Peroneal Tendon Tear — Longitudinal Split & Outer Ankle Pain Michigan

Medically reviewed by Dr. Tom Biernacki, DPM — Board-Certified Podiatric Surgeon — Balance Foot & Ankle, Howell & Bloomfield Hills, MI. Last updated April 2026.

What Is a Peroneal Tendon Tear?

The peroneal tendons — peroneus longus and peroneus brevis — run along the outer (lateral) aspect of the ankle, secured in a groove behind the lateral malleolus by the superior peroneal retinaculum. Peroneal tendon tears are most commonly longitudinal splits rather than complete transverse ruptures: the tendon frays along its length like a rope unraveling, rather than snapping cleanly. The peroneus brevis tendon is most frequently involved, typically splitting around the posterior edge of the fibula. These injuries cause persistent lateral ankle pain, swelling, and weakness that is often misdiagnosed as a chronic ankle sprain — in fact, up to 25% of patients with “chronic ankle sprains” have concurrent peroneal tendon pathology. At Balance Foot & Ankle in Howell and Bloomfield Hills, Michigan, Dr. Tom Biernacki, DPM evaluates and treats peroneal tendon injuries. Call (810) 206-1402.

Causes and Risk Factors

Peroneal tendon tears typically result from: acute inversion ankle sprain (the peroneal tendons contract forcefully to resist ankle rolling, creating sudden tensile overload — brevis tears at the fibular groove edge); chronic repetitive overloading in high-arch (cavus) foot type where the ankle rolls outward repeatedly during gait; and peroneal subluxation — where the retinaculum is torn, allowing the tendons to snap over the fibula during activity, creating mechanical abrasion. Risk factors: high-arch foot type (increases lateral column loading); previous ankle sprains (attenuates retinaculum); and the distal fibular groove shape (a shallow or convex groove provides less tendon containment than a concave groove).

Diagnosis — MRI vs. Ultrasound

Clinical findings: tenderness directly over the peroneal tendons posterior to the lateral malleolus (distinct from ligament sprain tenderness); pain with resisted eversion; and swelling in the peroneal tendon sheath. Both MRI and musculoskeletal ultrasound can diagnose longitudinal peroneal tears with high sensitivity. MRI provides better visualization of the full tendon extent and associated retinaculum; ultrasound allows dynamic assessment — the tendons can be imaged in real time during ankle motion to assess subluxation. We perform in-office diagnostic ultrasound at Balance Foot & Ankle. CT arthrogram is reserved for cases with concurrent osteochondral lesion or bone pathology.

Conservative Management — 60–70% Success in Partial Tears

Conservative management is appropriate for partial-thickness longitudinal tears without subluxation: a cam boot or short leg cast for 4–6 weeks to immobilize the tendons; followed by physical therapy focusing on peroneal strengthening, proprioception retraining, and lateral ankle stabilization. Custom orthotics with a lateral flange and varus correction for cavus foot types to reduce the inversion stress that loads the peroneal tendons. Platelet-rich plasma (PRP) injection into the peroneal tendon sheath — emerging evidence suggests improved healing rates in partial-thickness tendon tears. Return to full activity typically 3–4 months. Conservative management is less successful in high-grade tears (>50% tendon thickness), tears with subluxation, or in patients with cavus foot who continue to overload the lateral column.

Surgical Management — Debridement, Tubularization, and Repair

Surgical treatment for peroneal tendon tears depends on tear grade and tendon viability: low-grade longitudinal split — debridement of frayed tendon edges and tubularization (suturing the split tendon closed) preserves tendon volume and restores function; high-grade split with >50% viable tissue — debridement and repair; peroneus brevis tear with insufficient viable tissue — tenodesis (suturing the damaged brevis tendon to the longus tendon, which becomes the primary evertor); and concurrent retinaculum repair for subluxating tendons. Fibular groove deepening may be added if the groove is shallow. Recovery: 6–8 weeks non-weight-bearing after tendon repair, 4–5 months to full athletic activity.

Peroneal Tendon Injury Management in Howell & Bloomfield Hills Michigan

Dr. Tom Biernacki, DPM evaluates persistent lateral ankle pain with in-office ultrasound and provides comprehensive conservative and surgical management of peroneal tendon injuries at Balance Foot & Ankle. Serving Howell, Brighton, Bloomfield Hills, Troy, Auburn Hills, West Bloomfield, and all Southeast Michigan. If your “ankle sprain” has not fully resolved at 6–8 weeks, peroneal tendon pathology should be evaluated. Book your evaluation or call (810) 206-1402.

Peroneal Tendon Tear Treatment in Michigan

Peroneal tendon tears cause chronic outer ankle pain that’s frequently misdiagnosed as recurrent ankle sprains. Our podiatrists use ultrasound and MRI to accurately diagnose longitudinal splits and provide targeted conservative and surgical treatment.

Learn About Our Peroneal Tendon Treatments → | Book Your Appointment | Call (810) 206-1402

Clinical References

1. Dombek MF, et al. Peroneal tendon tears: a retrospective review. J Foot Ankle Surg. 2003;42(5):250-258.
2. Redfern D, Myerson M. The management of concomitant tears of the peroneus longus and brevis tendons. Foot Ankle Int. 2004;25(10):695-707.
3. Sobel M, et al. Longitudinal splitting of the peroneus brevis tendon: an anatomic and histologic study of cadaveric material. Foot Ankle. 1991;12(3):165-170.

Your Board-Certified Podiatrists

Dr. Tom Biernacki, DPM

Board-Certified · FACFAS

Dr. Carl Jay, DPM

Board-Certified Podiatrist

Dr. Daria Gutkin, DPM

Podiatrist

Dr. Tom Biernacki, DPM

Affiliate Disclosure: This page contains affiliate links to products we recommend. If you purchase through these links, Balance Foot & Ankle may earn a small commission at no additional cost to you. We only recommend products we use with our patients.

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.