1. Department of Orthopaedic Surgery, Konkuk University School of Medicine, Konkuk University Medical Center, Seoul, Korea
2. Department of Orthopaedic Surgery, Myongji Hospital, Goyang, Korea
3. Department of Orthopaedic Surgery, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Korea
4. Seoul National University Bundang Hospital, Seongnam, Korea