What causes most of the pain when you have a metatarsal stress fracture? Well, that’s what we’re talking about today on the Doc On The Run Podcast.
If you get a metatarsal stress fracture, the first thing that you’re going to notice is not that you have a broken bone in your foot, you’re going to notice pain. Typically, what happens is you notice a little bit of vague discomfort in your foot that progressively gets worse as you continue to train and run on it. And it gets worse the longer you run, and it feels worse when you walk barefoot on hard surfaces, going up and down wooden stairs, things like that.
But what really causes the pain? This is what somebody was asking me recently and what really causes most of the pain when you have a stress fracture is not that you’re moving the crack or rubbing broken pieces of bone together. Like if you break a toe and you literally snap that proximal phalanx bone in two, the edges of the bone are grinding against each other and that causes pain. But that’s not what happens with a stress fracture.
If you don’t actually have a crack in the bone, and you really have a stress reaction instead of an actual stress fracture, there’s no crack visible on an X-ray, on an MRI on a CT scan or an ultrasound study. So, since there’s no crack, you’re not getting paid because the crack in the ends of the bone at the crack are moving, that’s not what’s happening.
With a stress reaction, which is a little bit milder than what we think of as a normal stress fracture, is you have inflammation within the bone and many times specifically you have inflammation within the periosteum which is the little fibers layer covering the bone. When you get fluid in between the bone and the periosteum, it actually lifts the periosteum and when it lifts up off of the bone, you have hydrostatic pressure and you push on the foot, you move the foot, you pull on the muscles that are attaching to the bone, and it can sort of squish the periosteum, irritate the nerve fibers and cause pain.
That is also something that we can see on an ultrasound study. So, if you have an X-ray that doesn’t show anything we might be able to actually see that stress reaction evidenced by that fluid between the bone and the periosteum when we actually look at it with an ultrasound unit.
It’s really that when you’re pushing, moving and tugging it and you’re moving that fluid that’s in between the bone in the periosteum is what I really think causes most of the pain. I don’t have any research to back that up. So, I don’t have any proof of it. I’ve never cut anybody open and looked at the periosteum to see how much fluid is in there. But because I can see it on ultrasound, that’s why I think that’s what’s causing most of the pain. And when I do ultrasound on a runner who has a stress reaction, but not a true stress fracture, normally when I get right over the spot where I see the most fluid, it actually causes pain just from the pressure of the ultrasound unit itself.
If you want to learn more about metatarsal stress fractures and what to do with them, so you can actually get back to running as quickly as possible in spite of a stress reaction one of those metatarsals, you got to check out the stress fracture masterclass. You can get it for free at www.docontherun.com/stressfracturemasterclass. So, go check it out, and I’ll see you in the training.