Quantitative measures for evaluating the radiographic outcome of Legg-Calvé-Perthes disease.

BACKGROUND: Large sample sizes are needed if discrete outcome measures are used to perform outcome studies, whereas more practicable sample sizes are sufficient if continuous outcome measures are used. Recognizing the need to devise reliable continuous outcome measures for assessing the outcomes of treatment of Legg-Calvé-Perthes disease, we evaluated a method of quantifying the shape and size of the femoral head and the femoral-acetabular relationship from computer images of anteroposterior and lateral radiographs with the help of image-analysis software. METHODS: Radiographs of 121 skeletally mature individuals with healed Legg-Calvé-Perthes disease were analyzed, and the sphericity deviation score, femoral head enlargement, femoral neck growth inhibition, and composite femoral congruency arc were calculated. RESULTS: Each of these measurements was reproducible, with distinctly different values for hips in each of the Stulberg classes. Measures of sphericity and congruence (the sphericity deviation score and the composite femoral congruency arc) could very clearly discriminate between spherical and aspherical hips, and there was a strong correlation between these two measurements. CONCLUSIONS: The study shows that it is possible to have reliable quantitative measures of the outcome of Legg-Calvé-Perthes disease at skeletal maturity.

The fate of the joint space in Legg-Calvé-Perthes' disease.

OBJECTIVE: This study was undertaken to identify variations in the hip joint space in patients with healed Legg-Calvé-Perthes' disease (LCPD) and to correlate these changes with the radiological outcome of treatment. METHODS: The width of the joint space was measured on radiographs of 121 skeletally mature individuals with healed LCPD. The joint space width at the stage of healing in 79 patients was compared with the joint space at skeletal maturity. The hips were graded by the Stulberg classification and the femoral head radius was measured. Associations between the joint space width, the Stulberg class and the femoral head radius were tested. The reproducibility of measurement was tested by measuring 30 radiographs twice and computing the intra-class correlation coefficient (ICC). The joint space width was measured on radiographs of 25 patients taken both while recumbent and standing, to determine if the joint space alters on weight-bearing. RESULTS: The reproducibility of measurements was satisfactory; no difference was noted in the joint space in recumbent and weight-bearing films. Increased joint space was noted both at healing of the disease and at skeletal maturity; the width was minimally increased in Stulberg Class I hips and considerably increased in Class III, IV and V hips. There was a significant correlation between the increase in joint space and enlargement of the femoral head. CONCLUSIONS: An increase in joint space width occurs quite frequently following LCPD; the increase is most evident in hips with a poor outcome. The implications of this observation need to be elucidated.

Does proximal femoral varus osteotomy in Legg-Calvé-Perthes disease predispose to angular mal-alignment of the knee? A clinical and radiographic study at skeletal maturity.

BACKGROUND: Though there is an impression that proximal femoral varus osteotomy (FVO) can result in a valgus deformity at the knee there is no agreement on this issue. This study was undertaken to ascertain whether a FVO predisposes to the development of genu valgum in children with Legg-Calvé-Perthes disease (LCPD). METHODS: One hundred and one children with unilateral LCPD who underwent a FVO during the active stage of the disease and 32 children who were treated non-operatively were followed till skeletal maturity. The FVO was performed with a 20° varus angulation in all the patients and weight-bearing was not permitted till the stage of reconstitution. The alignment of the knee was assessed clinically at skeletal maturity. A subset of 33 operated children also had full length standing radiographs of the limbs. The mechanical axis deviation, femur-tibial angle, lateral distal femoral angle and the medial proximal tibial angle of both limbs were measured on these radiographs. RESULTS: The frequency of clinically appreciable mal-alignment of the knee was not greater on the affected side in patients who had undergone FVO when compared to the unaffected limb and also when compared to the affected limb in non-operated patients. The mechanical axis of the lower limb of operated children was relatively in more valgus than that of normal limbs but they fell within the normal range. CONCLUSION: This study does not support the impression that a proximal femoral osteotomy for LCPD predisposes to clinically discernable degrees of genu valgum in children who have had 20° of varus angulation at the osteotomy site and who have avoided weight-bearing for a prolonged period following surgery. Further studies are needed to clarify if genu valgum would develop if early post-operative weight-bearing is permitted. LEVEL OF EVIDENCE: III.

The fate of the hip in spondylo-epi-metaphyseal dysplasia: clinical and radiological evaluation of adults with SEMD Handigodu type.

PURPOSE: This study was undertaken to document the fate of the hip with reference to its structure and function in patients with spondylo-epi-metaphyseal dysplasia tarda Handigodu type (SEMD(HG)). MATERIAL AND METHODS: Radiographs of 271 adult patients with SEMD(HG) were studied to identify the pattern of long-term sequelae in the hips. Several measurements of the proximal femur and acetabulum were made to quantify morphological alterations in the hip. Fifty-four adult patients were examined and administered a questionnaire to evaluate the extent of disability attributable to the hips. RESULTS: Three patterns of changes in the hips were noted: 35% had acetabular protrusio, 33% had subluxation of the hip, and 32% had no protrusio or subluxation. Distinctly different anthropometric measurements and dimensional alterations around the hip were noted in these three patterns. Patients with protrusio were relatively tall while those with subluxation were the shortest. All the patients had developed degenerative arthritis of the hips by the fourth decade of life irrespective of the pattern of hip involvement. The reduction in the range of hip motion and fixed deformities were most severe in patients with protrusio. All the patients had significant disability and very low functional hip scores. CONCLUSION: Degenerative arthritis of the hip develops in the majority of patients with SEMD(HG); the symptoms are severe enough to warrant reconstructive surgery by the fourth decade of life. Protrusio or subluxation develops in a third of the patients each; both these complications will influence the surgical approach if total hip arthroplasty is planned.

Loss of a condyle of the femur or tibia following septic arthritis in infancy: problems of management and testing of a hypothesis of pathogenesis.

PURPOSE: The study was undertaken to: (1) describe the characteristic radiological features and problems of management of the loss of one condyle of the femur or tibia following septic arthritis of the knee in infancy and (2) test a hypothesis of the cause of the loss of a single condyle. METHODS: Radiographs of eight children with the loss of one condyle of the femur or the tibia following septic arthritis in infancy were reviewed. The course and outcome in two of these children who underwent reconstructive operations were studied. The knees of 35 stillborn foetuses were dissected to determine if the presence of synovial septae could account for the isolated loss of one condyle following infection. RESULTS: All eight cases showed characteristic features of loss of half the epiphysis, the underlying physis and part of the adjacent metaphysis; the other condyle was totally spared. The two children who underwent elaborate reconstructive procedures had poor outcomes at skeletal maturity, despite a series of additional operations. The foetal cadaveric study showed that complete infrapatellar synovial septae are present in some foetuses approaching 40 weeks of gestation. CONCLUSIONS: The pattern of loss of a femoral or tibial condyle following septic arthritis is consistent with total preservation of the other condyle. The outcome of surgical reconstruction of the missing condyle is poor. The presence of a complete synovial septum could result in the localisation of infection to one half of the joint, with the destruction of one condyle.

To what extent does remodeling of the proximal femur and the acetabulum occur between disease healing and skeletal maturity in Perthes disease? A radiological study.

Radiographs of 75 children with unilateral disease were studied to quantify the extent of remodeling of the proximal femur and the acetabulum between healing and skeletal maturity in children with Perthes disease. The mean ages at disease onset, healing, and skeletal maturity were 8.3, 11.9, and 15.5 years, respectively. Fifty-seven children were treated surgically by subtrochanteric varus osteotomy with trochanteric epiphyseodesis; the remaining 18 children were treated nonoperatively. Assessment of the Mose's index and Stulberg grading and measurements of the proximal femur and the acetabulum were made at healing and at skeletal maturity. The Stulberg grade and the Mose's index did not change between healing and skeletal maturity in 88% and 95% of children, respectively. In operated children, there was significant improvement of the articulotrochanteric distance, acetabular depth, neck-shaft angle, and Sharp's angle between disease healing and skeletal maturity, but no such changes occurred in children who were not operated on. We conclude that because little change occurs in the shape of the femoral head and congruity of the hip between healing and skeletal maturity, the outcome of treatment based on these 2 variables can be assessed once the disease heals in children with late-onset Perthes disease.