How can a runner tell the difference between a cuboid stress fracture and this thing called capsuloligamentous strain? Well, that’s what we’re talking about today on the Doc on the Run podcast.
If you have this pain on the outside of your foot and you think, maybe I have a cuboid stress fracture, well, maybe you do, but probably not because they’re really rare. In fact, it’s less than 1% of all the stress fractures that happen in the foot in athletes. So probably not that common. But the thing called capsuloligamentous strain, well that’s also rare and well, what is it? We’re going to talk about both.
So capsuloligamentous strain, I wrote it up here, seems like a word where doctors think they’re getting paid by the letter or something. I mean, it’s so long, it pretty much runs right off the screen, but it’s not really that complicated. I also wrote up here in plain English, joint capsule strain. So what does that mean? Well, when we think about your foot, if we look at a foot model, it’s pretty simple. You have the cuboid bone and you have a joint capsule. So the joint capsule is basically holding the fluid inside the joint on either side of the cuboid, between the metatarsals and the cuboid and between the cuboid and the calcaneus or the heel bone right here.
The calcaneocuboid joint and the met cuboid joints, you have tendons and ligaments going around the joint, but the things that really hold it together, are the ligaments. So ligament comes from ligate meaning to hold together and so the ligaments are straps of collagen. They’re basically holding in position. But let’s say you roll your ankle and your foot rolls under you while you’re running. You roll it over this way, well you stretch all those ligaments, you stretch the joint capsule, you strain those tissues and you get this aching pain kind of like an ankle sprain. It’s just a midfoot sprain around those ligaments.
Well, you treat that differently than a stress fracture. So the joint capsule strain is actually something that takes a little bit longer to heal than the stress fracture in many cases because the cuboid bone itself has a really good blood supply. So I would personally rather have a cuboid stress fracture if I knew how I caused it and could avoid doing it again, because I could get it to heal quickly and pretty uneventfully I think, with some really simple things.
One other thing you should really think about here. There are a couple of things that you could do as sort of self-treatments that can help you in terms of self-diagnosis. And what do I mean by that? Well, it’s really simple. Let’s say you have a really high arched foot, but it’s flexible, like it will collapse if you can make it, you can forcibly push your arch down by rolling your ankle in and out. One thing you could do, is if you think you have capsuloligamentous strain and you know exactly what your pain numbers are, and then what you do is you actually use some pads to try to actually relax your foot a little bit by pronating it a little bit, then that could help.
How do you do that? Well, you do it like this. You basically think about this. This is your heel. This is your shoe. And you have a shoe insert sitting in there underneath you like this. So that’s one foot. Again, that’s your shoe. And then you have your other foot and you have your heel, you have the shoe around there. So you got the outside of the shoe, sole of the shoe, and you have your little insert sitting in there.
Pronation is tilting the heel bone in that direction toward the inside, rolling it inward. And if you do that, that relaxes your foot. So how do you do that? Well, what you do is you take a wedge of material that’s thicker on the outside and thinner on the inside. And if you take a wedge of material, whether it’s felt or just a varus or valgus wedge insert, by the way, the only difference between a varus wedge, which makes you actually supinate more or a valgus wedge, which actually tilts you over in that direction, is which way you do it. So if you take this, you flip it over the other way in this side, well then it’s actually becomes a varus wedge.
But you can take some material, you can get like an insert. You can order these online where it’s basically a heel wedge or varus wedge or valgus wedge, and you put that wedge under the insert, the existing insert, the soft one that it comes in the shoe. You put it under there in your running shoe and then you try it out. And if it actually feels way better, you’ve actually taken some of the stress and strain off of those ligaments and you know that that’s better. If it makes you worse, you’re more likely to have a cuboid stress fracture because when your foot pronates, it puts more pressure on the cuboid. It relaxes the ligaments, but it squishes the bone. So just using a wedge like that to actually try to reduce the stress on the ligaments by applying more stress to the bone, can actually help you tell the difference between the two. So again, if you use the wedge, that will work.
Another way to do it is to run on the road on the opposite side. So if you’ve been running on the road with your foot tilted like this and your other foot tilted like that and it’s underneath you, you’re on the road and it’s tilting you. If it’s all started on one side after you did a whole bunch of training on the road and you have high arches and you’re facing traffic and your left foot is sloped downward toward the road and you’re running with the cars coming toward you so you don’t get hit by one of them, well, that actually that extra supination from the road being sloped under your left foot might be leading to this capsuloligamentous strain.
So what you do is run on the opposite side of the street with your back to traffic. Pray you don’t get hit by a car. And when you run on the opposite side, it actually does the same thing. Use the road to pronate your foot underneath you. So then if you’re running with your back to traffic, your left foot is actually pronated a little bit. It relaxes the ligaments. If that’s better, more likely to be capsuloligamentous strain. If it’s worse, it’s worse because the pronation is squishing the cuboid and irritating the cuboid stress fracture.
That’s one of the other ways that you can tell a little more information to make sure you’re moving in the right direction. But again, if you’re not sure, can’t figure it out yourself, then get some help, talk to an expert. But you got to know the difference between these two to make sure you’re doing the right thing and you’re treating it appropriately.
So what does it really mean? Well, when we look at your foot, if you’ve got the heel bone sitting back here, the front of the heel bone or the calcaneocuboid joint, this is the tail sitting on top of there. And the cuboid though, is over here like that. The cuboid’s the thing we’re talking about. When you get a stress fracture in the cuboid, you get inflammation within the cuboid and it hurts. It’s sandwiched in between the fifth metatarsal, the fourth metatarsal, which applies stress to the cuboid in that direction and then the heel bone applies stress in that direction.
When your foot collapses, for example, like if you’re running on the slope of a road and the slope of the road is pronating your foot and flattening your arch out, it actually pushes your toes to the outside as you run, and that compresses the cuboid and if you do it over and over and over, it can actually lead to a stress fracture in the cuboid. If you’re doing something like jumping or CrossFit where you’re doing box jumps or you’re doing lots of jumping rope or something like that, you can get a stress fracture in the cuboid, but they are pretty rare with pure runners doing running activities.
Now, if you strain the foot, if you running and you trip in a pothole or you catch it on a root when you’re running, you do something that actually folds your foot over in an irregular way, you could get an injury to the cuboid, but you could also just sprain the ligaments on the top of the joint and get inflammation and pain. When we look in your foot from the top, what we’re talking about is you’ve got the metatarsal bones, again, the fourth and the fifth metatarsal bones lining up with the cuboid here, and then it lines up with a heel bone on the back. And so if the ligaments that connect these things on the top of your foot get overstretched and strained to the point that you basically have a sprain of the midfoot, like it could be the calcaneocuboid joint, it could be the fourth met cuboid joint, it could be the fifth met cuboid joint. It could be any of those.
But if you stretch those tissues and you get a strain, well that’s what we call a capsuloligamentous strain. So you’ve stretched the ligament and you’ve stretch the joint capsule together. You’ve strained both, and it hurts. Okay, so what can you do about it? Well, let’s say that you have this capsuloligamentous strain because your foot’s really, really, really supinated. Now, this is more common in people that have what we call a cavus foot. So the way Doctor Scheer, God rest his soul, wonderful man, taught me biomechanics, he actually said it’s really simple. A normal foot has a normal arch. A cavus foot has a very high arch, and the way you can as a student remember the difference between a regular foot, a flat foot and a cavus foot, is that a flat foot is like a pancake that’s pes planus, plain like flat like the plains. A cavus foot has like a cave underneath it. That’s a cavus foot. And a regular foot is a regular foot. But cavus foot has really, really high arch.
When you have really high arches, it actually tends to stretch the cuboid joint ligaments more than if you have a flat foot or you have a normal arched foot. So if you have a very, very high arch, you’re more likely to get this capsuloligamentous strain around the cuboid anyway. So an x-ray will not really show you a stress fracture in the cuboid most of the time. An x-ray will not show you the strain of any of these ligaments, not the calcaneocuboid ligaments, not the met cuboid ligaments, none of it. All it does is it shows us and the doctor may say, Oh, well, we can see the structure of your foot if we get an x-ray. Well, yeah, I can see the structure of your foot by looking at that cavus thing right there anyway. I don’t need an image of your foot in order to see that. I don’t need an x-ray to see that. I can see it from across the room when you’re walking barefoot.
So if you know have really high arches, you don’t need x-rays to see if you have high arches. So if you’re trying to rule out odd things, might be able to get that. But most of the reason that to get an x-ray in this case, if you have one of these two injuries and you’re trying to figure out which one it is, whether it’s a stress fracture or a strain in these ligaments, is so that you can justify getting an MRI.
Most insurance companies will not pay for your MRI unless you’ve already had x-rays. So if you called me and we were trying to figure out over a webcam, which one of these things you had and you wanted to get imaging and you didn’t have insurance, I would say skip the x-rays. Why waste the radiation? Why waste the money? Just get the MRI and I would write an order for your MRI. You get the MRI and we’d go through it on screen share, look at all the images, talk about it and see what the difference is. The difference you see on the MRI is that with the imaging of a stress fracture in the cuboid, this is totally different color. When the bones are white, the cuboid looks black when it has a stress fracture, and on another set of images where all the bones look black, it’s white when it has a stress fracture.
It looks totally different than the normal bones when you have a stress fracture in the cuboid. Now, if you get that MRI and the bone looks normal, it looks the same color, same brightness, everything as the neighboring bones, but the surface of it has changed in terms of its coloring and its brightness or its signal change, as we say in terms of medical terms for what it looks like on an MRI, if it looks different around the joint ligaments, then we know you have this capsuloligamentous strain and you would do some different stuff to protect it and let it heal.
But you’ve got to know what the right thing is to do. Again, the MRI can be helpful. You can’t get that without talking to a doctor in most cases, but it’s pretty easy to arrange if you go see your doctor, If you call somebody for a second opinion like me, who can order that thing for you, I order them in California and Texas, and you’ve got to make sure that you get on track so that you actually pick the right diagnosis, you don’t treat the wrong problem, and you get back to running as quickly as possible. That’ll help you more than anything else.
Now, if you like this episode, please like it, please share it, and I’ll see you in the next training.