Efficacy of fixed minidose warfarin prophylaxis in total hip replacement

OBJECTIVE--To determine whether a small fixed perioperative dose of warfarin would prevent deep vein thrombosis after total hip replacement. DESIGN--Prospective, randomised, double blind placebo controlled trial. SETTING--Winford Orthopaedic Hospital, Bristol. SUBJECTS--148 patients having primary total hip replacement. INTERVENTION--Warfarin 1 mg given daily for one week before and three weeks after surgery. MAIN OUTCOME MEASURE--Deep vein thrombosis diagnosed by the iodine-125 labelled fibrinogen uptake method. RESULTS--Deep vein thrombosis occurred in 25 (34%) of the patients given warfarin and 19 (26%) of the controls (difference 8%; 95% confidence interval -6.8% to 22.8%). CONCLUSION--Fixed minidose warfarin does not prevent deep vein thrombosis after total hip replacement.