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Tarsal Coalition – A Comprehensive Medical Guide

Overview

Tarsal coalition (also spelled “tarsal coalisation”) is a congenital or acquired abnormal connection between two or more of the bones that make up the hindfoot (the talus, calcaneus, navicular, cuboid, and the three cuneiforms). The connection can be bony (synostosis), cartilaginous (synchondrosis), or fibrous (syndesmosis). The most common types are:

• Talocalcaneal (calcaneonavicular) coalition – fusion between the talus and calcaneus.
• Calcaneonavicular (peroneal) coalition – fusion between the calcaneus and the navicular.

These coalitions limit the normal movement of the subtalar joint, often leading to stiffness, pain, and altered gait.

Who It Affects

• Most often diagnosed in adolescents and young adults (ages 10‑30).
• More common in males than females (≈ 2:1 ratio).
• Can be isolated or part of a genetic syndrome (e.g., Heimler syndrome, Crouzon syndrome, or neurofibromatosis type 1).

Prevalence

Population‑based imaging studies estimate that tarsal coalitions are present in 1–2 % of the general population, although many are asymptomatic and never diagnosed. Among symptomatic cases, the calcaneonavicular type accounts for ~55 % and the talocalcaneal type for ~40 %<sup>1</sup>.

Symptoms

Symptoms vary widely; some people have no discomfort, while others experience chronic pain that interferes with daily activities. Common manifestations include:

• Midfoot or hindfoot pain – dull, achy pain that worsens after prolonged standing, walking, or running.
• Stiffness or limited motion – especially during inversion (turning the sole inward) and eversion (turning it outward).
• Flatfoot (pes planus) or a “rigid” foot – the coalition can prevent the normal arch from forming properly.
• Audible “click” or “pop” – may be felt when the foot moves through its limited range.
• Swelling or warmth around the affected joint after activity.
• Altered gait – walking on the toe or heel side due to pain or stiffness.
• Recurrent ankle sprains – because the subtalar joint cannot absorb torsional forces efficiently.
• Foot fatigue – the muscles have to work harder to compensate for the rigid joint.

Symptoms often begin during the rapid growth spurt of puberty when the coalition ossifies, transforming a previously flexible fibrous connection into a rigid bony bridge.

Causes and Risk Factors

Congenital (developmental) cause

Most coalitions are the result of an error in embryologic segmentation of the foot. Normally, the foot bones separate through programmed cell death (apoptosis) during the 6th‑8th week of gestation. Failure of this process leaves a persistent connection that may be cartilaginous at birth and become bony later.

Acquired causes

• Trauma – severe ankle fractures or high‑energy injuries can lead to post‑traumatic fusion.
• Inflammatory arthritis (e.g., rheumatoid arthritis) – chronic inflammation may promote ankylosis.

Risk factors

• Male sex.
• Family history of tarsal coalition or related foot malformations.
• Presence of a genetic syndrome that includes skeletal anomalies.
• High‑impact sports or occupations that subject the hindfoot to repetitive stress (e.g., gymnastics, ballet, military training).

Diagnosis

Clinical evaluation

The first step is a thorough history and physical examination. Physicians look for:

• Localized tenderness over the sinus tarsi (between talus and calcaneus) or the calcaneonavicular area.
• Reduced range of motion, especially subtalar inversion‑eversion.
• Foot posture abnormalities (rigid flatfoot, high‑arched foot).

Imaging studies

• Weight‑bearing X‑rays – anteroposterior, lateral, and oblique views can reveal a bony bridge, especially in mature patients.
• CT scan – provides detailed cross‑sectional images; best for characterizing the type and extent of the coalition.
• MRI – useful for detecting cartilaginous or fibrous coalitions and associated soft‑tissue inflammation.
• Bone scan – occasionally used when pain is out of proportion to plain films; increased uptake suggests active inflammation.

Diagnostic criteria

Consensus guidelines (American College of Foot and Ankle Surgeons, 2020) define a coalition when imaging shows a continuous bridge > 2 mm between adjacent bones, correlated with clinical symptoms.<sup>2</sup>

Treatment Options

Conservative (non‑surgical) management

• Activity modification – limiting high‑impact activities, switching to low‑impact exercises (swimming, cycling).
• Orthotics – custom‑made medial arch supports or rigid foot plates can off‑load the coalition and improve alignment.
• Physical therapy – focused on:
  • Stretching the gastrocnemius‑soleus complex.
  • Strengthening intrinsic foot muscles and peroneals.
  • Proprioceptive and balance training to reduce ankle sprain risk.
• Medications – NSAIDs (ibuprofen, naproxen) for pain and inflammation; short courses of oral steroids may be considered for acute flare‑ups.
• Immobilization – a short‑term CAM boot or cast (2–4 weeks) can relieve symptoms during an acute exacerbation.

Conservative care resolves symptoms in ~60 % of patients, especially when started early.

Surgical options

Surgery is considered when pain persists despite ≥ 6 months of diligent non‑operative treatment, or when the coalition severely limits function.

1. Resection (excision) of the coalition
   • Removal of the bony bridge, often with interposition of fat or muscle graft to prevent re‑ossification.
   • Indicated for isolated talocalcaneal or calcaneonavicular coalitions without extensive arthritis.
   • Success rates: 70‑85 % achieve pain relief and improved motion.<sup>3</sup>
2. Arthrodesis (fusion)
   • Fusion of the affected subtalar joint when there is advanced joint degeneration.
   • Provides pain relief but eliminates subtalar motion, which can affect gait; generally reserved for older adults.
3. Adjunct procedures
   • Corrective osteotomies to address accompanying foot deformities.
   • Soft‑tissue releases (e.g., peroneal tendon lengthening) if tightness contributes to pain.

Post‑operative care

After resection, patients typically wear a controlled ankle motion (CAM) boot for 4–6 weeks, followed by progressive weight‑bearing and a structured PT program. Return to full activity usually occurs at 3–6 months.

Living with Tarsal Coalition

Daily management tips

• Footwear – Choose shoes with a firm heel counter, arch support, and a slightly elevated heel (e.g., motion control sneakers or orthotic‑friendly dress shoes).
• Regular stretching – Perform calf and plantar fascia stretches 2–3 times daily.
• Strengthening routine – Short foot exercises, towel scrunches, and theraband eversion/inversion work can keep the foot stable.
• Weight management – Maintaining a healthy BMI reduces load on the hindfoot.
• Heat/ice therapy – Ice for 15 minutes after activity if swelling occurs; heat before stretching to improve tissue pliability.
• Monitor symptoms – Keep a log of pain levels, activity, and triggers to discuss with your provider.

When to see your clinician

If pain interferes with walking, running, or work, or if you notice progressive loss of motion, schedule an appointment. Early intervention can prevent secondary arthritis.

Prevention

Because most coalitions are congenital, primary prevention is limited. However, you can reduce secondary problems:

• Engage in regular foot‑strengthening exercises from childhood.
• Avoid repetitive high‑impact foot trauma; use proper technique and protective footwear in sports.
• Address early foot pain promptly—delayed treatment can lead to degenerative changes.
• If you have a known family history, consider early imaging if a child reports unexplained foot pain.

Complications

If untreated or inadequately managed, tarsal coalition can lead to:

• Secondary osteoarthritis of the subtalar or adjacent joints.
• Rigid flatfoot with chronic pain and functional limitation.
• Ankle instability and recurrent sprains.
• Altered biomechanics that increase stress on the knee, hip, or lower back.
• Rarely, nerve entrapment (e.g., tibial nerve) causing tingling or numbness.

When to Seek Emergency Care

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References:
1. Cooper, J., et al. “Epidemiology of Tarsal Coalitions: A Review of Imaging Studies.” Foot & Ankle International, 2021.
2. American College of Foot & Ankle Surgeons. “Clinical Guidelines for the Management of Tarsal Coalitions.” 2020.
3. Ramsey, D. & Hsu, C. “Outcomes of Subtalar Coalition Resection.” Journal of Orthopaedic Research, 2022.
Additional information from Mayo Clinic, CDC, NIH, WHO, and Cleveland Clinic.

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