Tarsal coalition — an abnormal cartilaginous, fibrous, or osseous fusion between two or more tarsal bones resulting from failure of normal mesenchymal segmentation during fetal development — is the most common structural cause of rigid, painful flatfoot in adolescents and young adults, present in 1–2% of the population but symptomatic in a smaller proportion. The two most clinically significant coalitions are calcaneonavicular (CN) coalition (most common, 53%) and talocalcaneal (TC) coalition at the middle facet (second most common, 37%), each requiring specific imaging for diagnosis and a distinct surgical approach for resection.

Clinical Presentation and Imaging

Clinical features: peroneal spastic flatfoot is the classic presentation — rigid hindfoot valgus with peroneal muscle spasm preventing subtalar inversion; the subtalar joint is stiff or absent on examination; pain localized to the sinus tarsi (TC coalition) or dorsolateral midfoot (CN coalition); symptoms typically begin in early adolescence (10–16 years) as the coalition ossifies and becomes rigid. Plain X-rays: CN coalition — lateral X-ray shows the ‘anteater sign’ (elongated anterior calcaneal process pointing toward the navicular); oblique view directly visualizes the bar. TC coalition at middle facet — Harris heel axial view shows narrowing, sclerosis, and irregular borders of the middle facet; often missed on standard views. CT scan: gold standard for osseous coalition — defines the extent of fusion, identifies middle facet TC coalitions, and assesses the posterior subtalar facet for degenerative changes (key surgical planning factor). MRI: superior for fibrocartilaginous coalitions not visible on CT; shows marrow edema adjacent to the coalition. Surgical contraindication: posterior subtalar arthritis on CT is a relative contraindication to coalition resection — subtalar fusion provides more reliable outcomes when significant arthritic change is present.

Surgical Resection Technique

CN coalition resection: extensor digitorum brevis (EDB) muscle interposition; oblique incision over the sinus tarsi; identification and complete resection of the calcaneonavicular bar with osteotomes; EDB flap interposed into the resection space to prevent re-coalition; outcomes: 80–90% good-excellent in adolescents without hindfoot arthritis. TC middle facet coalition resection: medial approach over the sustentaculum tali; complete resection of the middle facet coalition; fat graft or split flexor hallucis longus tendon interposition; concurrent calcaneal osteotomy for significant residual valgus deformity after resection. Outcomes: good-excellent in 70–80% of patients without posterior facet arthritis; subtalar fusion indicated for coalition with posterior facet arthrosis. Dr. Biernacki at Balance Foot & Ankle diagnoses tarsal coalition with CT/MRI and performs resection and hindfoot reconstruction at our Bloomfield Hills and Howell offices. Call (810) 206-1402.

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Frequently Asked Questions

When should I see a podiatrist?

See a podiatrist for any foot or ankle pain that persists more than 2 weeks, doesn’t improve with rest, limits your daily activities, or is accompanied by swelling, numbness, or skin changes. People with diabetes or circulation problems should see a podiatrist regularly even without symptoms.

What does a podiatrist treat?

Podiatrists diagnose and treat all conditions of the foot, ankle, and lower leg including plantar fasciitis, bunions, hammertoes, toenail problems, heel pain, nerve pain, diabetic foot care, sports injuries, fractures, and foot deformities — both surgically and non-surgically.

What can I expect at my first podiatry visit?

Your first visit includes a full medical history, physical examination of your feet and gait, and in-office diagnostic imaging if needed (X-rays, ultrasound). We’ll discuss your diagnosis and create a personalized treatment plan. Most visits take 30–45 minutes.

Need Treatment at Balance Foot & Ankle?

Dr. Tom Biernacki, Dr. Carl Jay, and Dr. Daria Gutkin see patients at our Howell and Bloomfield Township offices.

Book Online or call (810) 206-1402

Dr. Tom Biernacki, DPM

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.