1. Department of Orthopaedic Surgery, Chungnam National University Hospital, Daejeon, Korea.
2. Department of Orthopaedic Surgery, Gil Medical Center, Gachon University College of Medicine, Incheon, Korea.
3. Department of Orthopaedic Surgery, CM Hospital, Seoul, Korea.
4. Department of Occupational and Environmental Medicine, Gil Medical Center, Gachon University College of Medicine, Incheon, Korea.