Consecutive patients undergoing
knee arthroplasty or tibial
osteotomy at four participating hospitals received either
enoxaparin, 30 mg subcutaneously every 12 h (n = 66) or an identical-appearing placebo (n = 65). All study medications started the morning after the operation and were continued up to a maximum of 14 days. Patients underwent surveillance with 125I-fibrinogen leg scanning and impedance plethysmography. Bilateral contrast venography was performed routinely at Day 14 or at time of discharge, if sooner.
Deep vein thrombosis was detected by venography in 35 of 54 patients (65%) in the placebo group and in 8 of 41 patients in the
enoxaparin group (19%), a risk reduction of 71%, P less than 0.0001. For the entire study group,
deep vein thrombosis was detected by either venography of non-invasive tests in 37 of 64 patients (58%) in the placebo group and in 11 of 65 patients (17%) in the
enoxaparin group, a risk reduction of 71%, P less than 0.0001. Proximal vein
thrombosis was found in 19% of the placebo patients and in none of the
enoxaparin patients, a risk reduction of 100%, P less than 0.001.
Bleeding complications occurred in 5 of 65 patients (8%) in the placebo group and in 4 of 66 patients (6%) in the
enoxaparin group, P = 0.71. There were no differences in the amount of blood loss, minimum
hemoglobin levels and number of units of packed red cells given between the two treatment groups. We conclude that a fixed dose regimen of
enoxaparin, started post-operatively, is an effective and safe regimen for reducing the frequency of
deep vein thrombosis after major knee surgery.