Oral Aspirin for Venous Thromboembolism Prophylaxis After Orthopedic Surgery: An Evidence-Based Review

Abstract Background: Venous thromboembolism (VTE) remains a major complication after total hip arthroplasty (THA), total knee arthroplasty (TKA), and fracture surgery. While anticoagulants such as low-molecular-weight heparin (LMWH) and direct oral anticoagulants (DOACs) are standard, aspirin (ASA) is increasingly considered due to its convenience, safety profile, and low cost. Methods: We systematically reviewed randomized controlled trials (RCTs) and international guidelines on ASA for orthopedic VTE prophylaxis. Nine RCTs and four guidelines were included. Outcomes assessed were deep vein thrombosis (DVT), pulmonary embolism (PE), major bleeding, and mortality. Results: In arthroplasty, EPCAT II demonstrated that short-course rivaroxaban followed by ASA was noninferior to extended rivaroxaban, whereas CRISTAL showed higher symptomatic VTE rates with ASA compared to enoxaparin when used from day 0. PREVENT CLOT established ASA as noninferior to LMWH for mortality after fracture surgery, with similar PE and bleeding rates but slightly more distal DVTs. Smaller RCTs from Asia and South America found no major differences between ASA and rivaroxaban, warfarin, or sequential regimens. Guidelines remain heterogeneous: ASH (2019) provides conditional recommendations, NICE (2018/2022) and AAOS (2022) endorse ASA in specific settings, and the 2024 European guideline emphasizes individualized prophylaxis. Conclusions: ASA is most reliably used as extended prophylaxis after initial anticoagulation in arthroplasty and as a pragmatic alternative to LMWH in trauma surgery. Anticoagulants remain superior when initiated immediately after arthroplasty. ASA’s favorable safety, low cost, and oral administration make it attractive in selected patient groups, though high-risk patients still benefit most from anticoagulants.