1. Department of Orthopaedic Surgery, Copenhagen University Hospital Hvidovre, Copenhagen, Denmark
2. Department of General Practice, Amsterdam UMC Location, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
3. Amsterdam Public Health Research Institute, Amsterdam, The Netherlands
4. Department of Orthopaedic Surgery and Traumatology, Copenhagen University Hospital Bispebjerg, Copenhagen, Denmark
5. Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
6. Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, England