Tarsal Coalition: Fibrous vs. Osseous Types, Symptoms, and

Reviewed by Dr. Tom Biernacki, DPM, FACFAS

Board-certified foot & ankle surgeon · 3,000+ surgeries · @MichiganFootDoctors (950K+ subscribers)

Last reviewed May 11, 2026 · (810) 206-1402

Quick answer: Treatment for tarsal coalition fibrous osseous surgical treatment follows a stepwise approach: 1) conservative care first (rest, ice, supportive footwear, OTC anti-inflammatories), 2) physical therapy and targeted exercises, 3) in-office treatments (injections, custom orthotics) if conservative fails at 4-6 weeks, 4) surgery for refractory cases. Most patients resolve at step 1 or 2. Call (810) 206-1402.

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

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Tarsal coalition is a congenital or acquired union between two or more tarsal bones — most commonly the calcaneonavicular and talocalcaneal joints — that restricts subtalar and midtarsal joint motion and produces a characteristic rigid flatfoot with peroneal spasm. Though present from birth, symptoms typically emerge in adolescence (ages 10–16) when the fibrous or cartilaginous coalition undergoes progressive ossification, limiting previously available motion. Adults occasionally present with symptomatic coalition following increased activity or ankle injury that stresses the restricted joints.

Types and Prevalence

Calcaneonavicular (CN) coalition — bridging between the anterior calcaneus and navicular — accounts for approximately 53% of tarsal coalitions and is most reliably identified on lateral oblique X-ray as the “anteater nose” sign (elongated anterior calcaneal process reaching the navicular). Talocalcaneal (TC) coalition — bridging the middle subtalar facet between the talus and calcaneus — represents approximately 37% of coalitions and is more difficult to identify radiographically, often requiring CT or MRI for diagnosis. TC coalition classically produces the “C-sign” on lateral X-ray (an incomplete C-shaped density formed by the talar dome and sustentaculum tali connected by the coalition). Coalitions may be fibrous (synchondrosis), cartilaginous, or fully ossified (synostosis), with increasing rigidity and symptom severity as ossification progresses.

Clinical Presentation

Symptomatic tarsal coalition produces: rigid or semi-rigid flatfoot with limited or absent subtalar inversion, peroneal spasm (reflexive peroneal muscle spasm that resists subtalar inversion — the “peroneal spastic flatfoot”), activity-related midfoot and hindfoot pain aggravated by walking on uneven ground, and recurrent ankle sprains from restricted subtalar motion. Physical examination reveals limited or absent subtalar inversion (under 5° for TC coalition) and midtarsal stiffness. The peroneal muscles may be in spasm (tense to palpation and resisting inversion). Weight-bearing CT or MRI confirms diagnosis, characterizes coalition morphology, and identifies secondary subtalar arthrosis that influences surgical planning.

Conservative Management

Conservative management is appropriate for fibrous or partially ossified coalitions without significant secondary arthrosis. A UCBL orthosis or custom rigid AFO that limits subtalar motion reduces mechanical stress on the coalition and adjacent joints. Short-leg cast immobilization for 4–6 weeks relieves acute pain flares. NSAIDs manage inflammatory symptoms. Conservative management produces satisfactory outcomes in 30–40% of symptomatic patients; failure after 3–6 months of conservative treatment represents surgical candidacy.

Surgical Treatment

Calcaneonavicular coalition resection — removing the coalition bridge through a sinus tarsi approach and interposing extensor digitorum brevis muscle or fat graft — produces excellent results (85–90% symptom improvement) when performed before secondary subtalar arthrosis develops. Talocalcaneal coalition resection is technically more demanding — the coalition is excised and replaced with a fat or muscle interposition graft through a medial approach. Results are less predictable than CN resection and depend heavily on coalition size (coalition occupying less than 50% of the posterior subtalar facet predicts better outcomes). Patients with advanced subtalar arthrosis require triple arthrodesis rather than resection. Concurrent calcaneal osteotomy (medializing or lateralizing shift) is added when significant hindfoot malalignment persists after resection.

Tarsal Coalition Evaluation at Balance Foot & Ankle

Dr. Biernacki at Balance Foot & Ankle evaluates suspected tarsal coalition with weight-bearing foot and ankle X-rays including lateral oblique view, and CT referral when clinical and radiographic findings suggest TC coalition requiring surgical planning. Early accurate diagnosis in adolescents allows resection before secondary arthrosis forecloses the most motion-preserving surgical options. Call (810) 206-1402 for evaluation of rigid flatfoot or persistent midfoot pain in adolescents or young adults.

Your Board-Certified Podiatrists

Dr. Tom Biernacki, DPM

Board-Certified · FACFAS

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Dr. Daria Gutkin, DPM

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Frequently Asked Questions

How long does treatment take to work?

Most patients see improvement in 4-8 weeks with consistent conservative care. Persistent symptoms after 8 weeks need imaging and escalation.

When is surgery needed?

Surgery is reserved for cases that fail 3-6 months of conservative care, structural deformities, or fractures requiring stabilization.

Is this covered by insurance?

Most diagnostic visits and conservative treatments are covered by Medicare and major insurers. Custom orthotics often require diabetic or post-surgical justification.

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.

In-Office Treatment at Balance Foot & Ankle

If home treatment isn’t providing relief for your foot and ankle conditions, our podiatry team at Balance Foot & Ankle can help with same-day evaluations and advanced in-office care.

Dr. Tom Biernacki, DPM

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.