Total Knee Arthroplasty and Bariatric Surgery: Change in BMI and Risk of Revision Depending on Sequence of Surgery

Abstract

Background Patients with obesity have higher risk of complications after total knee arthroplasty (TKA). We investigated the weight change at one and two years after Bariatric Surgery (BS) in patients that had both TKA and BS and the risk of revision after TKA depending on if BS was performed before or after the TKA. Methods Patients having BS within two years before or after TKA were identified from the Scandinavian Obesity Surgery Register (SOReg) and the Swedish Knee Arthroplasty Register (SKAR) between 2007 and 2019 and 2009 and 2020 respectively. The cohort was divided into two groups; patients with TKA before BS (TKA-BS) and patients with BS before TKA (BS-TKA). Multilinear regression analysis and Cox proportional hazards model were used to analyze weight change after BS and the risk of revision after TKA respectively. Results Of the 584 patients included in the study, 119 patients had TKA before BS and 465 had BS before TKA. We found no association between the sequence of surgery and total weight loss at one and two years after BS (risk ratio − 0.1 (95% confidence interval (CI) -1.7 to 1.5) and − 1.2 (CI -5.2 to 2.9 respectively), and the risk of revision after TKA (hazard ratio 1.54 (CI 0.5–4.5). Conclusion The sequence of surgery in patients undergoing both BS and TKA seems not to have any association with the weight loss after BS or the risk of revision after TKA.