SIGNIFICANCE OF DEEP VENOUS THROMBOSIS IN THE LOWER-EXTREMITY AFTER TOTAL JOINT ARTHROPLASTY

Thromboembolic disease continues to pose a significant risk to patient s undergoing total joint arthroplasty, but the clinical significance o f a deep venous thrombosis (DVT) in the postoperative period remains c ontroversial. This report reviews the outcome of 920 patients undergoi ng prospective obtained venograms after total hip and total knee surge ry. Six hundred two patients also obtained postoperative ventilation p erfusion scans (V/Q). All patients received one of the following forms of prophylaxis: aspirin (79%), warfarin (16%), or low-molecular-weigh t heparin (5%). The results show that 39% were without any clot, 36% h ad small calf thrombi, 19% had large calf thrombi, 2.5% had popliteal thrombi, and 3.8% had femoral thrombi. Calf thrombi occurred almost 2. 5 times more frequently after total knee arthroplasty than total hip a rthroplasty (67% versus 27%), yet the incidence of pulmonary embolism (PE) is the same in both groups. Intermediate or high probability V/Q results occurred in 103 patients (15%). There was a positive associati on between the size of a clot and the likelihood of an intermediate- o r high-probability V/Q scan. Thromboembolic events resulted in five sy mptomatic PE (0.5%) and two deaths (0.2%), one in the hospital on warf arin, and one as an outpatient on aspirin. From these data, the author s conclude that calf thrombi by themselves do not place a patient at r isk and are not accurate markers of a patient being at risk. Larger cl ots have a greater likelihood to embolize, but the size of the clot th at is clinically significant is undetermined. A significant chance of a PE after discharge from the hospital warrants some form of continuin g prophylaxis in outpatients.