Sinus Tarsi Syndrome: Diagnosis and Injection Technique

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

Sinus tarsi syndrome is a clinical entity characterized by persistent lateral hindfoot pain and instability localized to the sinus tarsi — the cone-shaped space between the calcaneus and talus containing fat, ligaments, and neurovascular structures. Despite being described for over 60 years, sinus tarsi syndrome remains underrecognized and frequently misattributed to chronic ankle sprain, subtalar instability, or simply “chronic ankle pain.”

Anatomy and Pathomechanics

The sinus tarsi is bounded by the posterior facet of the subtalar joint medially and contains the interosseous talocalcaneal ligament, cervical ligament, fat pad, and branches of the peroneal and posterior tibial nerves that provide proprioceptive information about subtalar position. Lateral ankle inversion injuries — the most common mechanism — can tear the cervical and interosseous ligaments, damage the fat pad, and disrupt the proprioceptive nerve supply, resulting in chronic post-traumatic synovitis, fibrosis, and disordered hindfoot kinematics. In patients without prior trauma, pes planus (excessive subtalar pronation) chronically impinges the structures within the sinus tarsi and may produce the syndrome in the absence of discrete ligamentous injury.

Clinical Diagnosis

The hallmark finding is point tenderness directly over the sinus tarsi — located approximately 1 cm anterior and inferior to the lateral malleolus on the anterolateral foot. Patients describe a constant dull ache with episodic sharp lateral pain during uneven terrain ambulation and report a sense of subtalar instability distinct from talocrural giving-way. The diagnostic test of choice is a sinus tarsi injection: infiltration of local anesthetic (1% lidocaine, 1mL) into the sinus tarsi — performed under fluoroscopic or ultrasound guidance — provides complete or near-complete temporary pain relief, confirming the diagnosis and distinguishing sinus tarsi syndrome from peroneal tendon pathology or calcaneocuboid joint pain.

Injection Technique

Under ultrasound guidance, the sinus tarsi is identified as the hyperechoic fat-filled space anterior to the posterior subtalar joint. A 25-gauge needle is advanced anterolaterally into the space, and correct positioning is confirmed by saline flush with observed fluid distension. A mixture of 1mL 1% lidocaine and 0.5mL betamethasone provides both diagnostic and therapeutic benefit. Repeat injections at 6–8 week intervals may provide sustained relief in inflammatory cases. MRI demonstrates sinus tarsi fat replacement with fluid or fibrotic tissue and ligamentous disruption in established cases.

Management Beyond Injection

Custom orthotics with medial rearfoot posting to limit subtalar pronation are effective for pes planus-associated cases. Physical therapy emphasizing subtalar proprioception re-education and peroneal strengthening addresses the dynamic instability component. Surgical arthroscopic debridement of the sinus tarsi with ligamentous repair or reconstruction is reserved for cases refractory to 6+ months of conservative care. Dr. Biernacki at Balance Foot & Ankle provides ultrasound-guided sinus tarsi injection and comprehensive management of posterior lateral foot pain. Call (810) 206-1402 for evaluation at our Bloomfield Hills or Howell office.

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When to See a Podiatrist

Many foot conditions can be managed conservatively at home, but some require professional evaluation. See a podiatrist promptly if you experience:

• Pain that persists for more than 2 weeks despite rest
• Swelling, redness, or warmth that isn’t improving
• Numbness, tingling, or burning in the feet
• A wound or sore that is not healing within 2 weeks
• Any foot concern if you have diabetes or poor circulation
• Nail changes that suggest fungal infection or other problems

At Balance Foot & Ankle, our three board-certified podiatrists — Dr. Tom Biernacki, Dr. Carl Jay, and Dr. Daria Gutkin — provide comprehensive foot and ankle care at our Howell and Bloomfield Hills offices. Most insurance plans are accepted.

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Board-certified podiatrists Dr. Tom Biernacki, Dr. Carl Jay, and Dr. Daria Gutkin see patients daily at our Howell and Bloomfield Township, MI offices.

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In-Office Treatment at Balance Foot & Ankle

If home care isn’t resolving your your foot or ankle concern, a visit with a board-certified podiatrist is the fastest path to accurate diagnosis and a personalized plan. At Balance Foot & Ankle Specialists, Dr. Tom Biernacki, Dr. Carl Jay, and Dr. Daria Gutkin offer same-day and next-day appointments at both our Howell and Bloomfield Hills offices. We perform on-site diagnostic ultrasound, digital X-ray, conservative care, advanced regenerative treatments, and minimally invasive surgery when indicated.

Call (810) 206-1402 or request an appointment online. Most insurance plans accepted, including Medicare, Blue Cross Blue Shield, Aetna, Cigna, and United Healthcare.

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

What is Foot pain?

Foot pain is a common foot/ankle condition that affects mobility and quality of life. Understanding the underlying cause is the first step in successful treatment. Our podiatrists at Balance Foot & Ankle perform a hands-on biomechanical exam, review your activity history, and use diagnostic imaging when appropriate to identify the root cause—not just treat the symptom. Many patients have been told to “rest and ice” without a deeper diagnostic workup; our approach is different.

Symptoms and warning signs

Common signs of foot pain include pain that worsens with activity, morning stiffness, swelling, tenderness when palpated, and difficulty bearing weight. If you experience sudden severe pain, inability to walk, visible deformity, numbness or color change, contact our office the same day or visit urgent care—these can signal a more serious injury such as a fracture, tendon rupture, or vascular compromise. Diabetics with any foot wound should seek same-day care.

Conservative treatment options

Most cases of foot pain respond to non-surgical care: structured rest, supportive footwear changes, custom orthotics, targeted stretching and strengthening protocols, anti-inflammatory medications when medically appropriate, and in-office procedures such as ultrasound-guided injections. We also offer advanced therapies including MLS laser therapy, EPAT/shockwave, regenerative injections, and image-guided procedures. Treatment is sequenced from least invasive to most invasive, and we explain the rationale at every step.

When is surgery considered?

Surgery is reserved for cases that fail 3-6 months of well-structured conservative care, when there is structural pathology (severe deformity, complete tear, advanced arthritis), or when imaging shows damage that will not heal without intervention. Our surgeons have performed 3,000+ foot and ankle procedures and prioritize minimally-invasive techniques whenever appropriate. We discuss recovery timelines, return-to-activity milestones, and realistic outcome expectations before any procedure is scheduled.

Recovery timeline and prevention

Recovery from foot pain varies based on severity and chosen treatment path. Conservative cases often improve within 4-8 weeks with consistent adherence to the protocol. Post-procedural recovery may range from a few days (in-office procedures) to several months (reconstructive surgery). Long-term prevention involves footwear assessment, activity modification, structured strengthening, and regular check-ins with your podiatrist if you have a history of recurrence. We provide written home-exercise plans and digital follow-up support.

Related Care at Balance Foot & Ankle

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