Randomized Controlled Trial of the Effectiveness of Continuous Passive Motion After Total Knee Replacement

Objective

To determine the effects of using a continuous passive motion (CPM) device for individuals with poor range of motion (ROM) after a total knee replacement (TKR) admitted for postacute rehabilitation.

Design

Randomized controlled trial.

Setting

Inpatient rehabilitation facility (IRF).

Participants

Adults (N=141) after TKR with initial active knee flexion <75° on admission to the IRF.

Intervention

Two randomized groups: group 1 (n=71) received the conventional 3 hours of therapy per day, and group 2 (n=70) received the addition of daily CPM use for 2 hours throughout their length of stay.

Main Outcome Measures

The primary outcome measure was active knee flexion ROM. Secondary outcome measures included active knee extension ROM length of stay, estimate of function using the FIM and Timed Up and Go test, girth measurement, and self-reported Western Ontario and McMaster Universities Osteoarthritis Index scores.

Results

All subjects significantly improved from admission to discharge in all outcome measures. However, there were no statistically significant differences in any of the discharge outcome measures of the CPM group compared with the non-CPM group.

Conclusions

CPM does not provide an additional benefit over the conventional interventions used in an IRF for patient after TKR, specifically in patients with poor initial knee flexion ROM after surgery.