Received: 2 August 2019
Accepted: 29 January 2020
First Online: 5 February 2020
Ethics approval and consent to participate
: The study was approved by the institutional ethics committee of the Medical School of the University of Leipzig (approval number: 276/16-ek); it was conducted according to ICMJE guidelines, and has been retrospectively registered with the German Clinical Trials Registry (identification number: DRKS00015693). This study also adheres to the STROBE guidelines. Written informed consent was obtained from all patients.
: Not applicable.
: ○CR is a member of the editorial board of this journal○CJ received royalties from Zimmer, Warsaw, USA; DepuySynthes, West Chester, USA; Medtronic, Minneapolis, USA; Zimmer, Nürnberg, Germany○CH is an independent consultant for Medtronic, Castel San Pietro, Switzerland○OG has received payments for lectures for Medtronic GmbH, Meerbusch, Germany und Aesculap AG, Tuttlingen, Germany○All other authors declare that they have no conflict of interest