Methods

Seventy-eight patients (87 hips) were consecutively treated by TRO from 1989 to 1994. All patients followed 15 years or more were included. Four patients (4 hips) with traumatic osteonecrosis and five patients (5 hips) followed less than 15 years were excluded. A total of 69 patients (78 hips) were included. Average age at the time of operation was 42 years. There were 51 men (57 hips) and 18 women (21 hips). The average follow-up was 17 years (range, 15 to 20 years). Type of osteonecrosis was as follows: Type B; 2 hips, Type C1; 50 hips, and Type C2; 26 hips. Stage was as follows: stage 2; 29 hips, stage 3A; 34 hips, stage 3B; 13 hips, and stage 4; 2 hips. Transtrochanteric anterior rotational osteotomy was performed in 76 hips and posterior rotational osteotomy was performed in 2 hips. Clinical evaluation was evaluated by Harris hip score. Kaplan-Meier survivorship analysis was performed based on the end point of conversion to total hip arthroplasty (THA) or re-collapse.