A Prospective Comparison of Warfarin to Aspirin for Thromboprophylaxis in Total Hip and Total Knee Arthroplasty

Current orthopedic practice requires consideration of contradictory recommendations regarding pulmonary embolism (PE) prevention among patients undergoing total hip arthroplasty (THA) and knee joint arthroplasty (TKA). A total of 696 consecutive patients underwent elective THA or TKA. Two hundred eighty-one patients received PE risk stratification per American Academy of Orthopaedic Surgeons guidelines. Of these patients, 152 standard-risk patients received aspirin, and 129 elevated-risk patients received warfarin. The comparator group of 415 patients received American College of Chest Physicians–recommended warfarin without PE risk stratification. Primary study outcomes were symptomatic PE, deep venous thrombosis, major bleeding, and death. The rate of symptomatic PE and venous thromboembolism among standard-risk group patients receiving aspirin was greater than the comparator group (4.6% vs 0.7% and 7.9% vs 1.2%, respectively). Most events (16/18) occurred among patients undergoing TKA. Patients with total joint arthroplasty at standard risk for PE receiving aspirin had a higher rate of symptomatic PE and venous thromboembolism than did patients receiving anticoagulation.