Is Pharmacological Thromboprophylaxis Truly Necessary: Predictive Factors for Venous Thromboembolic Events Post-Total Knee Arthroplasty in an Asian Population

Introduction: Venous thromboembolic prophylaxis is routinely used in elective total knee arthroplasty (TKA) patients worldwide, and current guidelines vary from aspirin to low molecular weight heparin in combination with mechanical prophylaxis, and direct oral anticoagulants. This study aimed to identify predictive or protective factors for VTEs in an Asian hospital and examine the efficacy of pharmacological VTE prophylaxis. Materials and Methods: A retrospective cohort study of 2,014 patients who underwent primary TKAs between 2017 and 2022 was performed. All patients received mechanical thromboprophylaxis postoperatively. Patients who were symptomatic were referred for radiological investigations to exclude VTE. We evaluated patient demographics, co-morbidities, and surgical parameters to establish the overall incidence of symptomatic VTEs and risk factors for VTEs. Results: There were 23 (1.14%) incidences of symptomatic VTEs, of which 1 patient developed pulmonary embolism, and 22 deep vein thrombosis. The incidence of VTE was 0.69% (10/1449) for patients on mechanical prophylaxis only, 2.08% (9/432) for patients on aspirin, 3.67% (4/109) for patients on clexane, 0% (0/19) for patients on clopidogrel, and 0% (0/5) for patients on DOACs. Multivariate analysis revealed length of stay (P < 0.001), the need for blood transfusion (P = 0.007), choice of thromboprophylaxis (P = 0.049), and diagnosis (P = 0.048) were independent risk factors for VTE. The use of tranexamic acid did not significantly affect VTE rates in the model (P = 0.059). Conclusion: Pharmacological thromboprophylaxis may not be required post-operative in the Asian population. The identification of risk factors in this study allows surgeons to individualise risk counselling for patients listed for elective TKAs and choose appropriate thromboprophylaxis methods. Keywords: Knee arthroplasty, Arthroplasty, Replacement, Knee, Thromboprophylaxis, Venous thrombosis, Asians