Effectiveness of Continuous Passive Motion and Conventional Physical Therapy After Total Knee Arthroplasty: A Randomized Clinical Trial

BACKGROUND AND PURPOSE: This randomized clinical trial was conducted to compare the effectiveness of 3 in-hospital rehabilitation programs with and without continuous passive motion (CPM) for range of motion (ROM) in knee flexion and knee extension, functional ability, and length of stay after primary total knee arthroplasty (TKA). SUBJECTS: Eighty-one subjects who underwent TKA for a diagnosis of osteoarthritis were recruited. METHODS: All subjects were randomly assigned to 1 of 3 groups immediately after TKA: a control group, which received conventional physical therapy intervention only; experimental group 1, which received conventional physical therapy and 35 minutes of CPM applications daily; and experimental group 2, which received conventional physical therapy and 2 hours of CPM applications daily. All subjects were evaluated once before TKA and at discharge. The primary outcome measure was active ROM in knee flexion at discharge. Active ROM in knee extension, Timed "Up & Go" Test results, Western Ontario and McMaster Universities Osteoarthritis Index questionnaire scores, and length of stay were the secondary outcome measures. RESULTS: The characteristics of and outcome measurements for the subjects in the 3 groups were similar at baseline. No significant difference among the 3 groups was demonstrated in primary or secondary outcomes at discharge. DISCUSSION AND CONCLUSION: The results of this study do not support the addition of CPM applications to conventional physical therapy in rehabilitation programs after primary TKA, as applied in this clinical trial, because they did not further reduce knee impairments or disability or reduce the length of the hospital stay.