What exactly is shortening of a fracture when it shows up on a CT scan? Well, that is what we’re talking about today on the Doc On The Run Podcast.
I get lots of calls from runners who need a second opinion for something like a metatarsal stress fracture. This is probably the most common thing that I get when somebody has been injured, they go see a doctor, the doctor says you have to stop running and then they call me to find out, is that really true or not? Well, that depends. In many of the cases when these runners call me, they have already had an x-ray, maybe an MRI or a CT scan of the foot, something that actually looks at it in very good detail.
In this particular case, what happened was the runner wanted to know what it meant when her radiology report said that there was five millimeters of shortening of the second metatarsal bone, the one that had the stress fracture. In this episode, I’m going to explain what that means and how it shows up on a CT scan.
If you are listening to this, hopefully this explanation will make sense. If you are watching it on YouTube, obviously it is going to be much more clearer because I’m going to have some additional illustration and some actual pictures from a CT scan that show it on the Doc On The Run YouTube channel.
In this report, what does she have? One of the first things it said is in the findings, which is where the radiologist looks through your images and looks for stuff that is interesting, said fracture the distal diaphysis of the second metatarsal bone with five millimeters of shortening.
Diaphysis is the bone, the tubular part of the bone. So, what I’ve done is I’ve taken a piece of PVC pipe to kind of illustrate this idea for you. So, the bone is cortical bone. It is like a tube, like this pipe. It is round. The hard parts on the outside, the soft spot, the medullary canal is on the inside. So, in this case, the distal means further away from you. So if this was my metatarsal bone, this part’s proximal. It is closer to me. That part is distal. It is further away from me. So, out toward the toes is the distal diaphysis or part of this bone.
What happens is it broke, right? The CT shows that there’s five millimeters of shortening. Well, how does that happen? Okay. So, you run, and you run, and you run and you get a stress fracture. It breaks. You get a crack and let’s say it doesn’t really move out of place and it doesn’t move this way. If you did it this way, it would be longer, right? So, that way is shorter. There are two ways that it can shorten and how you can get five millimeters of shortening. Five millimeters would just be measured from this edge of this bone to this edge of this bone.
Basically, just here to here is all we’re talking about. We’re talking about between the cortex, the part that should fit together like a little puzzle. So, this one would fit together about like that and when you shorten it, there’s two ways it can happen. One of them is that it breaks apart and it slides five millimeters closer like that. That is one way it’ll happen is it shortens in this direction. The other way it can happen is where it slides into itself, and it slides right inside the other piece of bone with a pointy part like that going into the bone. It slides in and it shortens five millimeters. So, either one of those two ways can happen.
In her case, if you look at it, you can see that it is sitting like this. So, on the CT scan, you can see that it is basically offset a little bit. It is not real dramatic. It is not way off like this, but it is slightly off, and it slid five millimeters shorter. So, that cannot happen. If you look at this and you see how this works is that it can sort of twist and slide in there or it can just slide side by side and get shorter.
But in either case, that shortening of the bone can’t really happen unless it displaces, meaning it moves out of place. So, if it is not displaced, it is not going to get shorter because it is in the right place. It only gets shorter in general when it displaces or moves up. The exception to that is a complicated thing when you get resorption of bone, but we’re not really talking about that because that is pretty rare.
Hopefully this helps you understand a little bit about what shortening of a metatarsal bone is when you actually have a metatarsal stress fracture, you keep running on it, you ignore it, and then it actually moves out of place, and it causes things to be a little bit worse.
That can actually delay your healing. It can also make it so that if the bone itself is shorter, then it can basically make your toe look shorter because the joint capsule moves with the displaced bone. And when it gets shorter, it makes your toe attaching to that metatarsal look like it is a little bit smaller or sitting closer to your foot than the other toes, which looks kind of weird. It is not going to kill you, but it can happen.
If you like this episode, please like it, please subscribe. If you want to learn more about stress fractures and runners, you should come check out the stress fracture masterclass. It is where I do a deep dive into all the strategies I use with runners who have stress fractures and want to get back to running as quickly as possible. It is the exact same strategies I teach to doctors when I go lecture at medical conferences. You can get it for free at www.docontherun.com/stressfracturemasterclass. So, come check it out and I’ll see you in the training.
«« #922 Is time or intensity more important after running injury? | #924 Why running is better than lunges or planks when you have a plantar plate sprain »» |