1. Department of Orthopaedic Surgery, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
2. Department of Orthopaedic Surgery, International University of Health and Welfare, Minato-ku, Tokyo, Japan
3. Fujii Surgery-Gastroenterology-Orthopedics, Takamatsu, Kagawa, Japan
4. Department of Orthopaedic Surgery, Toyooka-daiichi Hospital, Iruma, Saitama, Japan
5. Department of Orthopaedic Surgery, Komazawa Hospital, Setagaya-ku, Tokyo, Japan