Funding for this research was provided by:
China Postdoctoral Science Foundation (2017M610323)
Natural Science Foundation of Jiangsu Province (BK20170126)
Received: 22 July 2017
Accepted: 23 April 2018
First Online: 9 May 2018
Ethics approval and consent to participate
: The Drum Tower Hospital’s review board approved this retrospective study and all participating subjects or their legal guardians signed the written informed consents..
: ZZ is a member of the Editorial Board of BMC Musculoskeletal Disorders. The other authors declare that they have no competing interests.
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