1. Department of Orthopaedics and Traumatology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
2. Jyväskylä Central Hospital, Jyväskylä, Finland
3. Primary Health Care Unit, Kuopio University Hospital, Kys, Pohjois-Savo, Finland
4. Folkhälsan Research Center, Helsinki, Finland
5. Department of Applied Physics, University of Eastern Finland, Kuopio, Finland