1. Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway.
2. Orthopaedic Research Center, Trondheim University Hospital, Trondheim, Norway.
3. Orthopaedic Center, Oslo University Hospital, Oslo, Norway.
4. Faculty of Medicine, University of Oslo, Oslo, Norway.
5. Aleris Radiology Center Trondheim, Trondheim, Norway.