DOC » #356 What is periosteal reaction in a stress fracture

#356 What is periosteal reaction in a stress fracture

Today on the Doc On The Run Podcast we’re talking about periosteal reaction in a runner with a stress fracture.

In this episode, we’re talking about something called a periosteal reaction. This is one of the things you may have seen on an x-ray report or an imaging report of some kind if you got a stress fracture and went to get x-rays of your foot, or your doctor read the x-ray report to you. 

A lot of times I get people who call me for telemedicine visits, and they’re a little bit confused about what that really means, because it is a weird term, periosteal reaction. I’m going to try to make it simple and help you understand.

There are lots of different things that can cause this thing that is called a periosteal reaction, everything from bone tumors to all kinds of other stuff. It doesn’t really matter, bone infections, all different things that irritate the bone can cause this thing on an x-ray that is referred to as a periosteal reaction. Well, here’s what it really means. 

You have a bone in your foot, let’s say your metatarsal bone where you’re more likely to get a stress fracture, and you have a covering of the bone called the periosteum. It’s a fibrous layer that covers and protects the bone, and when it gets irritated, it actually starts to react. When it reacts, a couple things can happen. For example, if you have fluid accumulating between one layer and another, it will swell outward, and it makes a little shadow on the x-ray. That’s one of the first things that you can see when you get a stress fracture.

Most of the time when runners have a stress fracture, they think they have a stress reaction or they think they’ve had a stress response, and they go get x-rays, most of the time, nothing shows up at all. It may confuse you why it is that a doctor would ask you to come back four to six weeks later and repeat the x-rays of your foot to try to tell what’s going on, because you think, “Well, you took an x-ray before and it wasn’t broken, so why would you do that again?” Well, the periosteal reaction is part of the reason why. 

Sometimes when it’s been anywhere from a few weeks to a couple of months after you have had an injury that we think of as a stress fracture, you can get a periosteal reaction that shows up on the x-ray.

What you actually see is that, if you have the bone and it gets irritated and you have this sort of swelling around the bone, and then it starts to ossify, it turns into sort of a white lump around the bone. That’s where you actually have a bone callus that’s starting to form. 

But, what precedes that is this thing called periosteal reaction, where you have this little shadow around the bone. You don’t see a crack in the bone, you don’t see a break in the bone. The bone’s straight, the bone looks normal, other than this little cloudy, hazy area right around where the bone has been irritated. That irritation is the periosteum or the covering of the bone that’s been irritated, and that is what we see on an x-ray that the radiologist or your doctor calls a periosteal reaction.

If you have a periosteal reaction, it doesn’t mean there’s a crack in the bone, but it does mean that you’ve had irritation to the bone. Now, obviously your doctor is going to make sure that you don’t have other things like a bone tumor or a bone infection or something worrisome. But, in most runners, this is pretty simple. 

You ramp up your activity, you get pain in a specific place. We look at you, we poke on it, we push on it, it hurts, and surprise, surprise, we take an x-ray and you can find a periosteal reaction. Well, that is not there initially. If you go run 50 miles today and your foot hurts tomorrow, and the next day you go get an x-ray, you will not see a periosteal reaction. You will not see anything. But, if you go back in, say, two months or something, it’s very likely that you would see a periosteal reaction.

But, there’s a very wide timeframe from less than a couple of weeks to actually more than several weeks before the periosteal reaction shows up on an x-ray, or you see a bone callus forming on the x-ray where you’re actually getting calcium deposited in that area, that little hazy cloud around the bone. 

It’s not something I do as a general routine, because I think if you look at your foot, you poke around on your foot and you can diagnose it clinically, which is what the doctor does anyway when they get an x-ray and your x-ray is negative, when there’s nothing on the x-ray and you have a stress fracture, well, I think that that’s good enough in most cases. 

If your history matches the story of a stress fracture, most doctors, I think, will basically say, “You have a stress fracture, but in four to six weeks when we x-ray it again and then it shows proof of your stress fracture, then we can definitively say that you have a stress fracture.”

But, the periosteal reaction is one of the earliest findings that you can see on your x-ray when you have a stress fracture in one of the metatarsal bones in your foot, before you even see a crack. In some cases, the crack never actually shows up at all. 

But, that’s what a periosteal reaction is. It’s just an outward sign on your x-ray that you’ve had a lot of irritation and there’s been some swelling and deposition of calcium around the bone in that spot. It may not surprise you that if you poke around on your foot, that spot is right where it’s sore. 

That’s what a periosteal reaction is on an x-ray when you’re a runner and you have a stress fracture.

If you think you have a stress fracture, and you are trying to figure out whether or not you can run, you need to check out How to Fast-Track Your Running Injury in Record Time!

Give me 3 days, and I’ll help you figure out where you are are now, and how you can get back to running in record time. Get started for free right now!

Go to https://www.docontherun.com/fasttrack/ and grab your seat now. I’ll see you in the training.