Prevention of venous thromboembolism with aspirin following knee surgery: A systematic review and meta-analysis

Venous thromboembolism (VTE) is a well-known complication following orthopaedic surgery. The incidence of this complication has decreased substantially since the introduction of routine thromboprophylaxis. However, concerns have been raised about increased bleeding complications caused by aggressive thromboprophylaxis. Attention has grown for aspirin as a safer thromboprophy-lactic agent following orthopaedic surgery. A systematic review using MEDLINE, Embase and Web of Science databases was undertaken to compare the effectiveness of aspirin prophylaxis following knee surgery with the current standard prophylactic agents (low molecular weight heparin [LMWH], vitamin K antagonists and factor Xa inhibitors). No significant difference in effectiveness of VTE prevention was found between aspirin, LMWH and warfarin. Factor Xa inhibitors were more effective, but increased bleeding complications were reported. As evidence is limited and of low quality with substantial heterogeneity, further research with high-quality, adequately powered trials is needed.