1. Department of Orthopaedic Surgery, Doai Memorial Hospital, 2-1-11 Yokoami, Sumida-ku, Tokyo 130-8587, Japan
2. Department of Orthopaedic Surgery, Tokyo Medical and Dental University Hospital of Medicine, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
3. Department of Orthopaedic Surgery, Soka Municipal Hospital, 2-21-1, Soka, Soka City, Saitama 340-8560, Japan