1. Orthopedic Institute and Department of Orthopedics The First Affiliated Hospital, Soochow University Suzhou Jiangsu 215006 P. R. China
2. School of Public Health Soochow University Suzhou 215123 P. R. China
3. Jiangsu Provincial Key Laboratory of Advanced Robotics, School of Mechanical and Electric Engineering Soochow University Suzhou 215123 P. R. China
4. National Institute for Food and Drug Control Beijing 102629 P. R. China
5. Center for Health Science and Engineering (CHSE), School of Materials Science and Engineering Hebei University of Technology Tianjin 300130 P. R. China
6. Tianjin Key Laboratory of Spine and Spinal Cord Tianjin Medical University General Hospital Tianjin 300130 P. R. China