What is peroneal tendonitis?

Peroneal tendonitis, also known as peroneal tendinopathy, is an injury affecting the peroneal tendons in the ankle. Peroneal tendon injuries are common. The peroneal tendons arise from the peroneal muscles in the outside of the leg. There are two tendons – peroneus longus and peroneus brevis. The tendons course along the outside of the ankle and attach to the foot. The main action is to evert the ankle – rocking the ankle outwards.

Peroneal tendon problems

Generally, the most common peroneal tendon problem is swelling or inflammation known as peroneal tendonitis. In some cases, peroneal tendon tears can occur most commonly affecting the peroneus brevis. We think that tears occur more commonly in the peroneus brevis due to a poorer blood supply. Also, this tendon wedges between the peroneus longus and the ankle bone causing friction. Finally, peroneal tendon subluxation or dislocation can occur after a twisting ankle injury causing the tendons to move over the bone on the outside of the ankle.

How do specialists diagnose peroneal tendonitis? 

Injury to these tendons can occur either as a result of repetitive overuse or an acute injury such as an ankle twist. Typically, symptoms include pain at the back of the outside of the ankle with walking or running, swelling, and weakness. Often, there is tenderness on the outside of the ankle. Pain occurs with the pulling of the foot downwards and inwards as the tendons stretch.

Ultrasound or MRI shows thickening of the peroneal tendons and inflammation of the tendon sheath. In addition, ultrasound is good at seeing a peroneus brevis tear or peroneal tendon subluxation.

Peroneal tendonitis treatment

Firstly, simple treatments can be very effective for peroneal tendonitis. Ice, rest, and a walking boot can help. In addition, anti-inflammatory tablets such as ibuprofen reduce inflammation and pain. GTN patches can also help with the pain. Secondly, physiotherapy to strengthening the peroneal tendons, calf muscles, and small muscles of the foot plays a role. Thirdly, orthotics to support flat or high-arched feet can reduce the forces on the peroneal tendons.

Injections can be helpful in more difficult cases of peroneal tendonitis. Cortisone injections are rarely used due to the possibility of tendon damage. However, a cortisone shot can help in severe cases that don’t improve. In some cases, we consider PRP injections for peroneal tendon problems especially if there are peroneal tendon tears.

Finally, we only consider surgery if simple measures fail. Options include peroneal tendon repair or tendonesis where the damaged tendon is sewn to the normal tendon. Sometimes, the surgeon may need to reshape the heel to reduce the forces on the tendon. Generally, patients take up to 4 months to recover after surgery.

Final word from Sportdoctorlondon

Peroneal tendonitis is a common tendon injury affecting the outside of the ankle. Common findings include pain and swelling in the outside of the tendon. Overall, simple treatments such as ice, medication, physiotherapy, and orthotics can help. We only consider injections or surgery in difficult cases.

Dr. Masci is a specialist sport doctor in London. 

He specialises in muscle, tendon and joint injuries.