1. Department of Trauma Surgery and Sports Medicine, Garmisch-Partenkirchen Medical Centre, 82467 Garmisch-Partenkirchen, Germany
2. Institute for Community Medicine, SHIP/Clinical-Epidemiological Research, University of Greifswald, 17489 Greifswald, Germany
3. Department of Orthopedics and Traumatology, Paracelsus Medical University, 90471 Nuremberg, Germany