Therapeutic Ultrasound for the Shoulder: Is there evidence?
THERAPEUTIC ULTRASOUND IN THE TREATMENT OF SHOULDER CONDITIONS: IS THERE ANY EVIDENCE?
Perhaps one of the most grossly overused and potentially misrepresented modalities used on patients is ultrasound. Unfortunately, many of my PT colleagues use this a ton and the chiropractic community abuses it as well. Little evidence supports its use. The FDA has approved low intensity pulsed ultrasound for bone healing after fractures and I have seen this work. Many studies have shown that pulsed ultrasound helps facilitate healing in injured medial collateral ligaments in the knee. Studies on ultrasound are “all over the map” in regards to treatment parameters, treatment times, treatment size area, etc. So what gives?
First, ultrasound works in a few ways. Continuous ultrasound is uses sound waves and heat to heat tissue. The sound waves are proposed to help with increased collagen synthesis (the stuff that primarily makes up our organs, ligaments, joint capsules), improving bone healing and in some instances, break up bone in tissue that shouldn’t have it (read on). Some have also proposed that it helps with nutrient diffusion in tissues because it essentially “opens up the cells” through the wave vibration which allows tissues to be penetrated with nutrient rich blood. Again, these things are believed to happen, but they haven’t been proven unequivocally.
Well, a recent study in Physical Therapy investigated using ultrasound to treat shoulder conditions. It was a systematic review, meaning that the authors essentially found every study possible and analyzed the data. Researchers found that there were benefits in using ultrasound for calcific tendonitis and that in studies showing that it was of benefit, treatment times were longer and more energy delivered per session. Basically, we need longer treatment times and a little more “juice” from the ultrasound.
For what it’s worth, calcific tendonitis is a process by which bony deposits form in the rotator cuff in response to injury. It is painful and limits function because bony tissue is in what should be purely tendinous tissue. Ultrasound may work by helping to break up the bony deposits through vibration of the sound waves. Most of the studies showing poor results had short treatment times and weak intensity from the ultrasound.
So what can you do if your therapist is using ultrasound to make sure it’s being used right? First of all, don’t let them do it more than 5 treatments if you aren’t noticing any changes. Secondly, and this is the key – make sure the treatment area is no larger that 2x the size of the ultrasound head!! This is my biggest pet peeve with people that use ultrasound. Intuitively, it should make sense to you that the larger the area treated, the more the wave diffuses and loses its effectiveness. Third, I suggest that your therapist use the 3 MHz frequency instead of the 1 MHz. Some studies have shown that 1 MHz actually results in less positive effects because so much of the wave is refracted off of the bone (1 MHz is used for deeper tissues historically). Last, make sure your treatment time is roughly 10-15 minutes.
Alexander LD et al, Phys Ther, 2010; 90: 14-25