Peroneal Tendon Injury

Peroneal tendonitis is an irritation to the tendons that run past the back outside part of the ankle. The two tendons involved are the peroneus longus and peroneus brevis. The tendonitis usually occurs because these tendons are subject to excessive repetitive forces during standing and walking. Certain foot shapes such as a higher arched foot tend to increase the force that the peroneal tendons are exposed to and may thereby predispose to the development of peroneal tendonitis. Treatment is aimed at decreasing symptoms and correcting any precipitating factor. Non-operative treatment may include: anti-inflammatory medications, activity modification, ice, muscle strengthening, ankle bracing, and/or orthotics. Occasionally surgery is beneficial.

Clinical Presentation:

Patients with peroneal tendonitis present with pain and, occasionally, swelling in the outside and back (posterolateral) part of the ankle. This tends to be a chronic condition, so there is often no precipitating event. However, sometimes patients will report an activity that aggravated their symptoms.

The peroneal tendons run behind the prominent bone on the outside of the ankle. There are two tendons, the peroneus brevis and peroneus longs. These tendons help to control the position of the foot during walking. They also responsible for the muscle contraction that moves the foot out to the side (eversion of the foot). Peroneal tendonitis is an irritation to the peroneal tendons. Essentially, the tendons are repetitively overloaded and the subsequent inflammatory response (attempt at healing) creates pain and discomfort. This inflammatory response is the reason why patients with peroneal tendonitis will often have startup pain and pain first thing in the morning. The mechanism by which peroneal tendonitis develops is akin to a rope that is repetitively overloaded. Just as a rope can become frayed -some patients with peroneal tendonitis will also have some tearing of the tendons. However, when tearing of the tendon occurs it is usually in line with the tendon, essentially causing a split in the tendon. Patients with peroneal tendonitis are usually able to walk although they may have a limp. When peroneal tendonitis is severe it often prevents patients from participating in dynamic sporting type activities that require sudden changes of direction.

Physical Examination

Patients with peroneal tendonitis will often walk with a limp. Looking at the outside of the ankle, there will may be some subtle (or not so subtle) swelling behind the lateral malleolus [the prominent bone on the outside of the ankle]. Pressing on this area will often create discomfort. Many patients will have a higher arch foot (subtle cavus foot) with increased ankle inversion compared to eversion. This foot pattern predisposes a patient to increased load over the region of the peroneal tendons during walking. The sensation and muscle strength is usually intact, although the sural nerve innervates the outside of the foot and will on occasionally be irritated by the inflammation and swelling. This can lead to either decreased sensation or a burning over the lateral or outside aspect of the foot. In rare instances some patients may have a complete tear of one of the peroneal tendons and in this situation there may be weakness in the ability to move the foot out to the side (eversion of the foot.)


Patients with peroneal tendonitis, but no significant peroneal tendon tear, can usually be treated successfully non-operatively. Treatment is aimed at decreasing the load through the peroneal tendons and subsequently decreasing the inflammation. In patients with a large peroneal tendon tear or a bony prominence that is serving as a physical irritant to the tendon, surgery may be beneficial. Physical irritants can include a prominent peroneal tubercle or a bone spur off of the back (posterior aspect) of the fibula (prominent bone on the outside of the ankle). Surgery is performed to: clean up the tendons themselves debridement or synovectomy); repair any significant tearing of the tendons; and if necessary smooth out the tract that the peroneal tendons run in.

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