1. Institute of Sports Medicine, Peking University Third Hospital, Beijing 100191, P.R. China
2. Department of Orthopaedic Surgery, Cangzhou Combinational Hospital of Chinese and Western Medicine, Cangzhou, Hebei 061001, P.R. China
3. Department of Orthopaedic Surgery, Harrison International Peace Hospital, Hengshui, Hebei 053500, P.R. China