Flexor Hallucis Longus Tendinopathy: The Dancer’s Tendon

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

The flexor hallucis longus (FHL) tendon runs from the posterior lower leg through a fibro-osseous tunnel behind the medial malleolus to insert at the base of the distal phalanx of the great toe. It is the primary plantarflexor of the hallux — a function critically important in ballet dancers (who rely on it for pointe work), runners, and gymnasts. FHL tendinopathy is underdiagnosed in non-dancer populations, often labeled as posterior ankle pain or Achilles pathology without specific FHL examination.

Anatomy and Mechanism of Injury

The FHL has two critical zones of potential pathology: the fibro-osseous tunnel behind the medial malleolus and sustentaculum tali where it is compressed during maximum ankle plantarflexion, and the knot of Henry at the plantar midfoot where it crosses the flexor digitorum longus. In ballet dancers, repeated forced plantarflexion compresses the FHL against the posterior talar process — producing stenosing tenosynovitis analogous to trigger finger in the hand. In runners and hikers, hypertrophic muscle belly extending too distally into the tunnel creates impingement. A low-lying FHL muscle belly is an important anatomical variant detectable on MRI that predisposes to this impingement pattern.

Clinical Presentation

FHL tendinopathy presents with posteromedial ankle pain provoked by hallux dorsiflexion and active great toe plantarflexion against resistance. Triggering or crepitus with great toe motion — a “trigger hallux” phenomenon — is pathognomonic when present. Tenderness is maximal posterior to the medial malleolus and along the FHL tunnel, distinct from the Achilles insertion or plantar fascia origin. Nodular tendon thickening may be palpable. Importantly, passive great toe dorsiflexion (the “Silfverskiold-modified FHL stretch test”) reproduces posterior ankle pain in the majority of affected patients.

Diagnostic Imaging

Musculoskeletal ultrasound demonstrates FHL tendon thickening, peritendinous fluid, and dynamic assessment of triggering or impingement in real time. MRI provides superior characterization of FHL intrasubstance tears, tunnel stenosis, and the presence of a low-lying muscle belly. Posterior ankle impingement from os trigonum or posterior talar process hypertrophy frequently co-exists with FHL pathology and must be identified as it may require simultaneous surgical management.

Treatment

Conservative management includes activity modification, FHL stretching (dorsiflexing the great toe with the ankle in neutral), physical therapy targeting eccentric FHL loading, and ultrasound-guided corticosteroid injection into the FHL tendon sheath for tenosynovitis. Custom orthotics with forefoot posting may reduce FHL demand in functional hallux limitus. Surgical FHL tendon sheath release is indicated for stenosing tenosynovitis refractory to 3–6 months of conservative care and produces reliable, rapid return to activity. Dr. Biernacki at Balance Foot & Ankle provides hands-on exam plus imaging when needed and treatment of FHL tendinopathy including diagnostic ultrasound and surgical release when needed. Call (810) 206-1402 for an evaluation at our Bloomfield Hills or Howell office.

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When to See a Podiatrist

Many foot conditions can be managed conservatively at home, but some require professional evaluation. See a podiatrist promptly if you experience:

• Pain that persists for more than 2 weeks despite rest
• Swelling, redness, or warmth that isn’t improving
• Numbness, tingling, or burning in the feet
• A wound or sore that is not healing within 2 weeks
• Any foot concern if you have diabetes or poor circulation
• Nail changes that suggest fungal infection or other problems

At Balance Foot & Ankle, our three board-certified podiatrists — Dr. Tom Biernacki, Dr. Carl Jay, and Dr. Daria Gutkin — provide comprehensive foot and ankle care at our Howell and Bloomfield Hills offices. Most insurance plans are accepted.

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Board-certified podiatrists Dr. Tom Biernacki, Dr. Carl Jay, and Dr. Daria Gutkin see patients daily at our Howell and Bloomfield Township, MI offices.

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In-Office Treatment at Balance Foot & Ankle

If home care isn’t resolving your your foot or ankle concern, a visit with a board-certified podiatrist is the fastest path to accurate diagnosis and a personalized plan. At Balance Foot & Ankle Specialists, Dr. Tom Biernacki, Dr. Carl Jay, and Dr. Daria Gutkin offer same-day and next-day appointments at both our Howell and Bloomfield Hills offices. We perform on-site diagnostic ultrasound, digital X-ray, conservative care, advanced regenerative treatments, and minimally invasive surgery when indicated.

Call (810) 206-1402 or request an appointment online. Most insurance plans accepted, including Medicare, Blue Cross Blue Shield, Aetna, Cigna, and United Healthcare.

Most Common Mistake We See

The most common mistake we see is: Waiting too long before seeking care. Fix: any foot pain lasting more than 4 weeks, or any sudden severe symptom, deserves a professional evaluation rather than more rest.

Warning Signs That Need Same-Day Care

Frequently Asked Questions

When should I see a podiatrist?

If symptoms persist past 2 weeks, affect your normal activity, or are accompanied by red-flag symptoms (warmth, redness, swelling, inability to bear weight).

What does treatment cost?

Most diagnostic visits and conservative treatments are covered by Medicare and major insurers. Out-of-pocket costs vary by your specific plan.

How quickly can I get an appointment?

Most non-urgent cases see us within 5 business days. Urgent cases (sudden pain, possible fracture) typically same or next business day.