Prevention of venous thrombosis in patients undergoing major orthopaedic surgical procedures.

A summary of the relative effectiveness of the various prophylactic approaches is shown in Table 13. From this it can be seen that for studies comparing active prophylaxis with no prophylaxis, aspirin was relatively ineffective, while dextran, oral anticoagulants and low dose heparin were approximately equally effective, each being associated with a risk reduction of approximately 50 per cent. Low dose heparin and DHE showed a risk reduction of 52 per cent in one study, while LMWH showed a risk reduction of 72 per cent.