Long term results of centralising intertrochanteric osteotomy in Legg-Calvé-Perthes' disease. (Report on 60 cases).

The writers propose a new classification of Legg-Calvé-Perthes' disease into three degrees of increasing gravity. Grade 1 includes hips with minimal or no flattening of the epiphysis, normal relations between the head of the femur and the acetabulum, and a normally orientated epiphyseal cartilage. Grade 2 comprises hips with slight epiphyseal flattening (one third or less), the epiphyseal growth cartilage is horizontal, the femoral head is partly uncovered due to epiphyseal subluxation, but becomes normal in the abduction test. Grade 3 hips show severe epiphyseal flattening (more than one third), the epiphyseal growth cartilage is horizontal, and the epiphyseal subluxation persists even in the abduction test. In our opinion, the advantage of this classification, which is not dependent on a determination of the extent of the necrosis, is that it is less subjective, and can be applied more easily and immediately, as compared with Catterall's classification. The results in sixty cases of intertrochanteric centralising osteotomy were constantly satisfactory in grades 1 and 2, but unsatisfactory in grade 3. The writers consider that surgical intervention is unnecessary in patients with hips in grade 1, while femoral osteotomy is contra-indicated in grade 3 cases. In the latter event, surgical intervention, if considered necessary, should be a pelvic osteotomy or cheiloplasty of the femoral epiphysis. Centralising osteotomy is the operation of choice in patients of grade 2. The results were better in patients who were less than six years of age at the time of operation.