Tarsal Coalition

Modern Study Review (AI-Generated)

High-Yield Summary

Tarsal coalition is a congenital or developmental abnormality characterized by an abnormal connection between two or more tarsal bones, leading to hindfoot stiffness, recurrent ankle sprains, and flatfoot deformity. It affects approximately 1% of the population, with a slight male predominance and a likely hereditary component. Early diagnosis is critical to prevent secondary degenerative changes and optimize functional outcomes. Modern management balances conservative measures with surgical intervention tailored to coalition type and symptom severity.

Key Diagnostic Findings

Anatomy

• Common Coalitions: Calcaneonavicular and talocalcaneal (middle facet most commonly involved).
• Types of Coalition: Fibrous, cartilaginous, or osseous (synostosis).
• Developmental Timeline:
• Talonavicular ossifies between 3-5 years
• Calcaneonavicular between 8-12 years
• Talocalcaneal between 12-16 years (symptoms often arise after ossification)

Clinical Presentation

• Symptoms: Recurrent ankle sprains, hindfoot stiffness, painful flatfoot, limited subtalar motion.
• Physical Exam: Decreased hindfoot range of motion, palpable fullness over sinus tarsi (calcaneonavicular), rigid flatfoot deformity.

Imaging

• X-rays:
• Oblique foot views best for calcaneonavicular coalition (visible bony bridge or “anteater nose” sign).
• Harris (axial) view for talocalcaneal coalition (middle facet involvement).
• CT Scan: Gold standard for detailed visualization of coalition type, extent, and facet involvement.
• MRI: Useful for detecting fibrous or cartilaginous coalitions and associated soft tissue changes.

Classification Systems

Current Gold Standard Treatment

Non-operative Indications and Treatment

• Mild symptoms without significant functional limitation.
• Initial management includes:
• Activity modification to reduce repetitive stress.
• Orthotic shoe inserts to support the arch and limit hindfoot motion.
• NSAIDs for pain control.
• Immobilization (short leg cast or walking boot) during acute exacerbations.
• Physical therapy focusing on strengthening and proprioception.

Operative Indications and Treatment

• Persistent pain despite conservative management.
• Significant functional impairment or recurrent ankle instability.
• Progressive deformity or secondary arthritis.

Surgical Pearls:

• Protect neurovascular structures (sural nerve, FDL, FHL tendons).
• Use bone wax and interposition grafts to prevent reossification.
• Confirm restoration of subtalar motion intraoperatively after resection.

Modern Complications & Outcomes

Complications

• Recurrence of coalition due to incomplete resection or graft failure.
• Persistent pain or stiffness postoperatively.
• Neurovascular injury (sural nerve, tibial nerve branches).
• Secondary degenerative arthritis, especially if surgery delayed or coalition extensive.
• Nonunion or hardware complications in fusion procedures.

Outcomes

• Calcaneonavicular coalition resection: High success rate (>80%) with pain relief and improved function.
• Talocalcaneal coalition resection: Variable outcomes; better if no arthritis present.
• Triple arthrodesis: Reliable pain relief but loss of subtalar motion; reserved for advanced cases.
• Early diagnosis and intervention correlate with improved pain and functional outcomes.
• Long-term follow-up essential to monitor for arthritis and adjacent joint degeneration.

Classic Clinical Notes

Tarsal Coalition

Approach to Tarsal Coalition

• Incidence about 1%, Male > Female, probably hereditary component to it
• Associated Conditions:
• Apert Syndrome – synostosis of the tarsal and cranial bones, mid-face hypoplasia, syndactyly
• Nievergelt-Pearlman Syndrome – multiple congenital anomalies including tarsal and radioulnar synostosis
• PFFD, fibular hemimelia, ball and socket ankle (may represent adaptive changes of the ankle secondary to subtalar motion restriction because of the tarsal coalition)

• Can be fibrous, cartilaginous, or osseous
• Talonavicular ossify between 3-5 years; calcaneonavicular between 8-12 years; talocalcaneal between 12-16 years

(These times correlate with when they become symptomatic)

• The talocalcaneal coalitions most commonly involve the middle facet which is supported by the sustentaculum tali on the medial aspect of the talus.

• On history, get the history of pain; may find that they have recurrent ankle sprains, stiff flatfoot.
• On physical, note the stiffness of the hindfoot

• Get x-rays: Oblique X-ray show the calcaneonavicular coalition. Harris views visualize the talocalcaneal coalitions
• Then get a CT scan.

Treatment

• Basically 3 choices – symptomatic/conservative, excision, fusion
• Resection of calcaneonavicular coalitions give the best results. Talocalcaneal ones don’t fare as well. If there are degenerative changes present or if excision fails, then do a triple arthrodesis.

Approach

• Do the hx and px.
• Get the x-rays and CT to confirm diagnosis. Beaking does not equal arthritis.
• Send off for conservative management – activity modification, shoe modification, insole, short leg cast

Calcaneonavicular Coalition Excision

• Results are generally good; lean towards excision vs fusion.
• Oblique incision dorsolaterally, centered over the coalition (palpable as a fullness in the area of the sinus tarsi).
• Identify and sharply elevate EDB from its origin.
• Protect peroneal tendons and sural nerve in the lower part of the incision.
• Identify the coalition, and also identify where the TN, TC, and CC joints are to prevent injury to them.
• Use two sharp metacarpal osteotomes to cut out a rectangle of bone so that there is no bony bridge at the bottom.
• Bone wax to the surfaces; get a free fat graft from the buttock and put it in as a spacer.
• Repair EDB origin.

Talocalcaneal Coalition Excision

• If arthritis is present, or it involves ant/post facets – triple arthrodesis

(Be aware that excision tends to do not as well as in calcaneonavicular)

• Medial approach to the middle facet, approximately 6 cm in length, centered over the sustentaculum tali.
• Reflect abductor hallucis.
• Dissect out the tendons and neurovascular structures behind medial malleolus; FDL, FHL, and NV bundle are usually draped under sustentaculum and need to be dissected free and protected.
• Often easier to find the posterior facet and trace it distally to find the posterior edge of the coalition.
• The anterior aspect of the coalition can be found by finding FHL running directly beneath it.
• After defining the extent of the coalition, remove it with osteotomes, rongeurs, or power burr.
• Must completely resect until there demonstrated motion at the subtalar joint.
• Bone wax surfaces, then put retrocalcaneal adipose tissue as interposition (or take fat graft from buttock).

Last Updated on January 25, 2026 by orthonet