DVT IN PATIENTS WITH ANKLE FRACTURES: IS THERE A NEED FOR CHEMICAL PROPHYLAXIS?

Abstract

Introduction: Several institutes in continental Europe and the US now prescribe low molecular weight heparin for patients with ankle fractures being treated in a below knee plaster cast. Jorgensen et al reported an incidence of deep venous thrombosis (DVT) of up to 20% in patients treated in a cast. However, their study included patients with variable diagnoses, ranging from tendon ruptures to fractures. The aim of our study was to assess the incidence of DVT in patients with ankle fractures that have been treated conservatively in a below knee cast.

Method: We performed an ultrasound scan on patients with conservatively ankle fractures at the time of removal of the cast. The same ultrasound technician performed all the scans. The local regional ethics committee had approved this study.

Results: So far we have performed an ultrasound scan on 98 patients with ankle fractures. We are likely to complete the study in November 2006 (120 patients). We have encountered only 2 below knee DVTs (2.04 %). None of them involved the popliteal vein. Both patients were completely asymptomatic and were full weight bearing in the cast. A repeat scan showed no evidence of progression. None of the patients had an above knee DVT or a pulmonary embolism.

Discussion: The risk of deep venous thrombosis is said to be higher in patients with a plaster cast because of the decreased ability of the calf muscles to pump the venous blood back to the heart. Though some studies have indicated an incidence of up to 20%, the incidence in our population was only about 2%Thus, DVT is a rare event in patients with ankle fractures. Though it is a serious event, its rarity does not justify a blanket prophylaxis regimen for all patients with ankle fractures.