Peroneal tendonitis is a common cause of pain around the back and outer side of the foot, particularly around the ankle.
Frequently affecting runners or athletes who have upped their training, peroneal tendonitis usually develops slowly, gradually getting worse and worse.
Repetitive overloading or stretching of the peroneal tendons can cause small tears in the tendons which leads to inflammation, irritation, weakening and degeneration. The result is pain on the outer ankle which gets worse with activity.
Tendons are strong, cord-like structures that link muscles to bones. In order to move, our muscles contract, which pulls on the appropriate tendon which in turn pulls on the appropriate bone.
There are two peroneal muscles, peroneal longus and peroneal brevis.
They work to pull the foot and toes downwards, known as “plantarflexion” and to turn the foot outwards, known as “eversion”.
The tendons run down the back of the fibula (outer shin bone) through a groove on the outer side of the ankle behind the lateral malleolus.
Peroneus brevis attaches to the base of the little toe, while the peroneus longus tendon crosses under the sole of the foot attaching to the big toe.
Tendonitis occurs when the tendons are over-used or placed under too much tension, usually from repetitive movements causing a strain on the tendon.
Micro-trauma from overuse or repetitive tension on the peroneal tendons, or an ankle injury such as a sprain, damages the tendons which can lead to peroneal tendonitis.
There are a number of different causes of tendonitis in the peroneal muscles:
People suffering from peroneal tendonitis tend to complain of pain and tenderness around the back and outside of their foot and ankle.
The pain from peroneal tendonitis tends to come on gradually over a few weeks or months, gets worse with activity and eases with rest.
Symptoms often tends to be worse first thing in the morning, easing once you are up and about. It may also hurt to turn your foot inwards, known as inversion, as this movement stretches the tendons.
It can take a number of months for the symptoms of peroneal tendonitis to fully settle down so effective treatment is vital.
There are a number of other causes of pain on the outer side of the foot. If peroneal tendonitis isn't sounding quite like your problem, visit the Side Foot Pain section. Alternatively, if you want help working out what is causing your pain, visit the foot pain diagnosis section.
Tendonitis can occur in a number of places around the ankle and foot. Visit the foot tendonitis section to learn about the different types of tendonitis.
Page Last Updated: 11/12/18
Next Review Due: 11/12/20