1. Department of Orthopedics, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710032, P.R. China
2. Institute of Military Training Related Medical Sciences, The 150 Hospital of Chinese People's Liberation Army, Luoyang, Henan 471003, P.R. China
3. Institute of Orthopedics, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710032, P.R. China