Thromboprophylaxis in patients with lower limb immobilisation - review of current status.

The risk for venous thromboembolism (VTE) associated with lower limb immobilisation is unclear, owing to of a lack of evidence from studies in this patient group. However, six small, randomised control trials (RCTs), totalling 1536 patients, compared low molecular weight heparin (LMWH) with controls and showed a significant reduction in asymptomatic deep vein thrombosis (DVT) from 17.1% to 9.8%, with very low bleeding rates. This is likely to be an underestimate of the real risk reduction as most trials excluded high-risk patients from randomisation. There have been no other controlled trials in cast-immobilised patients using alternative prophylactic measures. Together with the RCTs, other cohort studies have identified risk factors that increase the risk for VTE in lower limb immobilisation. In summary, patients in lower limb cast (or brace) immobilisation should be risk assessed and those deemed high risk for VTE should receive prophylactic LMWH for at least the duration of cast immobilisation.