1. Department of Orthopaedic Surgery, Martina Hansen’s Hospital, Gjettum, Norway
2. Department of Physiotherapy, Martina Hansen’s Hospital, Gjettum, Norway
3. Department of Occupational Therapy, Martina Hansen’s Hospital, Gjettum, Norway
4. Centre of Biostatistics and Epidemiology, Oslo University Hospital, Oslo, Norway
5. Division of Radiology and Nuclear Medicine, Institute of Clinical Medicine, University of Oslo, Oslo, Norway