Today on the Doc on the Run podcast, we’re talking about tibialis anterior tendon lengthening for chronic fifth metatarsal stress fractures.
I had somebody ask me a question that I never would have guessed I would have got. This is about a surgical procedure called a tibialis anterior tendon lengthening in order to address a situation where they had the same stress fracture more than once. So, let’s talk about what happened. When we look at your foot, I’m not an artist, I’m a podiatrist. So, forgive me if this drawing is not so great.
But basically, here’s your foot. You have the heel bone back here, you’ve got the talus sitting on top of the heel bone, the tibia or shin bone sits on top of that. You have the navicular and the cuboid, and the cuneiforms and the fifth metatarsal bone actually sticks out more over here. And then you have the first metatarsal bone going here and third, fourth metatarsals over there and so on.
You have a muscle that is on the front of your leg, on the front of your shin or your tibia and it is called the tibialis anterior and what it does is it attaches on the inside of your foot. So, the muscle is up here, and you can feel it if you sit there and you put your foot on the floor and you pull your toes up toward your nose with your legs straight, you’ll see a muscle bulge out on the front of your shin just below your knee. That’s on the front of your shin, so that’s the front is anterior. So, this is the tibialis anterior because it’s in the front muscle.
Now, it has a tendon. That tendon comes down and attaches about here. So, the tendon attaches the muscle to the bone here. If you get a chronic fifth metatarsal avulsion stress fracture where you’re getting too much of tilt of the foot outward and so if you think about this, if we look at your foot from the front where this is your leg, this is your big toe, second toe, third toe, fourth toe, fifth toe, and that bump on the outside where your fifth metatarsal base is, if you have too much pressure on it, that is because the tibialis anterior is pulling up in that direction too much.
If this pulls up too hard over there, it ends up pulling your foot into this sort of position and that puts the base of the fifth metatarsal on the ground when you run because your foot is effectively tilted over too far. So, there is a surgical procedure called a split tibialis anterior tendon transfer. That’s one of them. There’s a couple of different ways to do it, but it’s a specific procedure that’s designed to reduce that excess pull in this direction.
What we do is we actually go in and we take the tibialis anterior, we split it, and we pull it up and we move it someplace else and attach it to a different location so that it has less pull. So, it has some pull here, but we move some of it over there. We basically divide it and split it so that it changes the amount of pull of your foot coming up. Because if again, if your tibialis anterior, when your foot comes off the ground, if you look at it, the tibialis anterior is the primary muscle that pulls your toes up toward your nose, the most powerful one. And if you look at it, your heel is like this and your forefoot is like this, but as your foot comes up, it tilts a little bit.
The other day I was casting somebody for custom orthotics, and I had to explain to him to relax because when he was pulling his foot upward and you could see the tibialis anterior sticking out on the front of his leg, meaning that he was firing that muscle. I said, look, man, when you do that, it’s tilting your forefoot relative to your rear foot. That’s going to get captured in the cast and that’s going to screw this all up.
When you pull upward, it puts more pressure on the outside of your foot at the base of the metatarsal and can lead to stress fractures. So, if you have a very high arch, your foot is supinated, you’re not pronated, you don’t have a flat foot, you’re more prone to get this problem. So, one of the surgical procedures for addressing somebody that has really high arches where their feet really tilt outward is to take part of the tibialis anterior tendon, split it, and then move it. We relocate it, put in a bone anchor so that it will still pull up, but it pulls differently, pulls in a different location.
Very interesting that somebody found this and wanted to ask this question because you’d have to do a lot of digging to find this procedure, first of all, and it’s not usually done for runners. It’s usually done for people that have a really bony, what we call cavus foot or super high arch foot, and they’re getting pain on the outside of their foot and maybe even getting stress fractures there, but they’re not runners.
Why would I worry about that? Well, the pros is that yes, it will actually decrease the amount of pressure for sure on the outside of the fifth metatarsal if you do that procedure. There’s nothing free in medicine. For every good thing, there’s a bad thing. So, the good thing, less pressure on the outside of the foot. The bad thing, it pulls upward, generally speaking, with less force.
We hear the term surgical precision, and we really do try to do things as precisely and anatomically correct as we can when we’re in surgery, but it’s never as good as the original. And when we do that, you may have problems pulling your foot up as much as you used to, and you may get stiffer after the surgery while it’s healing because you’re going to have to hold it still so you don’t pull the repair apart, take the tendon transfer and start, you know, if you’re walking onto the time on it right away, you might actually pull the anchor out or dislodge the tendon transfer that we put in a different place to try to adjust your forefoot relative to the ground.
If that happens and it doesn’t actually pull up as much, either because the tendon transfer has made the tibialis anterior weaker or because your Achilles tendon, which is the largest one in your body, gets stiffer after the surgery while you’re recovering, then the net result is that you have what we call an Aquinas deformity, meaning that your foot doesn’t come up as much. It may then mean that you’re going to get different issues when you run. Like if you run on trails and you’re running uphill, you have to pull hard to clear the ground as you swing through because you’re running uphill. And if you do that because you had this surgery, you can start getting maybe hip pain because your hip flexors in the front are pulling up a lot harder to try to clear the ground. So now you have a different problem.
You don’t really want to pursue surgery unless you really have to have surgery, but that should help you understand at least a little bit about it. I don’t know if you think about this. I would be surprised if you’re watching this right now actually thought of this. I know lots of doctors watch these videos and then call me and tell me that they found something interesting. So, my guess is more doctors are going to watch this video than patients. But if you’re into running biomechanics and you’re trying to figure this stuff out and somebody mentioned this surgical procedure to you, maybe this will help you understand it a little bit better.
If you want to learn more about stress fractures and particularly the fifth metatarsal stress fractures, the actual strategies I use with runners who get stress fractures so they can get back to running without things like complicated surgical procedures, I will teach you all those strategies. The same ones I actually shared today at the International Foot and Ankle Foundation meeting in Las Vegas, where I was giving a lecture on stress fracture paradigms for runners.
I’ll share those with you for free at the Stress Fracture Masterclass. You can come sign up and join me at www.docontherun.com/stressfracturemasterclasss. So go sign up and I’ll see you in the training.
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