1. Department of Orthopaedic Surgery, Yongdong Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
2. Department of Orthopaedic Surgery, Cha University College of Medicine, Sungnam, Korea.
3. Department of Orthopaedic Surgery, National Health Insurance Corporation Ilsan Hospital, Koyang, Korea.
4. Department of Orthopaedic Surgery, Jaesaeng Hospital, Sungnam, Korea.
5. The BK 21 Project for Medical Science in Yonsei University, Seoul, Korea.