1. Department of Orthopaedic Surgery, The Catholic University of Seoul St. Mary's Hospital, Seoul, Korea.
2. Department of Orthopaedic Surgery, Yonsei University College of Medicine, Seoul, Korea.
3. Department of Orthopaedic Surgery, International St. Mary's Hospital, Incheon, Korea.
4. Department of Orthopaedic Surgery, Seoul national University Bundang Hospital, Seongnam, Korea.