[1] Keio Univ, Dept Orthopaed Surg, Sch Med, Shinjuku Ku, Tokyo 1608582, Japan
[2] Univ Tokyo, Fac Med, Dept Orthopaed Surg, Tokyo 113, Japan
[3] Tokyo Med & Dent Univ, Dept Orthopaed Surg, Tokyo, Japan
[4] Kudanzaka Hosp, Dept Orthopaed Surg, Tokyo, Japan
[5] Hokkaido Univ, Grad Sch Med, Dept Spinal Reconstruct, Sapporo, Hokkaido, Japan
[6] Hokkaido Univ, Grad Sch Med, Dept Orthopaed, Sapporo, Hokkaido, Japan
[7] Dokkyo Med Univ, Dept Orthopaed Surg, Mibu, Tochigi, Japan
[8] Kanazawa Univ, Sch Med, Dept Orthoped Surg, Kanazawa, Ishikawa 920, Japan
[9] Nagoya Univ, Dept Orthopaed Surg, Grad Sch Med, Nagoya, Aichi 4648601, Japan
[10] Hamamatsu Univ Sch Med, Dept Orthopaed Surg, Shizuoka, Japan
[11] Chiba Univ, Grad Sch Med, Dept Orthopaed Surg, Chiba, Japan