1. Department of Orthopaedic Surgery, Ajou University School of Medicine, Wonchon-Dong, Yeongtong-Gu, Suwon 443-721, South Korea.
2. Department of Orthopaedic Surgery, Yonsei University College of Medicine, 134 Shinchon-Dong, Seodaemun-gu, Seoul 120-752, South Korea.
3. Department of Radiology, Yongdong Severance Hospital, 612 Eonjuro, Gangnam-gu, Seoul, South Korea.