Constant Passive Motion and Total Knee Replacement
Elimination of the Routine Use of Constant Passive Motion Machines following Total Knee Replacement
Orthopaedics and Rehabilitation and Rehabilitation Therapies
(Team members included MDs, RNs, PTs and a Social Worker)
A project resulting from the revision of the Total Joint Clinical Pathway
Project Summary
The non surgical subset of the Total Joint Clinical Pathway team was concerned with standardizing and improving care while trying to reduce costs and length of stay. One of the topics that came up for discussion was the use of Constant Passive Motion (CPM) machines for everyone who had undergone a total knee replacement (TKR). The literature on this subject was equivocal, with some studies suggesting that CPM use resulted in greater range of motion (ROM) either at discharge or some follow up date, decreased pain medication usage and/or shorter lengths of stay. Other studies did not support these results and found no differences in outcomes whether CPM was used or not.
The team wanted to ensure that knee ROM at discharge would not decrease as a result of not using CPMs routinely.
The team felt that there were situations where the use of CPM was warranted, however. The team established the following criteria:
- Knee flexion less than or equal to 45° by postoperative day 2.
- Intractable pain - pain not being managed by pharmacological means.
Either of these situations would result in the prescription for a CPM.
Staff and patients were educated regarding the new prescription parameters for CPM use.
In November 2000, a trial of using CPM only per specific criteria was initiated. Routine use of CPM machines was stopped.
One pre practice audit and 2 post practice change chart audits were performed and no statistical differences were found for initial or discharge ROM, or for degrees of change, with one exception. The exception shows that statistically the people from the 2nd post practice change audit had greater knee flexion at discharge than the people in the 1st post practice change audit.
Although discharge knee ROM was our main outcome measure, we collected some additional data, including the first post operative day out of bed, the distance walked at discharge, the length of stay and the discharge destination. Patients were out of bed earlier, distance walked at discharge increased and length of stay decreased from pre to the 2nd post change audit. More people were discharged directly home in the 1st and 2nd post change audits than in the pre change audit.
Although not a rigorous study, chart audits reveal that patient outcomes do not appear to have suffered as a result of the change to the pathway and, in fact, have actually improved for ROM, distance walked at discharge and LOS.
