1. Department of Orthopaedic Surgery, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
2. Department of Orthopaedic Surgery, Eunpyeong St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
3. Department of Orthopaedic Surgery, Kyung-Hee University Hospital at Gandong, School of Medicine, Kyung Hee University, Seoul, Korea.