 Despite good evidence that prophylaxis is effective, there is widespread under utilization of prophylaxis for VTE following major surgical procedures as well as medical conditions that produce weakness or prolonged bed rest. There is also good evidence that the risk of VTE continues for weeks after major orthopedic as well as other types of surgery. It is now recognized that VTE occurring in the hospital and outside the hospital setting is a single entity and that extended prophylaxis with anticoagulants reduces the risk. 