1. a Department of Orthopaedic Surgery, Shanghai Sixth People's Hospital, JiaoTong University, 600 YiShan Road, Shanghai 200233, P. R. China
2. b Department of Orthopaedic Surgery, Shanghai Tenth People's Hospital, Shanghai 200072, P. R. China
3. c Department of Orthopaedic Surgery, Shanghai Sixth People's Hospital, JiaoTong University, 600 YiShan Road, Shanghai 200233, P. R. China
4. d State Key Laboratory for Modification of Chemical Fibres and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, P. R. China
5. e Department of Orthopaedic Surgery, Shanghai Sixth People's Hospital, JiaoTong University, 600 YiShan Road, Shanghai 200233, P. R. China
6. f Department of Orthopaedic Surgery, Shanghai Sixth People's Hospital, JiaoTong University, 600 YiShan Road, Shanghai 200233, P. R. China