[1] Tokai Univ, Dept Orthopaed Surg, Sch Med, Hiratsuka, Kanagawa, Japan
[2] Gunma Univ, Dept Orthopaed Surg, Maebashi, Japan
[3] Hiroshima City Asa Citizens Hosp, Dept Orthopaed Surg, Hiroshima, Japan
[4] Chiba Univ, Dept Orthopaed Surg, Sch Med, Chiba, Japan
[5] Yamaguchi Rosai Hosp, Dept Orthopaed Surg, Yamaguchi, Japan
[6] Keio Univ, Dept Orthopaed Surg, Sch Med, Tokyo, Japan
[7] Natl Ctr Geriatr & Gerontol, Dept Orthopaed Surg, Obu, Aichi, Japan
[8] Tokyo Med & Dent Univ, Dept Orthopaed Surg, Tokyo, Japan