Foot Issues

Peroneal Tendon Problems

Causes
Tendons attach muscles to bone. Tightening a muscle puts tension on the tendon, which can move bone. Many tendons in the body are held in place by supportive connective tissue, such as a ligament or retinaculum. If the supportive tissue has been damaged or injured, the tendon may be free to slip out of its normal position. This is called subluxation. When the subluxed tendon slips back into place, this is called relocating. A tendon that forcefully snaps out of position and can’t relocate has dislocated.

The main cause of peroneal tendon subluxation is an ankle sprain. A sprain that injures the ligaments on the outer edge of the ankle can also damage the peroneal tendons. During the typical inversion ankle sprain, the foot rolls in. The forceful stretch on the peroneals can rip the retinaculum that keeps the peroneal tendons positioned in the groove. As a result, the tendons can jump out of the groove. The tendons usually relocate by snapping back into place.

The injury to the retinaculum may be overlooked at first while treatment focuses on the injury to other ankle ligaments. This means the subluxation may begin much later, and it may not seem to be caused by the initial ankle sprain. If not corrected, this snapping of the tendons can become a chronic and recurring problem.

An acute dislocation of the peroneal tendons is rare. It occasionally happens during sport activities that force the foot up and in, for example during skiing, ice skating, or soccer. At the moment the foot turns up and in, the peroneals violently contract to protect the ankle. This can cause the retinaculum to tear, allowing the tendons to slip out of the groove.

Differences in the anatomy of the groove may predispose some people to peroneal tendon subluxations. The groove may be too shallow. Or the ridge that helps deepen this groove may be too small or even absent. Sometimes, the retinaculum that keeps the tendons in the groove may be too loose. In these cases, patients may not recall any injury to explain the persistent snapping of the peroneal tendons.

Symptoms
Patients describe a popping or snapping sensation on the outer edge of the ankle. The tendons may even be seen to slip out of place along the lower tip of the fibula. It is common to feel pain and tenderness along the tendons. There may also be swelling just behind the bottom edge of the fibula.