, the fatigue characteristics of the femoral neck and the stability of the femoral component.

The range of motion of the MIS prosthetic system was calculated with a mathematical model that enabled calculation of prosthetic impingement angles. To assess the wear properties, four pairs of Zirconia heads on alumina acetabuli were tested in a hip simulato. To assess the probability of femoral neck fracture, 3 components were tested according to ISO7206. The stability of the femoral components were tested in five fresh cadaver using dynamic loading conditions. After this test, the load was increased until reconstructive failure occurred.

The ROM was in the order of 100 degrees of flexion and at least 30 degrees in other directions. The bearings showed remarkably low wear with a maximum of 0.02 mm3. All three stems survived the ISO-fatigue test. During the dynamic experiments the specimens did not fail, and no macroscopic damage was detected. Migration was only minor and stabilized during testing. The post-testing failure loads varied between 4.1 and 5.5 kN.

The ROM, stem-neck strength and wear properties of the system seem acceptable. The stability of the femoral component was satisfying; but the post-testing strength may be similar to loads that are applied on the hip at a falling accident. We conclude that these results are encouraging and warrant further studies to develop this system.


F. Variola G. Pezzotti O. Della Gaspera G. Falcone V. De Santis G. agliocchetti S. Sakakura I.C. Clarke

Alumina ceramic has been used in total hip arthoplasty since the 70’s and, in the last 30 years, a considerable evolution has occurred in designing the microstructural features of this material, taking advantage of improved processing techniques, as the hot isostatic pressing. As a result, a high degree of densification (> 99.5) has been achieved in materials with a high degree of purity and, especially, with a fine grain size ( 2 microns). The surface stress field acting on a femoral head inoperation is not only due to working conditions, but also to unexpected factors, as local impacts on the surface as a result of partial dislocations, formation of debris, etc. These additional factors greatly contribute to activate degradation mechanisms which, unfortunately, may lead to failure of the implant.

In this study, five alumina femoral heads were investigated, which were retrieved from patients after different periods of time. Among those investigated femoral heads, two belonged to a first-generation type of alumina material with a relatively coarse grainsize (average value 8 microns) and were retrieved due to surface degradation after long periods of implantation (19 and 17 years, respectively); the remaining three implants analyzed were instead recently manufactured implants with a fine grain size; they were retrieved after relatively short periods because of different causes as, for example, cup or stem loosening.

Surface stress analysis using the luminescence of Cr3+impurity in alumina was performed on the retrieved femoral heads and a statistical comparison was attempted among implants with different microstructural characteristics. The investigation led to estimate average residual stress and statistical stress distributions as a function of the location on the femoral head.

The analysis was performed both on the very surface and in the sub-surface of the head, using the confocal and the through-focus configurations of the optical spectrometer, respectively. Different statistical distributions of residual stress were observed in alumina femoral heads with different grain sizes and models were created to understand their dependence on processing and surface loading.


TRICLOT Philippe FERON Frank FOULT Herve

Based on our experience with an anatomically shaped-femoral stem - helitorsion stem - and on the concept of rotatory locking, we presents our results in osteointegration and bone remodeling.

The study is documented in a prospective study of 84 consecutive helitorsion implants with 6 years 8 month follow-up with no exclusion critera relative to age, gendre, morphology of the femur, bone density, etiology. The stem: forged titanium alloy; roughness 6.5 achieved with corundum treatment; conical proximally, cylindrical distally; double curvature in the sagittal plane; in the horizontal plane, replicates the natural helix of the femurits main feature-; HA coating(200μm) over its proximal 2/3. Stem insertion: helicoidal motion along the long axis of the femur and rotation in the horizontal plane. Rotation is mandatory. The stem is pushed down until the oval shape of the stem matches the oval shape of the femur – at each metaphyseal level – over a more or less extended height depending on the femoral morpho-type; this horizontal locking prevents further downard motion.

This uncemenred helitorsion stem yelds remarkably good radiological results: there is a radiological silence. We think that is attribuable to helitorsion with ensures an even distribution of loads, and applies oblique and not perpendicular loads to the bone-implant interface


Francesco Traina Barbara Bordini Manuela De Clerico Aldo Toni

Hydroxylapatite (HA) is widely employed as coating of cementless hip stems. Nevertheless there is a deficiency of long-term follow-up studies, and none, to our knowledge, with a ceramic on ceramic coupling, that it is important to avoid the effect of polyethylene wear on stem survival.

Between June 1990 and December 1991, 151 prostheses with an anatomic fully HA-coated cobalt-chrome stem, alumina bearing surfaces, and a threaded Ti-6Al-4V cup, were implanted in 147 consecutive patients (57 males, 90 females, average age 58 years). All were primary surgeries, there were no specific exclusions. Ten died for unrelated causes to the surgery, one died from postoperative complications; thirty nine of the surviving patients were lost to follow-up. The Merle D’Aubigné and Postel score was recorded before and after surgery at each review. An anteroposterior view and a frog-lateral view of the involved hip were taken at each follow-up review. The results were analysed by the Kaplan-Meier method to estimate the cumulative probability of revision.

In two cases, the prosthesis was completely removed with Gilderstone’s procedure because of septic loosening. Among the others, 10 cups required revision surgery for aseptic loosening, and 6 stems were revised for thigh pain. The mean Merle D’Aubigné rating improved from 10 before operation to 16.4. Bone stability was recorded in all cases but three in which there was a painfree fibrous stability. The Kaplan-Meier analysis at 12 years predicted asurvival rate for the prosthesis of 86% (95% CI 79 to 92), and for the stem of 93.8% (95% CI 89.7 to 98).

At 12 years the HA-coated stem has shown an overall good outcome while the threaded non HA-coated cup employed had a bad survival that had influenced the survival of the prosthesis. In conclusion we are confident to consider HA a viable and effective coating.


Vineet K Sarin Terry M Mattchen William R Pratt Bradford Hack

Wire cerclage is one of the oldest forms of internal fixation. Cerclage has numerous applications in orthopaedics as a primary method of fracture fixation and as a supplement to other forms of fixation. Traditional wire cerclage, however, has several disadvantages. Monofilament wire is prone to breakage. Multifilament braided cables tend to undergo fatigue failure and fray, releasing metallic particulate debris into the body. Both have a limited ability to maintain compression. This paper presents performance data on a novel flexible, high strength, high fatigue life cable that addresses the inherent problems associated with traditional metal wire cerclage.

The iso-elastic cerclage cable consists of a nylon core encased in a jacket of UHMWPE braided fibers. A tensioning instrument tightens the assembly with a metal clasp. Cable assemblies were tested under in vitro static and dynamic loading conditions. Viscoelastic response and wear behavior under in vitro loading conditions were characterized.

The iso-elastic cerclage cable displayed an ultimate tensile strength of pproximately 650 MPa and withstood over one million cycles of simulated physiologic load without failure. After 8 weeks of static loading, initial cable tension decreased by approximately 40%. After one million loading cycles against a bone plate, the iso-elastic cable displayed no evidence of fraying or fiber breakage.

The ultimate strength of the iso-elastic cable is comparable to that of traditional metal cable while its fatigue strength is clearly superior. After initial relaxation, the iso-elastic cable maintained compressive forces that are typical of the initial compression held by metal cerclage wires. The wear characteristics of the iso-elastic cable are clearly superior to those of multifilament metal cerclage cables. The iso-elastic cable shows high tensile strength and fatigue life. An iso-elastic cable has been developed to compensate for micro-movement within the bone fracture construct while maintaining a continuous compressive force across the fracture.


T. Ward H. Pandit D. Hollinghurst P. Moolgavkar A.B. Zavatsky H.S. Gill

Patellofemoral pain is a significant problem for patients with Total Knee Replacements (TKRs). It is hypothesized that pain is related to high patellofemoral forces (PFF). The aim of this study is to validate a model to estimate PFF after TKR, using a combination of non-invasive measurement and theoretical modeling.

Experiments were performed on four cadaver knee specimens to compare the PFF and the quadriceps force (QF) estimated by a model, with those measured using force transducers. Each knee was tested in its initial state and after implantation of three Scorpio designs: Cruciate Retaining (CR), Posterior Stabilised (PS), and the Posterior Stabilised Mobile Bearing (PS+). Each knee was extended/flexed under a simulated quadriceps load with 3 kg hung from the distal tibia. Relative movement of the bones was measured using a Vicon 612 motion analysis system. A 6DOF force transducer was used to measure PFFs and a uni-axial transducer was used to measure QFs. A fluoroscope simultaneously captured images of the leg extension activity. Parameters measured from the images were used as inputs to the model.

The measured and estimated PFF and QF matched closely between 20o and 80o of knee flexion for the TKRs. At higher flexion angles, the model overestimated the PFF by a maximum of 23N (7.6% max) for the PFF and by 31N for the QF (10.3% max). The estimated and measured Patellar Flexion Angles (PFA) were within 3.5o throughout the flexion range.

The model accurately predicts sagittal plane patellar kinematics and kinetics, using only fluoroscopy and externally measured forces as inputs. However, the model has a limitation in assuming that the extending moment is only due to the quadriceps.

Award for the best student biomaterials paper (US$ 2,000); a proper certificate


Tetsu Watanabe Tetsuya Tomita Takaharu Yamazaki Masakazu Fujii Kazuomi Sugamoto Hideki Yoshikawa

The current study aimed to analyze in vivo kinematics during deep knee bending motion by subjects with fully congruent designed mobile-bearing total knee arthroplasty (TKA) allowing axial rotation and anterior/posterior (AP) gliding.

Twelve subjects were implanted with Dual Bearing-Knee (DBK, slot type: Finsbury, UK) prostheses. These implants include a mobile-bearing insert that is fully congruent with the femoral component throughout flex-ion and allows axial rotation and a 4–6 mm limited AP translation. Sequential fluoroscopic images were taken in the sagittal plane during loaded knee bending motion. In vivo kinematics of knee prostheses were computed accurately using a 2D/3D registration technique, which uses computer-assisted design models to reproduce the spatial position of metallic femoral and tibial components from calibrated single-view fluoroscopic images.

The average femoral component demonstrated 13.4° external axial rotation for 0° to 120° flexion. On average, the medial condyle moved anteriorly 6.2 mm for 0° to 100° flexion, then posteriorly 4.0 mm for 100° to 120° flexion. On average, the lateral condyle moved anteriorly 1.0 mm for0° to 40° flexion, then posteriorly 8.7 mm for 40° to 120° flexion. The average subject experienced a lateral pivot pattern from −5° to 60° flexion, a central pivot pattern from 60° to 100° flexion, and a rollback pattern which bilateral condyles moved backward from 100° to 120° of knee flexion.

Subjects with DBK mobile-bearing TKA in some-degree reproduced femoral external rotation during increasing knee flexion and bicondylar posterior rollback during terminal flexion, due to surrounding soft tissue structures. The geometry of replaced articular surfaces and mobility of the mobile-bearing insert produced lateral-to-central pivoting motions during the flexion cycle, a phenomenon not typically observed in normal knees. Using the current technique, we characterized the unique kinematics of fully congruent designed DBK mobile-bearing knee prostheses.


Sophie Williams Eileen Ingham Martin Stone John Fisher

Different wear rates have been reported for ceramic-on-ceramic (COC) and metal-on-metal (MOM) hip replacements tested in simulators with different loading conditions and lubricants. We postulate that differences in wear rates may be associated with changes in lubrication and friction in the joint. This study aimed to compare the friction of COC and MOM bearings under different lubrication regimes, simulated by varying swing-phase loads and lubricants.

Alumina COC and CoCr MOM 28mm-diameter bearings were studied in a pendulum friction simulator. Flexion-extension of +/−25 degrees was applied to the head, a peak load of 2kN and swing-phase loads of 25N,100N, 300N used. Lubricants used included water, 25% and 100%-bovine serum.

COC and MOM bearings showed increased friction as the swing-phase load increased. COC bearings produced higher friction in 100%-serum compared to 25%-serum. In contrast, friction was lower when MOM bearings were tested in 100%-serum compared to 25%-serum. When COC bearings were tested in water, the friction decreased in comparison to testing in serum, however, MOM friction was higher in water.

Increasing the swing-phase load reduced the thickness of the fluid-film in the stance-phase and this increased friction. The increase in friction when COC bearings were tested in 100%-serum (compared to 25%) may be due to the increased forces required to shear the increased concentration of proteins, similarly friction is reduced in water. MOM bearing friction was reduced in 100%-serum, in this instance increased proteins may be acting as solid-phase lubricants, and similarly MOM friction increased in water.


Christoph von Hasselbach

From 1980–2004 a total of 928 uni knees were performed using the link “St. Georg” and “Endo-Modell” as well as the “Allegretto” device. Our last follow up concerning the first group 1980–1984 revealed an average survival rate of more than 15 years for 94,6 % of the patients, including cases of 24 years without any complaints. Since 2001 the uni knee also was performed as 1-day-surgery in out-patients. Is there any benefit in comparison with In-patients having the same surgery?

Since 2001 53 patients got a uni knee as out-patients. Exclusion criteria: body overweight, cardio-respiratory disease, diabetes, coagulopathy, allergy, malposition of the patella and insufficiency to use crutches. Socially excluded were patients with deficits in emergency supply, home care, personal compliance, local rehabilitation network and insurance problems. Our standards of the surgical procedure: Tourniquet, no cutting guides, antibiotic single shot, general anaesthetica, cemented components, heparine, compression stockings and a controlphone in the evening. At the first ambulatory follow up the second day after surgery we changed the compression stockings after removal of the drainage and started physiotherapy with lymphatic drainage and a special movement splint for exercise at home 3hours/day.

X-ray results and clinical investigation did’nt show a siginificant difference between In- and Out-patients. Out-patients had an average postoperative stay at the unit of 4,7 hours. 24 patients left by wheelchair and 29 by crutches. 46 used a private car for the transport and 7 an ambulance. At the beginning we saw only two “out-patient-specific-complications” in form of drainage disconnections, however without any consequences for the patients. We got 17 emergendy calls because of postoperative pain within the first 28 hours.

The follow up comparison of In- and Out-patients performing minimally invasive unicondylar knee prosthesis did not reveal benefits for ambulatory surgery concerning blood loss, pain, recovery, infections, thrombosis, personal care and surgical procedure. Insurance savings, however, were tremendous: 3800,- EUR for general insured patients and 7900,- EUR for private insurance.


James Wood Maurice Cates Audley Mackel Randall Morgan Robert Poggie

This paper reports the prospective 2 to 4 year clinical results of a porous tantalum monoblock tibia used in primary TKR, with comparison to a cemented modular tibial implant of the same articulating design.

The subject tibial implant is relatively flexible design comprised of a porous tantalum base plate and direct compression molded polyethylene, with initial fixation achieved by press-fitting two porous tantalum posts. The porous tantalum implant was used without bone cement in 72 knees and with cement in 29 cases. The comparative tibial component was a cemented modular design with the same articulating surface. Clinical and radiographic data were collected prospectively, and consecutively, for 165 primary TKR cases implanted from 2000 – 2003

James Wood, Maurice Cates, Audley Mackel, Randall Morgan, Robert Poggie

The early clinical and radiographic results for the porous tantalum monoblock tibia (cemented and cementless) and the modular cemented implant were statistically the same. The preliminary evidence suggests that cementless application of this design is an attractive alternative for younger, more active patients.


Youngbae Park Suk-Hoon Park Young Yong Kim Yong-San Yoon

In the cementless total hip arthroplasty, the position of the stem is pretty much determined by broach and rasping with which the is required for two reasons: one is to align the stem with the femur at the desired position and the orientation. The other is to achieve the conformity between the stem and the prepared proximal cavity surface in the femur. The robotic hip surgery can be a solution for the accurate of femoral canal shaping, but recent reports about the clinical follow-up study of the robotic hip surgery indicated frequent dislocation mainly due to the excessive soft tissue damage during robotic operation. In this paper, a guide being inserted into the femoral canal is proposed to restrict the undesired motion of the rasp inside the femur without extra incision.

A set of canal guide and custom rasp for the selected stem(versys fibermetal midcoat, zimmer co.)were developed and tested with 4 synthetic femurs (model 1130, Sawbones co.). After rasping, a plastic copy of the stem was inserted into the femur and sliced at 5 mm thickness. From obtained cross sections, percentages of the gap larger than 0.3mm between the stem and the bone was measured. 6_C_Results: In average, 79% of bone-implant interface was close contact. Valgus/varus deviations of the stem were 0.40±0.45 degree, which means the angle of axis of straight reamer and axis of final cut.

In average, 79% of bone-implant interface was close contact. Valgus/varus deviations of the stem were 0.40±0.45 degree, which means the angle of axis of straight reamer and axis of final cut.

The conformity of femoral canal with the femoral stem in this approach was higher than the conventional hip surgery and comparable to those in the robotic surgery. The alignment of the stem within the femur is also as good as those in the robotic surgery(0.34±0.67 approach does require neither expensive system nor CT scan. Also this approach can be executed swiftly without extra time and unnecessary large incision compared with the robotic surgery.


Y. Yabuki S. Yanagimoto H. Hotta T. Sasaki Y. Kawai N. Katagiri M. Jinzaki K. Satou

We investigated the incidence of PE (Pulmonary Embolism)and DVT (Deep Vein Thrombosis) after THA by the use of MDCT (multi-detect or row CT scan). The purpose of this study was to evaluate the meaning of blood coagulation molecular markers (FDP D-dimer, Soluble Fibrin Monomer Complex) for the prospect of PE and DVT after THA.

We studied 30 THA patients. There were 2 men and28 women. The value of D-dimer and SFMC before and after THA was examined. MDCT was carried out for DVT and PE investigation, in all cases 7 days after-THA. The relation between the values of blood coagulation molecular markers and existence of PE and DVT was evaluated.

PE occurred in 2 cases and DVT in 4 cases out of 30 cases. D-dimer values of these 2 PE cases in 7 days after THA were higher (18,39), compared with average values (12). Among DVT 4 cases, in 1 case DVT existed on thigh and in other 3 cases existed on calf. The SF values in 7 days showed extremely higher in only thigh DVT case (99), compared with average values (16.6). The value of SFMC fell down rapidly in a few days, representing the biphasic property.

MDCT is very effective for the diagnosis of PE and DVT. But it is difficult to make examination many times. It is very convenient to be able to evaluate PE and DVT by blood examination. From the results of this study, D-dimer may be sensitive for the diagnosis of PE and SFMC also may be useful for DVT. SFMC reacts more rapidly to abnormalities of thrombus and hemostasis. So it has possibilities to clarify the temporal responses of the DVT and PE more precisely.


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Christoph von Hasselbach U. Witzel

From 01/1988 to 04/2001 224 THR were performed assisted by a surgical robot (ROBODOC). The short term run of 5 years should reveal, if any benefit ore disadvantage could be detected comparing Robodo chips with hand -broached hips.

In all 224 cases a straight stem prosthesis with a proximal sleeve was used (S-Rom-Prosthesis). The cup was implanted manually (RM-Cup). The average follow up has been 5 years (4,0–6,2 years). At the last investigation 3 patients had died, 6 patients could not be reached. 215 patients (96%) were examined. According to Merle d’Aubigné pain and walking ability were mesured with a maximal score of 12 points.

Robot assisted hip surgery surely offers an improved primary stability of the stem because of the outstanding precision.

Missing stem loosening after 5 years seem to promiss a longer survival rate.

To avoid a high learning curve certificated qualifying courses are compulsory.


Prof. W. Thomas Dr. L. Lucente Dr. N. Mantegna

In cementless joint arthroplasty, the first goal is the stabilization of the prosthetic components, due to bone ingrowth. In the past, to achieve the best fixation, the orthopaedic surgeons used osteoconductive materials (HA, TriCa-Ph).

To accelerate the fixation process, we have developed an osteoinductive procedure with growth factors. A product born from cancellous bone (BMP’s), bone marrow (stem cells) and plateled-rich plasma (growth factors) is applicated to the tridimensional fixation surface (spongiosametall) of the prosthesis. Since June 2003, we have treated 15 arthroplasties with this procedure (11 THA, 4 TKA).

The average duration of clinical follow-up was 6 month (Range from 2 to 9 months). In case of THA, the average Harris Hip Score was 96(Range from 91 to 100). In case of TKA, the average of HSS scoring was 90(Range from 85 to 100). The radiographic exams were good. DEXA and RSA evaluations are in course.

In our opinion, the OSTEOKIN system is one of the most valuable growth factors system, to use always in arthroplasty surgery.


D.C Wirtz T Mumme A Schuh F Gohlke H.D Carl G Zeiler R Forst

Background: The aim of this prospective multi-center study was to evaluate the clinical and radiological results of a total of 314 uncemented femoral stem revisions using the modular MRP-titanium system.

Methods: 305 patients (111 males, 194 females, mean age 67.7) with 314 MRP-titanium systems were followed-up for a meantime of 3.2 years (1 to 9 years). Pre- and post-operatively all patients were clinically documented using the Harris hip score. Radiologically, the preoperative bony defects were assessed by the Paprosky classification. Post-operatively, periprosthetic bone remodeling was evaluated on the basis of radiographic evidence of bone apposition or resorption.

The modular MRP-titanium system has proven to be valuable in quite problematic cases of hip revision arthroplasty with extensive femoral defects. The system allows intraoperative adaptation of implant length and antetorsion angle to the actual situation, a feature not provided by non-modular femoral revision implants.