1. Department of Orthopedics, Tianjin Nankai Hospital, Tianjin 300100, P.R. China
2. Department of Orthopedics, The Second Hospital of Jilin University, Changchun, Jilin 130041, P.R. China
3. Department of Surgery, Peking Union Medical College Hospital, Beijing 100032, P.R. China
4. Department of Orthopedics, China-Japan Union Hospital of Jilin University, Changchun, Jilin 130033, P.R. China