1. Division of Orthopaedic Surgery, Oslo University Hospital, Oslo, Norway
2. Institute of Clinical Medicine, University of Oslo, Oslo, Norway
3. The Norwegian Arthroplasty Register, Department of Orthopaedic Surgery, Haukeland University Hospital, Bergen, Hordaland, Norway
4. Department of Clinical Dentistry, University of Bergen, Norway
5. Department of Clinical Medicine, University of Bergen, Norway