1. Kobe City Medical Center General Hospital, Department of Orthopaedics, 4-6, Minatojimanakamachi, Chuo-ku, Kobe-City, Hyogo 650-0046, Japan.
2. Aichi Medical University, Department of Orthopaedics, Nagakute, Aichi 480-1195, Japan.
3. Kyoto University, Department of Orthopaedics, 54 Kawahara-cho, Shogoin, Sakyo, Kyoto 606-8507, Japan.