1. Hospital of Southern Jutland, University of Southern Denmark; Orthopaedic Department; Aabenraa Denmark 6200
2. Bispebjerg and Frederiksberg Hospitals, University of Copenhagen; WHO-CC, Clinical Health Promotion Centre; Copenhagen Denmark
3. Lund University; Department of Health Sciences; Lund Sweden
4. Herlev and Gentofte Hospital, University of Copenhagen; Cochrane Anaesthesia, Critical and Emergency Care Group; Herlev Ringvej Herlev Denmark 2730
5. Sophiahemmet University; Lindstedtsvägen 8 Stockholm Sweden
6. University of Southern Denmark; SEARCH (Research group for synthesis of evidence and research), Research Unit for Musculoskeletal Function and Physiotherapy, Institute of Sports Science and Clinical Biomechanics; Campusvej 55 Odense M Denmark 5230