The relationship between change in the shape of the femoral head and the clinical results after transtrochanteric rotational osteotomy for osteonecrosis of the femoral head was investigated. Fifty-six hips in 50 patients, followed for at least 2 years, showed no progressive collapse and no osteoarthrotic change during that time. The growth of a superolateral osteophyte of the femoral head was observed postoperatively at a higher rate with progression of the preoperative stage. Excessive restoration of the rotated necrotic lesion of the femoral head was observed at a higher rate in hips with the growth of the superolateral osteophyte. The total Japanese Orthopaedic Association score at final follow-up in hips with these shape changes of the femoral head was significantly inferior to the score in hips without these changes. There was a tendency for hips with a low ratio of intact articular surface of the femoral head in the weight-bearing area to the acetabulum just after surgery to manifest these shape changes. Although such changes of the femoral head were considered to represent remodeling to stabilize the hip joint, excessive remodeling could worsen the clinical results.