1. Department of Physical Medicine and Rehabilitation, Østfold Hospital Trust, Grålum, Norway
2. Institute of Health and Society, Faculty of Medicine, University of Oslo, Oslo, Norway
3. Orthopaedic Department, Møre og Romsdal Hospital Trust, Ålesund Hospital, Alesund, Norway
4. Department of Orthopaedic Surgery, Innlandet Hospital Trust, Gjøvik Hospital, Gjøvik, Norway
5. Department of Orthopaedic Surgery, Østfold Hospital Trust, Grålum, Norway