1. Department of Orthopaedics and Traumatology Turku University Central Hospital, Rauhankatu 24 D 32, 20100 Turku, Finland.
2. The Coxa Hospital for Joint Replacement, Tahmelan Viertotie 26 A, 33250 Tampere, Finland.
3. Department of Public Health University of Helsinki, Mannerheimintie 172, 00014 Helsinki, Finland.
4. Invalid Foundation Orton Orthopaedic Hospital, Tenholantie 10, 00280 Helsinki, Finland.
5. Department of Orthopaedics and Traumatology Helsinki University Central Hospital, Sepänkatu 7A 26, 00150 Helsinki, Finland.