#842 What is cortical thickening that precedes a stress fracture? - DOC

#842 What is cortical thickening that precedes a stress fracture?

What is cortical thickening that precedes a stress fracture? Well, that’s what we’re talking about today on the Doc On The Run Podcast.



I know there are a lot of different confusing things that you can hear about from your doctor or from an MRI report or an x-ray report or an ultrasound report when you’re a runner and you get some aching pain that you think might be a stress fracture. And one of those findings that may be reported on your medical imaging study is a thing called cortical thickening.

I want to explain what that is so you can better understand it in case you happen to see it on an MRI report or your x-ray report or in your doctor’s notes and you want to try to figure out what it really means. All right, let’s talk about it.

When you got a bone like let’s say the tibia, the tibia is basically shaped like this, you have the tibial plateau or the part where your, in your knee and your femur sits on top of that, and your kneecap sitting over there. And then the bone comes down and gets skinnier and then it widens again to your ankle and there’s a lump on the inside of your ankle.

So, if you’re looking at this from the front, this would be the left because your right one would be over here and then you have the fibula bone on the outside, your talus bone sitting in here. And then your heel bone is underneath that. The cortex of the bone is the outer edge of the box. So, if you looked at a tube, let’s say look at a pipe, the cortex is this outer shell.

The cortex, if you look at it straight in, this is what the cortex would look like. It would be this thick rim that’s solid all the way around. If you look at it in this direction, like this way, well, this is what you see, you have a rim of bone on each side. If you’re starting to get a stress fracture or stress reaction before a stress fracture, you get inflammation within the bone because the bones getting stressed and let’s say it’s getting stressed in this area.

Well, it’s getting stressed because you’re applying too much stress to it. What’s your body do when you do that? Your body tries to respond by making it stronger. What happens if you use a shovel all day, if you start digging ditches, you get thickened skin to try to protect you from the friction and the abrasion of shoveling dirt all day. Right? So, in the same way that you get thickness in the skin, you get thickness in the bone when you apply chronic stress to it.

If you’re running and you think you have shin splints for you’re actually getting too much stress and you’re getting a stress reaction, your body responds by trying to make the bone thicker and that’s what you get is cortical thickening. Sometimes on an x-ray, sometimes on an MRI or a CT scan, ou can actually see that the bone is getting thicker in that area where you’re getting this increased stress applied.

All it is, is that it’s going to be the reverse color on an x-ray because on an x-ray, the bones are white, the background is black. So. you have to flip this to see it that way but basically it just looks thicker around that area. And on an MRI you’ll have inflammation within the bone and be bright white in that area. But then the bone would actually be much thicker on ultrasound, you can’t really see it so much because the ultrasound waves bounce off of the bone and don’t go through the bone so you can’t really measure the thickness on an ultrasound quite as much as you could on an MRI or an x-ray or a CT scan.

A CT scan is basically just X-rays that are done with a computer to get a very specific detail looks a lot like an MRI. But that cortical thickening you think that’s a good thing, however the increased blood flow in there can actually decrease the bone density so it gets thicker but it’s weaker. Then you start getting your crack if you just ignore it. So, that’s what cortical thickening is. Hopefully this helps you understand a little bit more about that binding on your MRI or CT scan or X-ray study that you get from your doctor when you have an overtraining injury. I

f you want to learn more about stress fractures, the frameworks I use, the way that I think about it, the process that I use, that the ways that you’ve got to the strategies that you have to apply in your case when you have a stress fracture whether you’re working with a doctor or not, you can check it out for free at www.docontherun.com/stressfracturemasterclass. So, go sign up and I’ll see you inside.