1. Department of Orthopaedic Surgery, Showa University School of Medicine, Shinagawa-ku, Tokyo, Japan
2. Department of Orthopaedic Surgery, Sassa General Hospital, Nishitokyo-shi, Tokyo, Japan
3. Department of Orthopaedic Surgery, National Hospital Organization Shizuoka Medical Center, Sunto-gun, Shimizu-cho, Shizuoka, Japan
4. Department of Orthopaedic Surgery, Showa University Fujigaoka Hospital, Yokohama City, Kanagawa, Japan