1. Department of Orthopaedics and Traumatology, Helsinki University Hospital, Helsinki, Finland
2. Department of Radiology, Helsinki University Hospital, Helsinki, Finland
3. Department of Orthopaedics and Traumatology, Central Finland Central Hospital, Jyväskylä, Finland
4. Primary Health Care Unit, Kuopio University Hospital, Kuopio, Finland
5. Folkhälsan Research Center, Helsinki, Finland
6. Department of Orthopaedics and Traumatology, University of Helsinki, Helsinki, Finland