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July 16, 2010

Continuous Passive Motion

I've learned how to use a nifty machine. It's called a continuous passive motion machine. The purpose of this machine is to help prevent the knee joint from becoming stiff and develop scar tissue following surgery. I've seen these machines used on people who have had knee replacement surgeries and they are also used for people who have had ACL repairs.

Studies show that the use of continuous passive motion in the first days and weeks following surgery improve range and help reduce scarring (and conceivably, pain) during early healing. However, after about six weeks, it shows no advantages in knee range of motion over never having had it.

How do we use it? As PT we use a goniometer to measure the angles of the knee in extension (when the leg is straight) and flexion (when the knee is bent). So a patient may lack 15 degrees of extension, which means they are 15 degrees away from having their leg fully straight (0 degrees). And they may only have 55 degrees of flexion (90 degrees is what we look like when we sit in a chair).

So I get the patient set up in the machine and see how far they can straighten and bend their knee with the machine helping them. We want the patient to feel challenged, but no so far into discomfort that it would prevent them from sleeping. So I may start with 0 degrees to 75 degrees -- definitely a challenge! Then I watch their face and eyes closely as the machine tests their end range. Basically, they say "Uncle!" and we back the machine off 2 to 3 degrees on either end of the range. Then we run the machine through several cycles of movement making sure the patient can tolerate it.

Ideally, at patient should be able to increase their range on the machine 2 to 3 degrees every 2 days or so. Some people progress faster. Some people progress slower. Patients who opt for joint replacement surgeries have been in pain for a long time. Folks have good days and bad days. Generally they know they have a rough road ahead, but are motivated to work through the pain in order to get to the long await reward of getting back to living their life.

"Tender" days are ones where a patient's pain does not seem as well controlled. On these days, we still push them in therapy, but as therapists, we need to recognize their limits so as not to break their spirit, or encourage them to holler stop prematurely as a protective mechanism from pain, which would serve to rob them of valuable therapy. This requires trust which comes from doing what you say you are going to do. It's also important to engage the patient actively in the movement which, while painful, encourages them to take some control of the pain.

Posted by linda at July 16, 2010 12:41 PM