Takashi Atsumi MD, Satoshi Yoshihara MD, Toshihisa Kajihara MD, Yasushi Takemura MD, Yasunari Hiranuma MD, Jun Toshima MD
Department of Orthopaedic Surgery, Fujigaoka Hospital, Showa University School of Medicine, Yokohama, Japan

We reviewed 64 hips of femoral head osteonecrosis associated with steroid administration treated by rotational osteotomy (range; 3-16 years). Anterior rotational osteotomy was performed in 41 hips, posterior rotational osteotomy in 23. The mean age was 32. The stages were II in 12 hips. III in 44, and IV in 8. Extent of non-collapsed viable area of the loaded portion on postoperative AP radiographs was divided into 3 groups. Group I: less than the lateral one third. Group 2: more than one third but less than two thirds. Group 3: more than two thirds. Recollapse was assessed on the follow-up AP radiographs. 6 of 8 nips with Group I disclosed recollapse. Collapse was prevented in 32 of 37 hips of Group 2. Out of 19 hips with Group 3, all hips showed no sign of recollapse. Recollapse was prevented if adequate viable area of the femoral head was obtained postoperatively.