The role of continuous passive motion after total knee arthroplasty

The usefulness of continuous passive motion after total knee arthroplasty r emains controversial. The reported benefits include decreased rates of knee manipulation, deep vein thrombosis, and postoperative use of analgesics, a nd a greater range of motion. Other studies have reported increased wound c omplications, bleeding, and pain. Lack of consensus on the use of continuou s passive motion exists because reported studies include many confounding v ariables. Several studies have shown that continuous passive motion in the hospital decreased the rate of knee manipulation from as high as 21% to as low as 0%. Although many studies show that range of motion may improve more rapidly with continuous passive motion, the ultimate range of motion at fo llowup is unchanged. At the author's institution, continuous passive motion is used three times per day (1 hour sessions), beginning on the first post operative day, within a 4 to 5 day inpatient hospital pathway. Of 132 knees that had a primary posterior-stabilized total knee arthroplasty, seven kne es (5%) had a manipulation for failure to obtain greater than 70 degrees fl exion. No patients had major wound complications that required reoperation. There is no specific charge to the patient for the continuous passive moti on because it is included in the hospital per diem charge. The literature a nd the author's data support the use of continuous passive motion to decrea se the rate of manipulation land its costs) for poor range of motion after total knee arthroplasty. If patients follow fixed inpatient hospital pathwa ys, the length land possibly cost) of hospital stay is not changed by use o f continuous passive motion. The data on the effect of continuous passive m otion on overall analgesic use and prevalence of deep vein thrombosis are n ot clear.