Posterior Ankle Pain in Dancers: Os Trigonum Syndrome and FHL Tendinopathy

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

Posterior ankle pain in dancers — particularly classical ballet dancers who repeatedly go en pointe or demi-pointe — has two common causes: os trigonum syndrome (impingement of the os trigonum between the tibia and calcaneus in forced plantarflexion) and flexor hallucis longus (FHL) tendinopathy or triggering. Both conditions produce posterior ankle pain with plantarflexion and are specifically associated with activities requiring maximal ankle plantarflexion. Distinguishing them is important because their surgical treatments are different, though they frequently coexist.

Os Trigonum Syndrome

The os trigonum is a secondary ossification center of the posterior talar process — present in 7–25% of the population — that fails to fuse with the talus and remains as a separate bone connected by a synchondrosis. In forced plantarflexion (ballet pointe position, football kicking, soccer striking), the os trigonum is compressed between the posterior tibia and the superior calcaneus — producing posterior ankle pain. Clinical features: posterior ankle pain reproduced with passive forced plantarflexion (the posterior impingement test); point tenderness posterior to the peroneal tendons in the retromalleolar-calcaneal space; the FHL tendon runs adjacent to the os trigonum and is often simultaneously inflamed. Imaging: lateral X-ray identifies the os trigonum; MRI shows edema at the synchondrosis and surrounding soft tissue inflammation. Conservative management: activity modification (reduce pointe work); corticosteroid injection at the os trigonum synchondrosis under ultrasound guidance; boot immobilization for acute flare. Surgical: posterior arthroscopic os trigonum excision — 6–8 weeks recovery; excellent results in dancers with early return to dance.

FHL Tendinopathy and Triggering

The FHL tendon passes through a fibro-osseous tunnel at the posterior ankle adjacent to the os trigonum — stenosis of this tunnel or FHL tendon thickening produces triggering (‘dancer’s tendinitis’): a palpable and audible clicking or snapping with active great toe flexion-extension, sometimes with the great toe intermittently locking in flexion. Treatment: FHL tendon sheath corticosteroid injection; FHL tendon sheath release (tenosynovectomy) when conservative management fails — usually performed concurrently with os trigonum excision when both are present. Dr. Biernacki at Balance Foot & Ankle evaluates posterior ankle pain with dynamic ultrasound and treats os trigonum syndrome and FHL tendinopathy in dancers and athletes. Call (810) 206-1402 at our Bloomfield Hills or Howell office.

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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

Posterior Ankle Pain & Os Trigonum Treatment in Michigan

Pain at the back of the ankle during plantarflexion — common in dancers and soccer players — may indicate os trigonum syndrome or FHL tendinopathy. Our podiatrists provide accurate diagnosis and both conservative and arthroscopic surgical treatment options.

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Clinical References

1. Abramowitz Y, Wollstein R, Barzilay Y, et al. Outcome of resection of a symptomatic os trigonum. J Bone Joint Surg Am. 2003;85(6):1051-1057.
2. Hedrick MR, McBryde AM. Posterior ankle impingement. Foot Ankle Int. 1994;15(1):2-8.
3. Ribbans WJ, Ribbans HA, Cruickshank JA, Wood EV. The management of posterior ankle impingement syndrome in sport: a review. Foot Ankle Surg. 2015;21(1):1-10.