Which orally administered antithrombotic agent is most effective for preventing venous thromboembolism after total knee arthroplasty? A propensity score-matching analysis.

Purpose: Even today, total knee arthroplasty (TKA) is associated with venous thromboembolism (VTE). The purpose of our study is to report the incidence of postoperative VTE and to compare the efficacy of commonly used orally administered antithrombotic agents.
Materials and Methods: Seven hundred ad ninety-nine patients who underwent primary TKA were retrospectively reviewed. The patients were prescribed one of three antithrombotic agents: aspirin (n = 168), rivaroxaban (n = 117), or apixaban (n = 514). Before surgery, patient demographics and risk factors were matched via propensity scoring. After surgery, all three groups took the agent for 7 days and underwent ultrasonography to check for VTE.
Results: The overall incidence of postoperative VTE was 15.4% (123/799). Only one patient developed symptomatic VTE. Female sex and staged bilateral TKA were risk factors for postoperative VTE. The postoperative VTE rates in the aspirin, rivaroxaban, and apixaban groups were 16.2%, 6.0%, and 17.1%, respectively, significantly lower in the rivaroxaban group (p <  0.02). The majority of VTEs in all three groups were calf-vein thromboses.
Conclusions: All agents showed enough efficacy as antithrombotic agents. Considering that aspirin is inexpensive, aspirin is a cost-effective option for preventing postoperative VTE.