Peroneal tenosynovitis in runners: symptoms and recovery

You're listening to the Restoring Human Movement Podcast, and now your host. Hey everyone, it's Dr. Mandy Riehl for the Restoring Human Movement Podcast. Thank you for joining the Movement Movement. I am driving right now, so please excuse the audio. Might be a little bit hazy here, but again, I am your handy running injury expert here at Performance Place and at Finish Line Personal Training. I'm going to be talking about a case study from myself from a couple years ago when I completed a 50k race that I hadn't really trained for and found myself with a foot-slash-ankle injury. Now, that foot-ankle injury wasn't super standard, but I have had a case of it before.

It was called peroneal tenosynovitis. So peroneal, meaning the peroneal muscles. There's two, well, technically there can be three. There's peroneal brevis, peroneus longus. And some people have peroneus tertius. I do, but it's essentially a vestigial muscle. It doesn't really do much, and a lot of people don't even have it. This is similar to the palmaris longus tendon, if y'all know about that. If you're curious, basically put your thumb and your pinky together and flex your palm towards your inner forearm. And if you see a big tendon right in the middle of your wrist pop up, that's your palmaris longus.

Congratulations, you have it. Not everyone does. So peroneus tertius is similar in the fact that it's vestigial. It doesn't do a whole lot, but it is present in some people. That's kind of besides the point, but peroneal tenosynovitis. And then we get to this tenosynovitis part. So tenno meaning tendon, sino meaning synovial, so synovial fluid, which can be found inside of tendon sheaths, and vitis, which is inflammation. So this is an inflammation inside of the tendon sheath itself. Now, the tendon sheath is kind of like a sausage casing around the tendon, but the tendon should be able to glide freely within the sheath itself.

So if you have tenosynovitis, what you might feel is this really sudden stabbing pain in the area of a tendon associated with movement. So at total rest, it usually doesn't hurt. It might have a dull ache with it, some underlying pain, but it's quite minor compared to when you move it, and it hurts like hell. So for me, when I finished this 50k, I think I had tweaked my ankle just a little bit, not enough to hurt during the race, but it was probably mile five of a 50k, which is around 31 miles. And when I finished the race, my foot had been hurting for maybe the last eight miles or so. And once I cooled down a little bit, I immediately texted Sebastian.

I said, oh my God, I think I have a stress fracture. It hurt to that degree. I was up in San Francisco, and I remember we were walking around, looking for food, and I could bear weight on it, but very painfully, and I was limping quite a bit. For me, there wasn't any visible inflammation. So this is one of the few itises that do not have visible inflammation. This can happen with tendonitis as well, but tendonitis is kind of a catch-all term in the more colloquial sense, whereas in the clinical sense, it's more of an acute inflammation. But there was no visible swelling. There was no bruising.

Just pain on the outside of my ankle, kind of near the outside ankle bone. And it really hurt when I flexed and pointed my foot. That was the main painful movement there. So with that, I texted Sebastian. I said, I have a stress fracture. You need to evaluate it when I get back home. He, wisely, was just okay. And it wasn't a stress fracture. It was tendonitis. But the kind of recovery from that was a week of rest, which I was planning on taking after that race anyway. But I had to keep moving during that rest period. So it wasn't total rest. It wasn't sit-on-the-couch rest. But I wasn't running yet.

But it was more, I was going on walks to tolerance. And by tolerance, I mean it was staying under like a 3 or 4 out of 10 pain level. And it wasn't getting worse throughout the walk. In reality, after that first couple days, as I walked, it actually got better and better during the walk. And it would maybe flare up a little bit afterwards once I cooled down and wasn't moving for a while. But it never flared up worse than it was before I started the walk. And that's key for relative activity. So there was relative rest. Again, I was moving. I was walking. I believe I did a little bit of lifting where I didn't really have to bend my foot much.

So usually hinge motions, deadlifts, RDLs, things like that are great to do in the meantime. And then gradually I got back into running. And once my foot was able to tolerate running, it got better really fast. So even though this is pretty painful and again, like right after the race, I could barely walk on it and I was scared. It was a stress fracture. The movement is key to actually squishing, so to speak, the inflammation out of the tendon sheath. Some people also experience this in their thumb. Lonevitis, if you look it up, is usually talked about in the hand or the thumb. And people can experience locking where the joint is put in a position, the tendon is usually in a short position.

So if you think bicep tendon, that would be if you're doing a bicep curl, that ending position is in a short position. So if that locking is going to happen, oftentimes it's in the short position and it just locks, right? You can't really move it. It just gets stuck there. And that hurts. But I didn't actually experience that with the peroneal tenosynovitis. I'm not entirely sure why. My theory would be that the tendon is fairly long in comparison to the tendons around the thumb. And that length may help move the inflammation around in the tendon sheath versus if it's a short tendon sheath, perhaps the inflammation doesn't have that many places to go.

That's completely a theory. That's just my thought. I'm not sure if that's objectively correct. But for peroneal tenosynovitis, I haven't heard many cases of it locking. Though again, if you look up tenosynovitis, that will be on the checklist. Just a reminder, too, diagnoses can come with some of the symptoms and not all. So if you're like me and you go to Dr. Google to look up, hey, my knee hurts or my foot hurts or whatever hurts and, you know, what is it? Some of the diagnoses don't check all of the list. So for tenosynovitis, again, locking pain with movement, it can be very sharp pain. It may not check all of those boxes, but this is why you go to a medical professional and get it evaluated.

And again, just a reminder, too, I'm a real person. I'm not just a podcast person. I treat ultra runners, trail runners, and distance runners at Performance Place. Check out the link below if you need some help. But past that, the peroneal tenosynovitis, at the end of the day, was due to me under training and maybe that little ankle tweak in the middle of the race. Typically, in the middle of a trail race, if you have a little ankle tweak and you're strong and you're trained, it's no big deal. It's just going to pass and it's not even going to hurt. But if you are under trained and your tendons aren't exposed to that level of load and you're already pushing your body to its, well, frankly, past its limit in a training sense, it can cascade into something like this.

And I had learned that the hard way. And thankfully, I was running fully back in two weeks. Again, the first couple runs were uncomfortable after a week of relative rest, but it got better and better and I was fully back after two weeks. Now, I have had a patient that had tenosynovitis in their peroneal muscles and they didn't do anything, like total rest, no relative rest. They didn't do anything for a few weeks. I think I want to say it was three or four weeks and it still hurt like hell when they came in to see me. So movement is absolutely key to this. I would argue that movement is key to any tenosynovitis because you need to get that inflammation out of the tendon sheath itself, which is only really going to happen with movement since it's trapped in there.

And the tendon can move around in that sheath to a degree. That's where the pain comes from if it's really stuck and really swollen and it'll help squish it out once it's tolerable. If you have any questions or you've experienced this yourself, give us a call or email us. Our email is info at p2sportscare.com. This isn't a super common diagnosis, so I'm always curious to hear y'all's experience with it and what it might have felt like to you and what helped it. Until next time.