Progression and regression of deep vein thrombosis after total knee arthroplasty.

In this study, patients indicated for primary total knee arthroplasty were prospectively evaluated with serial ascending venography in the index extremities to elucidate the incidence, timing, and evidence of propagation or diminution of any associated deep vein thrombosis. One of 30 limbs evaluated with preoperative venography was positive. Seventy-six knees in 59 patients were evaluated with early and late postoperative venograms. Overall, 47% of limbs were positive at early venography and 54% were positive at late venography. Comparison of early and late results revealed that, in the unilateral arthroplasty group, 86% of eventually positive limbs were already positive within one day after surgery. In the bilateral arthroplasty group, 85% of eventually positive limbs and 87% of eventually positive patients were already positive within one day after surgery. Five percent of unilateral arthroplasty patients and 12% of knees in bilateral arthroplasty patients demonstrated thrombosis proximal to the deep veins of the calf at the early venogram. Late venography demonstrated thrombus formation proximal to the deep veins of the calf in 12% of knees in the unilateral and bilateral groups. No limbs with thrombi less than 9 cm in length at early venography demonstrated thrombosis in or proximal to the popliteal vein at late venography. All thromboses demonstrating propagation into or above the popliteal vein between the early and late venograms did so despite warfarin therapy that had been initiated at the time of the initial positive venogram.