What Are the Peroneal Tendons? For specialized treatment, see our peroneal tendon care at Balance Foot & Ankle.
The peroneal tendons are two tendons—the peroneus longus and peroneus brevis—that run behind the lateral (outer) ankle malleolus through a fibro-osseous groove and attach to the foot. The peroneus brevis attaches to the base of the fifth metatarsal (the bony prominence on the outer foot), while the peroneus longus courses under the foot to attach at the first metatarsal base and medial cuneiform. Together they evert the foot (turn the sole outward) and provide critical dynamic stability against ankle inversion. These tendons are frequently injured during ankle sprains and are a significant cause of persistent lateral ankle pain that is often misdiagnosed as a chronic sprain.
Types of Peroneal Tendon Injuries
Peroneal tendinopathy (tendinitis/tendinosis) is the most common peroneal injury, resulting from repetitive overuse, particularly in runners and athletes with high-arched feet or chronic ankle instability. It produces diffuse posterior and inferior lateral ankle pain that worsens with activity and improves with rest. The tendons are tender to palpation along their course behind the fibula.
Peroneus brevis tears are longitudinal splits within the tendon, typically at the posterior fibular groove where the tendon is under the most mechanical stress. They are frequently associated with ankle sprains and chronic instability. The peroneus brevis attachment at the fifth metatarsal base can also avulse (pull off) during ankle sprains, producing a bony fragment on X-ray that mimics a fifth metatarsal fracture. Peroneus longus tears are less common but occur at the cuboid tunnel (where the tendon curves around the cuboid bone) and can be associated with a painful os peroneum (accessory bone in the tendon).
Peroneal tendon subluxation occurs when the tendons dislocate out of their groove behind the fibula—usually from an acute ankle dorsiflexion injury that tears the superior peroneal retinaculum (the tissue holding the tendons in their groove). Patients feel and sometimes hear a snapping sensation at the outer ankle. This is distinct from a sprain and requires specific treatment.
Diagnosis
Clinical examination includes palpation of the peroneal tendons along their course, resisted eversion testing (pain or weakness with resisted eversion suggests tendon pathology), and provocative tests for subluxation (circumduction of the ankle while palpating the tendons behind the fibula). X-rays assess for avulsion fractures and os peroneum. MRI is the most valuable imaging study for characterizing tendon tears (longitudinal splits, partial tears, complete tears), tendinosis, and retinaculum integrity. Ultrasound can dynamically assess subluxation and tendinopathy.
Treatment
Conservative treatment for peroneal tendinopathy includes activity modification, physical therapy (eccentric strengthening, stretching of the peroneal muscle-tendon unit, proprioceptive training), ankle bracing to reduce inversion stress, and temporary immobilization in a CAM boot for acute exacerbations. Most cases of tendinopathy respond to 6–12 weeks of structured rehabilitation.
Small longitudinal peroneus brevis tears can be managed conservatively, but larger tears, complete tears, and tendon subluxation typically require surgical repair. Peroneal surgery involves debridement of the torn tendon edges and repair, reconstruction of the superior peroneal retinaculum for subluxation, and—when the tendon is extensively damaged—tendon transfer procedures. Recovery after peroneal surgery involves 6 weeks of non-weight-bearing followed by progressive rehabilitation and return to sport at 4–6 months. Addressing concurrent ankle instability (ligament reconstruction) at the time of peroneal surgery improves outcomes by eliminating the mechanical cause of tendon stress.
Frequently Asked Questions
How do I know if I have a peroneal tendon injury vs. an ankle sprain?
Both ankle sprains and peroneal tendon injuries can result from an inversion mechanism and cause lateral ankle pain and swelling. Key distinguishing features: peroneal tendon pain is located posterior (behind) to the lateral malleolus, along the tendon course, while typical ankle sprain pain is anterior and inferior to the malleolus (at the ATFL and CFL ligaments). Peroneal pain is reproduced by resisted eversion against resistance, while sprain pain is reproduced by palpation of the ligament. Peroneal subluxation produces a characteristic snapping sensation behind the fibula. If lateral ankle pain persists beyond 6–8 weeks of appropriate sprain treatment, MRI evaluation for peroneal pathology is warranted—peroneal tendon injuries are a common cause of chronic lateral ankle pain that is initially misdiagnosed as a persistent sprain.
Can a peroneal tendon tear heal without surgery?
Small, partial peroneal tendon tears—particularly small longitudinal splits of the peroneus brevis—can sometimes heal or become asymptomatic with conservative treatment: immobilization in a boot, physical therapy, and activity modification over 3–6 months. However, complete tears, large longitudinal splits, and tears in patients with concurrent ankle instability rarely resolve with conservative care alone and typically require surgical debridement and repair. Peroneal tendon subluxation (dislocation from the fibular groove) also generally does not respond to non-surgical treatment and requires retinaculum reconstruction. The decision between conservative and surgical treatment is based on tear size and type on MRI, the patient’s activity demands, and response to initial conservative management.
What causes peroneal tendon injuries?
Peroneal tendon injuries result from three main mechanisms: acute trauma (ankle inversion sprains that forcefully load the peroneal tendons as they resist inversion), repetitive overuse (running, jumping sports, activities with high mileage or training load increases), and anatomical predisposition (high-arched foot—pes cavus—which places the peroneal tendons under increased tension; a prominent or aberrantly shaped fibular groove; and a low-lying peroneus brevis muscle belly that fills the groove). Chronic lateral ankle instability is a major risk factor—recurrent ankle sprains repeatedly stress the peroneal tendons, which work harder to compensate for lax ligaments, predisposing them to overuse tears and subluxation. Athletes who have had recurrent ankle sprains and develop persistent lateral ankle pain should be evaluated for peroneal pathology.
Medical References & Sources
- American Orthopaedic Foot & Ankle Society — Peroneal Tendon Injuries
- PubMed Research — Peroneal Tendon Injury Outcomes
- PubMed Research — Peroneus Brevis Tears and Ankle Instability
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Dr. Tom Biernacki, DPM is a board-certified podiatric surgeon at Balance Foot & Ankle in Howell and Bloomfield Hills, Michigan. He diagnoses and treats peroneal tendon injuries, including tendinopathy, longitudinal tears, and subluxation, with conservative and surgical approaches.
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Dr. Tom Biernacki, DPM is a double board-certified podiatrist and foot & ankle surgeon at Balance Foot & Ankle Specialists in Southeast Michigan. With over a decade of clinical experience, he specializes in heel pain, bunions, diabetic foot care, sports injuries, and minimally invasive surgery. Dr. Biernacki is a member of the APMA and ACFAS, and his patient education content on MichiganFootDoctors.com and YouTube has reached over one million views.
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