Effects and Complications of Apixaban versus Aspirin for Venous Thromboembolism Prophylaxis after Total Hip or Knee Arthroplasty

Background: Major orthopaedic procedures, such as total hip arthroplasty (THA) and total knee arthroplasty (TKA), carry risk for thrombotic complications. To reduce the incidence of postoperative venous thromboembolism (VTE), surgical patients are often prescribed antiplatelet or anticoagulant treatment. The objective of this study was to compare rates of VTE events and complications between apixaban and aspirin for VTE prophylaxis following primary THA and TKA. Methods: We searched a research network using Current Procedural Terminology and International Classification of Diseases, Tenth Revision codes for patients who underwent a THA or TKA from 2018 to 2023. Patients were then categorized into cohorts of patients who received only aspirin (81 or 325 mg, twice daily) or patients who received only apixaban (2.5 mg, twice daily) for VTE prophylaxis. Odds ratios with 95% confidence intervals were calculated to compare the associations of selected prophylaxis with VTE events and complications, and Chi-square analyses were performed to determine the significance of differences. Statistical significance was defined as a two-sided alpha value < 0.05. Results: Patients who received apixaban after THA had increased odds of deep vein thrombosis (5.22, 4.60 to 5.93), pulmonary embolism (7.85, 6.55 to 9.41), transfusion (1.5, 1.27 to 1.81), hemarthrosis (1.87, 1.26 to 2.24), myocardial infarction (1.12, 1.03 to 1.23), and readmission (1.18, 1.09 to 1.28) within 90 days after surgery. Patients who received apixaban after TKA had increased odds of deep vein thrombosis (4.57, 4.15 to 5.02), pulmonary embolism (6.05, 5.33 to 6.88), transfusion (1.6, 1.36 to 1.96), hemarthrosis (1.48, 1.03 to 2.12), myocardial infarction (1.42, 1.29 to 1.63), stroke (1.16, 1.09 to 1.53), and readmission (1.84, 1.61 to 2.11) within 90 days after TKA. Conclusions: Apixaban is associated with increased odds of thrombotic events and bleeding complications in the postoperative period of THA and TKA compared to aspirin. This highlights the potential risks associated with apixaban use and the importance of using data to guide patient management in the absence of standardized clinical guidelines.