Orthopaedic surgery as a model for drug development in thrombosis.

Venous thromboembolism after total hip replacement or total knee replacement represents a significant complication of these surgical techniques, with profound clinical and economic consequences. As the detection of venous thromboembolism is particularly difficult in this setting, its prevention with thromboprophylactic agents is the most appropriate strategy. The anticoagulants currently used for thromboprophylaxis in orthopaedic surgery are injectable low-molecular-weight heparins (LMWHs) and oral coumarin derivatives such as warfarin. Orthopaedic surgery provides a good model with which to investigate the antithrombotic potential of novel agents, because of the relatively high venous thromboembolism event rates, and the opportunity to detect and quantify bleeding. This paper provides an overview of the clinical burden of venous thromboembolism in orthopaedic surgery and the benefits and limitations of current thromboprophylactic modalities. In addition, geographical differences in treatment regimens regarding the choice of agent, timing of initiation and duration of thromboprophylaxis, and how these influence the incidence of venous thromboembolism, will be discussed.