[1] NHO Utsunomiya Natl Hosp, Dept Orthopaed Surg, Shimookamotocho 2160, Utsunomiya, Tochigi 3291193, Japan
[2] Jichi Med Univ Hosp, Dept Hematol, Yakushiji 3311-1, Shimotsuke, Tochigi 3290498, Japan
[3] Jichi Med Univ Hosp, Dept Orthopaed Surg, Yakushiji 3311-1, Shimotsuke, Tochigi 3290498, Japan
[4] Dokkyo Med Univ Hosp, Dept Histopathol, Kitakobayashi 880, Shimotsuga, Tochigi 3290293, Japan