1 Department of Orthopedics, University Medical Center Regensburg, Asklepios Klinikum Bad Abbach, Kaiser-Karl-V.-Allee 3, 93077, Bad Abbach, Germany. felix.greimel@ukr.de.
2 Department of Orthopedics, University Medical Center Regensburg, Asklepios Klinikum Bad Abbach, Kaiser-Karl-V.-Allee 3, 93077, Bad Abbach, Germany.
3 Center for Clinical Studies, University Medical Center of Regensburg, Franz-Josef-Strauss-Allee 11, 93053, Regensburg, Germany.
4 Orthopaedic Center in Helios, Helene-Weber-Allee 19, 80637, München, Germany.