1. Department of Health Sciences and Medicine, University of Lucerne, 6002 Luzern, Switzerland
2. Department of Trauma Surgery, Leiden University Medical Centre, 2300 RC Leiden, The Netherlands
3. Department of Orthopedics and Trauma Surgery, Lucerne Cantonal Hospital, 6000 Luzern, Switzerland
4. Department of Surgery, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands
5. Department of Surgery, University Hospital Heidelberg, 69117 Heidelberg, Germany