Why the CPM Machine Failed to Solve Knee Surgery Recovery

The Continuous Passive Motion machine (CPM) does not increase a patient’s range of motion or strength. It does not or shorten recovery. In doesn’t help, and can often hurt a patient’s knee.
The X10 Knee Machine is not a CPM machine. It relies on an entirely different mechanism. It does not hurt to use, and is the only machine that builds range of motion and strength. The X10 reports patient data wirelessly so surgeons and other professionals can monitor daily progress.

The CPM machine is a story of failed early research and technology. If you are interested in the enormous body of research about the Continuous Passive Motion machine click here (as compiled by orthopedic surgeon, Dr. David Halley).

The Great Hope of the Late 1970’s

Robert Salter (MD) and John Saringer (an engineer) commercialized the CPM in 1978. The original idea was to stimulate cartilage production in knees, at which the machine succeeded extremely well in rabbits, but not for humans. Human knee cartilage has no blood supply and consequently cannot grow back.

Range of Motion

Soon patients began using the Continuous Passive Motion machine to increase knee range of motion. Most research studies, before 2005, compared the range of motion of patients who used the CPM to patients who had only bed-rest. When that comparison was made it looked as though the CPM had a tremendous effect. However, after 2005, the experiments on the CPM evolved. These studies compared people who used the CPM to those who did not use the CPM, but who also were not confined to their beds. The non-CPM control group could move about.  None of these studies showed that the CPM could increase range of motion better than those who simply moved about. The results were remarkably clear: the CPM does not increase knee range of motion.

The CPM lost its allure in a single decade. Surgeons who took a close look at the research stopped using the device. It did not do what was claimed.

Moving from a six-week cast to modern recovery

In the early 1970’s most civilian knee surgery patients had their knees in a cast for six weeks, and were largely confined to bed. The military not only did not cast injured knees, they immediately got patients up and moving. At that point in time the research showed that some movement was superior to no movement. Dr. Salter reasoned that if some movement was better, continuous movement would be better still, and hence the invention of the CPM.

What Continuous Passive Motion Does

Basically, the CPM flexed a patient’s leg through a prescribed arc. In order to work properly, the patient was to lay absolutely still for up to 20 hours a day. The purpose behind laying still was to preserve the alignment between the patient and machine. However, simply moving a patient’s head disrupted the alignment, and to make matters worse, the machine itself moved over the surface of the bed. Even bolting the machine down did not solve the alignment problem. Because of the alignment problem patient’s legs only experienced 68% of the prescribed arc. And the CPM was painful for most patients. Lastly they were not very compliant.

Surgeons who have kept abreast of the research, as a rule do not prescribe the CPM, though some will admit that they offer it if patients ask for it.

X10: Picking up where the CPM Machine left off

Today there is a new class of recovery machines called PMKR. This stands for Pressure Modulated Knee Rehabilitation. A PMKR machine, like the X10, delivers the results that were hoped for with the CPM: fast recovery, fast return to work and life, avoidance of complications, beating the dangers of scar tissue development. Many thousands of patients have used PMKR, and as surgeons learn about it, they are quickly adopting this technology. For more about the X10 visit: What is the X10.

X10 and MUA (Manipulation Under Anesthesia) Recovery

X10 patients are more than 20 times less likely to need an MUA. While 28% of the typical knee replacement MUA patients need a second MUA, we are unaware of any our nearly 5,000 patients, who started their recovery on the X10, who have had a second MUA. Why risk it?

Our clinical team is ready to help you at any time with your knee surgery recovery. Call us at 1-855-910-5633. Email us at info@x10therapy.com. Schedule a 15 minute call with us: click on the Want to Learn More? image on this page.