1. Department of Orthopedic Surgery, Yeson Hospital, Bucheon, Korea.
2. Department of Orthopedic Surgery, Dongguk University Ilsan Hospital, Goyang, Korea.
3. Department of Orthopaedic Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
4. Department of Orthopedic Surgery, Seoul National University Hospital, Seoul, Korea.