1. Department of Clinical Analysis, Surgical Outcomes and Analysis, Southern California Permanente Medical Group, San Diego, CA, USA;
2. Department of Orthopaedics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden;
3. Swedish Hip Arthroplasty Register, Gothenburg, Sweden;
4. Australian Orthopaedic Association National Joint Replacement Registry, Adelaide, Australia;
5. Sahlgrenska University Hospital, Gothenburg, Sweden;
6. Southern California Permanente Medical Group, Irvine, CA, USA