Critically Appraised Topic
The patient who led me to pursue this question is a 64 year old female with a diagnosis of knee osteoarthritis who underwent a TKA. This patient has insufficient knee flexion ROM, pain, and has a decreased level of function.
Does CPM machine use increase knee flexion ROM, decrease pain, and increase function after a TKA?
Clinical Bottom Line
Based on the outcomes from Bruun-Olsen et al. and Beaupre et al., providing CPM in addition to standard physical therapy does not increase active knee ROM, decrease pain, or increase function. Bruun-Olsen et al. (PEDro score 8/10 with 63 subjects) determined that CPM sessions did not influence knee ROM, pain, or function compared to a control group. The most significant threats to this study’s internal validity were having more than one assessor and modifying the active exercises based on pain level. This decreased the level of standardization among subjects. Similarly, Beaupre et al. (PEDro score 8/10 with 120 subjects) determined that CPM treatments did not impact knee ROM, pain, or function compared to a control group. The most significant threats to this study’s internal validity were reassigning some subjects to the CPM group, modifying the active exercises based on patient tolerance, and poor compliance with CPM use. Based on the results of these two studies there is moderate evidence to suggest that CPM use in addition to standard physical therapy does not increase knee ROM, decrease pain, or increase function in patients with osteoarthritis status post TKA as compared with standard physical therapy alone.
Rudisile, Cheryl, "The effect of continuous passive motion on knee flexion, pain, and function after total knee arthroplasty" (2011). PT Critically Appraised Topics. 25.