1. Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, SE413 45 Gothenburg, Sweden
2. Department of Orthopaedics, Sahlgrenska University Hospital, SE413 45 Gothenburg, Sweden
3. Department of Radiology, Sahlgrenska University Hospital, SE413 45 Gothenburg, Sweden
4. Department of Registration, Cancer Registry Norway, 0379 Oslo, Norway
5. Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, SE413 45 Gothenburg, Sweden