1. Institute of Orthopedics, Chinese PLA General Hospital, Beijing Key Lab of Regenerative Medicine in Orthopedics, Key Lab of Musculoskeletal Trauma & War Injuries, PLA, No. 28 Fuxing Road, Beijing 100853, P. R. China
2. Department of Orthopedics, Tianjin Hospital, No. 406 Jiefang Nan Road, Tianjin 300211, P. R. China
3. Department of Surgery, Ludwig-Maximilians-University, Nussbaumstr. 20, Munich 80336, Germany
4. State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, P. R. China
5. School of Biomedical Sciences, University of Hong Kong, No. 21 Sassoon Road, Pokfulam, 999077 Hong Kong, P. R. China