The Comparison of Aspirin and Direct Oral Anticoagulant as Thromboprophylaxis Following Total Knee Replacement: A Retrospective Study.

 Venous thromboembolism (VTE) is still a major challenge after major orthopaedic surgery, including total knee replacement (TKR). The aim of this study was to estimate the risk of VTE with aspirin-only pharmacologic prophylaxis following primary TKR surgery versus direct oral anticoagulant (DOAC).  The study included 476 patients who underwent primary TKR from 2016 to 2020. All patients received thromboprophylaxis with DOAC (DOAC group) (  = 267) or aspirin (aspirin group) (  = 209). Clinical outcomes were evaluated and compared between those who received DOAC and aspirin. The primary outcome was the incidence of VTE. The secondary outcome was wound complications.  Aspirin and DOAC were comparable in preventing VTE in patients who underwent primary TKR. The incidence of deep vein thrombosis was similar in the aspirin (10%) and factor Xa inhibitor groups (10.1%), (  = 0.98) with zero case of pulmonary emboli in both groups. There was no significant difference between the aspirin (1.4%) and DOAC groups (1.5%) regarding wound complication (  = 0.95).  Postoperative thromboprophylaxis with aspirin only was not associated with a higher risk of postoperative VTE compared with DOAC following TKR. Considering the wide availability and cost-effectiveness, aspirin may serve as a promising alternative to DOAC for VTE prophylaxis.