Retraction Note: BMC Musculoskelet Disord 21, 271 (2020)

https://doi.org/10.1186/s12891-020-03291-5

This article has been retracted by the Editor at the request of one of the corresponding authors Wan-shou Guo. Contrary to the statement in the article, the authors did not obtain appropriate ethical oversight for this study. Pei Liu, Hua-chen Yu, Jian-lei Guan, Wei-guo Wang and Qi-dong Zhang agree with this retraction. Xiao-hong Mu and Zhao-hui Liu have not responded to correspondence from the Editor about this retraction.