Deep-vein thrombosis and continuous passive motion after total knee arthroplasty.

Seventy-five of 150 consecutive patients who underwent total knee arthroplasty had routine physiotherapy and seventy-five had continuous passive motion of the lower limb that had been operated on as well as routine physiotherapy. A pulmonary embolus did not develop in any patient, but about 40 per cent had thrombosis in the veins of the calf, whether passive motion had been administered or not. Radiographically, the deep-vein thrombosis was seen to extend into or proximal to the popliteal vessel in 5 per cent of the patients in each group. Sex, age, obesity, or a history of hypertension or diabetes did not influence the incidence of venous thrombosis, but there was a higher incidence in patients in whom cement was used for fixation of the total knee components, irrespective of the use of continuous passive motion of the limb.