Louis M KwongDepartment of Orthopaedic Surgery, Harbor-UCLA Medical Center, Torrance, CA, USAAbstract: Rivaroxaban (Bayer AG, Leverkusen, Germany) is a highly selective direct inhibitor of factor Xa. It has completed Phase III clinical trials evaluating its efficacy and safety against enoxaparin in the prophylaxis against venous thromboembolism (VTE) in orthopedic patients following primary total hip and total knee arthroplasty. Rivaroxaban has been extensively studied worldwide in 12,729 patients in the Regulation of Coagulation in Major Orthopedic Surgery Reducing the Risk of DVT and PE (RECORD) program. Pivotal clinical trials have demonstrated the superior efficacy in reducing total VTE in comparison with both the North American and European regimens of enoxaparin. Safety of the drug was found to be excellent, with no demonstrable cardiovascular or hepatic effects and no statistically significant increase in major bleeding. A pooled analysis of data collected on the patients from the four RECORD trials revealed rivaroxaban to be the first antithrombotic agent to demonstrate superiority over another antithrombotic (enoxaparin) in reducing symptomatic VTE and all-cause mortality. While there was a significant difference in the composite safety endpoint of major and clinically relevant nonmajor bleeding in the pooled analysis with the use of rivaroxaban compared with enoxaparin, there was no significant difference in major bleeding or in any other bleeding.Keywords: rivaroxaban, venous thromboembolism, hip replacement, knee replacement