Low molecular weight heparin compared with dextran as prophylaxis against thrombosis after total hip replacement.

The effect of low molecular weight (LMW) heparin given once daily as prophylaxis against venous thrombosis was compared with that of dextran 70 in an open randomised trial of 100 patients undergoing elective total hip replacement. Four patients were withdrawn after randomisation and thus 96 were included in the final analysis. The development of thrombus was surveilled by the 125I fibrinogen test, and positive readings were verified by venography. Nine of 47 patients given LMW heparin developed thromboses (19%) compared with 18 of 49 given dextran (37%) (p = 0.09). Two further patients who received LMW heparin developed thromboses after leaving hospital (clinical signs became apparent on days 13 and 17, respectively), giving an overall rate of thrombosis in this group of 23%. Minor wound haematomas occurred in two of 47 in the LMW heparin group and three of 49 in the dextran group (4% and 6%, respectively), and blood loss, transfusion requirements, and reduction in postoperative haemoglobin concentration did not differ between the two groups. The studied LMW heparin given subcutaneously once a day was no less safe or effective than dextran in preventing thromboembolism after total hip replacement.