An analysis of 438,733 hips based on the Nordic Arthroplasty Register Asso- ciation database

1Department of Orthopaedics and Traumatology, Turku University Hospital; 2Department of Biostatistics, Turku University, Turku; 3Hjelt Institute, Helsinki University, Helsinki, Finland; 4The Norwegian Arthroplasty Register, Department of Orthopaedic Surgery, Haukeland University Hospita; 5Department of Clinical Medicine, University of Bergen, Bergen, Norway; 6The Danish Hip Arthroplasty Register, Center for Clinical Databases, Department of Clinical Epidemiology; 7Competence Center for Clinical Epidemiology and Biostatistics, North, Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus; 8Department of Orthopaedic Surgery and Traumatology and Clinical Institute, Odense University Hospital, Odense, Denmark; 9The Swedish Hip Arthroplasty Register, Department of Orthopaedics, Institute of Surgical Sciences, Sahlgrenska University Hospital, University of Gothenburg, Molndal, Sweden and Orthopaedic Department, Massachusetts General Hospital/Harvard Medical School, Boston, MA, USA; 10Swedish National Competence Center Musculoskeletal Disorders, Skane University Hospital, Lund, Sweden; 11The Coxa Hospital for Joint Replacement, Tampere, Finland. Correspondence: keijo.makela@fimnet.fi Submitted 13-09-10. Accepted 14-01-03