[1] Univ Oslo, Inst Clin Med, Oslo, Norway
[2] Oslo Univ Hosp, Res & Commun Unit Musculoskeletal Hlth, Oslo, Norway
[3] Univ Southern Denmark, Dept Sports Sci & Clin Biomech, Res Unit Musculoskeletal Funct & Physiotherapy, Odense, Denmark
[4] Lillebaelt Hosp, Kolding, Denmark
[5] Lillebaelt Hosp, Dept Orthopaed Surg, Vejle, Denmark
[6] Odense Univ Hosp, Odense, Denmark
[7] Lund Univ, Fac Med, Orthopaed Clin Epidemiol Unit, Dept Clin Sci,Lund Clin, Lund, Sweden