A prospective study was done of forty-five hips in forty-three patients who had Ficat stage-III avascular necrosis of the anterosuperior part of the femoral head. The patients had been followed for an average of sixty-five months (range, thirty-six to 126 months) after an operation that included a valgus-flexion intertrochanteric osteotomy, curettage of necrotic bone, and grafting of autogenous bone to the avascular segment. The patients were 32 +/- 8 years old (mean and standard deviation). Patients who were more than forty-five years old, had an underlying systemic disease, had been treated with steroids, had more extensive involvement of the femoral head, or were poorly motivated were excluded from the study. The mean preoperative Harris hip score was 34 +/- 10 points, and the mean score at the most recent assessment was 90 +/- 7 points. Six hips (13 per cent) failed; failure was defined as a Harris hip score of less than 70 points or the performance of a subsequent replacement arthroplasty. Survivorship analysis demonstrated cumulative survival without such failure to be 87 per cent at five years; the ten-year cumulative survival was essentially unchanged. The results of this study suggest that the role of intertrochanteric osteotomy and bone-grafting of the femoral head should be considered anew for the treatment of avascular necrosis of the hip in younger patients who have not received steroids. The results of this procedure should be compared again with those of arthroplasty in the treatment of this condition.