Insufficient Evidence for Routine Use of Thromboprophylaxis in Ambulatory Patients with an Isolated Lower Leg Injury Requiring Immobilization: Results of a Meta-Analysis.

Abstract

There are no generally accepted guidelines for the prevention of venous thromboembolism (VTE) in ambulatory patients requiring immobilization after an isolated lower leg injury. Our objective was to evaluate the effectiveness and safety of pharmacological interventions for preventing VTE in these patients. Meta-analysis of randomized controlled trials. We searched PubMed/Medline, EMBASE and the Cochrane Central Register of Controlled Trials for trials with random allocation of thromboprophylaxis, notably low molecular weight heparin (LMWH) versus no prophylaxis or placebo, in ambulatory patients with below-knee or lower leg (including the knee joint) immobilization. Outcome was analyzed using MIX to calculate the pooled risk ratio/relative risk (RR) for each outcome, along with its 95% confidence interval (CI). The RR of asymptomatic deep vein thrombosis (DVT) was 0.66 (95% CI 0.44; 1.02) for below-knee immobilization and 0.51 (95% CI 0.37; 0.70) for lower leg immobilization. Low molecular weight heparin versus no prophylaxis or placebo was evaluated. The incidence of symptomatic DVT and PE was too low to show any statistically significant difference between thromboprophylaxis and controls in both groups. Although only one adverse bleeding event was considered to bemajor, the RR for any adverse bleeding event was 1.94 (95% CI 1.03; 3.67). There is insufficient evidence to warrant routine use of thromboprophylaxis in ambulatory patients with below-knee or lower leg immobilization after an isolated lower leg injury. The incidence of symptomatic VTE is too low to show a relevant clinical benefit from thromboprophylaxis.