1. Department of Musculoskeletal Biomechanics and Surgical Development; Sapporo Medical University; Sapporo Japan
2. Department of Orthopaedic Surgery; Sapporo Medical University School of Medicine; Sapporo Japan
3. Faculty of Agriculture; Shinshu University, Minami-minowa, Kami-ina; Nagano Japan
4. Sports Orthopaedic Center, Yukioka Hospital; Osaka Japan