1. Department of Orthopedic Surgery, Yonsei University College of Medicine, Seoul, Korea.
2. Department of Orthopedic Surgery, Hanyang University College of Medicine, Seoul, Korea.
3. Department of Orthopedic Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
4. Department of Orthopedic Surgery, Seoul National University College of Medicine, Seoul, Korea.