the effect of aspirin and enoxaparin on the prevention of venous thromboembolism in patients with ankle sprain and cast immobilization: a randomized clinical trial

Background: the incidence of venous thromboembolism (vte) and its prophylaxis in patients with an ankle injury and cast immobilization are controversial. objectives: this study aimed to investigate the effect of aspirin and enoxaparin on vte prevention in patients with an ankle sprain and cast immobilization. methods: in a double-blind, randomized clinical trial, 90 eligible patients were divided into three groups: patients who did not receive the drugs (the control group), patients who received aspirin (325 mg/d) for 3 weeks (the asa group), and patients who received enoxaparin (40 mg/d subcutaneously) for 3 weeks (the enoxaparin group). after 3 weeks, the plaster was opened, and the d-dimer level was measured if there was a vte symptom during the study. otherwise, at the end of the study, the bilateral lower-limb complete compression ultrasonography (ccus) and color doppler ultrasound were used to image the lower limb venous system. results: sixty-eight patients completed the study. the mean±sd values of d-dimer in the control, asa, and enoxaparin groups were 0.33 (0.47) μg/dl (median=0.18 μg/dl), 0.32 (0.14) μg/dl (median=0.3 μg/dl) and 0.32 (0.25) μg/dl (median=0.21 μg/dl), respectively (p>0.05). the positive d-dimer was seen in 2 patients (8%) of the control group, 2 patients (8.3%) of the asa group, and 2 patients (10.5%) of the enoxaparin group (p>0.05). the color doppler ultrasound was negative in all patients. conclusion: because none of the 68 patients in the current study developed vte during our 30 days follow-up period, it seems that prophylaxis treatment is unnecessary in patients with an ankle sprain and cast immobilization. further studies on more patients with a longer period of follow-up are recommended.