Zuyun Yan1, Rui Fang1, Tang Liu2. 1. Department of Orthopedics, the 2nd Xiangya Hospital, Central South University, 139 Renmin Road, Changsha, Hunan, 410011, China. 2. Department of Orthopedics, the 2nd Xiangya Hospital, Central South University, 139 Renmin Road, Changsha, Hunan, 410011, China. liutang1204@csu.edu.cn.