An Empirical Study Using Range of Motion and Pain Score as Determinants for Continuous Passive Motion Outcomes Following Total Knee Replacement Surgery in an Adult Population

BACKGROUND: The continuous passive motion (CPM) machine is one means by which to rehabilitate the knee after total knee replacement surgery. PURPOSE: This study sought to determine which total knee replacement patients, if any, benefit from the use of the CPM machine. METHODS: 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 degrees 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. RESULTS: Both groups of patients healed at similar rates. The incidence of adverse events, length of stay, and functional outcomes was comparable between groups. CONCLUSION: 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.