[1] Capital Med Univ, Dept Orthopaed, Xuanwu Hosp, Beijing 100053, Peoples R China
[2] Natl Clin Res Ctr Geriatr Dis, Beijing 100053, Peoples R China
[3] Charite Univ Med Berlin, D-113353 Berlin, Germany
[4] Purdue Univ, Dept Interdisciplinary, Life Sci, W Lafayette, IN 47907 USA
[5] Tsinghua Univ, Chui Yang Liu Hosp, Dept Orthopaed, Beijing 100020, Peoples R China