Introduction:

To date, there have been few reports of the results of revisions for failed metal-on-metal hip arthroplasties (MoM HA's). These series have included relatively modest numbers, and classification of the severity of adverse local tissue reaction (ALTR) has been under-reported. In this study, early outcomes and complications are analyzed as a function of pre-operative MRI grade and intra-operative ALTR severity to determine their prognostic value.

Introduction and Aims: Cartilage injury often leads to secondary osteoarthritis. However, the progression of cartilage lesions after injury has not been fully documented. Factors predictive of the rate and severity of progression are largely unknown. This study analysed the relationship between arthroscopic, histologic, and magnetic resonance imaging findings after acute joint trauma.

Method: Twenty patients were recruited into the study at a mean three months after acute knee injury. Each patient underwent cartilage-specific magnetic resonance imaging (MRI) sequences of the affected knee after injury and at six months, one year, and two years after arthroscopy. Cartilage lesions were graded on MRI and arthroscopy. Synovial fluid was sampled, and a 1.8 mm biopsy was obtained from the edge of cartilage lesion. Control biopsies were obtained from fresh cadaver donors. Cells undergoing DNA fragmentation in biopsies were counted.

Results: All cases of partial or full thickness cartilage loss were detected by MRI. Biopsies from cartilage lesions had significantly more cells undergoing DNA fragmentation (41%) than control biopsies (12%), suggesting apoptotic cell death. On MRI follow-up, cartilage lesion grade improved in five patients, worsened in two, and did not change in 13 patients. The percentage of cells undergoing DNA fragmentation correlated significantly with keratan sulfate levels in synovial fluid (R = 0.68). Keratan sulfate levels were markedly higher in knees with progressive lesions (72 vs. 31 microgm/ml).

Conclusion: Cartilage cell viability can directly impact the potential for repair. The development of accurate markers that may predict the eventual fate of the lesion is of tremendous clinical value. Elevated levels of matrix degradation products such as keratan sulfate can be predictive of a poorer prognosis.

Introduction: This study evaluated the clinical and radiological outcomes of Chiari osteotomy for severe coxa irregularis and subluxation of the femoral head.

Materials and Methods: The study group included patients with late Legg-Calvé-Perthes disease (6 patients), posttraumatic avascular necrosis (1 patient), and multiple epiphyseal dysplasia (1 patient). The mean age at surgery was 11.4 years (range, 6.8 to 14.7). The clinical parameters evaluated included changes in pain, limp, and range of motion of the hip. Radiographic measurements were made to determine the width of the medial and superior joint spaces, acetabular coverage, lateral epiphyseal extrusion, and the Stulberg classification.

Results: At a mean follow-up of 5 years (range, 1.1 to 11.0 years), pain disappeared completely in 5 patients or markedly decreased, enough to complete normal daily physical activities, in the remaining 3 patients. Limping gait disappeared completely in 2 patients, but the remaining 6 patients had minimal limps. All the components of the range of hip motion increased significantly. Acetabular coverage averaged 55% (range, 33 to 87%) before operation and 88% (range, 79 to 97%) at the final follow-up. Lateral epiphyseal extrusion was 49% (range, 39 to 83%) before operation, and 18% (range, 8 to 40%) at the final follow-up. Joint spaces were not changed significantly after surgery.

Discussion: In conclusion, Chiari osteotomy has its own indications, as a salvage procedure, for older children and adolescents with subluxated, severe coxa irregularis. The current study confirms the efficacy of the operation in terms of the functional and radiological improvements.

Introduction: The authors introduce a modified technique of iliac splitting and expanding shelf (ISES) arthroplasty for severe LCPD, and report on the intermediate outcomes.

Materials and Methods: This new procedure is a modification of the previously reported tectoplasty of Saito (1986) and the shelf arthroplasty of Catterall (1992). Only the sartorius muscle and the indirect head of the rectus femoris muscle are detached, leaving the abductors intact. A superiorly hinged bony flap was raised from the lateral iliac wall just above the hip joint capsule. A corticocancellous bone plate was harvested from the inner table of the iliac wing, and was placed between the lateral hip joint capsule and the bony flap. The triangular space between the split iliac wall and the bone plate was packed with autogenous cancellous bone chips and Osteoset® (Wright-Medical, Arlington, Tennessee, USA). The repaired indirect head of the rectus femoris muscle gave stability to the shelf. After 4 weeks in a Petrie cast, the hip was mobilized, and partial weight bearing was started postoperative at 6 weeks. Twenty one hips in 21 children older than 8 years presenting with early (18 hips) and late (reossification) (3 hips) LCPD were treated by ISES arthroplasty. All patients were followed up for more than 2 years (range, 2 to 8.5 years).

Results: There were significant functional and radiological improvements after operation. One patient needed a secondary varus osteotomy to solve persistent subluxation. The poorest result occurred in a very obese child, presenting with early stage of Catterall IV involvement at age 11.5 years.

Discussion: Our modified technique of the shelf arthroplasty, sparing the abductor mechanism, appears to be a reliable and effective method to augment the superolateral coverage of the femoral head in severe LCPD.

Introduction: In severe Legg-Calve-Perthes (LCPD) disease with subluxated femoral head, the acetabulum sometimes takes a bicompartmental appearance. This study analyzed acetabular pathoanatomy using a 3-D CT program.

Materials and Methods: A 3-D CT software program that affords the section of 2-D image in any plane was used to analyze the acetabular pathoanatomy, with specific reference to the morphology of the inner surface of the acetabulum. Thirteen children with the bicompartmental acetabulae (12 LCPD and 1 AVN subsequent to septic hip arthritis) were evaluated.

Results: The anterior half of the acetabulum was concentric. The contour of the acetabular margin in the posterior half of the acetabulum consisted of two different arcs – an arc of the iliac acetabulum (superior) and the other arc of the acetabular fossa of the ischium (medial). The junction of these two arcs was located at the triradiate cartilage, which was increased in mediolateral thickness at this point. The osteochondral articular margin of the ischium posterior to the non-articular acetabular fossa was thickened forming a ridge. The mediolateral thickness of the non-articular acetabular fossa was thinner than that of the normal contralateral side. The combination of these focal morphologic changes of the acetabular fossa rendered the bicompartmental appearance on plain AP radiograph of the pelvis.

Discussion: The authors conclude that bicompartmentalization of the acetabulum apparently reflects the altered biomechanics of the hip joint due to the subluxated femoral head. The abnormal osteocartilaginous hypertrophy appears to be caused by synovial irritation and an eccentric molding effect of the subluxated femoral head.

Introduction: The purpose of this prospective study was to evaluate the therapeutic value of Pulsed Electromagnetic Fields (PEMF) in the treatment of the osteonecrosis of the femoral head (ONFH).

Materials and Methods: One hundred-eight consecutive hips with ONFH (80 patients) treated with PEMF between June 1990 and June 1998 were analyzed. The average age was 37 years. The average follow-up period was 6.9 years. According to the ARCO staging system, 3 hips were stage I, 85 hips stage II, and 20 hips stage III. Hips were evaluated clinically with a modified Harris hip scoring system and degree of pain relief. Radiographic progression was defined as either an advance in ARCO stage or progressive collapse of the femoral head more than 2 mm.

Results: Clinical improvement was achieved in 81 hips (75%). Hip pain was relieved or decreased at an average of six months following initiation of PEMF therapy in the 81 hips with clinical improvement as well as some radiographically progressed hips. Radiographic progression was seen in 35 hips (32.4%). Total hip arthroplasty (THA) had been performed in 20 hips (18.5%). Kaplan-Meier survivorship analysis demonstrated that the probability of conversion to THA within 5 years after PEMF was 16% overall. Conversion to THA was significantly higher in patients who had the necrotic lesion laterally, in the subgroup C (more than 30% involvement of necrosis), and in patients older than the mean age.

Discussion: These results demonstrate that PEMF can modifiy the natural course of ONFH. PEMF is recommended in patients who are less than forty years old with early stage disease with small necrotic involvement. Refinement of PEMF could make it a more efficacious non-invasive method of treatment.

The purpose of this study was to investigate the efficacy of oral alendronate for the older children with osteogenesis imperfecta. Eight boys and 6 girls with average age of 9.7 years were given oral alendronate, 10mg everyday for those > 35kg, 10mg every other day for those 20 – 35 kg, and 10mg every three days for those < 20 kg. Treatment period averaged 3.3 years (range, 2.1 to 3.6). The number of fractures decreased by 39% in the lower extremity, although not statistically significant. Ten patients or their parents reported improved well-being during the treatment period. Z score for bone mineral density improved from −3.75 to −1.18 in the lumbar spine, and from −3.84 to −2.74 in the femur neck. Restoration of the collapsed vertebral bodies was observed, and the metaphyseal bands appeared on the simple radiographs. Urinary excretion of calcium and N-telopeptide of type I collagen were decreased by 64% and 47%, respectively. Abdominal discomfort was reported in five patients, one of which needed temporary switch to intravenous protocol. Iliac crest biopsy including the physis showed expanded primary spongiosa area with numeric multi-nucleated cells, which had heterogenous immunoreactivity for osteoclast markers.

This study revealed beneficial effects of oral alendronate in osteogenesis imperfecta patients, supported by radiological, biochemical and histological findings. We believe that oral alendronate is a more convenient method of bisphosphonate treatment for osteogenesis imperfecta, especially in older children.