1. Department of Family Medicine, SMG-SNU Boramae Medical Center, Seoul, Korea.
2. Department of Orthopedic Surgery, Soonchunhyang University Bucheon Hospital, Bucheon, Korea.
3. KT Lee's Orthopedic Hospital, Seoul, Korea.
4. Department of Orthopedic Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.