Increased Risk of Postoperative Complications Following Total Knee Arthroplasty in Patients Who Have Metabolic Syndrome.

Abstract

Postoperative outcomes after total knee arthroplasty (TKA) are influenced by patient comorbidities. Metabolic syndrome (MetS) combines hypertension, diabetes, obesity, and dyslipidemia, which have been associated with increased short-term surgical complications. However, its independent impact on TKA outcomes beyond the perioperative period (> 90 days) remains unclear. This study compared outcomes following TKA between patients who had and did not have MetS, including a) mechanical complications (mechanical loosening and periprosthetic fracture), b) infectious complications (surgical site infection and periprosthetic joint infection), and c) reoperations (all-cause revision, septic revision, and manipulation under anesthesia), at 90 days, one year, and two years. A national all-payer database was queried using International Classification of Diseases, Ninth and Tenth Revision (ICD-9/10) codes to identify 1,255,079 patients who underwent TKA from 2010 to 2023. Among these, 386,813 (30.8%) had MetS. Outcomes were assessed at 90 days, one year, and two years. Student's t-tests and Pearson's Chi-square tests were used for unadjusted comparisons, and multivariable logistic regressions estimated odds ratios (OR) with 95% confidence intervals (CI). At two years, MetS was associated with increased odds of mechanical loosening (OR [odds ratio] 1.62, 95% CI [confidence interval] 1.43 to 1.83, P < 0.001), periprosthetic fracture (OR 2.84, 95% CI 2.42 to 3.32, P < 0.001), surgical site infection (OR 1.79, 95% CI 1.70 to 1.87, P < 0.001), periprosthetic joint infection (OR 1.53, 95% CI 1.43 to 1.65, P < 0.001), all-cause revision (OR 2.25, 95% CI 2.06 to 2.46, P < 0.001), and septic revision (OR 1.85, 95% CI 1.04 to 3.34, P = 0.040). Among MetS components, hypertension and diabetes were the strongest predictors. Metabolic syndrome is independently associated with increased risk of mechanical-, infectious-, and revision-related complications following TKA. These findings may help guide perioperative risk stratification, closer medical care coordination, and shared decision-making in this population.