Flexor Hallucis Longus Tendinopathy: Dancer’s Tendinitis and Posterior Ankle Pain

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

Flexor hallucis longus (FHL) tendinopathy is the most common cause of posterior ankle and medial hindfoot pain in dancers — particularly ballet dancers working in demi-pointe and full-pointe positions — though it increasingly affects recreational runners, gymnasts, and any athlete requiring repetitive forceful great toe plantarflexion. The FHL tendon is uniquely vulnerable at the fibro-osseous tunnel beneath the sustentaculum tali, where it is subject to significant compressive and tensile forces during toe-off and plantarflexion loading.

Anatomy and Mechanism of Injury

The FHL arises from the posterior fibula and courses through a tight fibro-osseous tunnel between the medial and lateral tubercles of the posterior talus — the same region implicated in posterior ankle impingement. It then passes beneath the sustentaculum tali in a second constrictive tunnel before inserting on the distal phalanx of the hallux. During ballet pointe work, the FHL undergoes near-maximal excursion through both tunnels simultaneously — creating high friction and compressive load that drives chronic tendinosis and, in severe cases, longitudinal splitting or partial tears. Triggering of the hallux (“trigger toe”) occurs when intratendinous nodule formation prevents smooth gliding through the retrotalar pulley.

Clinical Presentation

Posterior ankle and medial heel pain exacerbated by great toe plantarflexion is the hallmark presentation. Resisted great toe plantarflexion in ankle plantarflexion reproduces pain at the posterior medial ankle. Passive dorsiflexion of the hallux (Strayer test) at various ankle positions localizes the restricted tunnel segment. A palpable nodule at the medial ankle producing “clicking” or triggering with hallux motion is pathognomonic for intratendinous nodule formation. Tenosynovitis produces soft-tissue swelling along the tendon course from the posterior ankle to the plantar midfoot.

Nonoperative Management

Activity modification is the first intervention — reducing or eliminating repetitive forced plantarflexion activities for 6–8 weeks. Custom orthotics with a first metatarsal cutout reduce FHL load during push-off in walking. Physical therapy focuses on intrinsic foot muscle strengthening, FHL eccentric strengthening through restricted range, and gastrocnemius/soleus flexibility to reduce compensatory FHL demands. Ultrasound-guided corticosteroid injection into the FHL tendon sheath (avoiding intratendinous injection) reduces tenosynovitis and provides a therapeutic window for rehabilitation. PRP injection is preferred when significant intratendinous pathology is present on ultrasound.

Surgical Options

When conservative management fails after 3–6 months, endoscopic FHL tendon release through the fibro-osseous tunnel at the posterior talus provides reliable symptom relief with minimal morbidity. Two posteromedial portals allow complete retrotalar pulley release under direct visualization. Any intratendinous nodule preventing smooth excursion is débrided. Concurrent posterior ankle impingement (os trigonum excision) is addressed through the same portals. Open FHL tenolysis through a medial posteromalleolar approach is reserved for failed endoscopic release or significant intratendinous pathology requiring open débridement.

Posterior Ankle Pain Evaluation — Balance Foot & Ankle

Dr. Biernacki diagnoses FHL tendinopathy with on-site diagnostic ultrasound. Serving Bloomfield Township, Howell, and all of Michigan.

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Frequently Asked Questions

How do I know if I sprained or broke my ankle?

Both cause pain, swelling, and difficulty walking. Key differences: fractures often cause more immediate severe pain, tenderness directly over bone (not just ligament), and inability to bear any weight. X-rays and the Ottawa Ankle Rules help determine if imaging is needed.

How long does an ankle sprain take to heal?

Grade I (mild): 1–2 weeks. Grade II (moderate): 3–6 weeks. Grade III (complete tear): 2–3 months. Chronic instability from improperly treated sprains can persist and may require surgery.

What is the best treatment for a sprained ankle?

RICE protocol (Rest, Ice, Compression, Elevation) for the first 48–72 hours, followed by protected weight-bearing as tolerated. Physical therapy rehabilitation is critical for high-grade sprains to restore strength and proprioception and prevent chronic instability.

Need Treatment at Balance Foot & Ankle?

Dr. Tom Biernacki, Dr. Carl Jay, and Dr. Daria Gutkin see patients at our Howell and Bloomfield Township offices.

Book Online or call (810) 206-1402

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.