Abstract

Deep vein thrombosis (DVT) occurs in over two-thirds of patients undergoing major orthopaedic surgery (for hip fracture or hip or knee replacement) unless they are given prophylaxis.¹ Low-dose heparin is the prophylactic drug most commonly used by orthopaedic surgeons in the UK;² it reduces the incidence of DVT by half and lowers the risk of fatal pulmonary embolism by two-thirds.³ Low-molecular-weight (LMW) heparins, which affect only one component (factor Xa) of the clotting cascade, were developed in an attempt to reduce the risk of major bleeding that accompanies treatment with conventional (unfractionated) heparins.^3–5 Do LMW heparins have advantages over the cheaper conventional forms?