Peroneal Tendon Injuries

Pain along the outside of the ankle is often blamed on an ankle sprain, but the peroneal tendons can be the actual source of the problem. We see this particularly in patients who have had repeated ankle sprains, participate in sports involving cutting and side-to-side movement, or have foot alignment that places additional stress on the outside of the ankle. Some patients have gradually worsening pain, while others describe a sudden pop or snapping sensation after an injury.

The important distinction is whether the tendon is simply irritated, partially or completely torn, or actually moving out of its normal position. Those findings can require very different treatment.

The Peroneal Tendons and Their Job

The peroneus longus and peroneus brevis are two tendons that travel along the outside of the lower leg and behind the fibula, or outer ankle bone.

The peroneus brevis attaches to the base of the fifth metatarsal. The peroneus longus continues underneath the foot and attaches near the base of the first metatarsal.

Together, these tendons help turn the foot outward and provide important dynamic stability to the ankle. They are particularly active when the foot needs to resist an unexpected shift or when the body is moving quickly from side to side.

The tendons normally sit in a groove behind the fibula and are held there by a strong band of tissue called the superior peroneal retinaculum.

How Peroneal Tendon Injuries Develop

Peroneal tendon injuries can occur suddenly or develop gradually.

A twisting injury can place significant force through the tendons. Repeated ankle sprains can also weaken the supporting structures and leave the tendons working harder to stabilize the ankle.

Overuse is another common pathway. Running, jumping, skiing, tennis, soccer, basketball, and other activities involving repetitive side-to-side motion can repeatedly load the tendons.

Foot structure can also matter. A high-arched or varus foot may place greater stress on the lateral side of the ankle, increasing the work required from the peroneal tendons.

There can also be an anatomical reason for tendon instability. A shallow fibular groove or an unusually low-lying muscle belly can make it easier for the tendons to become irritated or displaced.

What Patients Usually Notice

The symptoms depend on what has happened to the tendon.

Patients with tendon irritation or degeneration usually describe pain behind or just below the outside ankle bone. The area may become swollen or tender, and symptoms often increase with activity.

A tendon tear can cause similar pain but may also produce weakness, persistent swelling, or difficulty with activities requiring ankle stability.

Tendon subluxation or dislocation is different. Patients often describe a snapping or popping sensation behind the outside ankle bone, particularly when the ankle moves. Some can actually feel the tendons move out of position.

A history of recurrent ankle sprains is another important clue. In some patients, what has been treated repeatedly as an ankle sprain is actually an underlying peroneal tendon problem.

What We Look for at the First Visit

We begin by watching how the patient walks and examining the overall alignment of the foot and ankle.

We palpate the peroneal tendons along their course and look for swelling or tenderness. We test eversion strength and assess whether resisted movement reproduces the patient’s familiar pain.

We also check ankle stability. A peroneal tendon injury and chronic lateral ankle instability can occur together, and treating only one of them may leave the patient with continued symptoms.

For suspected tendon instability, we may watch the tendons while the ankle moves. The ability to reproduce the snapping or displacement during the examination can be particularly helpful.

X-rays allow us to evaluate bone alignment, previous injuries, fractures, and other structural abnormalities. Ultrasound can be useful because it allows us to watch the tendons dynamically as they move. MRI provides a more detailed assessment of tendon degeneration, partial tears, complete tears, and associated soft-tissue problems.

Tendonitis, Tendon Tears, and Subluxation Are Different Problems

We think about peroneal tendon injuries along a spectrum.

Tendinopathy or tendinosis means the tendon has become irritated or structurally abnormal from repeated loading. This does not necessarily mean the tendon is torn.

A tendon tear means some or all of the tendon fibers have been disrupted. Tears may be acute after trauma or develop gradually from chronic degeneration.

Subluxation or dislocation means the tendon is moving out of its normal position behind the fibula. This often involves injury to the superior peroneal retinaculum.

These distinctions matter because a patient with an irritated tendon may improve with rehabilitation, while a patient with a significant tear or recurrent tendon displacement may have a structural problem that cannot be solved by therapy alone.

Problems That Can Look Similar

Lateral ankle pain has several possible causes.

We may need to distinguish a peroneal tendon injury from a lateral ankle sprain, chronic ankle instability, a fifth metatarsal stress injury, an osteochondral lesion of the talus, or a subtalar joint problem.

The location of the pain, the mechanism of injury, the physical examination, and imaging help us determine which structure is responsible.

Starting With Nonsurgical Treatment

Not every peroneal tendon injury needs surgery.

For tendon irritation and selected partial tears, we may temporarily reduce activities that repeatedly aggravate the tendon. A walking boot or ankle brace can provide additional protection when ordinary walking continues to cause pain.

Physical therapy then focuses on restoring strength, ankle control, balance, and proprioception. Rehabilitation is particularly important when previous ankle instability contributed to the tendon injury.

We also address the mechanics behind the problem. Footwear may need to change, and an orthotic may be appropriate when foot alignment is contributing to excessive lateral loading.

The goal is not simply to make the ankle hurt less. We want the tendon to gradually regain its ability to tolerate the demands being placed on it.

When Surgery Becomes the Right Choice

Surgery is not automatically necessary just because an MRI shows a tendon tear. We consider surgery when the tendon has significant damage, the symptoms continue despite appropriate nonsurgical treatment, or the tendon repeatedly slips out of its normal position.

The goal is to fix the problem that is actually causing the symptoms, rather than simply treating what appears on an imaging study.

If the tendon is damaged but still healthy enough to repair, we can clean out the unhealthy portion and repair the remaining tendon. In some cases, the tendon is reinforced or reshaped so that it can function more normally.

If one tendon is too badly damaged to repair on its own, we may connect it to the healthier peroneal tendon. This allows the healthier tendon to help take over the work of the damaged one.

When the tendons are repeatedly snapping out of place behind the ankle bone, we may need to repair the tissue that normally holds them in position. In some patients, we also make changes to the groove behind the fibula to give the tendons a more secure path.

If chronic ankle instability is contributing to the problem, we may need to address that at the same time. Otherwise, the tendon can continue to be exposed to the same forces that caused the original injury.

What Peroneal Tendon Surgery Is Like

The exact operation depends on what we find with the tendon and the ankle.

Before surgery, we explain what we expect to repair and what you should expect afterward. Depending on the procedure, the ankle may need to be protected in a splint or boot, and you may need to limit how much weight you put on the foot for a period of time.

The early part of recovery is about protecting the repair while it heals. That can be frustrating, particularly for patients who are used to being active. We would rather allow the tendon to heal properly than have you advance too quickly and place unnecessary stress on the repair.

As healing progresses, physical therapy helps restore motion, strength, balance, and control. We gradually increase the demands placed on the ankle.

The tendon may start feeling much better before it is ready for running, jumping, or cutting. Returning to sports is therefore based on strength, stability, range of motion, and functional ability rather than simply how many weeks have passed.

What We Watch for During Recovery

We monitor for persistent pain, weakness, stiffness, wound problems, nerve irritation, and recurrent tendon instability.

The sural nerve runs near the surgical area and can occasionally become irritated during treatment. We also pay close attention to whether the repaired tendon is regaining appropriate strength and whether the ankle remains stable as activity increases.

What Can Happen Without Treatment

A mild tendon problem may settle with appropriate activity modification and rehabilitation. A significant tear or unstable tendon can behave differently.

Continued loading of a damaged tendon can lead to progressive degeneration, weakness, or worsening pain. Recurrent tendon displacement can also contribute to ongoing ankle instability.

This does not mean every MRI abnormality requires surgery. The decision depends on whether the structural finding matches the patient’s symptoms and examination.

What a Good Outcome Means

A good outcome means more than an intact tendon on an MRI.

We want patients to walk comfortably, have a stable ankle, regain appropriate strength, and return to the activities that matter to them. For an athlete, that may mean returning to cutting and jumping sports. For another patient, success may simply mean walking, exercising, and going through the day without lateral ankle pain or a feeling that the ankle is giving way.

Our approach is to determine what happened to the tendon, why it happened, and whether the problem can heal with protection and rehabilitation or requires structural repair. Treating the tendon without addressing the instability or alignment that contributed to the injury can leave the original problem unresolved.

Dr. Athar’s perspective on Peroneal Tendon Instability:

Peroneal tendon instability is that unsettling sensation of a tendon snapping or popping over the outside of your ankle bone. This can be incredibly distracting and often painful. I typically recommend surgery when this mechanical flipping becomes a regular occurrence that interferes with your activity or causes persistent pain. My threshold for intervention is based on the anatomy of the groove behind your fibula.

There is also a soft tissue sling (retinaculum) that holds the tendons in place. This can be injured, stretched, or torn. Certainly, we can try, physical therapy, bracing, medication, and injections. However, if these are not helpful, we consider surgery. Non-surgical interventions are not a mechanical solution and often are not enough to keep them from sliding out of position. During our visit, I’ll explain how we can surgically deepen that groove and repair the retinaculum around your tendons. I want you to set the direction of your treatment. If you’ve reached the point where you no longer trust your ankle to behave during a workout or a walk, we can discuss the definitive solution.

To me, a good outcome is a silent ankle. Success means you can move, pivot, and push off without that annoying, sharp snap or the constant worry that your tendons are out of place. It’s about getting you back to your baseline where your tendons glide smoothly and efficiently, exactly where they belong. I chose the foot and ankle specialty because I enjoy the precision required to restore complex mechanical systems like this.

My fellowship training focused heavily on these stabilizing procedures, using techniques that allow for a secure repair while minimizing irritation to the tendons themselves. My goal is to use that specialized training to provide a durable result that allows you to return to the sports and hobbies you love with a foundation that is finally back in its proper alignment.