[1] Tohoku Univ, Dept Orthopaed Surg, Sch Med, Sendai, Miyagi, Japan
[2] Matsuda Hosp, Dept Orthopaed Surg, Sendai, Miyagi, Japan
[3] Iwate Cent Prefectural Hosp, Dept Orthopaed Surg, Morioka, Iwate, Japan
[4] Kuwano Kyoritsu Hosp, Dept Orthopaed Surg, Fukushima, Japan