Summary
Objectives: To assess the efficacy and safety of low molecular weight heparin (LMWH)
as deep venous thrombosis (DVT) prophylaxis following total knee arthroplasty. Data
sources: Medline 1986 to June 1997, Embase, and manufacturers were used to identify
randomized controlled trials. Review methods: Trials included were randomized studies
of LMWH with routine radiological screening for DVT. Placebo or active controls were
included. Two reviewers independently screened trials for inclusion, and assessed
their quality. Pooled relative risk estimates of DVT and proximal DVT rates were calculated
using a DerSimonian and Laird random effects model. Sensitivity of the results to
the type of control used and the quality of the trial was assessed. Results: The relative
risk of DVT for a patient given LMWH is 0.73 (95% CI 0.66 to 0.80) when compared with
patients treated with adjusted dose heparin or warfarin controls. The relative risk
for proximal DVT is 0.58 (95% CI 0.38 to 0.90). The relative risk of pulmonary emboli
in the LMWH group was 0.55 (95% C.I. 0.20 to 1.57). No excess of bleeding was recorded
in the LMWH group. Conclusions: Low molecular weight heparin is more efficacious than
either adjusted dose heparin or adjusted dose warfarin, when used to prevent DVT and
proximal DVT following total knee arthroplasty.
