Peroneal Tendinopathy: Outer Ankle Pain That Will Not Settle

You rolled your ankle on a curb, a trail root, or a basketball court. The swelling settled, the bruising faded, and you went back to walking normally within a few weeks. That part went the way it was supposed to.

Months later, the outside of the ankle still hurts. It is quiet in the morning, builds through a long walk, and aches that evening. It objects to uneven ground and to the crowned edge of a road. You have been calling it "my bad ankle" since the sprain, and nobody has looked at it since.

In a good number of these cases the ligament healed and the pain moved somewhere else: into the two peroneal tendons that run down the outside of the calf, hook around the bony bump on the outer ankle, and pass underneath the foot. Tendon pain behaves differently from ligament pain, and it needs a different plan.

Why lingering outer ankle pain is often tendon, not the old ligament

Peroneus longus runs around the outer ankle bone and crosses under the foot to attach near the base of the big toe. Peroneus brevis attaches to the outside of the midfoot. Together they turn the foot outward and control the moment your weight rolls over the outside edge of the foot.

That is the movement an inversion sprain forces past its limit. The same event that injures the ligaments loads the peroneal tendons hard, and those tendons are left steadying a foot that has become less certain of itself.

These injuries are missed often enough that the delay has been measured. A 2021 case report and literature review in Trauma Case Reports reports that only 60% of peroneal tendon injuries are diagnosed at the initial visit to an orthopaedic surgeon, and that for the remaining 40% the median time to the correct diagnosis is 7 months. A 2013 review in the British Journal of Radiology by Schubert says conditions of the peroneal tendons "still tend to be underdiagnosed as a cause of lateral ankle pain".

If the outside of your ankle has hurt for more than three months after a sprain, the assumption that it is "just the old sprain" deserves a proper look.

How a therapist tells the tendons apart from the ligament

Most of this is settled by history and hands, before any imaging is ordered.

Where it hurts. Ligament pain sits in front of and below the outer ankle bone. Peroneal pain sits behind and below it, and follows the tendons up the outside of the lower leg or forward into the midfoot.

What provokes it. The 2021 review describes the distinction this way: people with lateral ligament trouble after recurrent sprains report instability on uneven terrain, while peroneal tendon pathology presents as chronic pain and disability. In plain terms, a ligament problem makes the ankle feel like it might give way. A tendon problem hurts.

When it hurts. Tendon pain has a delay built into it. It warms up during the first ten minutes of a walk, builds as the load accumulates, and is at its worst the next morning. That 24-hour pattern is one of the more useful things you can report.

What it does under resistance. Your therapist will ask you to push the foot outward against their hand, and will repeat it with the ankle held in different positions to bias one tendon over the other. Pressing along the tendons behind the outer ankle bone does the same job. Reproducing your pain that way points at the tendon rather than the ligament.

None of these findings stands alone. Ligament and tendon problems live together often, and a plan usually has to address both. The recurrence side of that story is covered in more depth in our post on ankle sprain rehab and why sprains keep coming back.

The two things this can be instead, and why they matter

Two other diagnoses change the plan completely. Both need ruling out before anyone starts a loading programme.

A bone injury in the fibula. The fibula is the thin outer bone of the lower leg. A stress injury in it behaves differently from a tendon: the pain localises to a small patch you can point to with one finger, it hurts on hopping or impact rather than on resisted movement, and it worsens with running load instead of warming up. Night pain and pain at rest push the suspicion further toward bone. A rapid jump in training volume, low energy availability, or a previous stress fracture all raise the stakes.

For acute injuries there is a validated way to decide whether an X-ray is needed. A 2022 systematic review and meta-analysis in BMC Musculoskeletal Disorders by Gomes and colleagues pooled 15 studies covering 8,560 adults and found the Ottawa ankle rule had a sensitivity of 0.91 and a specificity of 0.25. A negative result is therefore good at ruling a fracture out, while a positive result raises the odds only about 1.5 times. The authors are explicit that it belongs alongside clinical judgement rather than instead of it.

Tendons that slip out of place. The peroneal tendons sit in a shallow groove behind the outer ankle bone, held there by a band of tissue. A sprain can tear that band, after which the tendons flick forward over the bone and back again. People describe a snap, a pop, or a feeling that something moves. Schubert's review notes these patients typically have a history of ankle sprain, and that when the slipping is intermittent a clinician can often provoke it by moving the foot upward and outward.

A slipping tendon is a mechanical problem inside a torn restraint, and loading a tendon that snaps over a bone edge a few thousand times a day does not solve the snapping. This is one of the situations where a surgical opinion belongs in the conversation early, and your physiotherapist should be saying so rather than persisting with exercise.

What a high arch or a stiff foot has to do with it

Foot shape changes how much work these tendons do.

A high-arched foot with the heel tipped inward puts body weight further toward the outside edge of the foot. The peroneals then work harder on every step to stop that edge rolling under. Schubert's review notes that a cavovarus hindfoot position, which is the clinical name for that high arch with an inward-tipped heel, appears to be a predisposing factor for peroneus longus tendon injury.

A stiff foot compounds it. A foot with limited motion absorbs less shock through its own joints, so more of each landing has to be managed by muscle and tendon. Limited upward ankle motion does something similar: when the ankle cannot bend forward far enough over the foot, the body finds the range elsewhere, often by rolling out through the forefoot.

Your therapist will look at your standing alignment, the mobility of the ankle and midfoot, how your heel behaves when you rise onto your toes, and what your calf length allows. Foot shape is information rather than a fault to correct. It tells you how much capacity these tendons need and how much a change in footwear or surface is likely to help.

The loading programme that actually treats it

Tendons respond to load applied in the right dose over enough time. Everything else is support.

Direct evidence for peroneal tendon loading programmes is limited, and it is honest to say so. Most of what guides practice comes from tendinopathy work in better-studied tendons, combined with the literature on rehabilitating the unstable ankle. The principles carry across. The exact protocol numbers do not, which is why an individual assessment beats a downloaded programme.

On the ankle side the evidence is stronger. A 2024 systematic review and meta-analysis in BMC Sports Science, Medicine and Rehabilitation by Su and colleagues pooled 33 randomised controlled trials covering 1,154 people with chronic ankle instability. Combining strength and balance training produced larger improvements in patient-reported function than either strength training or balance training alone, while balance training on its own did more for dynamic balance. The 2021 JOSPT clinical practice guideline on lateral ankle ligament sprains by Martin and colleagues reaches the same practical place: therapeutic exercise and balance training carry the strongest recommendations in this area.

A plan usually moves through four stages, and the stages overlap rather than finishing cleanly.

• Settle the irritation. Cut the loads that flare it: less side-to-side work, less uneven ground, a temporary drop in running volume. Complete rest is rarely the answer, because tendons lose capacity fast when unloaded.
• Build basic strength. Isometric holds turning the foot outward against a band or a wall, then slow resisted work through range. Slow is the point, because tendon adaptation responds to time under load rather than repetitions rushed through.
• Add calf and foot capacity. Heel raises progressed from two legs to one, flat ground to a step, bodyweight to loaded. The calf and the peroneals share control of the ankle at push-off, so a weak calf leaves the tendons doing more.
• Rebuild control and speed. Single-leg balance, then balance on uneven surfaces, then hopping, cutting, and the movements your sport asks for.

Your therapist will use your 24-hour pain response to set the dose. Pain during the exercise that settles within a day and does not build session to session is generally acceptable. Pain that is worse the following morning, or climbs across the week, means the dose was too high. The same logic applies to every tendon and is explained further in our post on Achilles tendinopathy and how loading programmes are built.

Footwear, terrain, and why trail runners get this

Peroneal tendons object to sustained sideways demand, which is why certain surfaces and shoes show up repeatedly in the history.

Uneven ground. Trail running puts the foot on a new angle every stride. Each unexpected inward tilt is caught by the peroneals. An hour of technical trail asks far more of them than an hour of flat pavement, even at the same pace and distance.

Cambered surfaces. Running on the sloped shoulder of a road, or always on the same side of a track, tips one ankle inward for the whole session. A small angle held for a long time is exactly the load a tendon accumulates damage from quietly.

Shoes with a high, soft stack. A tall midsole raises you further from the ground and lengthens the lever acting on the ankle when the foot lands off-centre. Some runners find a firmer, lower, wider shoe steadier. Some do not. Worn-out shoes do something similar, because midsoles compress unevenly and usually collapse on the outside edge first.

Sudden changes. A change rather than a level sits behind most of these cases: a first trail season after years of road, a new shoe, a return to sport after time away, or a training block that added distance and hills in the same week. That is the story behind most running overuse injuries, and the one told in our post on shin splints in runners.

How long this honestly takes

Tendons remodel slowly. A tendon sore for six months does not become a comfortable tendon in three weeks, and any timeline offered before an assessment is a guess.

What an assessment can tell you is which way the odds sit. Recovery tends to be quicker when the problem is recent, when pain is mild and predictable, when strength testing is close to the other side, and when you can adjust your training for a while. It tends to be slower when the pain has been there a year, when the calf and the peroneals have lost strength, when foot shape is loading the tendons hard on every step, and when the sport cannot be modified.

Progress in tendon rehab is rarely a straight line, and a flare after a heavier week does not mean the plan has failed. Pain also improves before capacity does, which is the point at which people return to full training and restart the cycle. Your therapist should be testing strength and load tolerance rather than asking only whether it hurts.

There is also a reason not to keep loading indefinitely without review. A 2014 case report in the Journal of Chiropractic Medicine by Bruin and von Piekartz describes a patient with a history of chronic ankle sprains who was treated with manual therapy and eccentric exercise, improved only partly, and turned out to have partial and complete tendon ruptures needing surgery. The authors' conclusion is the useful one: when an injury does not improve with care, tendon rupture should be considered. A plan producing nothing after a fair trial needs rethinking rather than repeating.

What a first visit looks like

Physiotherapy is a direct-access profession in British Columbia, regulated by the College of Health and Care Professionals of BC, so no physician referral is needed to book an assessment. Some extended-health plans require one for reimbursement, so check with your insurer before your first visit.

A first physiotherapy assessment for outer ankle pain spends most of its time on history and testing. Your therapist will ask how the original injury happened, how many times the ankle has been rolled since, where the pain sits, what brings it on, how it behaves the next morning, and what your shoes and training have been doing lately. Bring your running shoes. The wear pattern on the sole is real information.

The physical examination covers ankle and midfoot movement, calf length, standing alignment, strength of the muscles turning the foot outward, single-leg balance, heel raise capacity, and whether the tendons slip when the foot is moved through certain positions. You will likely be asked to walk, and to hop if it is tolerable.

Most cases need no imaging, and results need careful interpretation when it is ordered. A 2023 study in Foot and Ankle Orthopaedics by Smoker and colleagues scanned 170 people with no peroneal symptoms and found abnormalities in 20% of peroneus longus tendons and 12.1% of peroneus brevis tendons. Counting every unusual finding, the figures were 34% and 22%. The authors caution against over-interpreting imaging without a detailed history and physical examination. An abnormal scan in a painful ankle does not prove the scan found the pain.

You should leave the first visit with a working explanation, two or three exercises at a dose you can manage, and a plan for what to change in your training or footwear.

When to see a doctor instead

Book with a physician or go to urgent care rather than starting physiotherapy if any of the following apply. Sudden inability to put weight on the ankle after an injury, bone tenderness over the back edge or tip of either ankle bone, or an obvious deformity all need an X-ray first. Pain that wakes you at night or is present at complete rest, especially in a runner who recently increased load, needs a bone injury ruled out. Fever, spreading redness, or heat around the ankle needs same-day assessment. Numbness, pins and needles, or weakness lifting the foot points at a nerve rather than a tendon. Calf pain with swelling, warmth, or shortness of breath needs emergency assessment, since a blood clot is a medical emergency.

If your ankle injury came from a motor vehicle crash, ICBC funds a set number of physiotherapy treatments without pre-approval when a claim is open, and you can book directly. Workplace injuries go through WorkSafeBC. Physiotherapy is not covered by the BC Medical Services Plan (MSP) for most people, so private extended-health coverage or self-pay is the usual route.

This article is general information, not personal medical advice. A regulated practitioner can confirm whether the patterns described apply to you.

Frequently asked questions

What is peroneal tendinopathy?

Peroneal tendinopathy is pain and reduced load tolerance in the two peroneal tendons that run down the outside of the lower leg, hook around the bony bump on the outer ankle, and pass into the foot. These tendons turn the foot outward and help control the moment your weight rolls over the outside edge of the foot. The pain typically sits behind and below the outer ankle bone and builds with activity rather than appearing suddenly.

How do I know if my outer ankle pain is a tendon or the old ligament?

The history usually separates them. A ligament problem tends to produce a feeling that the ankle might give way, especially on uneven ground, while a tendon problem produces pain that builds during activity and is worst the following morning. Location helps too: ligament pain sits in front of and below the outer ankle bone, peroneal pain sits behind and below it. A physiotherapist can confirm it by testing resisted outward movement of the foot and pressing along the tendons.

Why did my ankle pain start months after the sprain healed?

Because the sprain changed how the ankle is controlled, and the tendons took on more of that work. The same inward roll that injures the lateral ligaments loads the peroneal tendons hard, and they continue to compensate for an ankle that has become less certain of itself. Tendon problems accumulate over weeks and months rather than appearing at the moment of injury, so the timeline often looks disconnected from the original event.

Is peroneal tendon injury often missed?

Yes. A 2021 case report and literature review in Trauma Case Reports reports that only 60% of peroneal tendon injuries are diagnosed at the initial visit to an orthopaedic surgeon, with a median time to correct diagnosis of 7 months for the rest. A 2013 review in the British Journal of Radiology describes these conditions as still tending to be underdiagnosed as a cause of lateral ankle pain. Outer ankle pain lasting more than about three months after a sprain is worth a proper assessment.

Could it be a stress fracture in the fibula instead?

It could, and the two feel different. A bone stress injury tends to be sharply localised to a small patch you can cover with one fingertip, hurts on hopping or impact rather than on resisted movement, and gets worse with running load rather than warming up with it. Pain at rest or at night raises the suspicion further. A rapid increase in training, low energy availability, or a previous stress fracture all make it more likely and warrant medical assessment.

What does it mean if my tendons snap or click over the ankle bone?

That can mean the tendons are slipping out of the shallow groove they normally sit in behind the outer ankle bone, usually because the band of tissue holding them there was torn during a sprain. People describe a snap, a pop, or a sense that something moves across the bone. This is a mechanical problem that a loading programme alone will often not resolve, and it is one of the situations where a surgical opinion belongs in the conversation early.

Does a high arch cause peroneal tendinopathy?

A high-arched foot with an inward-tipped heel places body weight further toward the outside edge of the foot, so the peroneal tendons work harder on every step. A 2013 review in the British Journal of Radiology notes that this foot position appears to be a predisposing factor for peroneus longus tendon injury. Foot shape is not something to correct. It tells your therapist how much capacity these tendons need and whether footwear or orthotic changes are likely to help.

What exercises treat peroneal tendinopathy?

The core is graded loading of the muscles that turn the foot outward, usually starting with isometric holds against a band or a wall, then progressing to slow resisted work through range. Calf strengthening through heel raises matters because the calf and the peroneals share control of the ankle at push-off. Balance and single-leg control work is then added, since a 2024 meta-analysis in BMC Sports Science, Medicine and Rehabilitation found combining strength and balance training produced larger gains in self-reported function than either alone. The specific selection and dose depend on your assessment.

How long does peroneal tendinopathy take to recover?

It depends on how long the pain has been present, how irritable it is, how much strength has been lost, and how much your activity can be adjusted. Tendons remodel slowly, and a problem present for six months does not resolve in three weeks. Progress is rarely a straight line, and pain usually improves before capacity does, which is why your therapist should be testing strength and load tolerance rather than relying on the pain score alone.

Should I get an MRI or ultrasound?

Most cases do not need imaging, and the findings need careful interpretation when they are obtained. A 2023 study in Foot and Ankle Orthopaedics scanned 170 people with no peroneal symptoms and found abnormalities in 20% of peroneus longus tendons and 12.1% of peroneus brevis tendons. The authors caution against interpreting imaging without a detailed history and physical examination. Imaging is most useful when a tear, a slipping tendon, or a bone injury is suspected, or when a fair trial of treatment has produced nothing.

Can I keep running with peroneal tendinopathy?

Often yes, at a modified volume and on friendlier surfaces. Complete rest tends to work against you, because tendons lose capacity quickly when they are unloaded. The usual adjustments are reducing distance, avoiding technical trails and cambered road shoulders for a while, and using the 24-hour pain response as the guide: pain that settles within a day and does not build across the week is generally acceptable, while pain that is worse the next morning means the dose was too high.

Do I need a referral to see a physiotherapist in BC?

No. Physiotherapy is a direct-access profession in British Columbia, regulated by the College of Health and Care Professionals of BC, so you can book an assessment without a physician's referral and without a confirmed diagnosis. Some extended-health insurance plans require a referral for reimbursement even though the profession does not, so confirm with your insurer before your first visit.

Sources

• Papadakis et al., "Peroneus brevis tendon injuries: Report of two cases and review of literature," Trauma Case Reports, 2021
• Schubert, "MRI of peroneal tendinopathies resulting from trauma or overuse," British Journal of Radiology, 2013
• Gomes et al., "Diagnostic accuracy of the Ottawa ankle rule to exclude fractures in acute ankle injuries in adults: a systematic review and meta-analysis," BMC Musculoskeletal Disorders, 2022
• Su et al., "Effects of combination of strength and balance training on postural control and functionality in people with chronic ankle instability: a systematic review and meta analysis," BMC Sports Science, Medicine and Rehabilitation, 2024
• Martin et al., "Ankle Stability and Movement Coordination Impairments: Lateral Ankle Ligament Sprains Revision 2021," Journal of Orthopaedic and Sports Physical Therapy, 2021
• Smoker et al., "Prevalence of Abnormal Ultrasonographic Findings in Asymptomatic Peroneal Tendons," Foot and Ankle Orthopaedics, 2023
• Bruin and von Piekartz, "Musculoskeletal Management of a Patient With a History of Chronic Ankle Sprains: Identifying Rupture of Peroneal Brevis and Peroneal Longus With Diagnostic Ultrasonography," Journal of Chiropractic Medicine, 2014
• College of Health and Care Professionals of BC, physiotherapist scope of practice