1. Department of Orthopaedic and Trauma Surgery Waldkrankenhaus Erlangen Erlangen Germany
2. Department of Orthopaedic Surgery University Medicine Rostock Rostock Germany
3. Department of Orthopaedics Sahlgrenska University Hospital, Sahlgrenska Academy, Gothenburg University Gothenburg Sweden
4. Department of Orthopaedic Surgery Centre Hospitalier—Clinique d'Eich and Luxembourg Institute of Health Luxembourg