The role of continuous passive motion following total knee arthroplasty

A retrospective study of 94 knees with postoperative continuous passive motion (CPM) therapy was compared with a control group of 116 knees with no postoperative CPM following kinematic condylar total knee arthroplasty (TKA) performed in 1983. The diagnoses were similar in both groups, with osteoarthritis in 167 knees, rheumatoid arthritis in 34 knees, osteonecrosis in four knees, traumatic arthritis in four knees, and psoriatic arthritis in one knee. Average flexion at hospital discharge was 87.7 degrees in the control group and 90.2 degrees in the CPM group (p less than 0.02). Seventy-four percent of the CPM group and 60% of the control group had achieved 90 degrees of flexion by the time of hospital discharge. The number of days to achieve 90 degrees averaged 10.3 in the control group and 7.7 in the CPM group (p less than 0.001). There was no significant difference in flexion at two or three months or at one year after operation between the two groups. Five knees in the control group and one in the CPM group required manipulation. The duration of hospitalization was not significantly different between the two groups. Hemoglobin levels, operative blood loss, and transfusion requirements were not significantly different. Patients with CPM following TKA achieve motion earlier than those without CPM, but ultimate motion and complications are not affected.