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

When a “Simple Sprain” Doesn’t Heal

You rolled your ankle six months ago. The swelling went down, you limped through it, and figured it would get better on its own. But you’re still having pain — aching with activity, occasional sharp twinges, maybe a sense that the ankle isn’t quite “right.” Your primary care doctor tells you sprains take time. But six months? Twelve months?

The truth is that ankle pain persisting beyond 6–8 weeks after an “ankle sprain” should trigger investigation for underlying diagnoses that are commonly missed in the initial evaluation. Many of these conditions are definitively treatable once accurately identified — but they don’t respond to rest-and-wait management, because they’re not simple sprains.

Here are seven conditions that are frequently misdiagnosed as ankle sprains — and what to do about them.

1. Osteochondral Lesion of the Talus (OCD Lesion)

The talar dome — the top surface of the ankle bone that fits inside the ankle joint — is frequently damaged during the impact of an ankle sprain. The cartilage can crack or separate from the underlying bone, creating an osteochondral lesion (OCD). These lesions do not heal on their own once the cartilage is detached, and they cause persistent ankle joint pain, swelling, and sometimes locking or catching sensations.

OCD lesions are missed on standard ankle X-rays in 50% of cases — MRI or CT is required. When identified, treatment options range from protected weight-bearing for stable lesions to arthroscopic surgery for unstable or large defects. Left untreated, OCD lesions progress to post-traumatic ankle arthritis.

2. Sinus Tarsi Syndrome

The sinus tarsi — a small canal just in front of the lateral malleolus on the outer ankle — contains ligaments, fat, and nerve endings that are frequently injured in ankle sprains. When scar tissue and fibrosis develop within this canal, patients experience persistent, specific tenderness directly over the sinus tarsi, worsened by walking on uneven terrain.

Sinus tarsi syndrome is diagnosed by clinical examination (point tenderness in the sinus tarsi) and confirmed by diagnostic injection (local anesthetic injected into the sinus tarsi — if pain temporarily resolves, the diagnosis is confirmed). Treatment ranges from cortisone injection and orthotics to arthroscopic debridement of the sinus tarsi contents.

3. Peroneal Tendon Tear or Subluxation

The peroneal tendons run behind the lateral malleolus in a groove lined by a retinaculum (a ligamentous band). During an ankle sprain, the peroneal tendons can tear longitudinally (a split tear) or the retinaculum can be disrupted, allowing the tendons to dislocate (sublux) out of their groove. Both conditions cause posterior-lateral ankle pain that persists after the ligament sprain heals.

Peroneal tendon subluxation produces a distinctive snapping or popping sensation at the back of the lateral malleolus with ankle movement. Peroneal tears cause lateral ankle pain reproduced by resisted eversion (turning the foot outward). MRI confirms the diagnosis. Surgical treatment — tendon repair and/or groove deepening to contain the tendons — is often required for complete tears and recurrent subluxation.

4. Chronic Ankle Instability

When an ankle sprain tears the lateral ligaments completely (Grade III), or when Grade I–II sprains are not adequately rehabilitated, the ligaments heal in a stretched, lax state that no longer provides adequate stability. Patients describe the ankle “giving way” unpredictably — on stairs, uneven ground, or during sports. Over time, repeated giving-way events create cartilage damage and the cycle accelerates toward post-traumatic arthritis.

Chronic instability is diagnosed by clinical testing and stress radiography. Initial treatment is aggressive rehabilitation of peroneal muscle strength and proprioception. When conservative treatment fails (typically 3–6 months of consistent PT), the modified Broström ligament reconstruction procedure provides reliable return to stability — success rates exceed 90% in properly selected patients.

5. Posterior Ankle Impingement / Os Trigonum

Posterior ankle impingement is pinching of soft tissue or bone at the back of the ankle joint, occurring when the ankle is plantarflexed (pointed down). It’s particularly common in ballet dancers, soccer players (toe-pointing position), and gymnasts — but can occur in any patient after an ankle injury. An accessory bone called the os trigonum (present in approximately 10% of people) can become symptomatic after ankle trauma.

Symptoms: pain at the back of the ankle, behind the Achilles tendon, reproduced by forced plantarflexion. MRI confirms the diagnosis. Treatment: cortisone injection initially; surgical excision of the os trigonum or impinging posterior process when conservative care fails — often performed arthroscopically with rapid recovery.

6. Syndesmotic (High Ankle) Sprain

The syndesmosis is the ligamentous connection between the tibia and fibula just above the ankle joint. High ankle sprains — injuries to this complex — occur when the ankle is forcefully externally rotated (twisted outward) rather than inverted. They are substantially more serious and slower-healing than standard lateral ankle sprains, but are often misidentified as “ankle sprains” without the appropriate modifier.

Classic presentation: pain above and around the ankle joint (not over the lateral ligaments), worsened by the “squeeze test” (compressing tibia and fibula together above the ankle reproduces pain), and with external rotation of the foot. High ankle sprains take 2–3x longer to heal than lateral sprains — often 6–12 weeks for incomplete injury. Significant instability requires surgical fixation with screws or tightrope device to prevent chronic widening of the ankle mortise.

7. Stress Fracture

Stress fractures of the calcaneus, fibula, talus, or navicular can occur from the impact loading of an ankle sprain episode or from repetitive loading in athletes. These fractures may not be visible on initial plain X-rays, creating a false sense of reassurance (“X-rays are normal, it’s just a sprain”). MRI detects bone marrow edema — the earliest sign — weeks before X-ray changes develop.

Persistent focal bony tenderness (not soft tissue tenderness) after an ankle injury warrants follow-up imaging. Navicular stress fractures deserve special mention: they are notoriously subtle on X-ray, occur in young athletes in the dorsal central third of the navicular, and require immediate non-weight-bearing when diagnosed — delayed treatment leads to complete fracture and the need for surgery.

Getting the Right Diagnosis

The key point across all seven conditions: they don’t respond to generic “ankle sprain” treatment because they are distinct diagnoses requiring specific interventions. Persistent ankle pain beyond 6–8 weeks after a sprain warrants evaluation by a foot and ankle specialist — not just reassurance that healing “takes time.”

At Balance Foot & Ankle, we perform comprehensive ankle evaluations that go beyond the initial sprain assessment, including appropriate imaging, stress testing, and diagnostic injections to identify the specific pathology causing your symptoms. If your ankle still hurts months after a sprain, contact us — there’s likely a specific, treatable answer to why.

Foot or Ankle Pain? We Can Help.

Balance Foot & Ankle — Howell & Bloomfield Township, MI

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Chronic Ankle Pain After a Sprain?

If your ankle still hurts months after a sprain, there may be an underlying issue like a missed fracture, cartilage damage, or chronic instability. At Balance Foot & Ankle, Dr. Tom Biernacki provides thorough evaluation and targeted treatment for persistent ankle pain.

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Clinical References

1. Waterman BR, et al. “The Epidemiology of Ankle Sprains in the United States.” Journal of Bone and Joint Surgery. 2010;92(13):2279-2284.
2. van Rijn RM, et al. “What Is the Clinical Course of Acute Ankle Sprains? A Systematic Literature Review.” American Journal of Medicine. 2008;121(4):324-331.
3. Golditz T, et al. “Functional Ankle Instability as a Risk Factor for Osteoarthritis.” Journal of Orthopaedic & Sports Physical Therapy. 2014;44(8):611-617.

Dr. Tom Biernacki, DPM

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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.