There was great hope at one time for Continuous Passive Motion
In the 1970’s & 80’s machines called CPM’s (Continuous Passive Motion) were developed to try to aid in knee replacement recovery. Doctors used CPM’s because the concept of early motion after knee replacement made sense. Since then many studies have evaluated their effectiveness. Results both in the short and long terms were controversial, conflicting and in the end unimpressive. These conclusions are not surprising. Even so you may still see CPM’s in use today by some doctors and hospitals. Drew Logue from Advanced Physical Therapy describes his own use of a CPM machine for a football injury when he was younger, and how it compares to the X10 that he uses daily with knee replacement patients in this video clip.
X10™ Computer Controlled PMKR: Pressure Modulated Knee Rehabilitation
Regaining passive range of motion (ROM). During the first few days and weeks post TKA there is a golden opportunity to take action and avoid a life-long restriction in range of motion. To take advantage of this opportunity it is necessary to extend and flex the leg with just enough pressure to naturally “pump” fluid from the periarticular tissue. This process will expel the fluid that contains the seeds (Fibroblasts) that will develop into scar tissue. The critical zone in which to accomplish this is less than one degree in size, right at the edge of comfortable movement. Applying too much pressure will move the leg beyond this small region and cause the fluids in the knee to become overly compressed, and can cause intense pain. Applying too little pressure will not move the leg enough, is ineffective in squeezing out the fluid, and is in general non-productive use of the patient’s time. Only the patient, listening to his own body, knows the maximum amount of pressure with which he is comfortable. Only with movement within these very tight angles can fluid be expelled from the region, and range of motion regained.
The X10 accomplishes this goal of productive early movement after surgery. Extremely sensitive patented pressure technology puts control over the amount of pressure exerted on the leg into the hands of the patient. The patient sets the maximum pressure he is comfortable with, and then can focus on making rapid gains in range of motion without fear of sharp or excessive pain. As the patient achieves increases in range of motion she adjusts the pressure as frequently as needed to continue to work within her own unique pain threshold. Patients do not waste their valuable rehab time with motion that has become too easy. Instead they are able to make each session on the X10 highly productive.
CPM machines do not possess the necessary technology to work within the narrow, very precise window of effectiveness, where meaningful gains in ROM can occur. CPM parameters are set by the caregiver; it is very difficult to properly set up a patient in a CPM device. The motion alternates between two fixed angles with very little opportunity for improvement. This often results in spending valuable time on ineffective movement, time that could be better applied elsewhere. There is also the potential to aggravate the knee with excessive motion beyond the pain threshold, setting back the patient’s recovery.
Regaining Strength Leads to Active Range of Motion
Achieving passive normal ROM is only the first step in a full recovery. This must be followed by muscle strengthening to achieve active ROM. The X10™ has three very important strengthening components: strength at end of stroke, eccentric strengthening, and concentric strengthening.
A) Strength at end of stroke. Watch this video animation to see this unique X10 feature in action. As we learned above, the entire weight of the leg is lifted passively by the X10 to preselected (and then adjustable) angles. The patient is encouraged then to actively extend and flex his leg muscles until the leg can be lifted off the supporting ankle pads using the patient’s own strength. The target angle is then advanced and the exercise is repeated. The leg movement is performed with no resistance from the X10. This unique feature of the X10 allows for a gentle transition from passive to active movement very early in recovery.
B) When full ROM is regained the patient can then begin eccentric, and concentric strengthening with resistance. The X10 allows this regimen to begin with as little as one lb. of resistance and can be gradually increased in one lb. increments. Therapists have referred to this as “infinitely adjustable cuff weights.”
CPM machines do not possess any strengthening protocols. They are, by definition, passive devices. Gaining ROM without a corresponding increase in strength can lead to relapses in ROM soon after therapy has concluded.
Available data identifies potential problems early. X10 patient results are wirelessly collected and made digitally available to therapists and surgeons with patient consent. Timely information reporting offers a new opportunity for corrective action to be initiated early when it is most effective and needed. This feature offers the possibility to reduce or perhaps avoid knee manipulations (MUA) in the future.
Data and Visual Biofeedback are powerful motivators. It has been shown in multiple studies (e.g. for tension headaches, chronic back pain) that tense muscles in an injured area exacerbate pain and stop movement. The same principle applies to post-op knee rehab. Beginning with the first session on the X10 Visual Biofeedback assures patients that they are in control of their movement. They will not experience unnecessary pain and they no longer have to “guard” (tense up) to avoid potential discomfort. When patients understand they can create their own range of motion gains a very tangible positive reinforcement loop is begun. The negative (fear) of pain is suppressed, and replaced with the positive (expectation) of progress. Success becomes a motivator. The X10 puts a tool in their hands to make their desire for full motion a reality.
CPM machines do not offer real-time data reporting or Visual Biofeedback.
CPM Compliance is Low: “People just do not like to use it.”
Patients almost universally dislike CPM machines; they are often compared to torture devices. Darlene shares her experience with both a CPM machine and X10 for her TKA recovery in this video.
“What I dread, more than surgery, is having to strap my leg into the continuous passive motion machine for six hours a day when I get home from the hospital. While you’re flat on your back staring at the ceiling, the monotonous motion machine bends your leg, it straightens your leg. Bend. Straighten. Bend. Straighten. Six hours of this. The police should strap suspects into these things. They’ll confess to anything.”
S. Lopez, LA Times
CPM Patient Results are Notably Inferior to X10™
The X10™ achieves the significant rehabilitation benchmarks of 110º in 3 weeks. These same benchmarks were not seen in the Cochrane Study of CPM results even at 6 months.
The promise of the CPM created a generation of surgeons who tried them out in the hope that they would help TKA patients recover more quickly to avoid the development of fibrosis and scar tissue. If these devices had worked a long list of recovery issues would have been put in check, and patient results would have improved. The CPM did not live up to these expectations.
A Note about X10™
The X10 makes good on the promise of early movement with little pain, reduction of fluids, prevention of scar tissue creation and high patient compliance. Patient results have been impressive helping X10 patients complete range of motion activities at three weeks that have not been seen at six weeks or even six months.
And click here to view and print the white paper.
2. TKA abbr. Total Knee Arthroplasty. The surgical procedure to replace the weight-bearing surfaces of the knee]/ joint to relieve pain and disability.
3. Periarticular. of, relating to, occurring in, or being the tissues surrounding a joint
4. Fibroblast. A fibroblast is a type of cell that synthesizes the extracellular matrix and collagen, the structural framework (stroma) for animal tissues, and plays a critical role in wound healing. Fibroblasts are the most common cells of connective tissue in animals.
5. Eccentric Muscle Training. This is the muscle action when the muscle fibers lengthen to lower a load.
6. Concentric Muscle Training. This is the muscle contraction when a weight is lifted.
7. Manipulation Under Anesthesia (MUA) is multidisciplinary manual therapy treatment system which is used to improve articular and soft tissue movement using specifically controlled release, myofascial manipulation, and mobilization techniques while the patient is under moderate to deep IV sedation using monitorized anesthesia care (MAC). This procedure is used by specially trained chiropractors and orthopedic surgeons as a means of breaking up scar tissue around a joint without complete range of motion.