#433 What is a posterior process talus fracture? - DOC

#433 What is a posterior process talus fracture?

Today on the Doc On The Run Podcast we’re talking about posterior process fractures of the talus.


This comes from a discussion I recently had with a runner during a telemedicine visit, and she called me for a second opinion. Now she rolled her ankle and went to the emergency room, they gave her a brace, they gave her an ACE wrap to compress it, she was told to do some exercises, and frankly she improved a lot.

She got back to running, but she’s had intermittent pain in the back of her ankle, not at the same place where she got the sprain, but she’s had this pain that’s been going on for a long time, and then she got an x-ray and someone told her she might have a posterior process fracture of the talus, but they didn’t really explain exactly what that was, and so she was told to take some time off of running for a little while and see if it improves.

Well, she asked me, “What exactly is a posterior process fracture?” Well, all right, I’ll show you. So this is a foot model here, and if you can see this, this is the talus bone, this bone right here, it’s in between, you have the heel bone that you stand on, then you have your tibia up here, and in between the tibia and the heel bone is your talus.

The  talus is sandwiched in between these two, and you can see it’s sitting there squished right in between the tibia and the heel bone. And so what does that mean? Well, the back of your ankle is the posterior aspect of your ankle, and the back of the talus is where the posterior process is. The posterior process is this big bump that you see sitting on the back of the talus sitting over your heel bone.

What’s the significance of that? Well, there’s a groove right there, and the thing that sits in this groove at the back of the posterior process, it runs right through that groove, well that’s the flexor hallucis longus tendon goes through there. And so flex means to pull down, hallucis just refers to the big toe because the hallux is actually the medical term for your big toe, and longus means that it’s long. There’s one that’s short that starts within the foot, and then there’s a long one that starts up in your leg and ends at the toe. That ones longer, so it’s called the flexor hallucis longus tendon.

Well that thing curves right down around the back of the ankle, and if you get a fracture or a crack in that part of the talus, when you roll your ankle really, really badly, well that can cause chronic pain, because what happens is that you get a little crack there, and every time you take a step, you’ve got the FHL tendon (flexor hallucis longus) going right around here and it wraps around as it goes down around the bottom of your foot, and every time you take a step and you pull down with the big toe, it actually pulls on the posterior process fracture and it moves it and that causes pain.

So they’re relatively rare injuries, I’ll tell you that, but because they’re relatively rare, they’re also sometimes missed. And I give lectures at medical conferences about subtle fracture patterns, I’ve been doing that for about 10 years or so, lecturing at medical conferences on this topic, because I did some research on another rare fracture called a Lateral Process Fracture, and in that study we actually looked at all of these patients that came into the hospitals and clinics over a three-year period, and what we found is that if a posterior process fracture was noticed on the x-ray, there was actually a statistical probability that you would also have a Lateral Process Fracture.

So unfortunately, if you have an injury and we go looking for your trouble, as soon as we find something, well, a lot of times doctors see it and they think, well, that’s the problem, and they make the diagnosis of that thing, but then they miss the other thing sometimes.

If that happens and you have chronic pain, well, you need to address it. So sometimes a posterior process is an actual fracture, and sometimes it’s a natural occurrence where the bone just hasn’t fully ossified, and technically you have this other thing called an Os trigonum it doesn’t really matter the specifics of the terms or what that means, it just means you have a natural separation of the two pieces where it never, ever completely fused together. And sometimes patients are told that they have a posterior process fracture when they really don’t.

But in either case, if your pain is on the back of your ankle and it hurts when you do stuff with your big toe, for example, if you’re doing calf raises, if you stand up on the balls of your feet and your heels are way up off the ground, then you’re having to pull hard with your big toe to maintain your balance in that position. And so when I look at a patient and they tell me that there’s pain on the back of the ankle here and I suspect maybe that’s the flexor hallucis longus tendon where it rubs around the posterior process, what I do is I basically take them and I just push up on their big toe, I put my thumb under the big toe, and then I’ll tell him to push down as hard as they can.

If they do that and they have pain in the back of the ankle, that can signify that you actually have inflammation of that tendon, or you have inflammation and irritation of the posterior process of the talus, so that’s something to think about and check.

But if you have chronic pain, if you think you have posterior ankle pain where you might have problems with your posterior process, or you think maybe you sprained your ankle and maybe something’s broken and got missed, join us for the masterclass, the web class that we do on ankle pain in runners, and I think you’ll learn a lot about some of the things you can check all on your own, and some other questions you can ask your doctor so that you can make sure that you can get that better and get back to running as quickly as possible.