Rotational open wedge osteotomy in the treatment of older Legg-Calvé-Perthes disease with extensive lesion －early restoration and results with a mean of 9 year follow-up－

Introduction : We evaluated the effectiveness of rotational open wedge osteotomy (ROWO) for older Legg-Calvé-Perthes disease (LCPD) with extensive lesions. The main concept of ROWO is repositioning the posterolateral viable segment below the acetabular roof through dual open wedge osteotomy. Materials and Methods: We reviewed 30 hips in 30 patients with LCPD and extensive lesions treated by ROWO, with a mean follow-up of 9.3 years (range: 5–21 years). The mean age was 8.3 years (range: 7–11.7 years). All hips had small viable bones in the posterolateral epiphysis preoperatively. Ten hips were classified as lateral pillar B/C, and 20 as Group C. Twenty-nine hips were Catterall Group 3, and one as Group 4. The fragmentation stage was most frequently observed at the time of operation. After osteotomy, the mean anterior rotational angle was 36°, with a mean varus of 18°. The repair process, femoral head morphology, acetabular coverage, and the angle between the femoral neck and diaphysis were assessed radiographically. Results : The repair rate in the viable area below the acetabular roof improved from 0.2% preoperatively to 83% at 6 months, 98% at 1 year, and 99% at the final follow-up on AP radiographs. Regarding morphology, spherical congruency was observed in 26 of 30 hips at the final follow-up (Stulberg classification: Class I: 7, Class II: 19). Class III was noted in four hips within the lateral pillar C group. No hips were classified as Class IV or V. The acetabular head index improved from a preoperative mean of 69 to 84 at the final follow-up. The lateral neck-shaft angle improved from 33° preoperatively to 32° at the final follow-up. Conclusions: This procedure is effective in accelerating repair and promoting femoral head sphericity in older LCPD patients with extensive lesions by repositioning the viable epiphysis below the acetabular roof.