Influence of Obesity on Mid-term Revision Rates and Mortality After Elective Total Hip Arthroplasty—Analysis From the German Arthroplasty Registry (EPRD)

Background: Obesity has been associated with increased revision rates in total hip arthroplasty (THA). There is ongoing discussion as to whether this justifies postponing or denying THA to these patients. This study was initiated to determine the influence of obesity on revision rates and mortality after primary elective THA in Germany. Methods: The German Arthroplasty Registry (EPRD) provided data of 403,073 elective THAs with a valid body mass index (BMI) for analysis. Cumulative revision rates up to 7 years and 1-year mortality were calculated for BMI groups (nonobese, obesity grade 1, 2, and 3). Results: Increased revision rates with rising BMI were found. The main differences in revision rates appeared within the first postoperative months. This was most distinctive for periprosthetic joint infections during the first year after surgery (0.7% in nonobese, 1.3% in grade 1, 2.1% in grade 2, and 4.2% grade 3 obesity). Similar effects were observed in cementless and cemented stems. Revision rates in morbidly obese patients were not influenced by hospital caseload. Age- and sex-standardized mortality was lower than expected in most groups, but also increasing with rising BMI. Conclusions: Obesity increased the risk of revision following primary elective THA, particularly for periprosthetic joint infection in morbidly obese patients. However, the absolute risks of this potentially life-improving surgery may be acceptable for the patients affected. The potential risks and benefits should be weighed up individually for each patient, taking into account their BMI and any other risk factors they have. Level of Evidence: Level III, Therapeutic Study.