Clinical effectiveness of low-level laser therapy as an adjunct to eccentric exercise for the treatment of Achilles’ tendinopathy: a randomized controlled trial. Tumilty S, McDonough S, Hurley DA, Baxter GD.
From the Abstract
To investigate the effectiveness of low-level laser therapy (LLLT) as an adjunct to a program of eccentric exercises for the treatment of Achilles’ tendinopathy.
Randomized controlled trial with evaluations at baseline and 4, 12, and 52 weeks.
Both groups of participants performed eccentric exercises over a 3-month period. In addition, they received either an active or placebo application of LLLT 3 times per week for the first 4 weeks; the dose was 3J per point.
Baseline characteristics exhibited no differences between groups. At the primary outcome point, there was no statistically significant difference in VISA-A scores between groups (P>.05). The difference in VISA-A scores at the 4-week point significantly favored the placebo group (F(1)=6.411, sum of squares 783.839; P=.016); all other outcome scores showed no significant difference between the groups at any time point. Observers were blinded to groupings.
The clinical effectiveness of adding LLLT to eccentric exercises for the treatment of Achilles’ tendinopathy has not been demonstrated using the parameters in this study.
This study was interesting for a lot of reasons, and it turned out to be a lot more of an investigation, work, and writing compared to what I expected before reading. The first thing that I found interesting about this study, is because it found low level laser therapy (LLLT) ineffective for tendinitis. This result tends to back up the comments from quackwatch.com author Stephen Barrett, who thinks that LLLT doesn’t help treat any condition.
Secondly, at 4 weeks out, the placebo/sham treatment group improved MORE than the laser group, which was the same thing researchers commented on in the Anodyne study for neuropathy. I expect worse healing rates for both studies are likely just bad luck/chance/coincidence, but had chance gone the other way, I would bet dollars to donuts that the pro laser folks would be trumpeting the “positive trends” that didn’t quite reach statistical significance. In the case of this study, the worse outcome at four weeks did reach significance, which makes you go hmmm.
The third thing that caught my attention, is that the LLLT treatment and research seems really contentious. I expect the yeah sayers to blow off negative findings like this study, by likely saying the researchers are biased, however, the primary author in this paper, Steve Tumilty, really looks like he was a true believer. Tumilty did a pilot study in 2008 that also found no significant differences, and in 2010 he was the primary author on an extensive review and meta-analysis on LLLT for tendinopathy, which I thought was fairly biased in favor or laser therapy being effective in spite of clearly conflicting research. In his review he noted that 25 trials of laser therapy and tendinopathy, that 12 trials showed positive effects, while 13 didn’t. Apparently, they hadn’t seen Ben Goldacre’s Ted Talk about publication bias in medical research in which Ben shows when there is an apparent even split in the research, the truth is often much worse, as both researchers and journals only like to publish positive findings, while negative findings often just get trashed. Subsequently taking only the positive trials and averaging the improvements, like Tumilty did in his review, is something I would give the stinkeye to. And doing so, it only came to an average pain reduction of 13.6 mm on a 100 mm pain scale, which on a 1-10 point pain scale corresponds to decreasing pain just 1.36 points, which sounds like much ado about nothing. Anything that over several weeks of treatment that drops my pain only about 1 point, that’s likely psychological anyway, isn’t something I’d want to pay for, which is probably why a number of insurance companies also refuse to pay for it.
Fourth, in Tumilty’s review he went on and on about the correct parameters being necessary for the LLLT to be effective, and noted in this paper that his pilot study (which also failed to show a treatment benefit from LLLT) might have used too intense a light, and that his pilot study had been criticized for that, for their laser parameters being too intense. Because of these criticisms, he decreased the laser intensity for this study to be right in the middle of the “World Association of Laser Therapy” guidelines. What happened, you may ask? Turns out that other LLLT practitioners criticized their laser for being too light. I guess sometimes you can’t win for trying.
Fifth, the eccentric exercise program (Alfredson’s protocol), 6 sets of 15 reps every day morning and night, showed immediate benefit that appeared to be steady and linear improvements up until 12 weeks when the exercises were discontinued. Once discontinued, the gains were good, but they mostly stopped with there still being some residual treatment. Tendinitis/tendinopathy is one of my pet areas, so I have reviewed Alfredson’s papers and even did his protocol in my office for a while before deciding that I thought 6 sets of 15 twice per day is overkill (not that it doesn’t work), but realizing that I think 3 sets of 15 works just as well. Later, I discarded the eccentric only exercise, not that it didn’t work, but because concentric exercise was found to benefit tendons too, and more conventional exercises (heavy eccentric and concentric exercise) are superior. Eccentric only exercise is just so 1990s. Anyway, what I thought was interesting and relevant to all exercise programs, which all seem to work to greater or lesser degrees, is that if you stop doing them and still have symptoms, even if lesser, you are likely going to stop improving. For instance, if you have tendinitis and after 12 weeks you are 80% better, you might want to keep up your exercise program until your are 100% better, or else that nagging 20% might still be there a year later.
Regardless, I remain pretty skeptical of the whole laser thing. I mentioned in my last blog that when laser therapy was performed on me, I couldn’t feel a thing, good or bad, such that if I was blindfolded, I wouldn’t even know the machine was on. This leads me to believe that maybe it’s like TENS/EMS, where early on there were a lot of studies going back and forth as researchers, physical therapists, and sports/strength coaches learned how to set up the machines so they will work. It also makes me think that perhaps it’s more like ultrasound or spinal manipulation/mobilization, where no matter how they slice it, the benefits just aren’t there to be found or so minimal as to just not matter.
I also want to say hat’s off to Steve Tumilty and his fellow authors. I thought they had a fair amount of bias going in, but they designed a great study with a placebo/sham device that had both subjects and researches agnostic as to the which was the real device until the end. They also published their paper with findings that went, seemingly at least, against their interests. Of course, at the end they called for more research to be done, so hope springs eternal. I just hope it’s not funded by government (meaning our) dollars.
Thanks for reading my blog. If you have any questions or comments (even hostile ones) please don’t hesitate to ask/share. If you’re reading one of my older blogs, perhaps unrelated to neck or back pain, and it helps you, please remember Spinal Flow Yoga for you or someone you know in the future.
Chad Reilly is a Physical Therapist, obtaining his Master’s in Physical Therapy from Northern Arizona University. He graduated Summa Cum Laude with a B.S. Exercise Science also from NAU. He is a Certified Strength and Conditioning Specialist, and holds a USA Weightlifting Club Coach Certification as well as a NASM Personal Training Certificate. Chad completed Yoga Teacher Training at Sampoorna Yoga in Goa, India.