Received: 18 October 2019
Accepted: 17 March 2020
First Online: 3 April 2020
Ethics approval and consent to participate
: This retrospective study was approved by the institutional review board of the canton Zurich “Kantonale Ethikkommission des Kantons Zürich” KEK-ZH_Nr. 2013–0598.
: All patients participating in this study declared in a written informed consent to agree to the use of their data for clinical investigations. This procedure was monitored and approved by the institutional review board of the canton Zurich.
: Christian Gerber received royalties from Zimmer-Biomet which is related to the subject of this work. All other authors hereby declare that they have no potential conflicts of interest to disclose.