268 patients (330 knees) undergoing primary TKA were randomized into three groups, receiving either rivaroxaban (10mg) for 7 or 10 days post operation, or low molecular weight heparin (5000IU) for 2 days followed by aspirin 100mg for 5 days. The purpose of the study was to analyze the incidence of venous thromboembolism among groups to determine the safety and efficacy of prophylaxis regimens, over 3 months post-surgery. Results indicated that 10 day rivaroxavan treatment was superior in reducing VTE incidence, than 7 day treatment or heparin and aspiring treatment, without increasing complications.