1. Department of Orthopaedic Surgery, Eastern Chiba Medical Center
2. Department of General Medical Science, Chiba University
3. Department of Orthopaedic Surgery, University of Tsukuba
4. Department of Orthopaedic Surgery, Sawara Prefectural Hospital
5. Department of Orthopaedic Surgery, Toho University Sakura Medical Center
6. Department of Orthopaedic Surgery, Chiba University