Rotational open wedge osteotomy in a patient aged older than 7 years with Perthes' disease--a preliminary report.

Rotational open wedge osteotomy was performed on 20 hips in 19 older patients with Perthes' disease with an extensive lesion. All subjects had little viable bone in the posterolateral epiphysis preoperatively. The repair process was observed radiographically until 1 year postoperatively. The patients' mean age at the time of operation was 7.8 years old. The stages were fragmentation in 16, healing in 4. After osteotomy, the proximal section was rotated anteriorly, and the posterolateral viable segment was moved below the lateral acetabular roof. The mean rotational angle was 33 deg, with a mean of 18 deg of varus. We analyzed the rate of repair in the viable area below the acetabular roof pre- and postoperatively. The mean rate was 1.1% preoperatively and 68% at 6 weeks postoperatively, 78% at 3 months, 88% at 6 months, and 100% at 12 months. We believe that repair was accelerated by the operation.