1. Department of Orthopedic Surgery, SNU Seoul Hospital, Seoul, Korea.
2. Department of Orthopedic Surgery, Seoul National University Hospital, Seoul, Korea.
3. Department of Orthopedic Surgery, Kangwon National University Hospital, Chuncheon, Korea.
4. Department of Orthopedic Surgery, Inje University Busan Paik Hospital, Busan, Korea.
5. Department of Orthopedic Surgery, Seoul National University College of Medicine, Seoul, Korea.