Willow Curve Device for Pain: Strong Claims, Weak Evidence

willow curve

Willow Curve is advertised as the “world’s first digital anti-inflammatory device”, “a laser smart device” designed to relieve joint pain with thermal and photonic energy. It contains over 150 bio-sensory and bio-therapeutic components that continuously monitor the body’s thermal and electrical response to the device, and computer chips use that information to tailor a digital prescription on the fly. That prescription consists of “multiple energies” that change thousands of times a second.

It’s not clear exactly what the sensors sense, or how they work. It’s not clear how the device responds to information from the sensors to alter the output of heat and light, and it’s not clear how it chooses the appropriate dose for that patient. They don’t divulge information like intensity and wavelength for the various treatment protocols. They claim that the treatment “stimulates 15 bio-physiological processes for treating the joint and surrounding tissues.” Which 15 are those, exactly? They say that the Willow Curve dilates blood vessels, slows nerve response time (is that a good thing?), releases endorphins, blocks specific pain receptors, and detoxifies by removing toxic debris from the joints.

They offer no evidence in support of these claims. I tried to get clarification from the company, but they didn’t answer my inquiries.

The Willow Curve is portable and battery powered, but looks somewhat cumbersome. It is curved, and can be applied to various parts of the anatomy. It measures 6.5″x3.74″x 4.75″, weighs 2.85 pounds, and costs $599.

Red flags

There are a lot of red flags that make me suspicious that this company may not be entirely on the up-and-up. The Truth in Advertising website discovered that:

  • Several of the patient testimonials are faked: the “customer photos” are taken from stock images.
  • They claim that the device has “helped save people from invasive surgery like knee replacement.” They offer no evidence that this is true. In a video commercial, Chuck Woolery tells us that NHL Hall of Famer Charlie Sanders cancelled his knee replacement surgery after using the Willow Curve, but elsewhere on the website they say “he significantly postponed his knee surgery.” So which is it? A commenter on the Truth in Advertising website provided this additional information:

FYI Charlie Sanders died in July 2015. He had a malignant tumor underneath his knee, only discovered during his knee replacement surgery. Had he not used [the Willow Curve] and delayed the surgery, maybe he would have lived.

  • It is said to treat a long list of conditions, but there is no evidence that it has been studied for any of those conditions.
  • They claim it “has been used successfully to treat a number of conditions in thousands of hospitals and clinics nationwide,” but that seems unlikely for a device that was invented so recently, and they don’t name any of those institutions.

Toxic joint syndrome?

One of the conditions the Willow Curve allegedly treats is “toxic joint syndrome,” a condition defined in this (unpublished) article as:

a constellation of signs and symptoms associated with an unhealthy joint resulting from injury and/or disease…[such as] …pain, swelling, redness, restricted movement, clicking or crunching, a catching sensation, reduced capacity for repetitive or enduring action(s), limitation of activities, failure of the joint to perform, radiographic changes, abnormal joint fluid and arthroscopic findings.

The author is Ronald Shapiro, the researcher who did the studies cited on the Willow Curve website; and in “Part 2” of his article he joins forces with a retired doctor, Charles A. Bertrand. Bertrand graduated from medical school in 1948, so he must be in his 90s by now. He is a cardiologist who served as an expert witness in malpractice cases for over 20 years and wrote a book about being an expert witness. I wondered why he would suddenly speak out to promote a device to treat knee pain, and I then I realized that he is on the company’s medical advisory board. And Shapiro is the company’s medical director. Conflict of interest, anyone?

Part 2 reads like a commercial for Willow Curve. The only mentions of “toxic joint syndrome” on the Internet are on sites associated with Willow Curve, so it is probably a bogus diagnosis invented to help promote a commercial product.

Clinical trials of Willow Curve

There are only two clinical trials, both carried out by the company’s Medical Director, Ronald Shapiro, in conjunction with other authors, most of whom are also associated with the company.

The first trial, in 2005, didn’t actually study the Willow Curve at all: it studied a precursor device, The MedLite. The title was “Safe and Effective Relief of Knee Pain for Patients with Renal Insufficiency and Renal Failure” — but it didn’t study patients with kidney disease! The subjects were patients with chronic knee pain and normal kidneys. It was a randomized, open label crossover study comparing ibuprofen 200 mg, ibuprofen placebo, and the MedLite device. It was a small preliminary study with only 26 subjects. Patients’ self-assessment of pain with the device was not significantly different from ibuprofen or placebo. The authors said it “outperformed” the other groups, but the only statistically significant difference between the device and ibuprofen was for flexion change. There was no significant difference in extension change or change in number of steps compared to ibuprofen, although it was significantly better than placebo for extension change and number of steps. We would expect that an impressive device providing heat would outperform an inert pill.

The study was essentially negative (patients didn’t report more pain relief than with placebo) but they found a way to make it look positive. They measured what they called “objective knee improvement” by a contrived composite of objective findings and differences in total pain scores between baseline and day 6, and lo and behold! They managed to get a highly significant difference favoring the device. They waved away the fact that subjects didn’t report improvement of their knee pain by speculating that true effectiveness might be obscured by “the extremely wide variation in pain perception” among their subjects (something they had not tested for).

The second trial, in 2013, was a pilot study conducted by three members of the Willow Curve Medical Advisory Board. In my opinion, the disclosure statement fails to adequately disclose their conflict of interest. At least this study actually tested the Willow Curve device. The subjects were 69 patients with chronic knee pain, randomly assigned to 4 groups of approximately 17 patients each. The groups got either treatment with the device set to provide only dynamic kinetic thermal energy, set to provide only dynamic photonic energy, set to provide both modalities, or a disabled sham device. It looks to me like the methodology was reasonably good. The findings: the fully activated device performed better than sham. The partially activated devices trended “in the direction of improvement” compared to sham, but the results weren’t statistically significant.

I have some questions about the graphs that perhaps a statistician could answer: they threw out some of the outliers; was that legitimate? They graphed the quartile ranges, and there is considerable overlap. I suspect that if they had calculated 95% confidence intervals, there would have been considerable overlap there, too. Isn’t this an indication that a repeat study might have gotten different results?

They did an exit poll that showed patient satisfaction, but they didn’t ask whether the patients had been able to detect which group they were in. Could there have been clues like heat sensations allowing them to detect when the device was activated? Even the authors of this study pointed out that it was only a pilot study and would have to be confirmed by larger studies. And we know how often the results of small pilot studies with a high risk of bias are reversed by subsequent larger, better-designed studies.

The study they didn’t do but should have: a comparison of the Willow Curve with other devices that provide the same modalities. Are the improvements due to heat that could be provided in other ways, or is there really something special and more effective about their sensors and computer chips? I’d want to know that before I spent six hundred dollars on their product. In the Q and A section, they ask, “How does Willow Curve compare to laser units on the market?” The answer compares cost and convenience, not effectiveness.

Is Willow Curve a scam?

They ask that on their Q&A page, and their answer is a mixture of paranoia, “they laughed at Galileo” arguments, and “we have testimonials.” They say people fear what they don’t understand, and Willow Curve is so revolutionary that it scares skeptics. They compare people who question its effectiveness to the members of the British parliament in 1878 who opined that lightbulbs were a useless invention. I’m not scared at all, and I’m not calling it useless or a scam. I’m just asking to the kind of evidence any reasonable person ought to ask for before believing in the effectiveness of any new treatment or drug.

Willow Curve makes a lot of claims, but there is no credible evidence to back them up. There are a lot of unanswered questions and red flags. Even if the effect is significant, it appears to be small in magnitude. Willow Curve appears to be unlikely to cause direct harm, and I don’t doubt that anything that delivers heat might help relieve pain; but I’m not persuaded that the Willow Curve has any unique advantages over other, much less expensive products. If you can afford to spend $600 on an experiment that might have real or placebo effects, you might want to try it. They do offer a money-back guarantee. My inclination would be to stick to less expensive, more evidence-based treatments until Willow Curve has been properly tested.

This article was originally published in the Science-Based Medicine Blog.

Dr. Hall is a contributing editor to both Skeptic magazine and the Skeptical Inquirer. She is a weekly contributor to the Science-Based Medicine Blog and is one of its editors. She has also contributed to Quackwatch and to a number of other respected journals and publications. She is the author of Women Aren’t Supposed to Fly: The Memoirs of a Female Flight Surgeon and co-author of the textbook, Consumer Health: A Guide to Intelligent Decisions.

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