Aims

Osteofibrous dysplasia (OFD) is a rare benign lesion predominantly affecting the tibia in children. Its potential link to adamantinoma has influenced management. This international case series reviews the presentation of OFD and management approaches to improve our understanding of OFD.

Introduction: Flexor tendon repair in the hand often results in a poor functional outcome due to adhesion formation between the tendon repair and the surrounding tissues. The most effective method of minimizing adhesions is immediate postoperative mobilization; however this results in an increased rate of repair failure. Many suture techniques have been developed that increase the repair strength at the expense of increased complexity, requiring a high level of skill, excessive handling of the tendon and wide exposure.

Aim: To develop an intra-tendinous device for repair of the flexor tendons of the hand that is quick to perform and provides a tendon repair equivalent in strength to commonly used suture techniques.

Materials and Methods: A device was designed and machined out of Shape Memory Alloy (NiTiNOL) with barbs facing in opposite directions, such that when introduced into tendon substance the barbs hold the tendon ends opposed. The device is drawn into the tendon ends using a length of suture and requires only one passage of the needle in each free tendon end.

80 porcine deep flexor tendons were harvested from adult porcine forelimbs and randomized into four groups of twenty tendons. Three groups were repaired using either a two, four or six strand repair, and the remaining group was repaired with the new device. Half of each group was repaired using a core technique alone; the remainders were supplemented with a Silfverskiöld Peripheral Cross Stitch.

The repairs were pre-loaded to 1N in a Zwick Linear Tensiometer, with subsequent distraction to failure at 10mm/min. When preloaded the tendon dimensions were measured at the repair site as well as above and below in order to assess repair site bulk. During loading the Force to Produce 3mm Gap (FPG) was recorded as was the Ultimate Strength (US) following failure.

Statistical Methods: Data was illustrated diagrammatically using box and whisker plots in order to aid comparison of the new device to the traditional suture techniques. The data was also analyzed using one-way ANOVA.

Results: The three traditional suture techniques showed a significant increase in FPG and US with increasing numbers of strands for both core repairs alone and those with supplemental peripheral repair.

The FPG of the new device was superior to the Cruciate when used alone and was equivalent to the Savage when augmented with a peripheral repair. The US of the new device was superior to the Cruciate both with and without a peripheral repair.

Conclusion: We present a new device for flexor tendon repair which is very simple to use, yet performs as well as traditional suture techniques.

We plan to continue development of the device to optimize its hold on the tendon. We also plan to perform cyclical testing in physiological conditions

Total Elbow arthroplasty can be a valuable treatment option in the painful or stiff elbow but outcomes have been disappointing previously. The history of total elbow arthroplasty has been disappointing in the past. Implants initially were a coupled articulation and were a rigid hinge. There was then a move to resurfacing type of designs although there was an issue with instability postoperatively with these implants. The semiconstrained coupled implant was developed in the mid 1970s by Coonrad. The idea behind the implant was that the loose polyethylene coupling provides inherent stability while decreasing the amount of loosening that was seen with the rigid hinge implants previously. We are reporting our results of our experience with a single type of semiconstrained implant that has been used in our unit since 1999.

A semiconstrained total elbow arthroplasty was performed in thirteen patients over a period of 7 years period in our unit. Mean age at time of surgery was 60 years (44–70) M:F ratio 11:2. The aetiology of the joint pathology was Rheumatoid Arthritis (n= 10), psoriatic arthritis (n= 2) & posttraumatic (n =1).

The patients were followed up for a mean duration of 4.5 years. They were assessed for range of motion, Mayo elbow function scores and radiographic evaluation and complication rate. 9 of the 13 elbows had a good to excellent result. There were 5 complications overall. There was two ulnar neuropathies that eventually resolved and one ulnar component that had to be revised 2 weeks after initial insertion. 3 had condylar fractures none of which required further operation. One patient had evidence of radiographic loosening but was asymptomatic.

In our experience the semiconstrained total elbow replacement is a valuable option in the treatment of painful stiff the elbow.

Aim: To compare strength the to failure of Silversjold type B repair (SJBR) using bites two, four and six millimetres from the repair site of an ex-vivo porcine flexor tendon model.

Methods: Seventy freshly harvested procine flexor tendons were transected and randomised to repair using either SJBR or simple running epitendinous repair with and without a two strand Modified Kessler repair (MKR), repairs also performed spanning four and six millimetres from the repair site.

Biomechanical testing was performed with a Zwig tensinometer using a one neuton preload and a distraction rate of 20mm/min. Bulking was measured with a digital micrometer and each repair group was tested for mean load to repair failure and mean load to 2mm gap formation. In each case the mechanism of failure was recorded.

Results: The addition of an epitendonous suture statistically increases strength to failure over a core suture alone. The SJB with MKR at all distances was stronger than the the standard epitendonous suture with MK. Optimal strength was obtained at a distance of 6mm from the repair site. Data was assesed using an ANOVA analysis. Repairs failed in all repairs by suture breakage.

Conclusion: The use of an epitendonous suture adds valuable strength to a flexor tendonn repair. The SJBR is somewhat more complicated that a standard running suture however the augmentation in strength makes this worthwhile. The placement of IHM is optimal at 6mm from the repair site and did not statistically increase the tendon bulk.

Introduction and Aims: Periprosthetic fracture is a serious complication of increasing incidence in joint replacement. Our aim was to evaluate periprosthetic fracture patterns in our series of 1152 primary hip arthroplasties using a cementless proximally hydroxyapatie coated anatomic stem and to identify risk factors from parameters measured in our assessment of these patients.

Method: All patients with periprosthetic fracture following primary total hip arthroplasty using the Anatomique Benoist Girard I (ABG I) hip system were identified. Parameters studied included time of fracture after surgery, patient age and fracture classification. The pre-operative cortical index in the fracture group was measured and compared with a group matched for age, gender, diagnosis, and body mass index.

1152 ABG I primary hip arthroplasties were performed in 1037 patients from 1991–1997. Osteoarthritis was diagnosed in 93% of cases. The average age was 65 years; there were 536 females and 501 males. Mean follow-up was 79.6 months.

Results: Thirty-two patients, 16 male and 16 female, suffered a periprosthetic fracture. Thirty-one patients were treated for osteoarthritis and one for a femoral neck fracture. We retrieved complete records on 28 patients.

The average age of the fracture group was 73 years, compared to 65 years for the whole series (p< 0.0001). The incidence of periprosthetic fracture increased with age. The relative risk for patients over 70 years for peri-prosthetic fracture is 4.7 greater (95% CI 2.14–10.21).

Distinct fractures patterns were related to time from initial surgery. Four fractures occurred within three months of surgery; these early fractures exhibited a particular pattern. The remaining 24 occurred between four and 114 months after surgery. These late fractures exhibited a different but consistent fracture pattern. Two fractures in the early group were identified immediately post-operatively. All others presented after minor low energy trauma.

The mean cortical index in the fracture group was 47% and in the matched group 51%. If the pre-operative cortical index is below 50%, the risk of periprosthetic fracture is 4.75 greater (odds ratio 4.75 CI 1.5–15.00).

All fractures were adequately classified and managed by guidelines in the Vancouver classification.

Conclusion: This study identified distinct fracture patterns related to time from surgery. Cortical index and age have predictive value in pre-operative assessment of fracture risk: cortical index below 50 and age above 70 are risk factors for periprosthetic fracture and should be considered with other parameters to minimise risk of this complication.

Aims: To confirm that the augmented (MGH) Becker extensor tendon repair is a strong four-strand technique that allows earlier mobilisation of repaired tendons after only 3/52 of postoperative static splinting and to assess functional outcome using revised disabilities of arm, shoulder and hand (DASH) score.

Methods: In this prospective study we used the augmented Becker (MGH) suturing technique with Ethilon. Postoperatively patients were immobilised 3 weeks in volar splint and then fully mobilised with physiotherapy. 3/12 postoperatively all patients had final assessment in hand clinic for: pulp to palm distance, power grip, pinch grip, pain, Dragan criteria of progress, total active motions (TAM) of the fingers and revised DASH score.

Results: Eighteen patients had extensor tendon lacerations repaired with augmented Becker (MGH) technique. Results were compared with the uninjured hand and statistically evaluated. At the final assessment the average pulp to palm distance was 0cm. All patients had good pinch and power grip (> 80% of uninjured hand for dominant hand and > 60% for non-dominant hand) and were free of pain with excellent progress using Dragan criteria. Average TAM was 268° without statistically significant difference between this and the uninjured side. Average scaled DASH score was 7.6 and within normal values. We had no wound complications or ruptures of repaired tendons.

Conclusion: Augmented (MGH) Becker technique is a strong four-strand extensor tendon repair technique that allows early mobilization of patients after only 3/52 of static splinting postoperatively. Injured fingers can then be safely mobilized with expected full return of movements at 3/12 postoperatively.

Introduction and Aims: Third generation alumina ceramic-on-ceramic bearings are being increasingly used in hip replacement surgery as an alternative to polyethylene because of the unacceptably high wear of polyethylene bearings and associated osteolysis leading to failure of hip replacement. Follow-up time with these modern ceramic bearings is still short.

Method: We report the minimum five-year follow-up of our first 300 hip replacements with these bearings in 283 patients, done between June 1997 and February 1999. Three hundred ceramic-on-ceramic Osteonics Securfit or Securfit Plus stems were used with the Osteonics Securfit cup in all cases – these are cement-free and hydroxyapatite coated. The bearings were third generation alumina ceramic femoral heads and cup inserts manufactured by CeramTec. The average age was 58 years and there were 52% females. Osteoarthritis was the diagnosis in 93% and inflammatory arthritis in four percent. We used 92% 32mm bearings and eight percent 28mm bearings.

Results: Mean Harris hip score improved from 56 pre-operatively to 94 at five years. Complications included: three non-fatal and no fatal pulmonary emboli, one deep and four superficial infections. There were four revisions for periprosthetic femoral fracture, one for cup malposition and one for sciatic nerve palsy in a patient with proximal focal femoral deficiency. There were a further four re-operations for psoas tendonitis where the psoas tendon was released. There were no re-operations for bearing failure and none of the ceramic components failed catastrophically, although a small number of acetabular inserts chipped around the rim during insert and were discarded. Of particular interest is the fact that there was no osteolysis seen in any of these hips, either around the acetabulum or around the femur. The usual small lytic areas noted around the calcar and the trochanteric regions of the femur that are commonly seen with polyethylene bearings were completely absent in this group. Three of the hips squeak intermittently with vigorous activity.

Conclusion: Third generation ceramic-on-ceramic bearings have only been available for seven or eight years. Early results using these new bearings are encouraging, in that osteolysis to date has not been seen in this series. No hip in this series has been revised for failure of these ceramic implants. It will be a further five to 10 years before we can be certain how these newer bearings will perform in the long term, but the five-year results are encouraging.

Introduction: Acetabular osteolysis is common behind cups with holes (the reported incidence is 9% to 36%). Fluid pressure has been implicated in the pathogenesis of osteolysis.

Aim: To test the hypothesis that a polyethylene liner in a metal cup can act as a pump in vivo.

Methods: This study was performed during revision surgery in six cases. The components were from several manufacturers. All were ingrown uncemented cups that had osteolytic lesions associated with holes in the cup.

A cannula was placed through the capsule into the hip joint and another was placed through the periosteum and bone of the ilium into the osteolytic lesion above the ingrown cup. The continuity of these two spaces through the holes in the cup was confirmed by the injection of methylene blue. Pressure transducers were then connected to both cannulae. Measurements were taken while applying compression and distraction forces across the artificial hip joint.

Results: Compression and distraction loads produced a rise (48mmHg) and a fall (35mmHg) respectively in the pressure in the osteolytic lesion but no change in the hip joint pressure, thereby, demonstrating a pumping action. After exposing the prosthesis we were able to demonstrate 1mm to 2mm of in-out excursion of the polyethylene liner in the metal cup, which may explain the mechanism of the pumping effect.

Discussion: The polyethylene liner in the metal shell can act as a pump. Compression and distraction forces, such as occur in normal gait, produce changes in fluid pressure, which are transmitted through the holes and may cause osteolysis behind the cup.

Introduction: Osteolysis is a recognised complication in both cemented and cementless arthroplasty. This may be caused by macrophage mediated reaction to small particulate polyethylene debris. The effective joint space describes the area where polyethylene particles may travel, such as through holes in the cup, to cause a local osteolytic process.

Methods: Twenty four cases of osteolysis (in twenty three patients) requiring revision were identified from patients on whom we had performed the primary arthroplasty. These cases were compared to an overall group of 560 primary hip arthroplasty cases performed during the same time and with the same implants.

Results: The 24 index cases were revised for osteolysis. This represents 4.3% of the total group in this series of implants. Secondary loosening of the acetabular component was present in 7/24 with 13/24 cups being well fixed at the time of revision. All the cups with secondary loosening had evidence of bone ingrowth & had been undermined by the osteolytic process. In 4 cases, either a pelvic fracture or pelvic dissociation had occurred through an osteolytic lesion. In 21 cases femoral stems were revised, but none of these were loose, and none had significant osteolysis around the stems.

The average time from primary procedure to revision was 72 months. The osteolytic group was younger than the overall group at the time of index surgery (53 years vs 63 years, p< 0.0001). There were 16 females and 7 males (p = 0.06). The osteolytic group were also less likely to have an initial diagnosis of primary osteoarthritis than the control group (p=0.05). Other diagnoses in the osteolytic group included dysplasia, previous trauma and inflammatory arthropathy.

Acetabular liner thickness was assessed for all patients. The osteolytic group had a significantly higher proportion of cases with polyethylene thickness of less than 7mm (p < 0.005), and less than 6mm (p < 0.0001). There was no difference in the mean height and weight of the two groups.

Conclusion: Osteolysis is multifactorial and facilitated by screw holes in the acetabular shell that increase the “effective joint space.” Younger females with small ace-tabular components and thin polyethylene are most at risk. Alternate bearing surfaces or acetabular components without holes may alleviate this problem. These cases represent our experience with osteolytic lesions within the acetabulum requiring revision. There were no cases of cup loosening in our overall group other than the 7/24 that had been undermined by the osteolytic process. Revision to ceramic on ceramic bearing implants is our preferred method of treating this problem.

Introduction: Thromboembolic complications are common in both elective and trauma orthopaedic practice. Despite the many studies reported in the literature, there remain a number of unanswered questions regarding the use of thrombophylaxis. The aim of this study was to establish the current practice amongst Irish consultant orthopaedic surgeons regarding thromboprophylaxis.

Materials and Methods: A detailed confidential written questionaire was sent to all consultant orthopaedic surgeons in the republic of Ireland. Surgeons were asked to indicate the type of mechanical and chemothromboprophylaxis in the setting of total hip arthroplasty, knee arthroplasty and hip fracture. They were also questioned regarding 1) time of commencement of therapy 2) duration of therapy 3) method of diagnosis of DVT 4) Estimated incidence of mortality from pulmonary embolism in the last five years 5) Whether there was established protocol for DVT prophylaxis in their unit. 6) Reason for not using chemothromboprophylaxis if not used and 7) whether their method of treatment was influenced by anaesthetic concerns.

Results: The response rate was seventy percent. Over ninetyfive percent of surgeons used a combination of physical and chemical modalities. There was a wide variation between type of therapy, commencement time and duration of prophylaxis. There was a higher rate of intervention and duration of therapy in elective practice. A unit policy regarding thromboprophylaxis existed in a majority of hospitals (54.7%). Forty-seven per cent of respondents felt that there had been no post-operative mortality in their practice in the previous five years from pulmonary embolism. Twenty-six percent of respondents felt that anaesthetists influenced the type of prophylaxis used. The results of this survey shows that venous thromboembolism is regarded as a significant complication of orthopaedic surgery and that most orthopaedic surgeons take active steps to try and prevent its occurrence. There was a higher rate of intervention in this groug of surgeons compared to previous surveys of British orthopaedic surgeons. This may reflect a higher standard of care or a concern regarding the high rate of litigation in the republic of Ireland. However there is no consensus as to the optimum therapy which reflects the conflicting evidence available in the many publications on this subject.

Aim: A prospective randomised clinical trial was performed to evaluate two forms of immobilisation in the treatment of colles fractures not requiring manipulation.

Methods: Patients were randomised to either plaster cast (PC) or a removable splint: wrist splint (FWS) according to date of presentation. Patients who had associated injuries to the same upper limb, previous wrist fracture, and open fractures, below 20 years or impaired cognitive function were excluded. The hospital ethical committee approved the study and informed consent was obtained from patients. Patients were reviewed at one week, two weeks, six weeks and twelve weeks following enrolment into the trial. Radiographs were performed on the first four visits. Subjective data was obtained using a patient questionnaire. Levels of pain, comfort in cast, swelling and any modifications to the cast were documented. Was used at six and twelve weeks to assess Clinical assessment was performed by a qualified physiotherapist using the demerit score of Sarmiento which combines range of motion, grip strength and functional assessment.

Results: There were thirty-seven patients in the PC group and thirty-four in the FWS group. They were well matched in terms of age and sex distribution One patient in the PC group required manipulation under anaesthesia due to loss of position at one week. There was no statistical difference between either treatment method in radiological position. Nine patients in the PC group required change of cast due to loosening or discomfort. A further eight patients in the PC group required cast trimming. Visual analogue scores for pain and cast discomfort were lower in the FS group (p< 0.05). Grip strength compared to the opposite side was higher in the FS group (55.9% Vs 47.8% at week six, 71.8% Vs 65% at week twelve). Functional assessment demonstrated a higher score in the FS group at six weeks. However the difference did not reach statistical significance at repeat examination at twelve weeks.

Conclusion: In this study there was no difference in either method in maintaining fracture position. However there was greater patient satisfaction and earlier rehabilitation in those patients treated in a futura wrist splint. Patients treated in plaster cast required a greater use of plaster room resources. We feel that the use of a removable wrist splint in suitable patients with either undisplaced or minimally displaced distal radial fractures is validated by this study.

Introduction: Compartment syndrome is a well recognised complication of tibial diaphyseal fractures. The sequelae of late treatment can be devastating to both patient and surgeon. The aim of this study was to identify the incident, outcome and possible risk factors of compartment syndrome treated in a regional trauma unit.

Patients and Methods: A total of six hundred and twenty three tibial diaphyseal fractures were managed over a four year period (1995–1999). Two hundred and forty three of these were treated using a reamed intramedullary nail. One hundred and ninety four of these were closed and forty nine were open. AO radiological classification and Tscherne soft tissue classification were used to grade severity of injury. The mechanism of injury was recorded for all tibial fractures. Patients who were diagnosed with compartment syndrome were clinically and radiologically evaluated.

Results: Compartment syndrome was diagnosed in seventeen cases with an average follow up of twenty eight months (range 8–48 months). This represented a rate of compartment syndrome of 2.7% of all tibial fractures but 6.9% of cases treated with a reamed tibial nail. The average age of patients was twenty four years (range 18–42 years). Fractures were closed in twelve cases and open in 5. Results in this group were good in ten cases, fair in four cases and poor in three cases (Edwards Classification). Six patients developed complications following fasciotomy including drop foot, equinus contracture, muscle weakness and MRSA infection. In patients with complications, the interval between onset of symptoms and decompression was greater than ten hours. All patients who developed compartment syndrome had been treated using a reamed intramedullary nail.

Discussion: There was a statistically significant association between the use of intramedullary reaming and development of compartment syndrome (p< .05). We recognised a hitherto undescribed trend of compartment syndrome following reamed intramedullary nailing of tibial fractures sustained during sport activity. This may relate to higher initial compartment pressure in this group at the time of fracture. Increased awareness may avoid the consequences of late treatment of compartment syndrome.