An Empirical Study Using Range of Motion and Pain Score as Determinants for Continuous Passive Motion

Abstract

The continuous passive motion (CPM) machine is one means by which to rehabilitate the knee after total knee replacement surgery. This study sought to determine which total knee replacement patients, if any, benefit from the use of the CPM machine. For the study period, most patients received active physical therapy. Patients were placed in the CPM machine if, on postoperative day 1, they had a range of motion less than or equal to 45° and/or pain score of 8 or greater on a numeric rating scale of 0-10, 0 being no pain and 10 being the worst pain. Both groups of patients healed at similar rates. The incidence of adverse events, length of stay, and functional outcomes was comparable between groups. Given the demonstrated lack of relative benefit to the patient and the cost of the CPM, this study supported discontinuing the routine use of the CPM.