Tag Archives: plantar fasciitis

Cannabis Oil for Plantar Fasciitis

There seems to be increasing advocacy for the use of cannabis oil (medical marijuana) for plantar fasciitis recently, mostly from what I can see, from those who sell it. If you hang out in some of the online communities for those with plantar fasciitis, you see a lot of very bad advice being given, mostly based on anecdotes. In the last year or so, the most popular advice was to use magnesium supplements to cure plantar fasciitis. This was all the rage for a while with an extraordinary number of people advocating its use based on it working for them (when we have no idea if it actually worked or not or if it was just a placebo or just part of the natural history or any other explanation). There is no mechanism that I could find by which it could affect plantar fasciitis. More recently, the volume of advice for the magnesium supplements has started to drop off but is being replaced with an increasing amount of advice for the use of cannabis oil to treat plantar fasciitis. Some of the testimonials are quite compelling … if they are true.

Cannabis oil for Plantar Fasciitis

I have not paid much attention to the medical uses of cannabis oil or marijuana and the evidence for that use. I do watch and read the news stories about how it should be legalized. Those news stories almost always tell a compelling story of someone who is sadly very ill and not much available to help them, but the cannabis oil did miraculous things for them. Many jurisdictions are starting to legalize it and the commercial legal sales of the product are proving quite lucrative. Personally, I have a neutral opinion on if it should be legal or not. I see the superficial arguments in news stories that it should be and see the equally superficial arguments of the dangers of it. Sound bites for the news do not lend themselves to deeper analysis, but unfortunately, play a big role in informing public opinion and inspiring politicians to act.

Given all the attention that it was getting, the strength of the arguments to legalize it and politicians who are passing laws to legalize it, I assumed that there must be some pretty good evidence supporting its use in a number of medical conditions. After all, politicians would not be legalizing it unless there is good evidence it that it helps … wouldn’t they? 😉 ?

When I started to see the advice come up to use it for plantar fasciitis, I thought I would do a hunt for the actual evidence for its use to treat different medical problems. After all, there would have to be some evidence that it cures cancer as why would there be so many claims that it did. Surely, people would not make shit up about it wouldn’t they? 😉 ?

I was genuinely quite shocked to find just how little evidence there is for the medical use of cannabis oil or marijuana to treat anything. It certainly does not cure cancer. There is a summary of the systematic reviews and meta-analyses on it at the Science-Based Medicine blog from Steve Novella (link). Yes, there are some good early results in a very limited range of medical conditions. It is very clear, however, that the claims for the benefits massively outstrip the evidence for those claims. I really was quite surprised at the lack of evidence to support its medical use (and I know I am probably going to get anecdotes in the comments below about how it worked or me … blah, blah, blah. Please do not waste your time posting a comment about that as it won’t be approved. Suggest you read this instead: But, but … it worked for me).

Back to its use for plantar fasciitis. There is no evidence that it helps (anecdotes are not evidence). There is no pathophysiological mechanism by which it could help. Plantar fasciitis is a mechanical problem. Pharmacological interventions (eg cannabis oil) do not help mechanical problems and only may mask the symptoms (which is not always necessarily a bad thing). The only way that cannabis oil could help plantar fasciitis is by helping those with a chronic pain problem feel better about themselves. It is not a treatment for plantar fasciitis.

One irony in all this is that those who are mostly advocating the use of cannabis oil, tend to be those into “natural” therapies (another bogus claim to be addressed another time) and tend to advance the argument that the “medical establishment” do not know how to treat the root cause of problems (another bogus claim to be addressed another time) who just use drugs to mask the real problem (another bogus claim to be addressed another time). Is that not exactly what they are doing in advocating cannabis oil for plantar fasciitis?

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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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