1. Department of Orthopedics Changzheng Hospital Naval Medical University Shanghai 200003 P. R. China
2. Department of Orthopedics General Hospital of Southern Theatre Command of PLA Guangzhou 510010 P. R. China
3. Department of Orthopedics Shanghai General Hospital Shanghai Jiao Tong University School of Medicine Shanghai 200080 P. R. China
4. Department of Neurology Renji Hospital Shanghai Jiaotong University School of Medicine Shanghai 200127 P. R. China
5. Department of Ophthalmology Changhai Hospital Shanghai 200433 P. R. China
6. Senior Department of Orthopedics The Fourth Medical Center of PLA General Hospital Beijing 100048 P. R. China