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

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).

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

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).

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

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).

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 cadaver study using six pairs of lower limbs was conducted to investigate the accuracy of computer navigation and standard instrumentation for the placement of the Birmingham Hip Resurfacing femoral component. The aim was to place all the femoral components with a stem-shaft angle of 135°.

The mean stem-shaft angle obtained in the standard instrumentation group was 127.7° (120° to 132°), compared with 133.3° (131° to 139°) in the computer navigation group (p = 0.03). The scatter obtained with computer-assisted navigation was approximately half that found using the conventional jig.

Computer navigation was more accurate and more consistent in its placement of the femoral component than standard instrumentation. We suggest that image-free computer-assisted navigation may have an application in aligning the femoral component during hip resurfacing.

Introduction and Aims: Open femoral fracture is a serious injury. We have asked the question: do open femur fractures in polytrauma patients correlate with higher injury severity scores, increased length of stay and higher mortality rates than in closed femur fracture polytrauma patients.

Method: We undertook a retrospective review of a prospectively gathered trauma database at a Level 1 trauma centre. We identified multiple-injured patients with femur fractures who presented in a 36 month period. The cases were divided into 2 groups; open femur fractures (n=33) and closed femur fractures (n=80). Data was collected on demographics, precipitating event, length of stay spent in the ICU, number of associated injuries, ISS, AIS for affected systems, number of femoral surgeries and disposition. Data was analyzed using parametric statistical tests with a significance level of 0.05.

Results: Our analysis revealed that an average, patients in the open femur fracture group spent 8 + 9 days in ICU, sustained 4 + 1 associated injuries, underwent 2 + 1 femoral surgeries, had an ISS of 29 + 13, and died of their injuries in 30.3% of cases. Patients in the closed femur fracture groups spent 8 + 9 days in ICU, sustained 4 + 1 associated injuries, underwent 1 + 1 femoral surgeries, had an ISS of 29 + 14, and died of their injuries in 12.5% of cases. One-way ANOVA showed no statistically significant difference between groups in terms of time spent in ICU, ISS and number of associated injuries. The average number of surgeries was significantly greater in the open femur fracture group (p-value 0.000). A Chi-squared analysis of disposition indicated that patients with femur fractures were more likely to die of their injuries (p-value 0.020).

Conclusions: Findings of the current study demonstrate that while the presence of an open femur fracture does not correlate with an increase in ISS or increase ICU length of stay it may act as a marker for more serious prognosis in polytrauma patients.

Introduction: Little is known about the psychological morbidity associated with orthopaedic trauma.

Purpose: Our study aimed to determine the extent of psychological symptoms and whether patient psychological symptoms were predictive of outcomes following orthopaedic trauma.

Methods: All patients attending 10 orthopaedic fracture clinics at 3 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 9 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.

Results: Of 215 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.

Conclusions: 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.

Introduction and Aims: The combination of ipsilateral intertrochanteric and femoral shaft fractures is an uncommon pattern associated with high-energy trauma. This retrospective study used self-report measures to evaluate functional outcome of patients sustaining this fracture pattern and compared two common treatment methods.

Method: Three patient-based outcome measures, the Short Form-36 (SF-36), Short Musculoskeletal Functional Assessment (SMFA), and Lower Extremity Functional Scale (LEFS) were used to evaluate the functional outcome of twenty-one patients (13 male, mean 46.7 +/− 16.5 years) treated with a reconstruction nail (n=11) or with a sliding hip screw and retrograde nail (n=10).

Results: Mechanisms of injury included motor vehicle accidents (66.7%) and falls from height (14.3%). SF-36 physical and mental component scores were less than Canadian norms, with mean values of 35.9 (p=0.0001) and 43.7 (p=0.02), respectively. There was a trend towards better functional outcome in the group treated with the sliding hip screw with retrograde nail despite this group sustaining more severe injuries as measured by ISS (p=0.004), number of days in hospital (p=0.027), and number of days in ICU (p=0.009).

Conclusion: Functional outcome following treatment of ipsilateral intertrochanteric and femoral shaft fractures was reduced compared to Canadian norms. Despite having sustained more severe injuries, the sliding hip screw with retrograde nail group showed a trend towards better outcome as compared to the group treated with the reconstruction nail.

Introduction and Aims: Patient-based functional outcome and strength following plate fixation of diaphyseal fractures of the radius and ulna is unknown. Therefore, the purpose of this study was to investigate patient-based functional outcome and objectively measured strength following plate fixation of fractures of both bones of the forearm (BBOF).

Method: 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 years). Post-operative protocol included short-term immobilisation followed by active-assisted ROM and strengthening starting between four and six weeks. All subjects were assessed in person at follow-up with a detailed examination of strength of their injured and non-injured arms. Isometric muscle strength was objectively measured with the Baltimore Therapeutic Equipment work simulator (model WS-20). Standardised anteroposterior and lateral radiographs were made of both forearms.

Results: 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%).

Conclusion: Restoration of anatomic alignment with stable internal fixation following BBOF fracture results in good to excellent functional outcome. Despite this, significant reduction in strength of the elbow, forearm, wrist and grip should be expected following this injury, and is an area for potential improvement in post-operative care.

Introduction and Aims: Midcarpal instability is a common cause of wrist pain that remains poorly understood. A simple surgical treatment has been developed involving plication of the dorsal wrist capsule and ligaments. We hypothesised that: wrist stiffness varies in the population; laxity permits excessive displacement; and plication stiffens the joint decreasing motion.

Method: Twelve human cadaveric forearms were potted using bone cement and were secured to the stationary baseplate of a slider. The hand was fixed through the metacarpal bones to the mobile section of the slider, and a compressive load was applied. With the wrist positioned in neutral orientation, a force was applied by an Instron mechanical testing machine (Model 8874, Instron, Canton, MA), simulating a midcarpal shift test. Stiffness (force/displacement) was measured at baseline, with the capsule sectioned, and then following a surgical procedure consisting of plicating the ligaments and capsule with three mattress sutures at the midcarpal joint.

Results: Baseline testing revealed large variability in midcarpal joint stiffness: mean baseline stiffness was 16.5 + 5.9 N/mm, ranging from 9.3 to 28.1 N/mm. Following plication/repair, mean stiffness increased significantly by 20% to 19.8 + 8.5 N/mm (p < 0.02). All surgical repairs withstood the testing without failure. These data confirm a wide range of laxity at the midcarpal joint and provide a mechanical basis for the success observed with capsular plication of the joint.

This increased stiffness decreases motion under comparable loading conditions. In individuals who have excessive motion causing wrist symptoms, increasing the stiffness by capsular plication of the supporting ligaments decreases the motion to relieve symptoms. This technique has found success in clinical practice to relieve symptoms in patients with midcarpal instability.

Conclusion: Midcarpal joint stiffness spanned a threefold range supporting our hypothesis that there is a large variation of ligament laxity in the population. Suturing the dorsal wrist capsule and underlying ligaments significantly increased the stiffness of the wrist when a volar force was applied across the midcarpal joint.

Introduction and Aims: Calcium sulfates and phosphates have become popular as bone graft substitutes, however, their in-vivo performance has not been well characterised. 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.

Method: 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 12 weeks, defect sites were evaluated histologically for tissue and inflammatory response, area fractions of residual graft material, and bone ingrowth in the defects.

Results: 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 12 weeks, this group contained more total mineralised 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. Both 100% CaSO4 and the 3 CaSO4 – HA/TCP formulations showed good bone formation.

Conclusion: The group with the highest proportion of HA/TCP lasted longest, suggesting increased HA/TCP proportions reduce the rates of dissolution, without compromising bone formation in this model. Results suggest that a range of composites could be created to match the spectrum of resorption rates demanded by clinical applications.

Introduction and Aims: To compare the outcomes between primary and revision total hip arthroplasty in patients at one institution with regard to demographics, complication rates and functional outcome. Further study of the problems associated with revision total hip replacement, focused on complication rates, would appear to be warranted.

Method: 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.

Results: Five hundred and forty-seven patients underwent primary total hip replacement and 213 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 post-operative 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 socres (p< .0001).

Conclusions: Revision hip arthroplasty does not bring to the patient the same degree of benefit as the primary operation. The reason for this is multi-factorial and includes a higher complication rate and lower functional outcome.

Introduction and Aims: Bone cement (Polymethylmethacrylate) is commonly used to augment internal fixation in osteoporotic bone. An inconsistency exists among surgeons regarding the appropriate mixing time for bone cement to achieve optimal screw purchase. The study addresses the effect of cement viscosity on fixation augmentation in both healthy and simulated osteoporotic canine bone.

Method: Fourteen canine femora were plated using eight-hole DC plates and 3.5mm screws, repairing transverse diaphyseal osteotomies with and without a gap. In the left femora, cement was mixed for one minute (liquid) prior to injection into drilled and tapped holes that were either properly sized (2.5mm) or over-drilled (3.2mm) to simulate osteoporotic bone. In the right femora, cement was mixed for five minutes prior to injection (thick paste). Four-point bending stiffness for each plated construct was normalised to baseline stiffness, followed by failure loading.

Results: Within the properly sized holes, there were no significant differences in bending stiffness with or without a gap at the fracture site. 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 simulating osteoporotic bone, there was no difference 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).

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.

Conclusion: 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.

Introduction and Aims: Open femoral fracture is a serious injury. We have asked the question: do open femur fractures in polytrauma patients correlate with higher injury severity scores, increased length of stay and higher mortality rates than in closed femur fracture polytrauma patients.

Method: We undertook a retrospective review of a prospectively gathered trauma database at a Level 1 trauma centre. We identified multiple-injured patients with femur fractures who presented in a 36-month period. The cases were divided into two groups: open femur fractures (n=33) and closed femur fractures (n=80). Data was collected on demographics, precipitating event, length of stay spent in the ICU, number of associated injuries, ISS, AIS for affected systems, number of femoral surgeries and disposition. Data was analysed using parametric statistical tests with a significance level of 0.05.

Results: Our analysis revealed that on average, patients in the open femur fracture group spent eight + nine days in ICU, sustained four + one associated injuries, underwent two + one femoral surgeries, had an ISS of 29 + 13, and died of their injuries in 30.3% of cases. Patients in the closed femur fracture groups spent eight + nine days in ICU, sustained four + one associated injuries, underwent one + one femoral surgeries, had an ISS of 29 + 14, and died of their injuries in 12.5% of cases. One-way ANOVA showed no statistically significant difference between groups in terms of time spent in ICU, ISS and number of associated injuries. The average number of surgeries was significantly greater in the open femur fracture group (p-value 0.000). A Chi-squared analysis of disposition indicated that patients with femur fractures were more likely to die of their injuries (p-value 0.020).

Conclusions: Findings of the current study demonstrate that while the presence of an open femur fracture does not correlate with an increase in ISS or increase ICU length of stay, it may act as a marker for more serious prognosis in polytrauma patients.

Twelve pairs of fresh-frozen, cadaveric femora were harvested. Each right femur was prepared for the cemented insertion of the femoral component of a total hip implant. Left femora served as matched intact controls. Following insertion of the implants, the distal tip of the stem was identified and an oblique osteotomy was made to represent a periprosthetic fracture. Proximally, plates were secured with cables and distally by bicortical screw fixation (c+s). The twelve pairs of femora were randomly divided into three groups: 1. Zimmer Cable-Ready System, 2. AO 4.5 mm broad, LC-DCP, with Wire Mounts and Double Luque Wires, 3. Dall-Miles Cable Grip System. Specimens were mounted and deforming forces were applied to test the biomechanical stiffness of the constructs. Following testing the plate-cable combinations, the proximal cables were removed and replaced with unicortical screws (s+s). Repeat testing was then performed as per the above protocol.

The stiffness of the constructs relative to intact bone decreased (p< 0.05) with fixation utilising cables plus screws (c+s) during four-point bending (69–77%) and offset rotational loading (61–64%). When testing unicor-tical plus bicortical screw fixation (s+s) in these modes, a similar effect was seen. There was no difference between plate systems (ANOVA, p> 0.05). Comparisons of stiffness between cable plus screw combination versus unicor-tical plus bicortical screw combination revealed that the latter method of fixation (s+s) was more rigid (p< 0.05).

Our study showed that the three plate-cable systems displayed similar biomechanical stiffness. In addition, when the cables were replaced proximally with unicortical screws, more rigid fixation was obtained in all but one plane of testing.

We conclude that the method of plate stabilisation by screws or cables is more significant than the type of plate used for periprosthetic fracture stabilisation.

Two hundred and seventeen consecutive patients (238 hips) underwent total hip arthroplasty using the St Michael’s stem and a non-porous screw ring cup. Patients were followed prospectively clinically using the St Michael’s hip score and radiographically. At an average of 11.9 years (10-13.5 years), 55 patients (59 hips) had died, 23 patients (23 hips) were lost to follow-up. The St Michael’s hip score improved from 13.4 pre-operatively to 21.7 (out of a possible 25) at the latest follow-up. Thirty-seven (24%) of the acetabular components have been revised for aseptic loosening and an additional seven components are radiographically loose. No femoral components have been revised. Using Engh’s criteria one femoral component is definitely loose and two femoral components have stable fibrous ingrowth. Significant stress shielding was noticed in 23 hips (17%) without clinical consequences. Minor osteolysis was seen in 13 hips most commonly around the proximal femur and has not caused symptoms. The St Michael’s stem with its large pore size madreporic surface has comparable results to other porous coated stems with smaller pore size.

The St Michael’s stem provided reliable ingrowth and fixation with an acceptable degree of stress shielding. The non-porous screw ring cup had a high failure rate.

We report a case of late dissociation of a one-piece metal-backed acetabular component, associated with a prolific soft-tissue reaction to the polyethylene debris. The polyethylene liner was not visible on the radiographs. The metal-backed shell could not be removed because of bone ingrowth. We recommend that modular systems be utilised in cementless arthroplasty of the hip and that radiographic markers be incorporated in the polyethylene of the acetabular cup.