In a retrospective review of 30,499 unilateral TKA patients receiving either 325 mg aspirin daily, low-molecular-weight heparin (enoxaparin 40–60 mg daily), synthetic pentasaccharide factor Xa inhibitors (fondaparinux 2.5 mg daily), or vitamin K antagonist (warfarin, all doses), Cafri et al. reported no difference with aspirin when compared to the other agents in the prevention of pulmonary embolism, deep vein thrombosis or venous thromboembolism. Here, F10 is linked to pulmonary embolism.