In the unstable patellofemoral joint (PFJ), the patella will articulate in an abnormal manner, producing an uneven distribution of forces. It is hypothesised that incongruency of the PFJ, even without clinical instability, may lead to degenerative changes. The aim of this study was to record the change in joint contact area of the PFJ after stabilisation surgery using an established and validated MRI mapping technique. A prospective MRI imaging study of patients with a history of PFJ instability was performed. The patellofemoral joints were imaged with the use of an MRI scan during active movement from 0° through to 40° of flexion. The congruency through measurement of the contact surface area was mapped in 5-mm intervals on axial slices. Post-stabilisation surgery contact area was compared to the pre-surgery contact area. In all, 26 patients were studied. The cohort included 12 male and 14 female patients with a mean age of 26 (15–43). The greatest mean differences in congruency between pre- and post-stabilised PFJs were observed at 0–10 degrees of flexion (0.54 cm. 2. versus 1.18 cm. 2. , p = 0.04) and between 11° and 20° flexion (1.80 cm. 2. versus 3.45 cm. 2. ; p = 0.01). PFJ stabilisation procedures increase joint congruency. If a single axial series is to be obtained on MRI scan to compare the pre- and post-surgery joint congruity, the authors recommend 11° to 20° of tibiofemoral flexion as this was shown to have the greatest difference in contact surface area between pre- and post-operative congruency

Introduction. Conventional pre-operative planning for total hip arthroplasty mostly relies on the patient radiologic anatomy for the positioning and choice of implants. This kind of planning essentially remains a static approach since dynamic aspects such as the joint kinematics are not taken into account. Hence, clinicians are not able to fully consider the evolving behavior of the prosthetic joint that may lead to implant failures. In fact, kinematics plays an important role since some movement may create conflicts within the prosthetic joint and even provoke dislocations. The goal of our study was to assess the relationship between acetabular implant positioning variations and resultant impingements and loss of joint congruence during daily activities. In order to obtain accurate hip joint kinematics for simulation, we performed an in-vivo study using optical motion capture and magnetic resonance imaging (MRI). Methods. Motion capture and MRI was carried out on 4 healthy volunteers (mean age, 28 years). Motion from the subjects was acquired during routine (stand-to-sit, lie down) and specific activities (lace the shoes while seated, pick an object on the floor while seated or standing) known to be prone to implant dislocation and impingement. The hip joint kinematics was computed from the recorded markers trajectories using a validated optimized fitting algorithm (accuracy: translational error ≍ 0.5 mm, rotational error < 3°) which accounted for skin motion artifactsand patient-specific anatomical constraints (e.g. bone geometry reconstructed from MRI, hip joint center) (Fig. 1). 3D models of prosthetic hip joints (pelvis, proximal femur, cup, stem, head) were developed based on variations of acetabular cup's inclination (40°, 45°, 60°) and anteversion (0°, 15°, 30°) parameters, resulting in a total of 9 different implant configurations. Femoral anteversion remained fixed and determined as “neutral” with the stem being parallel to the posterior cortex of the femoral neck. Motion capture data of daily tasks were applied to all implant configurations. While visualizing the prosthetic models in motion, a collision detection algorithm was used to locate abnormal contacts between both bony and prosthetic components (Fig. 2). Moreover, femoral head translations (subluxation) were computed to evaluate the joint congruence. Results. Simulations showed collisions occurring at maximal ranges of motion in the anterosuperior part of the acetabulum. Both prosthetic and bony impingements were observed, especially while lacing shoes and lying down. The more the inclination and anteversion were important, the lower the frequency of impingements was noted (e.g. 23% at 40°/0°, 13% at 45°/15°, 5% at 60°/30°). Subluxations followed the same trend (e.g. 4.0 mm at 40°/0°, 1.5 mm at 45°/15°, 0.2 mm at 60°/30°). They occurred in a posterior direction as a consequence of impingements. Conclusion. Daily tasks could expose the prosthetic hip to subluxation and impingement located in anterosuperior position. This location could be explained by the high hip flexion required to execute the motions (≥ 95°). Considering the kinematics solely, increasing inclination and anteversion seems to decrease possible conflicts, but mechanical aspects (stress, wear) should also be considered in the definition of ideal cup positioning

Bone defects are frequently observed in anterior shoulder instability. Over the last decade, knowledge of the association of bone loss with increased failure rates of soft-tissue repair has shifted the surgical management of chronic shoulder instability. On the glenoid side, there is no controversy about the critical glenoid bone loss being 20%. However, poor outcomes have been described even with a subcritical glenoid bone defect as low as 13.5%. On the humeral side, the Hill-Sachs lesion should be evaluated concomitantly with the glenoid defect as the two sides of the same bipolar lesion which interact in the instability process, as described by the glenoid track concept. We advocate adding remplissage to every Bankart repair in patients with a Hill-Sachs lesion, regardless of the glenoid bone loss. When critical or subcritical glenoid bone loss occurs in active patients (> 15%) or bipolar off-track lesions, we should consider anterior glenoid bone reconstructions. The techniques have evolved significantly over the last two decades, moving from open procedures to arthroscopic, and from screw fixation to metal-free fixation. The new arthroscopic techniques of glenoid bone reconstruction procedures allow precise positioning of the graft, identification, and treatment of concomitant injuries with low morbidity and faster recovery. Given the problems associated with bone resorption and metal hardware protrusion, the new metal-free techniques for Latarjet or free bone block procedures seem a good solution to avoid these complications, although no long-term data are yet available.

Cite this article: Bone Joint J 2024;106-B(10):1100–1110.

Purpose. Factors contributing to chronic postoperative pain (CPOP) are poorly defined in young people and developmental considerations are poorly understood. With over 5 million children undergoing surgery yearly and 25% of adults referred to chronic pain clinics identifying surgery as the antecedent, there is a need to elucidate factors that contribute to CPOP in young people. The present study includes patients undergoing hip preservation surgery at a children's hospital. Methods. The HOOS and the SF-12 Health Survey were administered to 614 patients prior to surgery with 422 patients completing follow-up data (6-months, 1-year, and 2-years post-surgery). Examining baseline characteristics for those who completed follow-up versus those who did not, the only significant difference was that patients with more than one surgery were less likely to complete follow-up measures. Pain, quality of life, and functioning across time were examined using SAS PROC TRAJ procedure, a mixture model that estimates a regression model for each discrete group within the population. Longitudinal pain trajectories were empirically grouped. Baseline preoperative characteristics of age, gender, preoperative pain, quality of life, functioning, and mental health that could potentially distinguish trajectory groups were examined. Results. A three trajectory model (low pain, pain improvement, and high pain) emerged indicating three different treatment responders. Pain trajectory groups did not differ significantly on gender, presurgical age, BMI, prior hip surgery, surgical type, joint congruence, or Tönnis grade. The pain trajectory groups differed significantly from each other on presurgical pain, pain chronicity, quality of life, and functioning. Those in the high pain group and pain improvement group endorsed having presurgical depression at significantly higher rates and lower presurgical quality of life compared to those in the low pain group (p<.01). Similarly, those in the high pain group reported significantly worse functioning prior to surgery compared to the pain improvement group (p<.0001) and those in the low pain group (p<.0001). Conclusions. Chronic pain is a common problem and surgery can be a trigger. There may be a subset of hip preservation surgery patients who are predisposed to chronic pain independent of hip health. The results demonstrate the need for preoperative screening prior to hip preservation surgery. A prospective, interventional study to identify patients at risk for a poor pain trajectory is underway. Significance. This is the largest study to date to examine longitudinal pain, quality of life, and functioning trajectories for adolescent and young adults undergoing hip preservation surgery. Chronic pain is a serious public health concern, with the United States spending $19 billion annually on pain-related disability. Identifying predictors of poor long-term outcomes in adolescents and young adult samples with postoperative pain may prevent the development of chronic pain into adulthood as well as inform presurgical preparation and postsurgical care

Aims

Treatment of Weber B ankle fractures that are stable on weightbearing radiographs but unstable on concomitant stress tests (classified SER4a) is controversial. Recent studies indicate that these fractures should be treated nonoperatively, but no studies have compared alternative nonoperative options. This study aims to evaluate patient-reported outcomes and the safety of fracture treatment using functional orthosis versus cast immobilization.

We have been following all modern trends in the treatment of Legg-Calve-Perthes disease during several decades (from nonoperative treatment, revascularization procedures, varization femoral osteotomies to various pelvic osteotomies). Last few years we have started to use triple pelvic osteotomy in patients older than seven years, in order to shorten treatment period, establish solid containment and subsequent remodelation of femoral head, and achieve final spheric hip congruence. In the period from 1996 to 2004 we had 28 such surgical interventions. Patient age at surgery was between 7 and 10 years. All hips were uncontained preoperatively, and in fragmentation stage. Twelve hips were classified as Catterall group III and sixteen hips as Catterall group IV. Triple pelvic osteotomy according to Tonnis (modified by Vladimirov) was performed in all cases. Average follow-up period was 40 (28–96) months. Treatment result was good in all patients, with full functional recovery. Spheric joint congruence was achieved in 24, and aspheric congruence in other 4 cases. Average period for union of osteotomies was 10 weeks, followed by introduction of full weight bearing, considerably earlier than in patients with similar age and disease stage, treated by combination of Salter pelvic osteotomy and femoral shortening

Aims

Hyaline cartilage has a low capacity for regeneration. Untreated osteochondral lesions of the femoral head can lead to progressive and symptomatic osteoarthritis of the hip. The purpose of this study is to analyze the clinical and radiological long-term outcome of patients treated with osteochondral autograft transfer. To our knowledge, this study represents a series of osteochondral autograft transfer of the hip with the longest follow-up.

Introduction: Insufficient femoral head coverage is found in a variety of diseases, with acetabular dysplasia as the most frequent disorder and the triple pelvic osteotomy as the most recently introduced surgical treatment. Objective: The study analyses pre- and postoperative pathoanatomical characteristics of triple in comparison to Salter and Chiari osteotomies, with a logistic regression analysis of outcome predictor and effect explanator factors in relation to the chosen type of operation. Methods: The study involved 136 adolescents, treated with Salter and Chiari osteotomies or a triple pelvic osteotomy. The patients were between 10–20 years old at the time of operation. The following data from all the patients were analysed: illness history, operative parameters, preoperative and postoperative pathoanatomic data. The data was statistically processed using the statistical software SPSS, defining standard descriptive values, and by using the appropriate tests of analytic statistics. Results: The average CE angle after triple pelvic osteotomy was 43.5 degrees, more improved than after the Salter osteotomy (33.0 degrees) and Chiari osteotomy (31.4 degrees). Postoperative spherical congruence was also more frequent after the triple osteotomy than after the other two types of operations. Preoperative painful discomfor was found to be a valid predictor of indications for the triple osteotomy over both Chiari and Salter osteotomies. The valid explanators of the effect of the triple osteotomy are: postoperative joint congruence (compared to the Chiari osteotomy) and increase in joint coverage (compared to Salter osteotomy). Conclusion: Triple pelvic osteotomy is the method of choice in the management of acetabular dysplasia and other disturbances of hip joint containment in adolescent age

Aims

To investigate the risk factors for unsuccessful radial head reduction (RHR) in children with chronic Monteggia fractures (CMFs) treated surgically.

Aims

To investigate health-related quality of life (HRQoL) of older adults (aged ≥ 60 years) after tibial plateau fracture (TPF) compared to preinjury and population matched values, and what aspects of treatment were most important to patients.

Introduction and purpose: Kienböck’s disease was described by R. Kienbock in 1910. From that date onwards, multiple surgical techniques for its treatment have been described. Amongst these techniques is the one we have used: a radial osteotomy with Nakamura effect; this is a radial osteotomy with a wedge-shaped base and minimum dorsal width with subsequent osteoclasia carried out distally to the distal radioulnar joint to prevent any alterations in joint congruence. The aim of this study is to assess the results of this technique and compare them with those described in the literature using other surgical techniques. Materials and methods: We selected patients with Kien-böck’s disease stage II and IIIA that underwent surgery using the technique described and we subsequently assessed clinical and radiological parameters both pre and postoperatively. Results: Of the 17 patients diagnosed with Kienböck’s disease in our department, only 11 were operated using the technique described above. In these patients it was possible to see that a greater number had their dominant arm affected, there was a greater percentage of ulnar plus variants, the radial inclination angle was higher and the main symptom was pain. At this time, having undergone surgery, the patients are stable both clinically and radiologically, with the exception of 1 case that required rescue surgery. Satisfactory union was seen in 100% of cases after osteotomy. Conclusions: During the initial stages, surgical treatment is preferable, and osteotomies are the techniques most frequently used. Radial osteotomy with Nakamura effect is a technique with excellent results, comparable to those seen with other techniques applied used during the initial stage

Aims: The purpose of this paper is to review a series of ankle post-traumatic deformities treated by arthroplasty, þbula lengthening, bone graft and correction of the malunion. Methods: 30 cases, mean age 40 (±15), were operated 6–30 months after injury and followed up at 5 years. Clinical Maryland foot score (MFS) and X-ray evaluation were performed pre op and at follow up. After medial revision of bone and soft tissue structures, through a lateral transmalleolar approach, mal-union of the posterior malleolus or sinking of the lateral tibial plafond were corrected using autologous cortical cancellous bone graft covered by its periosteal ßap. Postoperative treatment consisted of immediate continual passive motion weightbearing allowed after an average of 8–12 weeks after surgery. Results: Pre op MFS was 64±8 and post-op it was 82±11. 11 patients had excellent results with normal range of motion, no pain, and no progression of the arthritis. The result in 9 cases was good with a normal range of motion, little pain after long walk, and no progression of arthritis. 7 cases were fair because of a decrease in the range of motion and progression of arthritis and moderate pain. 3 poor cases needed arthrodesis. Conclusions: Fibula lengthening, bone graft and correction of malunion were effective treatment of ankle post-traumatic valgus deformity in order to delay ankle fusion in young patients. The success of the procedure was correlated to the severity of arthritis and the joint congruity obtained by surgery

Aims: Thirty-three patients with condylar fractures of the middle and proximal phalanges were treated with internal fixation using self-tapping titanium lag screws. The results were studied prospectively and prognostic factors identified. Methods: The age range was 14–45 (mean 26 years). Five patients presented at more than five weeks post injury. Four patients had bicondylar fractures. The surgical technique, which utilises a lateral approach, is outlined. All surgery was performed by the senior author (DS), semi-electively, within five days of presentation. Patients were seen in the 4th postoperative day for mobilisation and protective splintage. Results: The results were satisfactory in the majority of cases. 21 patients had achieved a full range of movement when reviewed at six weeks and further eight at 12 weeks. The remainder were left with a flexion contracture of 10–35 degrees (mean 26). All patients achieved full flexion. All fractures healed and there was no loss of fixation. Conclusions: Internal fixation using a single lag screw through a lateral approach restores joint congruity, facilitates union and provides fixation stable enough to allow early mobilisation. Bicondylar and proximal phalangeal fractures had a poorer prognosis. Fractures presenting even at eight weeks can be taken down and reduced. Delay in fixation does not appear to influence the long-term outcome

Multi-ligament knee injuries require complex surgery. Hinged external fixators propose to control the tibio-femoral relationship, protect reconstructions and allow early mobilisation. However, a uniaxial hinge may be too simplistic for such a complex joint. We investigated the influence of an external fixation device on ligament strains and joint contact forces. Six fresh frozen cadaveric lower limbs (41–56 years old) were obtained. Displacement transducers (Microstrain, USA) were attached to mid-substance lateral (LCL) and medial collateral (MCL) ligaments, and the anterior and posterior cruciate (PCL) ligaments through minimal soft tissue incisions. Joint pressures were measured by transducers (Tekscan) introduced in the medial and lateral compartments through small sub-meniscal arthrotomies. Flouroscopic imaging was used to construct the hinged fixator centred over the epicondylar axis. Ligament tensile strains and joint contact forces were determined through a passive arc of 20 to 110 degrees of flexion and extension, with and without the external fixator (ExFix. ™. , EBI Biomet Australia). The application of the external fixation device resulted in minimal change in the mean peak percentage strain of the PCL, MCL and ACL ligaments, while the LCL peak percentage strain decreased. Generally the peak percentage strain for each ligament occurred at or near the same flexion angle in both the un-instrumented and instrumented case within each limb, but the peak percentage strain flexion angles varied significantly across limbs. Peak joint contact forces increased significantly (p < 0.05) in the lateral compartment after attachment of the external fixation device. There was no difference seen in the medial compartment joint contact forces. This study shows that a uniaxial hinged external fixator can be used in a multi-ligament reconstructed knee to maintain joint congruence and allow early postoperative rang of motion without compromising the results of reconstructions or repairs

Aim: The purpose of this study is to determine the outcome in patients with acetabular fractures treated either conservatively or surgically. Method: From 1990–2000, we treated 152 patients with 158 acetabular fractures. 63 patients were treated nonoperatively and 95 operatively. According to Tile classification there were 70 type A, 52 type B, 36 type C fractures. Mean follow up was 90 months (23–151 months). Indications for surgery were fracture displacement of more than 2mm, hip joint instability, intrarticular fragments and ipsilateral femoral fracture. Surgical approaches used included the kocher-Langenbeck and the triradiate approach. Follow up consisted of radiological examination and functional assessment using Merle d’ Aubigne score. Results: 53 conservatively treated patients followed up. 39 (73.6%) had excellent and good results and 14 (26.4%) fair and poor results due to excessive fracture comminution, severe osteoporosis, or they were too sick to be operated on. 83 operatively treated patients with 85 fractures were followed-up. Anatomic reduction was achieved in 57 fractures, satisfactory in 18 and poor in 10 fractures. Functional outcome was excellent or good in 60 (72.3%) patients and fair and poor in 23 (27,7%).The complications were 3 wound infections, 4 cases of femoral head osteonecrosis, 3 cases of secondary loss of reduction and 5 cases of significant ectopic ossification. Conclusion: The outcome of these difficult fractures depends on restoration of hip joint congruity and stability and correlates closely to radiographic result

Total meniscectomy has been shown to induce osteoarthritic changes in the underlying articular cartilage(AC) and bone in the natural knee (Fairbank 1948; McDermott 2006). This indicates the meniscus plays an important protective role, providing joint congruity and distributing contact forces, hence reducing contact stress. However, no friction and wear studies have been performed on meniscectomy. The aim of this study was to study the tribological response of the medial compartmental natural knee with and without the intact meniscus, under physiological dynamic loading and motion. The effect of normal and reduced loading was investigated. Eighteen month old bovine medial compartmental knees were used. A pendulum friction simulator (Simulation Solutions, UK) was used to apply a dynamic axial loads with peak loads of 1000N (normal) and 260N (reduced). Flexion-extension of amplitude 23degrees was applied and the experiments ran for 3600 cycles at 1Hz. Lubricant was 25% bovine serum in saline. A 9.4 Tesla MRI (Bruker) scanner and Analyze software (Mayo Clinic, US) were used to calculate wear volumes. A surface profilometer (Talysurf, Taylor-Hobson, UK) was used to measure the surface roughness of the specimen before and after the test. Coefficient of friction was found to increase with increased loading, with and without meniscus. With meniscus intact, no wear was found on AC and contact stresses were 4.9MPa and 2.8MPa, for normal and reduced loading respectively. On removal of meniscus, friction was higher at both loading conditions and surface fibrillation found on some of the AC surfaces. Contact stresses rose to 17.2MPa and 8.6MPa for normal and reduced loading. This study has shown for the first time, the direct elevation of the coefficient of friction, immediate surface fibrillation and biomechanical wear of AC upon removal of the meniscus. On removal of meniscus, peak stresses rose and surface damage occurred on AC surfaces. The removal of the meniscus means forces act across smaller areas and contact stresses are increased. Wear is increased due to the subsequent increase in direct solid-solid contact and loss of fluid support due to the unique biphasic nature of AC. This further supports retaining meniscus whenever possible in knee joint surgery

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

Traumatic osteonecrosis of the femoral head in adolescents has a poor prognosis due to collapse and degenerative change. We hypothesised that early bisphosphonate treatment to reduce osteoclast activity could allow revascularisation and repair with maintenance of joint congruity. Nine patients with documented osteonecrosis were treated with intermittent intravenous pamidronate (Aredia, Novartis) commencing within a mean 1 month of diagnosis (range, 5 to 91days). The dosing protocol has evolved over two years with the current dose being 9 mg/kg/year for 18 months. Mean follow up is 19.8 months (range, 13 to 30 months) with all patients followed for more than one year. There were 6 patients, who presented after unstable SCFE. Of these the index procedure had failed in three, requiring multiple early operations. The other three patients had sustained an inter-trochanteric fracture with a pelvic fracture, a traumatic hip dislocation and a femoral neck fracture respectively. Eight of the patients are painfree. Six have been instructed to fully weight bear, while two can partial weight bear and one is non-weight bearing. Seven of 9 patients do not show significant resorption of the femoral heads at the most recent follow up. Of the two patients with significant resorption, one patient began to resorb after his medication was ceased, so it was recommenced. He has subsequently undergone a realignment procedure. The other patient had resorption of a section of the femoral head, which had not re-vascularised by 18 months, and this was elevated and bone grafted. These two hips are considered functional in the short term as they are currently pain free, but their deformity is expected to bring about early osteoarthritis in adult life. This early experience lays the foundation for prospective clinical trials of bisphosphonate therapy in adolescents with osteonecrosis. It appears that bisphosphonate treatment protocols for adolescents will need to be prolonged. Our current practice is for a duration of around 18 months with normalisation of uptake on bone scan as the end point for therapy

Introduction: Autopsy findings (Jensen and Lauritzen 1976, Catterall et al. 1982) as well as own MRI studies (Lange et al. 1996) indicate that in Perthes’ disease there is an early cartilaginous enlargement of the femoral head. Lack of concomitant acetabular enlargement will lead to loss of containment and subluxation. We divided the transverse acetabular ligament (TAL) to promote expansion of the acetabulum for prevention of femoral head extrusion and loss of containment. Material and Methods: We report 13 patients with Perthes’disease belonging to Catterall group III or IV. The operation was performed when MRI showed a labrum lift near horizontal position indicating risk of loss of containment (Meiss 2001). There was an average cartilaginous head enlargement of 11 % in comparison to the uneffected side as measured by the Maximum Oblique Diameter. Division of the TAL was performed through an antero-medial approach (Ludloff 1913, Wein-stein 1993). A window of about 1,5 x 1 cm was created in the capsule which was left open. The TAL was divided but not removed. In all cases strict non-weightbearing was imposed postoperatively (use of a wheel chair and crutches) until well into the regeneration phase. The average period of non-weight-bearing was 1 year and 10 months. An abduction pillow was worn at night. Results: The results after an average follow-up of 4,2 years (range 2,6 -5,3 years) were evaluated according to Stulberg (1981) and Catterall (1982) with emphasis on the radiographic appearance (sphericity of the femoral head, joint congruity, containment [acetabulum head index], articulo-trochanteric distance). The result was excellent in 2 cases, good in 8, satisfactory in 2, and poor in 1 case. Two patients had a bad compliance for non-weightbearing and underwent additional bony procedures. The outcome was satisfactory and poor. Conclusions: Our data indicate that the combination of the division of the TAL and a strict conservative treatment gives very satisfactory results in Catterall group III and IV cases that present with signs of risk of loss of containment on MRI

Introduction Traumatic osteonecrosis of the femoral head in adolescents has a poor prognosis due to femoral head collapse and degenerative change. We hypothesised that early bisphosphonate treatment to reduce osteoclast activity could allow revascularisation and repair with maintenance of joint congruity. Methods Nine patients with documented osteonecrosis are presented. There were six patients, who presented after unstable SCFE. Of these the index procedure had failed in three, requiring multiple early operations. The other three patients had sustained an inter-trochanteric fracture with a pelvic fracture, a traumatic hip dislocation and a femoral neck fracture respectively. They were treated with intermittent intravenous pamidronate (Aredia, Novartis) commencing within a mean one month of diagnosis (range 5 to 91 days). The dosing protocol has evolved over two years with the current dose being 9 mg/kg/year for 18 months. Mean follow-up is 19.8 months (range 13 to 30 months) with all patients followed for more than one year. Results Eight of the patients are painfree. Six have been instructed to fully weight bear, while two can partial weight bear and one is non-weight bearing. Seven of nine patients do not show significant resorption of the femoral heads at the most recent follow-up. Of the two patients with significant resorption, one patient began to resorb after his medication was ceased, so it was recommenced. He has subsequently undergone a realignment procedure. The other patient had resorption of a section of the femoral head, which had not re-vascularised by 18 months, and this was elevated and bone grafted. These two hips were considered functional in the short term as they were pain free, but their deformity was expected to bring about early osteoarthritis in adult life. Conclusions This early experience lays the foundation for prospective clinical trials of bisphosphonate therapy in adolescents with osteonecrosis. It appears that bisphosphonate treatment protocols for adolescents will need to be prolonged. Our current practice is for a duration of around 18 months with normalisation of uptake on bone scan as the end point for therapy. In relation to the conduct of this study, one or more of the authors is in receipt of a research grant from a non-commercial source