Factor V Leiden and the risk of proximal venous thrombosis after total hip arthroplasty.

Deep vein thrombosis (DVT) remains a major cause of morbidity in patients undergoing total hip arthroplasty (THA). Despite postoperative DVT prophylaxis, 20-50% of THA patients still develop DVT. Currently, there is no accurate way of predicting which patients will develop DVT despite standard prophylaxis. The presence of factor V Leiden is the most common cause of inherited DVT risk. It has been postulated that patients who have factor V Leiden and are subjected to thrombogenic stressors such as THA would have an increased risk of thrombosis. The factor V Leiden genotype of 36 patients who developed proximal DVT after surgery and 45 control patients who had THA but did not develop DVT was determined. All patients had had prophylaxis against thrombosis using intermittent pneumatic compression alone or in combination with warfarin or aspirin. Surveillance for proximal DVT was performed on all patients prior to discharge by duplex ultrasound. The 2 groups were similar in age, sex, and type of operation. Three of 36 study patients who had developed DVT (8%) and 2 of 45 control patients who had not developed DVT (4%) were heterozygotes for factor V Leiden; these prevalences were not statistically different. Heterozygosity for factor V Leiden is not associated with DVT prophylaxis failure in patients undergoing THA.