Peroneal Tendon Tear

Overview

what it is and why it matters

Labeled anatomy of the foot showing tarsal bones (calcaneus, talus, cuneiforms, cuboid, navicular), metatarsals, and phalanges. — **Foot and ankle anatomy.** The foot contains 26 bones: seven tarsals in the back half (including the talus and the heel bone), five metatarsals forming the arch, and fourteen phalanges in the toes. The ankle joint sits between the talus and the two leg bones — tibia and fibula.

The peroneal tendons (brevis and longus) run in a groove behind the lateral malleolus and evert the foot, protecting against ankle inversion. Longitudinal splits of the peroneus brevis — especially at the retromalleolar groove — are the most common peroneal tendon injury. They are often associated with lateral ankle instability and can be subtle, presenting as persistent lateral ankle pain after an "ankle sprain" that fails to resolve.

Diagnosis

exam first, imaging second

Tenderness posterior and inferior to the lateral malleolus, pain with resisted eversion, and peroneal squeeze test. MRI is the definitive test, showing longitudinal split tears ("flattened" or bifid peroneus brevis on axial cuts). Dynamic ultrasound can demonstrate subluxation of the tendons over the malleolus.

Treatment Path

how care progresses at OSI

Immobilization

4–6 weeks of casting or walking boot for partial tears.

Physical therapy

Eversion strengthening and proprioceptive retraining.

Surgical Options at OSI

if non-operative care isn't enough

Full-thickness longitudinal tears, subluxing tendons, and failed conservative care require surgical management.

Overview

Diagnosis

Treatment Path

Immobilization

Physical therapy

Surgical Options at OSI

Further Reading

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