Aspirin prophylaxis is safe and effective for venous thromboembolism prophylaxis in low-risk patients undergoing aseptic revision total knee arthroplasty

Aims: While aspirin has been widely adopted as an effective method for deep vein thrombosis (DVT) prevention following primary total knee arthroplasty (TKA), concerns remain with regard to its efficacy in the setting of revision TKA (rTKA). However, the risk for thromboembolic events must be weighed against the increased potential for bleeding with more potent anticoagulants. This study aimed to compare venous thromboembolism (VTE) and transfusion rates between patients receiving aspirin with non-aspirin anticoagulation following aseptic rTKA. Methods: We identified patients undergoing aseptic rTKA from 1 January 2016 to 30 April 2023 in a national database. Those with infection, fracture, prior VTE, coagulopathy, or preoperative anticoagulant use were excluded. Patients were grouped by postoperative prophylaxis: aspirin alone or non-aspirin anticoagulants. Patients were allocated to one of two categorical treatment groups. Crossover between groups was permitted where clinically indicated. Propensity score matching (1:1) was performed on demographic details, insurance, comorbidities, postoperative home health use, hospital length of stay ≤ one day, surgery year, and Current Procedural Terminology (CPT) code, yielding 4,585 patients per group. Outcomes included 30- and 90-day DVT, pulmonary embolism (PE), overall VTE, and transfusion. Results: In the matched cohort, aspirin use was associated with lower 90-day DVT (0.8% (n = 38) vs 2.1% (n = 96)), PE (0.6% (n = 26) vs 2.2% (n = 102)), and VTE (1.1% (n = 51) vs 3.3% (n = 152); all p < 0.001). Transfusion was also lower in the aspirin group at 30 days (0.6% (n = 28) vs 1.2% (n = 56); p = 0.003) and 90 days (0.7% (n = 33) vs 1.4% (n = 65); p = 0.002). DVT ultrasound use within 30 days was significantly higher in the non-aspirin group (7.1%; n = 326) compared with aspirin (5.1%; n = 235); p < 0.001), which may partly account for the higher VTE detection. Regression controlling for CPT code confirmed reduced odds of VTE with aspirin. Conclusion: Aspirin is a safe, effective, and noninferior option for VTE prophylaxis following aseptic rTKA in appropriately selected patients.