1. Department of Orthopedics, Lihuili Hospital Affiliated to Ningbo University, Ningbo, Zhejiang 315211, P.R. China
2. Department of Orthopedics, Hwa Mei Hospital, University of Chinese Academy of Sciences, Ningbo, Zhejiang 315100, P.R. China
3. Department of Orthopedics, The Affiliated Hospital of Medical School of Ningbo University, Ningbo, Zhejiang 315100, P.R. China
4. Faculty of Electronics and Computers, Zhejiang Wanli University, Ningbo, Zhejiang 315100, P.R. China