1. Department of Orthopedic and Emergency Surgery, Alfried Krupp Klinikum Essen, Essen, Germany
2. Center for Orthopaedic and Trauma Surgery, University Hospital Giessen and Marburg, Marburg, Germany
3. Academy for Trauma Surgery, Munich, Germany
4. Department of Orthopaedic and Trauma Surgery, Cantonal Hospital Lucerne, Lucerne, Switzerland
5. Department of General, Trauma and Reconstructive Surgery, Ludwigs-Maximilians-University, Munich, Germany