Total knee joint replacements (also called total knee arthroplasty, or TKA) is a common surgery to ease the pain of arthritic knees. TKA used to require a long hospital stay with plenty of bed rest. These days, patients who get a TKA begin physical therapy right away, and they leave the hospital within a week. There is no time for bed rest in this new style of treatment. Research has consistently shown that getting a move on speeds up the healing process and increases the knee’s range of motion faster.
But questions remain as to what kind of mobilization is best. Most hospitals use a continuous passive motion (CPM) machine. A CPM device straps to the leg and constantly bends and straightens the leg while the patient lies in bed. CPM is expensive therapy that demands lots of medical attention and bed rest. There is no clear research to prove its effectiveness.
Slider boards are another form of passive mobilization. The patient’s heel is hooked into a cup on a board that slides freely up and down in a frame. The knee bends and straightens just like with the CPM machine, but the patient is actively part of the treatment. The boards can be used sitting or lying down. They are also cheap and require little medical help to use.
This study divided 120 patients who had gotten a TKA into three groups. While in the hospital, the first group did the standard exercise program along with an average of 1.7 CPM treatments per day. The CPM sessions lasted a little over an hour and a half. The second group did the standard exercise program and slider board sessions. They did an average of 1.7 slider board sessions each day, for an average time of 16 minutes per session. The third group did the standard exercise program only. The standard exercise program involved working with a physical therapist for about 30 minutes, including ice treatments before and after exercising.
All three groups went through the same series of tests before TKA, before discharge from the hospital, and three and six months after surgery. They filled out questionnaires about their general health and their knee pain and function. They also did tests of knee range of motion.
The results showed no differences between any of the three groups in any of the measurements three and six months after TKA. All together, 96% of subjects reported less pain and 82% reported better function at six months. Although this study showed less range of motion at hospital discharge than other studies of CPM machines, knee range of motion was comparable at the three- and six-month follow-up tests.
The results made the authors question the use of both CPM and slider boards. The conclude that, as long as patients who have had TKA just get a move on it, the extra treatments don’t add anything to standard exercises.