1. The Swedish Hip Arthroplasty Register, Gothenburg, Sweden.
2. Department of Orthopaedics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
3. The Swedish Hip Arthroplasty Register, Department of Orthopaedics, Lidköping Hospital, Lidköping, Sweden.
4. The Swedish Hip Arthroplasty Register, Department of Orthopaedics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.