1. Department of Traumatology and Orthopedic Surgery, Hospital Ludwigsburg, Posilipostr. 4, 71640 Ludwigsburg, Germany
2. Department of Orthopedic Surgery and Traumatology, Hospital Barmherzige Brüder Munich, Romanstr. 93, 80639 Munich, Germany
3. Department of Orthopedic Surgery and Traumatology, Inselspital, University Hospital Bern, University of Bern, Freiburgstr. 4, 3010 Bern, Switzerland