1. Department of Orthopaedic Surgery, Ewha Womans University Hospital and Ewha Medical Research Centre, 70 Chongro 6Ka, Seoul 110-126, Chongro Ku, Korea.
2. Department of Orthopaedic Surgery, Ewha Womans University Mokdong Hospital, 911-1 Mokdong, Seoul 158-050, Yangchun Ku, Korea.