Total Knee Arthroplasty in Patients with Non-Alcoholic Fatty Liver Disease: A Propensity Matched Study

Background Non-alcoholic fatty liver disease (NAFLD) is defined as a condition where fat accumulates in the liver secondary to conditions other than heavy alcohol use. The altered liver function ultimately affects the postoperative outcomes of total knee arthroplasty (TKA). While cirrhosis is known to influence postoperative outcomes, the independent impact of NAFLD remains unclear. This study aims to assess postoperative complications following TKA in patients with NAFLD. Methods A retrospective cohort study using the TriNetX database identified patients with NAFLD who underwent primary TKA between 2005 and 2025 (n = 20,663) and were propensity-matched to non-NAFLD controls. Patients were matched based on age, gender, race, and multiple systemic comorbidities. Outcomes included 30-day, 90-day, and 1-year postoperative systemic and local complications and mortality. Results At 30 days postoperatively, NAFLD patients had significantly increased odds of pneumonia (OR 1.35, 95% CI 1.07-1.70), emergency room visits (OR 1.30, 95% CI 1.21-1.41), urinary tract infections (OR 1.20, 95% CI 1.03-1.42), stiffness (OR 1.09, 95% CI 1.00-1.19), and dislocation of knee (OR 1.85, 95% CI 1.41-2.44) versus controls. At 90 days postoperatively, increased odds persisted for pneumonia (OR 1.35), urinary tract infection (OR 1.18), knee dislocation (OR 1.39), and emergency visits (OR 1.32), with an additional increased odds of pulmonary embolism (OR 1.20, 95% CI 1.01-1.42) and sepsis (OR 1.26, 95% CI 1.01-1.58). At 1 year, NAFLD remained associated with increased odds of pneumonia (OR 1.29), pulmonary embolism (OR 1.15), sepsis (OR 1.23), acute kidney failure (OR 1.18), urinary tract infection (OR 1.21), knee dislocation (OR 1.17) and emergency visits (OR 1.39), with an additional increased odds of acute kidney failure (OR 1.18, 95% 1.08-1.29) Conclusion NAFLD is associated with increased odds of postoperative medical and surgical complications following TKA and should be considered a clinically relevant risk factor during preoperative evaluation. These findings support the incorporation of NAFLD into perioperative risk stratification and optimization to improve patient outcomes.