[1] Univ Tsukuba, Inst Med, Dept Orthopaed Surg, 1-1-1 Tennodai, Tsukuba, Ibaraki 3058575, Japan
[2] Tsukuba Univ Hosp, Mito Kyodo Gen Hosp, Mito Clin Educ & Training Ctr, Dept Orthopaed Surg & Sports Med, Mito, Japan
[3] Showa Gen Hosp, Dept Orthopaed Surg, Kodaira, Japan
[4] Takahagi Kyodo Hosp, Dept Orthopaed Surg, Kenpoku Med Ctr, Takahagi, Japan
[5] Jichi Med Univ, Joint Ibaraki Western Reg Clin Educ Ctr, Univ Tsukuba Hosp, Dept Orthopaed Surg,Ibaraki Western Med Ctr, Chikusei, Ibaraki, Japan