1. Department of Orthopaedic Surgery and Traumatology, Odense University Hospital;
2. Department of Clinical Research, University of Southern Denmark, Odense;
3. Department of Regional Health Research, University of Southern Denmark, Odense;
4. Department of Orthopaedic Surgery, Naestved Hospital. Naestved;
5. Department of Orthopaedic Surgery, Copenhagen University Hospital, Hvidovre, Denmark