1. Department of Orthopaedic Surgery, Baerum Hospital, Vestre Viken Hospital Trust
2. Kalnes Hospital, Østfold Hospital Trust
3. Division of Orthopaedic Surgery, Oslo University Hospital
4. Institute of Clinical Medicine, Faculty of Medicine, University of Oslo
5. Department of Radiology and Nuclear Medicine, Oslo University Hospital, Oslo
6. Aleris Hospital, Tromsø, Norway