Low molecular heparin in prevention of thrombosis in orthopedic surgery

The review encompasses all published clinical studies of prophylactic treatment with low molecular weight (LMW) heparins marketed in Denmark when used to prevent thrombosis in patients undergoing elective or emergency orthopaedic operations. In elective hip surgery, LMW-heparin was more effective than placebo in reducing the incidence of deep vein thrombosis. There was significantly better anti-thrombotic effect of LMW-heparin, given in recommended doses, than of Dextran 70. When compared to low-dose heparin, the incidence of deep vein thrombosis was lowest using LMW-heparin, but only one study found the difference significant. LMW-heparin compared to low-dose heparin in combination with dihydroergotamine showed no significant difference with respect to either effect of safety. The use of LMW-heparin as prophylactic treatment for patients with either trochanteric or femoral neck fractures is as yet not nearly so well-documented. The relatively few studies that have been carried out show large variation between the different LMW-heparins. There is need for a study comparing the effect of LMW-heparin with that of low-dose heparin in these patients, both with respect to thrombosis prevention and influence on total mortality.