The Scientific Truth Behind The CPM Machine
Since the advent of knee replacement doctors understood that the operation eliminated arthritic pain, but did not restore patient to full function. Restoring full function required therapy post surgery. We present here the truth behind the CPM with the hope that patients who are presented with the CPM as an option for post surgery recovery will be empowered to make an informed decision on whether or not to use it.
In 1978 the only device that was available to hasten recovery was the CPM Machine.
Initially it appeared effective when used as an alternative to putting people in a cast for weeks.
However, when surgeons stopped putting patients in casts, and compared the use of the CPM to un-casted patients it no longer appeared to be effective.
There was no other device so doctors continued to prescribe the CPM, even though the scientific literature did not support its use, because there was nothing else. Study after study was conducted to reveal the truth behind the CPM machine some of which we share with you here.
Conclusions from Recent Medical Literature
Below, we show quotes from recent scientific studies that concluded that the CPM Machine has no positive effect on post-knee surgery recovery.
The Cochrane Review
The Cochrane Review, a rigorous study of multiple studies by a premier research organization, Cochrane Database
2014 Feb 6;(2):CD004260. doi: 10.1002/14651858.CD004260.pub3.
“AUTHORS’ CONCLUSIONS: CPM does not have clinically important effects on active knee flexion ROM, pain, function or quality of life to justify its routine use.”
If you still are considering using the CPM Machine for your recovery, please read the following. We have provided references so you can verify the incontrovertible evidence against now discredited device for yourself.
Herbold, Bonistall, Blackburn
Effectiveness of continuous passive motion in an inpatient rehabilitation hospital after total knee replacement: a matched cohort study.
PM R. 2012 Oct;4(10):719-25. doi: 10.1016/j.pmrj.2012.07.004. Epub 2012 Sep 6
“RESULTS: The outcome variables of 61 matched pairs of CPM users and non-CPM users were reported. No statistically significant differences were found in any of the outcome.”
Cigna Coverage Policy
Continuous passive motion following total knee replacement: a prospective randomized trial with follow-up to 1 year.
Knee Surg Sports Traumatol Arthrosc. 2006 Oct;14(10):922-6. Epub 2006 Feb 1
“CONCLUSION: No significant difference was observed between groups at all time intervals for each outcome variable … range of motion or reported pain.”
Danielle Tabor, MS, CNRN
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.
Orthop Nurs. 2013 Sep-Oct;32(5):261-5. doi: 10.1097/NOR.0b013e3182a3016
“AUTHOR’S NOTE: 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.”
Use of drop and dangle rehabilitation protocol to increase knee flexion following total knee arthroplasty: a comparison with continuous passive motion machine.
J Pak Med Assoc. 2015 Nov;65(11 Suppl 3):S32-4
IN SUM: D&D protocol provided more passive knee flexion than the use of CPM in the first two days after TKA and at discharge.
Effect of continuous passive motion on knee flexion range of motion after total knee arthroplasty
J Pak Med Assoc. 2015 Nov;65(11 Suppl 3):S32-4
RESULT: Continuous passive motion had no influence on knee range of motion after total knee arthroplasty at the time of discharge.
University Hospital Maastricht
Effectiveness of prolonged use of continuous passive motion (CPM), as an adjunct to physiotherapy, after total knee arthroplasty.
BMC Musculoskeletal Disorders20089:60 https://doi.org/10.1186/1471-2474-9-60
“AUTHOR’S CONCLUSION: Routine use of prolonged CPM in patients with limited RoM at hospital discharge should be reconsidered, since neither long-term effects nor transfer to better functional performance was detected.”
Chiu, Ng, Tang, Yau
Review article: knee flexion after total knee arthroplasty
Journal of Orthopaedic Surgery 2002: 10(2): 194–202
“IN SUM: Assessments before the operation, at 6 weeks, 23 weeks, 26 weeks, and 52 weeks postoperatively did not show any difference in the average knee flexion capacity among the 3 groups. Consequently, the authors did not support the use of short-term CPM after TKA.”
Orthopedic Clinics of N. America
Enhancing Recovery After Total Knee Arthroplasty
Orthopedic Clinics of North America, The, 2017-10-01, Volume 48, Issue 4, Pages 391-400, Copyright © 2017 Elsevier Inc.
“IN CONCLUSION: Although continuous passive motion (CPM) has been thought of as a method to improve range of motion after TKA, it has not been shown to improve range of motion, clinical outcomes, or discharge disposition.
In addition, it results in increased cost and has been associated with more persistent knee swelling. Because of these factors, its use has declined in recent years.”
Hospital for Special Surgery
Prospective Randomized Trial of the Efficacy of Continuous Passive Motion Post Total Knee Arthroplasty: Experience of the Hospital for Special Surgery.
J Arthroplasty. 2015 Dec;30(12):2364-9. doi: 10.1016/j.arth.2015.06.006. Epub 2015 Jun 1
“RESULT: Length of hospital stay was significantly less for the group who did not receive CPM. The use of CPM had no clinically relevant benefits with respect to AROM, clinical outcomes or discharge disposition and was associated with a cost of $235.50 per TKA.”
Finally, after more than 40 years there is something else… the X10.
The patented X10 is not built around the same mechanism as a CPM. The X10 is an advanced computerized machine, that increase both range of motion (ROM) and leg muscle strength (the CPM did not even attempt strength) and it does in a way that does not cause pain. It provides the most effective therapy we know of.
Your surgeon already knows the truth behind the CPM machine as the studies above are well regarded and very well known. As orthopedic surgeons become aware of the revolutionary X10 they are rapidly adopting it.
The X10 Meta-Blog
We call it a “Meta-Blog” because we step back and give you a broad perspective on all aspects of knee health, surgery and recovery.
In this one-of-a-kind blog we gather together great thinkers, doers, writers related to Knee Surgery, Recovery, Preparation, Care, Success and Failure. Meet physical therapists, coaches, surgeons, patients, and as many smart people as we can gather to create useful articles for you. Whether you have a surgery upcoming, in the rear-view mirror, or just want to take care of your knees to avoid surgery, you should find some value here.