1. Ortho Center Stockholm, Löwenströmska sjukhuset, Stockholm;
2. Karolinska Institutet, Department of Clinical Sciences, Danderyds sjukhus AB, Stockholm;
3. Aleris Elisabethsjukhuset, Uppsala;
4. Department of Diagnostic Radiology, Translational Medicine Malmö, Lund University, Malmö;
5. Epidemiology and Centre of Registers South, Skåne University Hospital, Lund, Sweden