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 Subtalar Instability: The Ankle Instability Below the Ankle Joint 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.
Subtalar instability — abnormal motion at the talocalcaneal (subtalar) joint complex beneath the ankle — is a frequently overlooked cause of chronic hindfoot symptoms following ankle sprains. While lateral ankle instability (talar tilt at the tibiotalar joint) receives most clinical attention, the subtalar joint can be independently or concurrently destabilized, producing symptoms that fail to resolve with standard ankle instability treatment because the correct joint is not being addressed.
Subtalar vs. Lateral Ankle Instability
| Feature | Lateral Ankle Instability (tibiotalar) | Subtalar Instability (talocalcaneal) |
|---|---|---|
| Joint involved | Ankle joint (tibia-talus) | Subtalar joint (talus-calcaneus) |
| Primary ligament | ATFL; CFL | CFL; cervical ligament; interosseous talocalcaneal ligament |
| Subjective complaint | Ankle gives way on uneven ground; lateral instability | Hindfoot feels unstable; difficulty on uneven ground; subtler giving-way |
| X-ray stress view | Talar tilt; anterior drawer at ankle | Subtalar stress views (Broden, varus stress) — often negative or ambiguous |
| Diagnostic gold standard | Stress X-ray; MRI for ligament tear | MRI for CFL and cervical ligament; arthroscopy (most sensitive) |
| Conservative treatment | Rehabilitation; ankle brace; peroneal strengthening | Same; may need sinus tarsi steroid injection as diagnostic and therapeutic |
| Surgical option | Modified Brostrom ligament repair | Brostrom extended to CFL; subtalar arthrodesis in severe cases |
The Sinus Tarsi Syndrome Connection
Sinus tarsi syndrome — pain in the sinus tarsi (the canal between the talus and calcaneus) — and subtalar instability frequently coexist because the sinus tarsi contains the cervical and interosseous talocalcaneal ligaments that stabilize the subtalar joint. Persistent sinus tarsi pain after ankle sprain that does not resolve with time and conservative care should raise suspicion for subtalar instability. A diagnostic corticosteroid injection into the sinus tarsi that produces temporary complete pain relief confirms the sinus tarsi as the pain source.
Conservative Treatment Protocol
| Treatment | Evidence | Application |
|---|---|---|
| Peroneal and ankle stabilizer strengthening | High | Same protocol as lateral ankle instability; proprioceptive training critical |
| Ankle-foot orthosis (AFO) or lace-up brace | Moderate | Limits subtalar inversion; useful for return to sport |
| Sinus tarsi corticosteroid injection | Moderate | Reduces inflammation; diagnostic if produces complete relief |
| Lateral heel wedge orthotic | Moderate | Reduces subtalar inversion tendency; valgus wedge 3-5 degrees |
At Balance Foot & Ankle in Howell and Bloomfield Hills, we evaluate subtalar instability as a cause of persistent hindfoot symptoms after ankle injury and provide conservative management or surgical referral when indicated. Call (810) 206-1402.
American Academy of Orthopaedic Surgeons: Subtalar Instability
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Doctor Answer
What is subtalar instability and how is it treated?
Subtalar instability involves laxity of the ligaments controlling the subtalar joint (beneath the ankle), causing the heel to rock excessively inward with walking and increasing ankle sprain risk. It often coexists with ankle instability and may be missed on standard ankle X-rays. I diagnose it with stress views or MRI and treat conservatively with proprioceptive training, peroneal strengthening, and bracing. Surgical reconstruction using the cervical ligament or sinus tarsi stabilization is reserved for persistent symptomatic cases.
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.