Tag Archives: neurology

Platelet Rich Plasma for Plantar Fasciitis – writing about something I know nothing about…

Platelet Rich Plasma for Plantar Fasciitis


I have to be honest and admit that the use of platelet rich plasma (PRP) for plantar fasciitis is something that I have had no more than a superficial interest in. I pretty much scanned the abstracts of the studies and systematic reviews as they are published of it in this thread and the one comparing it to other interventions on Podiatry Arena. I also note comments in social media on it from those whose views I respect. From my superficial understanding, it works, it does not work, it works, it does not work … a lot of the studies that compare it to other treatments do not do the “other” treatment very well (ie wrong dosing), which can easily bias the study to PRP being better. Some of the comments in social media from people who I consider real experts, especially in the context of tendinopathy are that it does not work, yet a lot of people claim it does. Yes, I know that the “plantar fasica” is not a “tendon” and it may or may not be appropriate to translate “tendinopathy” research to “plantar fasciitis” (not that this stops people doing so or not doing so if the research on it matches their pre-conceived biases!).

I do note that the most recent meta-analysis of PRP concludes that it is as effective as other interventions. I do note when I glance at most of the studies that do get included in the systematic reviews and meta-analyses that there does appear to be some methodological issue with almost all of them, so how much weight should be given to them?

Anyway, as you can see, I really do not know much about PRP for plantar fasciitis except for that superficial understanding of the evidence and listening to those whose views I normally respect. However, my interest in PRP picked up a week ago when at the AAPSM meeting in San Francisco in which there was a presentation on the topic.

I stand to be corrected and have not verified this by searching the literature, but he said two things in the presentation that I think I interpreted correctly that really got me interested:

1) Local anaesthetic deactivates the PRP. What this means is that if a lot of local was infiltrated in the area vs just a small superficial amount prior to the PRP injection then this may affect the clinical effectiveness of the PRP. Of more importance, if a lot of local was used in a study of PRP, then that would bias the study in the direction of the PRP not being effective. That study is unlikely to be excluded from a meta-analysis or systematic review if all the other methodological issues are sound (ie sample size, blinding etc).

2) The effectiveness of PRP in tendons (he did not mention this in the context of the plantar fascia) might depend on the leucocyte concentration in the PRP. I have not checked the literature on this, but I think he said the PRP works in tendons if the leucocyte concentration is high and does not work in tendons if the leucocyte concentration is low. If this is correct, then it is easy to see how a study could be biased against it working if the leukocyte concentration is low. Those low leucocyte concentration studies will be included the in the meta-analyses and biases them in the direction of PRP not being effective for tendons.

Again, I no expert (or even have a little knowledge) in this and I only superficially aware of the literature in this, but even I can see the issues here. The use of small vs high amounts of local before injecting the PRP and the effectiveness of high vs low concentration of leukocytes in the PRP are issues that need to be resolved and potentially could have huge impacts on the results of individual studies, systematic reviews and meta-analyses; and, more importantly, policy recommendations and clinical guidelines that grow out of that. I see this as a serious problem.

It may well be that if studies are repeated on the local anaesthetic dose and the leucocyte concentration that it does not affect the outcome and then will not bias the systematic reviews and meta-analyses. It is, however, an issue that should be resolved.

Does PRP work for plantar fasciitis? My conclusion is that we do not yet know.

Does this sound familiar? Its the same issues I wrote about on foot orthotic dosing … or am I just being biased or using the logical fallacy of ‘special pleading’?

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Craig Payne

University lecturer, runner, cynic, researcher, skeptic, forum admin, woo basher, clinician, rabble-rouser, blogger, dad. Follow me on Twitter, Facebook and Google+

Restiffic Foot Wrap for Restless Legs Syndrome

Restless legs syndrome is a common problem, too often without a satisfactory solution. Because of this, there is plenty of bad advice being given and many different treatments options available; many of which are underpinned by testimonials and anecdotes and with poor or no science or data. When extraordinary claims are made, then extraordinary evidence is needed to support the claims.

Recently a press release was put out for a study on a new product, The Restiffic foot wrap for use in restless legs syndrome. At last count, Google could find the press release carried on 27 websites. One thing all the websites had in common was that they just parroted the press release and demonstrated a total lack of critical thinking skills. I have already raised some issues with the press release elsewhere, but to reiterate:
restiffic
1. The press release was based on an uncontrolled study in a low impact factor journal. The study did claim to have control group, when it did not. It did have a reference group from unrelated studies on a totally different population that they wrongly did a statistical analysis on. What the study really was is uncontrolled single arm analyzed with a within groups analysis. These types of uncontrolled studies tend to massively overestimate effect sizes and we have no idea if all the effect obtained was not due to placebo or natural history. The claims in the press release and claims made by the company are not supported by the evidence. A properly controlled study is needed to base the claims on.

The reason you need a control group with the same characteristics as the intervention group is that in the statistical analysis of the data you subtract the placebo effect of the control group from the treatment effect in the intervention group to get what is the real effect of the intervention. That is why uncontrolled studies massively overestimate effect sizes (like the above study). I know they claimed to have a “control” group, but they did not. They just used a reference group from a meta-analysis of other studies to compare their outcome to. The placebo effect in restless legs syndrome is strong, so some of the effect, or a large part of it, or all of the effects in this study in question could have been due to placebo. We will not know as they did not have a properly constituted control group.

2. The company behind the product have been claiming that the product is FDA approved, when it is not. The product has simply been cleared as safe by the FDA and to make the claims that it is approved is likely to get them in trouble with the FDA as their guidelines are clear. The company does appear to have backed way from these claims recently.

I have nothing against this product and have full empathy with those who have restless legs syndrome and the lengths they often go to, to get relief. I just do not like seeing them targeted in marketing by products that offer a “cure” based on no science or nonsense.

The Restiffic Foot Wrap may turn out to be an effective product and I hope it does for those who have restless legs syndrome. The company should be applauded for supporting the above study which a lot of restless legs syndrome approaches are not subjected to, but more is needed. I just object to it being marketed implying that it is FDA approved and the strength of the claims as to how effective it is based on an uncontrolled study.

Kuhn, P., Olson, D., & Sullivan, J. (2016). Targeted Pressure on Abductor Hallucis and Flexor Hallucis Brevis Muscles to Manage Moderate to Severe Primary Restless Legs Syndrome The Journal of the American Osteopathic Association, 116 (7) DOI: 10.7556/jaoa.2016.088

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Craig Payne

University lecturer, runner, cynic, researcher, skeptic, forum admin, woo basher, clinician, rabble-rouser, blogger, dad. Follow me on Twitter, Facebook and Google+