Prevention of deep vein thrombosis in orthopedic surgery.

In the absence of thromboprophylaxis, venous thromboembolism (VTE) affects about 50 to 80% of the patients after total hip replacement (THR), total knee replacement (TKR), or hip frac- ture surgery. Since stratification of patients in those who will become symptomatic and those who will not, is not possible, primary high risk thromboprophylaxis should be provided to all pa- tients undergoing major orthopedic surgery of the lower extremity. Various non-pharmacologic and pharmacologic thromboprophylactic measures have been evaluated. With regard to pharmacolog- ic thromboprophylaxis unfractionated heparin has now almost completely been replaced by low molecular weight heparin (LMWH) for VTE pro- phylaxis. The use of acetylsalicylic acid for throm- boprophylaxis in patients undergoing major or- thopedic surgery of the lower extremities is not recommended. The optimal beginning of LMWH thromboprophylaxis is either 2 hours preopera- tively or 6 to 8 hours postoperatively. Extended thromboprophylaxis (beyond 7 to 10 days after surgery) is recommended for high-risk patients. New antithrombotics, such as fondaparinux or (xi)melagatran, significantly reduce the risk of asymptomatic but not of symptomatic VTE com- pared to LMWH. In the light of other potential side effects (e.g., an increased bleeding risk) and high costs the role of these new drugs in the pro- phylaxis of VTE in patients undergoing major or- thopedic surgery of the lower extremities remains to be established.