Peroneal tendonitis is a common foot injury with pain on either the outer side of the ankle or the outer side of the foot. The peroneal tendons are two in number, and run together under the outside of the ankle joint, where they stay together for a couple inches until they reach the middle part of the side of the foot. It is here that one stays on the side of the foot, attaching to the bone prominent on the outside of the foot. The other longer tendon runs underneath the foot to attach near the other side. These tendons are known as everters, because they help the foot to roll to the outside, or evert. This motion is very important during the normal walking cycle, and helps to balance the more powerful muscles on the other side of the foot that draw it inward.
The peroneal tendons can become injured during simple ankle sprains, as the twisting force that tears ankle ligaments can stretch and injure the peroneal tendons running near the ligaments. The peroneal tendons can also become injured without having a specific sprain. Walking on uneven surfaces, simple excessive climbing, using unstable shoes, and even compensating for arch pain can lead to peroneal tendonitis. The typical pattern of pain also includes sharp or achy pain to the side of the foot, where the majority of the time the pain is at it’s strongest. Bearing weight on the injured foot, twisting it inward, and moving on uneven ground like lawns or gravel can aggravate the pain. There is rarely ever swelling or bruising visible on the side of the foot, and there is never a cracking or popping sensation (unless the tendons are moving over the ankle bone or a fracture has occurred on the side of the foot- both of which are different conditions).
Fortunately, the treatment of peroneal tendonitis is relatively simple. In general, peroneal tendonitis needs rest, ice, anti-inflammatory medications, and ankle brace support. Cases that don’t respond to these measures need physical therapy to help with healing and strengthen the tissue. In addition to the above treatment, severe cases of peroneal tendonitis may require immobilization of the leg or surgery to repair the tissue damage. It is not uncommon for partial tears of the tendon to accompany the tendonitis, and often these need to be surgically repaired if the pain is not resolving with non-surgical treatment.