An international comparison of THA patients, implants, techniques, and survivorship in Sweden, Australia, and the United States

Elizabeth W Paxton; Guy  Cafri; Szilard Nemes; Michelle Lorimer; Johan Kärrholm; Henrik Malchau; Stephen E Graves; Robert S Namba; Ola Rolfson

doi:10.1080/17453674.2019.1574395

Authors

Elizabeth W Paxton Department of Clinical Analysis, Surgical Outcomes and Analysis, Southern California Permanente Medical Group, San Diego, CA, USA; Department of Orthopaedics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
Guy Cafri Department of Clinical Analysis, Surgical Outcomes and Analysis, Southern California Permanente Medical Group, San Diego, CA, USA
Szilard Nemes Swedish Hip Arthroplasty Register, Gothenburg, Sweden; Department of Orthopaedics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
Michelle Lorimer Australian Orthopaedic Association National Joint Replacement Registry, Adelaide, Australia
Johan Kärrholm Swedish Hip Arthroplasty Register, Gothenburg, Sweden; Department of Orthopaedics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; Sahlgrenska University Hospital, Gothenburg, Sweden
Henrik Malchau Swedish Hip Arthroplasty Register, Gothenburg, Sweden; Department of Orthopaedics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; Sahlgrenska University Hospital, Gothenburg, Sweden;
Stephen E Graves Australian Orthopaedic Association National Joint Replacement Registry, Adelaide, Australia
Robert S Namba Southern California Permanente Medical Group, Irvine, CA, USA
Ola Rolfson Swedish Hip Arthroplasty Register, Gothenburg, Sweden; Department of Orthopaedics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; Sahlgrenska University Hospital, Gothenburg, Sweden

DOI:

https://doi.org/10.1080/17453674.2019.1574395

Abstract

Background and purpose — International comparisons of total hip arthroplasty (THA) practices and outcomes provide an opportunity to enhance the quality of care worldwide. We compared THA patients, implants, techniques, and survivorship in Sweden, Australia, and the United States.

Patients and methods — Primary THAs due to osteoarthritis were identified using Swedish (n = 159,695), Australian (n = 279,693), and US registries (n = 69,641) (2003–2015). We compared patients, practices, and implant usage across the countries using descriptive statistics. We evaluated time to all-cause revision using Kaplan–Meier survival curves. We assessed differences in countries’ THA survival using chi-square tests of survival probabilities.

Results — Sweden had fewer comorbidities than the United States and Australia. Cement fixation was used predominantly in Sweden and cementless in the United States and Australia. The direct anterior approach was used more frequently in the United States and Australia. Smaller head sizes (≤ 32 mm vs. ≥ 36 mm) were used more often in Sweden than the United States and Australia. Metal-onhighly cross-linked polyethylene was used more frequently in the United States and Australia than in Sweden. Sweden’s
5- (97.8%) and 10-year THA survival (95.8%) was higher than the United States’ (5-year: 97.0%; 10-year: 95.2%) and Australia (5-year: 96.3%; 10-year: 93.5%).

Interpretation — Patient characteristics, surgical techniques, and implants differed across the 3 countries, emphasizing the need to adjust for demographics, surgical techniques, and implants and the need for global standardized definitions to compare THA survivorship internationally.