Condition Overview: Peroneal Tendinosis
Peroneal tendinosis isn’t the most common injury for runners, but if you’ve put in enough miles over the years, chances are good you’ve gone toe to toe with it at some point or will in the future. It can be a tricky injury since it can affect the lower leg, ankle and even the bottom of your foot due to the location of the muscles and tendons involved.
What is Peroneal Tendinosis?
Two muscles can be involved in this overuse injury, the peroneus longus and peroneus brevis. Both of these muscles originate at the fibula, the thin bone on the outside of your lower leg. The peroneus longus attaches to the upper ⅔ of the fibula and the peroneus brevis the lower ⅓. Both tendons pass behind the lateral ankle bone (lateral malleolus). The longus tendon then wraps underneath the foot and attaches to the bottom of the foot near the medial arch. The brevis attaches to the outer edge of the foot at the base of the 5th metatarsal. The overuse of these muscles and tendons can lead to irritation of the tissues which leads to pain.
The function of the peronei muscles is to evert the foot as well as plantar flexion of the ankle. They are also important ankle stabilizers and are commonly injured during an inversion ankle sprain.
Some of you are probably wondering why I’m using the term tendinosis in place of tendinitis. Recently, the medical field has moved away from the term tendinitis, because it implies that inflammation is present. Through biopsies of injured tendons, they’ve found that this isn’t always true. What we do know is that the tendon has thickened and that pain is present. Unless you want a needle jabbed into your tendon to determine the presence or absence of inflammatory cells, tendinosis is a more appropriate term.
Peroneal tendinosis presents as lateral foot pain that may or may not wrap around the bottom of the foot. Occasionally, this condition is mistaken for plantar fasciitis/fasciosis due to the pain wrapping around to the bottom of the foot. It’s not uncommon to have accompanying lateral lower leg pain throughout the muscle bellies and ankle pain. Swelling is rarely visible with this injury unless it is a result of an ankle sprain.
As with most tendinosis injuries, overuse is a common culprit. Overuse of these tendons can happen for various reasons. Excessive mileage, a rapid increase in mileage or intensity, muscle imbalances, faulty foot mechanics and activity on uneven surfaces.
Excessive supination is a common cause for runners. Less than 10% of the population actually supinates within their normal gait cycle but twisting an ankle, uneven surfaces and old shoes can cause supination. This stretches the muscle which puts it at a biomechanical disadvantage. The same concept applies to doing a pull up. Once you completely straighten your arms, the pull up becomes more difficult.
The best and most common treatment approach is a conservative one. I love seeing these injuries because they respond quickly to soft tissue treatments. Kinesiology tape provides benefits as well but will most likely be a supportive treatment and in most cases won’t resolve the issue alone. This approach typically allows for runners to continue training throughout treatment.
Other options include the typical rest, ice, compress and elevate (RICE) approach. I find that this takes longer and is less efficient. It also requires a break from running, and I have yet to meet a runner who was excited to do so. Surgery is only an option when symptoms become impossible to control, which is rare.
Also, be sure you are running on a flat surface. If you run on roads, they are usually crowned to allow for water run-off. Running on the shoulder puts your outside foot in a slightly supinated position. Try and switch up your running surfaces.
An option that is often overlooked is buying new or different shoes. It’s common for this injury to start flaring up when someone is running in a shoe that’s either past its mileage threshold or just not a good fit. I’ve seen this injury completely resolve without treatment by simply changing shoes. As always, I’d advise you to purchase your shoes at a local running specialty store to get the best fit.
So, if lateral foot pain has been troubling you, try running in different shoes regardless of your shoe’s age. If shoes don’t correct your issue, then seek help. If an injury doesn’t resolve itself within a week, it’s typically not going to and you need to find treatment options.