Peroneal tendonitis (or tendinopathy) is an overuse injury that causes pain over the outside (lateral) of your ankle or foot. You have three peroneal muscles, but peroneus brevis tendonitis is the most common, followed by peroneus longus tendonitis.
In this article:
Anatomy of the peroneal muscles
How do you know that you have a peroneal tendinopathy?
Common causes of peroneal tendinopathy in runners
Top tips for treating peroneal tendinopathy
We've also made a video about peroneal tendonitis:
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Anatomy of the peroneal muscles
Both the Peroneus Brevis and Peroneus Longus muscles are located on the outside of your lower leg.
The Peroneus Longus muscle starts from just below the head of the fibula. Its tendon runs behind the lateral malleolus of the ankle to the outside of your foot and wraps under your foot to attach the base of your big toe.
The Peroneus Brevis muscle starts just above the middle of your fibula and runs down the side of your leg. Its tendon also wraps around the outside of your ankle and it attaches to the outside of your foot at the base of the 5th metatarsal bone (the knobbly bit you can feel on the outside border of your foot).
Both these muscles help to point your foot down and to turn your foot out. They play a very important role in stabilising your ankle.
How do you know you have a peroneal tendonitis?
There are several different structures that can cause pain in the same area as the peroneal tendons so it’s always good to consult a physiotherapist to confirm the diagnosis. You may have a peroneal tendinopathy if:
You have pain on the outside of the ankle or heel in the area where the peroneal tendons run.
This pain is usually made worse by activities like running and walking and eases with rest.
If it is tender or sore when you press on the peroneal tendons. Make sure you test the other side as well, because even healthy tendons can feel a bit tender when you press on them. It has to be more tender than your other foot to be significant.
Turning your foot in fully (inversion) while it is pointing down (plantar flexion) may cause pain in the tendons. Remember, the pain you feel with this has to correlate with where the tendons are. This test can also cause pain in the ligaments or the tibial nerve (and its branches) if they are strained - where you feel the pain as well as the type of pain you feel is important when making the diagnosis.
Trying to turn your foot out (eversion) against resistance may cause you pain in the tendons. I find in practice that this is not always easy to reproduce. Sometimes you have to contract the tendons in a lengthened position (inversion + plantar flexion) or do an eccentric contraction to elicit pain in them.
Common causes of peroneal tendonitis in runners
Lateral ankle sprains are one of the most common causes for this injury. When you sprain your ankle by turning it in, the tendons undergo a severe stretch injury. If you then neglect the injury and don’t rehabilitate it properly it can lead to peroneal tendonitis/tendinopathy.
Chronic ankle instability. This usually develops as a result of an ankle sprain that’s not been treated properly which causes you to have poor control over your ankle. A sign that you may have an unstable ankle is when you find yourself spraining your ankle for no apparent reason – often when just walking. Not only do the peroneals strain every time you twist your ankle, but they tend to also get over-worked because the other muscles aren’t doing their part. This can easily be fixed through a good rehab programme that strengthens all the muscles around the ankle.
Soft or very flexible shoes act as an “unstable” base when you walk or run. For some runners this can cause the peroneal tendons to overwork and strain as they will have to work a lot harder to try and stabilise your ankle than if you were wearing a less flexible shoe.
Doing a lot of running on a cambered surface that forces your foot to turn in excessively (inversion) can also cause an overuse injury / tendinopathy in the peroneal tendons.
Top 5 tips for treating peroneal tendonitis/tendinopathy
Make sure that you wear supportive shoes.
Strengthen all the muscles in the lower leg that support the ankle – especially the Soleus.
Be careful when strengthening the peroneal muscles themselves – if the exercises are too hard you can make it feel worse.
Make sure you retrain your position sense/proprioception so that your brain knows exactly where you ankle is. That way it can control it better when you run and walk.
If you’re getting sharp pains/electric shock sensations/pins and needles go and see a physio because you may also have irritated the nerve that runs in that area.
Need more help with your injury? You’re welcome to consult one of the team at SIP online via video call for an assessment of your injury and a tailored treatment plan.
Best wishes
Maryke
About the Author
Maryke Louw is a chartered physiotherapist with more than 15 years' experience and a Masters Degree in Sports Injury Management. Follow her on LinkedIn, ResearchGate, Facebook, Twitter or Instagram.
