The peroneal tendons are the tendons that connect the muscles of the outer side of the calf to the foot. The two major peroneal muscles (peroneus longus and peroneus brevis) are situated on the outside of the leg, just adjacent to the calf muscles. The muscles are connected to bone by the tendons, which course along the outer side of the ankle and attach to the foot.
The peroneal muscles are important at everting the foot—the motion of rocking the foot outward from the ankle. In normal gait, the motion of the peroneal muscles is balanced by the muscles that invert the foot (rock the foot inward from the ankle).
The two peroneal tendons are very closely related—in fact, they sit one on top of the other right behind the fibula. This close relationship is thought to contribute to some of the problems that occur to the peroneal tendons, as they rub together behind the ankle.
The most common problem that occurs with the peroneal tendons is inflammation or tendonitis. The tendons are usually inflamed just behind the fibula bone at the ankle joint. This part of the fibula is the bump on the outside of the ankle (also referred to as the lateral malleolus), and the peroneal tendons are located just behind that bony prominence.
Peroneal tendonitis can either be the result of repetitive overuse or an acute injury. Typical symptoms of peroneal tendonitis include pain behind the ankle, swelling over the peroneal tendons, and tenderness of the tendons. Pain is usually worsened if the foot is pulled down and inwards, stretching the peroneal tendons. X-rays of the ankle are typically normal, and an MRI may show inflammation and fluid around the tendons.1
Typical treatment of peroneal tendonitis is accomplished with some simple steps, including:
Ice Application: Applying ice to the area can help to reduce swelling and help to control pain.
Rest: Rest is key and often helped with the use of crutches or a cane.
Anti-Inflammatory Medications: Medications, such as Motrin or Aleve, are anti-inflammatory and can reduce the swelling around the tendon.
Physical Therapy: Physical therapy can be beneficial to help restore normal ankle joint mechanics.
Walking Boots/Ankle Brace: Braces and boots are another way to reduce stress on the tendons and allow for rest and inflammation to subside.
Cortisone Injections: Cortisone injections are used infrequently, as they can lead to tendon damage. However, in cases of recurrent tendonitis that does not improve, a shot of cortisone may be considered.1
Peroneal Tendon Tears
Tears of the peroneal tendons are unusual, and almost always occur to the peroneus brevis tendon. Tears are thought to be the result of two issues with the tendon. One issue is the blood supply. Tears of the peroneus brevis almost always occur in the watershed zone where the blood supply, and thus nutrition of the tendon, is poorest. Second, is the close relationship of the two tendons, causing the peroneus brevis to be wedged between the peroneus longus tendon and the bone.2
Many doctors try to treat tears of the peroneus brevis with the same treatments for tendonitis listed above. Unfortunately, many of these patients don't find lasting relief of symptoms, and therefore surgery may be necessary. There are two surgical options for peroneus brevis tears:3
Tendon Debridement and Repair: During a tendon debridement, the damaged tendon and inflammatory tissue surrounding can be removed. The tendon tear can be repaired, and the tendon is "tabularized" restoring its normal shape. Tendon debridement and repair is most effective when less than 50% of the tendon is torn.4
Tenodesis: A tenodesis is a procedure where the damaged tendon is sewn to the normal tendon. In this case, the damaged segment of peroneus brevis is removed (usually a few centimeters), and the ends left behind are sewn to the adjacent peroneus longus tendon. Tenodesis is recommended for tears that involve greater than 50% of the tendon.5
Recovery after surgery involves several weeks of restricted weight-bearing and immobilization, depending on the type of surgery performed. Following immobilization, therapy can begin. Total time for recovery is usually 6-12 weeks, depending on the extent of surgery. Risks of surgery include infection, stiffness, and persistent pain. That said, the surgery is very successful, with patients reporting 85-95% success rates.4