Background: In young patients with nontraumatic femoral head osteonecrosis with extensive and collapsed lesions, joint preservation is a goal if total joint arthroplasty is to be avoided. We evaluated the effectiveness of a posterior rotational osteotomy in this patient population.

Methods: We reviewed thirty-five hips in twenty-eight young patients with nontraumatic femoral head osteonecrosis treated by posterior femoral neck rotational osteotomy. All femoral heads were collapsed, and seven hips showed joint-space narrowing. Lateral radiographs of the femoral head revealed that 15% of the mean posterior portion and 17% of the mean anterior portion of the femoral head consisted of radiographically apparent living bone. The mean age of the patients (ten women and eighteen men) was twenty-eight years. The mean follow-up period was eight years.

Results: Less than six months after surgery, the radiographically apparent area of living bone of the femoral head below the acetabular roof was shown to be 59% on the standard anteroposterior radiograph and 54% on the 45°-flexion radiograph. In thirty-three hips (94%), further collapse of the femoral head was prevented and an adequate amount of living bone was demonstrated on the loaded lateral portion of the femoral head on the final follow-up radiographs. Progressive joint-space narrowing was seen in four hips.

Conclusions: In young patients with osteonecrosis and extensively collapsed lesions of the femoral head, posterior femoral neck rotational osteotomy appears to be effective in delaying the progression of degeneration if an adequate area of living bone can be placed under the loaded lateral portion of the acetabulum.

Level of Evidence: Therapeutic Level IV. See Instructions to Authors on jbjs.org for a complete description of levels of evidence.