Fabrizio Perna, Federico Pilla, Matteo Nanni, Lisa Berti, Giada Lullini, Francesco Traina, Cesare Faldini, Istituto Ortopedico Rizzoli, 40136 Bologna, Italy
Author contributions: Perna F gives the most important contributions to the conception of the paper end designed it; Pilla F and Nanni M were of paramount importance in drafting the work and revising it critically; Berti L and Lullini G helped in the acquisition, analysis and interpretation of data for the work; finally Traina F and Faldini C give us the final approval of the version to be published.
Institutional review board statement: This study received the ethical approval from the institutional review board statement of the Rizzoli Orthopaedic Institute of Bologna (No. 0021967).
Informed consent statement: All patients involved in this study gave their written informed consent prior to study inclusion.
Conflict-of-interest statement: The authors declare no conflicts of interest.
Data sharing statement: Authors agreed to share data with the editor.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Fabrizio Perna, MD, Istituto Ortopedico Rizzoli, Via G. C. Pupilli 1, 40136 Bologna, Italy. firstname.lastname@example.org
Telephone: +39-051-6366368 Fax: +39-051-6366212
Received: January 23, 2017
Peer-review started: February 5, 2017
First decision: March 28, 2017
Revised: April 21, 2017
Accepted: May 12, 2017
Article in press: May 15, 2017
Published online: June 18, 2017