[Prevention of venous thromboembolism after major orthopedic surgery: update and contribution of a specific synthetic inhibitor of factor Xa].

Despite widespread use of antithrombotic agents, major orthopedic surgery (total hip arthroplasty, major knee surgery, fracture of the femoral neck) still raises a high risk of deep vein thrombosis and pulmonary embolism. Proper understanding of thromboprophylaxis in orthopedic surgery requires good knowledge of the mechanisms of coagulation and the point of action of different antithrombotic agents. Sodium fondaparinux is the first synthetic inhibitor selective for factor Xa. It is composed of five saccharide units obtained by chemical synthesis, thus eliminating the risk of contamination by a pathogenic agent of animal origin and batch variability. Clinical trials using sodium fondaparinux for the prevention of venous thromboembolism after major orthopedic surgery have demonstrated its superiority over low-molecular-weight heparin without increased risk of clinically pertinent bleeding if the first injection is given at the proper time. We present the main results of clinical trials.