Should I get an MRI of my healing plantar fascia tear before I start running? Well, that’s what we’re talking about today on the Doc On The Run Podcast.
This is a great question I got from a runner during a recent telemedicine visit. And this was a runner who actually called me for a second opinion because she had a tear in the plantar fascia. It felt like it was healing and she wanted to get back to running. And she was really hoping to get some kind of real positive affirmation or confirmation that she was okay to run and wanted to know whether or not she should get a repeat of the MRI that she had previously that actually discovered she had a partial tear in the plantar fascia and not just plantar fasciitis.
Now, this is a great question and it’s a completely reasonable one. In fact, I just discussed this with doctors last week at the International Foot and Ankle Foundation meeting, where I was actually lecturing on runners heel pain. And this is one of the things I discussed in detail with them.
The first thing is that I understand you want to get some test like an MRI or an X-ray or something that actually shows you that it’s definitely healed and ready to go. But there are a couple of problems with the MRI’s that you really have to understand, if you’re a runner who wants to get back to running quickly and you don’t want to just test the water, so to speak, but trying to run to see if it’s going to feel okay.
So here’s a couple of reasons why you really should not get an MRI to assess or confirm that your plantar fascia is completely healed and it’s completely okay for you to run without any additional evaluation or any additional consideration.
The first thing is that, when you get an MRI, depending upon where you have the study done, sometimes the slices or the sections that the MRI imaging actually pictures and takes images of your foot, well, those pictures sometimes can be three and a half or four millimeters apart. And if you actually look at that on a ruler and then compare it to your foot, three and a half to four millimeters is a long way in the foot. And even though you have close to 200 images on an MRI of your foot, there are very, very few of those images that are actually in the region where you actually have a tear in the plantar fascia when the slices are that far apart.
So if you have a little bitty tear in the plantar fascia that isn’t caught by the slice of the image that’s at every one of those intervals, like three and a half or four millimeters, then it looks like it’s healed when it’s actually not. So that’s the first reason is that you could get what we call a false negative, which means it falsely shows that nothing is happening when you actually have a tear that just wasn’t picked up by the MRI.
The second reason is that when you have healing of the plantar fascia and it’s in the phase of remodeling, you have to have inflammation to have that process happen and so you will see on the MRI, something we call signal change, which shows more inflammatory fluid in that area that can look like a really inflamed plantar fascia. It may be part of the remodeling process but not active acute inflammation. And it can even look like you have a calcaneal stress fracture or a stress fracture in the heel bone because sometimes that edema is happening in the heel bone, right where the plantar fascia attaches.
The other thing is that you can just never ever get an apples to apples comparison with an MRI compared to one you got previously. Even if you get it at the same institution, they can never position you exactly in the same place, in the same way, in the scanner.
So again, if you have these slices that aren’t in exactly the same place, sometimes you’ll actually have an interstitial tear that shows up on the second MRI that actually was invisible on the first one. And in that respect, when you get that MRI, you may actually be doing better. You may feel better clinically or the way that we judge you in clinic when we look at you or a doctor looks at you making your evaluation, if clinically you’re doing better but you get an MRI that shows what appears to be a new little bitty tear within the plantar fascia that just wasn’t on your first image, that is going to be profoundly discouraging.
I don’t generally get MRIs for people who have a tear or partial rupture in the plantar fascia. I think there are much better ways to assess that if you’re talking to somebody who’s experienced with working with runners, they can help you figure out whether or not it’s okay for you to run without getting an MRI.
In short, no, I do not think most people who are runners who have a tear in the plantar fascia or a partial rupture of the plantar fascia should get an MRI to prove to themselves or to prove to their doctor that it’s okay for them to run. There are much better ways to go about it and the MRI has several possibilities of leading you astray.