Department of Orthopedics, Xuanwu Hospital, Capital Medical University, National Clinical Research Center for Geriatric Diseases, No.45 Changchun Street, Xicheng District, Beijing, China.

Qijun Wang

Department of Orthopedics, Xuanwu Hospital, Capital Medical University, National Clinical Research Center for Geriatric Diseases, No.45 Changchun Street, Xicheng District, Beijing, China.

Peng Wang

Department of Orthopedics, Xuanwu Hospital, Capital Medical University, National Clinical Research Center for Geriatric Diseases, No.45 Changchun Street, Xicheng District, Beijing, China. wpspine@sina.com.

Chao Kong

Department of Orthopedics, Xuanwu Hospital, Capital Medical University, National Clinical Research Center for Geriatric Diseases, No.45 Changchun Street, Xicheng District, Beijing, China. kong988500@163.com.

Shibao Lu

Department of Orthopedics, Xuanwu Hospital, Capital Medical University, National Clinical Research Center for Geriatric Diseases, No.45 Changchun Street, Xicheng District, Beijing, China. spinelu@163.com.