Medically reviewed by Dr. Tom Biernacki, DPM
Board-certified podiatric surgeon | Balance Foot & Ankle, Howell & Bloomfield Hills, MI
Last reviewed: May 2026
The most important clinical decision with Posterior Ankle Pain: 10 Causes, Key Tests & How to Get the Right Diagnosis isn’t which treatment to choose — it’s identifying which subtype you have first. Our podiatrists see patients treated for the wrong subtype for months before the correct diagnosis leads to full resolution. Call (810) 206-1402 — expert podiatric care across Michigan.
Posterior ankle pain — pain behind the ankle — is a diagnostically rich area. Multiple tendons, bones, and nerves converge at the back of the ankle, and getting the diagnosis right determines whether treatment succeeds or fails. This is one of the most commonly mismanaged pain locations in the foot because the differential includes conditions requiring completely different approaches.
Posterior Ankle Pain: Full Differential Diagnosis
| Condition | Pain Location (Posterior Ankle) | Aggravating Position | Key Test / Finding | Treatment Direction |
|---|---|---|---|---|
| Insertional Achilles tendinopathy | Posterior heel at tendon-bone junction; bone attachment | Going upstairs; wearing shoes with heel counter; plantarflexion resistance | Tender at posterior calcaneal insertion; calcification on X-ray | Heel lift; eccentric strengthening; avoid compression |
| Non-insertional (mid-substance) Achilles tendinopathy | 2–6 cm above insertion; tendon body | Running; stairs; first steps AM | Tender along tendon body; fusiform swelling at tendon midportion | Eccentric calf loading protocol (Alfredson); load management |
| Achilles tendon rupture | Sudden gap felt at tendon; acute onset with pop | Happened with jump, sprint, or sudden plantarflexion | Thompson test (calf squeeze) — no plantarflexion = positive = rupture | Surgical vs. functional bracing (shared decision) |
| Haglund’s deformity (pump bump) | Posterosuperior calcaneal prominence; where Achilles meets bone | Shoe heel counter; pressure on prominence; running | Visible/palpable bony protrusion at posterosuperior calcaneus; X-ray confirms | Open-back shoe; heel lift; surgical prominence removal + Achilles repair if needed |
| Retrocalcaneal bursitis | Deep to Achilles at posterosuperior calcaneus; between tendon and bone | Plantarflexion; shoe pressure; pinching Achilles against calcaneus | Painful two-finger “pinch” compression at retrocalcaneal space | Heel lift; cortisone injection (avoid intratendinous); ESWT |
| FHL tenosynovitis / trigger toe | Medial posterior ankle; posteromedial | Passive great toe flexion and extension; pushing off | Passive great toe motion reproduces posteromedial posterior ankle pain | PT; sheath injection; surgical release if triggering |
| Os trigonum syndrome | Posterolateral ankle; posterior talar process | Forced plantarflexion — ballet pointe; downhill; shooting in soccer | Nutcracker test: forced passive plantarflexion reproduces posterior pain | Boot rest; cortisone injection; os trigonum excision (open or endoscopic) |
| Tarsal tunnel syndrome (posterior) | Medial ankle; burning/tingling radiates to heel and sole | Prolonged standing; narrow footwear | Tinel’s sign behind medial malleolus; nerve conduction study confirms | Orthotics; injection; surgical tarsal tunnel release |
| Peroneal tendinopathy (retro-malleolar) | Posterior to lateral malleolus; lateral posterior ankle | Eversion against resistance; lateral ankle loading | Tenderness at fibular groove; pain with resisted eversion | Eccentric peroneal strengthening; injection; repair if torn |
| Flexor digitorum longus tendinopathy | Medial posterior ankle, slightly medial to FHL | Resisted toe flexion; going up on toes | Tenderness medial to FHL; differentiate with selective resistance testing of individual toes | Similar to FHL: rest, PT, injection, surgery if needed |
The Most Important Tests for Posterior Ankle Pain
Thompson test: Patient prone, squeeze the calf. If the foot does not plantarflex, the Achilles is ruptured. This is mandatory for any patient presenting with acute posterior ankle pain after a “pop.”
Nutcracker test (plantarflexion stress): Passively move the ankle into maximum plantarflexion while applying a gentle posterior compression. Reproduction of deep posterolateral ankle pain points toward os trigonum or posterior talar impingement.
FHL test: Passively flex and extend the great toe while palpating the posterior medial ankle. Pain reproduced during toe motion = FHL involvement.
Tinel’s at medial malleolus: Tapping behind the medial malleolus reproduces tingling into the heel or sole = tarsal tunnel syndrome involvement.
Imaging for Posterior Ankle Pain
Standing ankle X-ray (lateral view): identifies Haglund’s deformity, posterior calcaneal ossification, os trigonum, traction spurs. MRI: differentiates Achilles tendon tear vs. tendinopathy vs. bursitis; identifies FHL sheath fluid; confirms os trigonum size and inflammation. Ultrasound: excellent dynamic assessment of peroneal subluxation and FHL triggering; guided injection platform. MRI is the gold standard for most posterior ankle pain that doesn’t resolve with 4–6 weeks of conservative care.
Balance Foot & Ankle provides specialized posterior ankle evaluation at Howell and Bloomfield Hills. Getting the right diagnosis is the difference between treatment success and months of mismanagement. Call (810) 206-1402.
American Academy of Orthopaedic Surgeons: Achilles Tendinitis
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For a complete clinical overview: Ankle Pain Conditions Guide — location-by-location ankle pain diagnosis and treatment
How do I know if ankle pain requires a doctor?
See a podiatrist if ankle pain follows an injury with swelling or bruising, if you cannot bear weight, or if pain persists more than 2 weeks or causes instability.
What is the most common cause of ankle pain?
Lateral ankle sprains are the most common. Peroneal tendonitis, Achilles tendonitis, and osteoarthritis are other frequent culprits depending on age and activity level.
Doctor Answer
What are the common causes of posterior ankle pain?
Posterior ankle pain — pain at the back of the ankle — is most often caused by Achilles tendinitis, os trigonum syndrome, flexor hallucis longus tendinopathy, or posterior ankle impingement. Treatment depends on the exact cause and may include rest, physical therapy, custom orthotics, anti-inflammatory medications, or in persistent cases, surgery. A podiatrist or foot specialist should evaluate to identify the exact source.
Dr. Tom Biernacki, DPM is a board-certified foot & ankle surgeon (ABFAS & ABPM) 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 made him one of the most-followed foot & ankle educators on YouTube.