Double osteotomy in the surgical treatment of Perthes' disease: Dega's transiliac osteotomy and subtrochanteric osteotomy.

Background. The combination of Dega transililiac and femoral subtrochanteric is used in our department in the treatment of Legg-Calvé-Perthes' disease. Subtrochanteric osteotomy, initially performed as varus-derotation osteotomy, is now mainly extension osteotomy with shortening. Femoral shortening is crucial for joint decompression and makes room for pelvic redirection after pelvic osteotomy. Material and methods. 34 children (36 hips) were analyzed retrospectively. All children were operated using subtrochanteric osteotomy with shortening and Dega's transiliac osteotomy of the pelvis. There were several variants of subtrochanteric osteotomy: extension osteotomy only, varus-extension, extension-varus-derotation, extension-derotation, and varus-derotation. In one case only varus osteotomy was performed. Before surgery 18 hips were Catterall group IV, 14 group III and 4 group II; in the Herring classification, 24 hips were group B, 11 group C, and 1 group A. All patients were evaluated clinically and radiologically at follow-up using the Stulberg classification. The mean follow-up was 8 years. Results. In the Stulberg classification 4 hips were scored after surgery as group I, 23 as group II, 4 as group III, 4 as group IV and only 1 hip as group V. In 6 patients limping was observed, 2 patients had a positive Trendelenburg sign, and 11 a positive Duchenne sign. The mean shortening of the lower limb was 0.25 cm. Six patients complained of pain after physical activity. Conclusion. Subtrochanteric shortening osteotomy of the femur combined with Dega transiliac osteotomy is a safe and valuable procedure for surgical treatment of Perthes' disease.