Peroneal Tendon Disorders
Overview
The peroneal tendons run behind the outer ankle and help stabilise the foot. Problems include tendinopathy, split tears, rupture and painful snapping or dislocation. These conditions often coexist with outer ankle instability or a high-arched foot that tilts inwards. A scan finding alone does not establish the pain source. Treatment should address the tendon and any instability, bone prominence or alignment issue that continues to overload it.
Symptoms
- Pain or swelling behind or below the outer ankle.
- Pain along the outer foot or beneath the cuboid.
- Snapping or a tendon moving over the fibula.
- Weakness or pain with pushing the foot outwards.
- Recurrent ankle sprains or reduced confidence on uneven ground.
Causes
An acute ankle injury can tear a tendon or the strong tissue band that holds it behind the fibula. Repeated loading can produce tendinopathy or a lengthwise split, particularly when the ankle is unstable, the heel tilts inwards, the bony groove behind the outer ankle is shallow or nearby bone prominences crowd the tendons.
Pain in this region can also arise from the ankle joint, a nearby sensory nerve, the heel bone, the fifth metatarsal or other tissues around the outer ankle. Diagnosis should therefore not rely on MRI wording alone.
Assessment and imaging
Examination follows both tendons from the calf to their insertions and assesses resisted strength, tendon movement, ankle ligaments, hindfoot alignment and foot shape. Dynamic ultrasound is useful for snapping or subluxation. MRI can define tendinopathy and tears, while weight-bearing X-rays assess alignment and associated bone problems.
Non-surgical treatment
- Temporary modification of running, uneven-ground and side-to-side loading.
- A brace or short period in a Moonboot for an acute flare or selected tear.
- Progressive peroneal, calf and whole-limb strengthening with balance rehabilitation.
- An insole or footwear adjustment when a high-arched inward-tilting foot or focal pressure contributes.
- Treatment of associated lateral ankle instability.
- Pain-relieving or anti-inflammatory medicine after checking that it is suitable for you. Injection near a peroneal tendon requires a precise diagnosis and caution because injection into tendon tissue can weaken it.
When may surgery be considered?
Surgery may be discussed for persistent pain from a defined tear, recurrent tendon dislocation, complete rupture, mechanical impingement or symptoms that remain limiting after appropriate rehabilitation. The condition of both tendons and the underlying alignment influence the procedure.
Options include removing unhealthy tissue and repairing a split tear, reshaping the tendon, repairing the tissue that holds it behind the fibula, deepening the bony groove, treating an impinging bone prominence, or joining or transferring tendons when one cannot be reconstructed. Correction of a high-arched inward-tilting foot or repair of unstable ankle ligaments may be needed at the same operation.
Recovery
A repaired or reconstructed tendon is protected in a splint, cast or Moonboot, often with restricted weight-bearing and movement initially. Rehabilitation then restores ankle movement, tendon gliding, strength, balance and sport-specific control.
Recovery is longer when surgery includes tendon transfer, ligament reconstruction or bone realignment. Swelling and weakness can persist for months.
Risks and limitations
- Wound problems, infection, blood clots or anaesthetic complications.
- Irritation of a nearby sensory nerve, numbness or scar sensitivity.
- Tendon adhesions, stiffness, weakness or recurrent tearing.
- Persistent snapping, pain or instability.
- Failure to address an underlying high-arched inward-tilting foot or ligament instability.
- Need for further surgery.
Frequently asked questions
Can a peroneal tendon tear heal without surgery?
Some partial or stable tears improve with protection and rehabilitation. Recurrent mechanical dislocation, complete rupture or a persistent tear that clearly matches the symptoms is less likely to settle without surgery.
Why does foot shape matter?
A heel that remains tilted inwards can repeatedly overload the peroneal tendons and outer ankle, increasing the risk of persistent or recurrent symptoms.
Is a snapping tendon dangerous?
Repeated dislocation can damage the tendon. Acute traumatic snapping or persistent symptoms should be assessed.
Can both peroneal tendons be damaged?
Yes. Both are inspected because treatment depends on how much healthy tendon remains.
Will MRI always show the cause?
No. Movement or snapping that occurs only during activity can be missed on an MRI taken at rest, and scan abnormalities must match the symptoms and examination.
General information
This page provides general information only. It cannot diagnose your condition or replace advice from a clinician who has assessed you. Your treatment and recovery plan may differ from the examples described here. Follow the instructions from your treating team. In an emergency, call 000 or attend the nearest emergency department.