1. Department of Trauma, Hand and Reconstructive Surgery, University Hospital Essen, 45147 Essen, Germany
2. Department of Orthopaedics and Trauma Surgery, GFO Kliniken Mettmann-Süd, 40724 Hilden, Germany
3. Department of Orthopaedics and Trauma Surgery, BG Klinikum Duisburg, 47249 Duisburg, Germany