Risk of revision total knee arthroplasty for patients with prior bariatric surgery or class III obesity

Background Bariatric surgery (BS) is indicated for select class III obesity patients undergoing total knee arthroplasty (TKA) to reduce obesity-related complications. This study assessed the effect of BS on TKA revision rates compared to the general population and class III obesity patients without a history of BS. Methods A national database identified patients who had primary TKA. They were divided into two groups: those with BS prior to TKA and those without. Patients without BS formed two control groups, a matched general population, and a matched class III obese cohort. The BS group was matched with controls based on age, Charlson Comorbidity Index (CCI), gender, and diabetes mellitus. Revision rates were analyzed using Kaplan-Meier survival analysis and hazard ratios (HR), calculated using Cox proportional hazard modeling. Results 14,292 BS patients were compared to 57,006 matched general population controls, and 19,504 BS patients were compared to 77,846 matched class III obesity control patients. BS patients had a higher risk of 5-year all-cause revision (HR: 1.13; P = 0.014) and revision due to periprosthetic fracture (HR: 1.39; P < 0.001) compared to the general population. Compared to class III obesity controls, BS patients had a lower risk of 5-year revision due to prosthetic joint infection (HR: 0.77; P = 0.001), with no difference in all-cause revision (P = 0.362). Conclusion BS does not reduce all-cause TKA revision risk compared to the general or matched class III obesity population. However, it lowers the risk of revision due to prosthetic joint infection when compared to patients with class III obesity.Level of Evidence: IV.