ULTRASOUND SURVEILLANCE FOR ASYMPTOMATIC DEEP VENOUS THROMBOSIS AFTERTOTAL JOINT REPLACEMENT

Prospective data on 202 consecutive patients who had a total of 123 to tal hip and ninety-four total knee arthroplasties were collected from two university medical centers. The findings of routine surveillance f or deep venous thrombosis performed with ascending contrast venography were compared with those of surveillance with duplex ultrasonography complemented with color-now Doppler imaging. All of the studies were p erformed between the third and seventh postoperative days. Of the 202 patients (342 extremities) who were examined, fifty-five (27 per cent) were found to have deep venous thrombosis; fifty-two (95 per cent) of the thrombi were in the calf and three (5 per cent) were in the proxi mal veins. All of the thrombi were clinically asymptomatic and all wer e nonocclusive, allowing passage of contrast medium around an intralum inal filling defect. Duplex ultrasonography with color-flow Doppler im aging correctly identified two of the three proximal thrombi and five of the fifty-two thrombi in the calf (sensitivity, 10 per cent). The s ensitivity for the detection of thrombi in the calf was zero of sixtee n at one of the institutions involved in the study and 14 per cent (fi ve of thirty-six) at the other. There were two false-positive findings on ultrasonographic examination; one involved a proximal thrombus and one, a distal thrombus, We believe that the interinstitutional variab ility and insensitivity of duplex ultrasonography with color-flow Dopp ler imaging for the detection of asymptomatic deep venous thrombi in t he calf after total joint replacement make it unreliable as a routine surveillance tool after total hip or knee arthroplasty.