Tarsal Coalition: Symptoms, Types, Causes and Treatment

Tarsal coalition is a fascinating but often overlooked condition that affects the bones of the foot, sometimes leading to pain, stiffness, and difficulty with movement—especially in children, teens, and young adults. Understanding this condition is crucial for timely diagnosis and effective management. In this comprehensive article, we’ll explore the symptoms, the different types, underlying causes, and modern approaches to treatment for tarsal coalition, all grounded in the latest research.

Symptoms of Tarsal Coalition

Tarsal coalition can be a silent anomaly for many, but when symptoms appear, they can significantly impact daily life. Recognizing these symptoms early can help guide appropriate care and improve outcomes for patients, especially young athletes or active individuals.

Symptom	Description	Common Age	Source(s)
Pain	Activity-related pain, often in hindfoot/midfoot	8–20 yrs	1 2 3 4 14
Stiffness	Reduced range of motion, especially subtalar	8–20 yrs	1 2 3 12
Recurrent Sprain	Frequent ankle sprains due to altered mechanics	Children+	2 3 5 14
Foot Deformity	Rigid flatfoot, rarely cavus or valgus/varus	Teenagers	2 3 14

Table 1: Key Symptoms

Activity-related Foot Pain

Pain is by far the most common symptom and typically emerges during physical activity. For many, it starts insidiously in the early teens, but can occasionally appear suddenly, often after a minor foot injury or sprain. The pain is most commonly felt in the hindfoot or midfoot region and is usually aggravated by walking, running, or prolonged periods of standing 1 2 3 4 14.

Reduced Mobility and Stiffness

Patients often notice a loss of flexibility in their foot, particularly a reduced range of motion in the subtalar joint. This stiffness can make it difficult to adapt to uneven surfaces, increasing the risk of further injury 1 2 3 12.

Recurrent Ankle Sprains

Because of the abnormal mechanics caused by the coalition, individuals may experience frequent, seemingly minor ankle sprains. This symptom can sometimes be the first clue that prompts a deeper investigation, especially in otherwise healthy, active children and teenagers 2 3 5 14.

Foot Deformities

The classic foot deformity associated with tarsal coalition is a rigid flatfoot, where the arch is lost and the heel turns outward (heel valgus). However, not all patients develop flatfoot—some may present with a high arch (cavus) or other subtle deformities 2 3 14. The foot may appear stiff and resist attempts at manual correction.

Types of Tarsal Coalition

Understanding the different types of tarsal coalition is essential, as each type can present with unique symptoms, imaging findings, and treatment challenges. Most coalitions affect specific joints in the hindfoot.

Type	Frequency (%)	Key Feature	Source(s)
Calcaneonavicular	50–53	Bridge between calcaneus & navicular	1 6 9 10
Talocalcaneal	37–45	Bridge between talus & calcaneus	1 6 9 10
Talonavicular	Rare	Bridge between talus & navicular	6 10 12
Other (e.g. cuneiform)	Very rare	Bridges in midfoot	10

Table 2: Major Types of Tarsal Coalition

Calcaneonavicular Coalition

• Prevalence: Most common type, accounting for about half of all coalitions 1 6 9 10.
• Location: Bridge forms between the calcaneus (heel bone) and navicular (midfoot bone).
• Symptoms: Often presents with dorsolateral foot pain and is typically easier to spot on standard X-rays 1 4 7.
• Onset: Usually symptomatic in late childhood or adolescence.

Talocalcaneal Coalition

• Prevalence: Second most common, seen in approximately 37–45% of cases 1 6 9 10.
• Location: Connects the talus (ankle bone) to the calcaneus.
• Symptoms: Medial hindfoot pain and greater subtalar stiffness; can be harder to detect on plain radiographs 2 4 7 9.
• Diagnosis: Often requires CT or MRI for clear identification.

Talonavicular and Other Rare Coalitions

• Prevalence: Much less common; talonavicular coalitions are rare and often associated with other congenital foot anomalies 6 10 12.
• Other types: Coalitions can occasionally involve cuneiforms or other tarsal bones, typically presenting as part of a more complex foot deformity 10.
• Symptoms: Often asymptomatic, especially when isolated.

Histological Types

Tarsal coalitions are further classified by the tissue type bridging the bones:

• Osseous (bony): Complete fusion, most rigid.
• Cartilaginous: Less rigid, may ossify with age.
• Fibrous: Least rigid, sometimes harder to detect 2 7 8 12.

Causes of Tarsal Coalition

To understand why tarsal coalitions form, we must look at developmental biology and genetics, as well as other, less common causes.

Cause	Mechanism	Typical Onset	Source(s)
Congenital	Failure of bone segmentation	Birth–adolescence	2 10 11 13 14
Genetic	Inherited (autosomal dominant)	Childhood	3 10 11
Acquired	Trauma, arthritis, infection	Variable	3 12
Associated Syndromes	Limb anomalies	Birth	11 12

Table 3: Causes of Tarsal Coalition

Congenital (Developmental) Causes

• Primary mechanism: Most tarsal coalitions are congenital, resulting from a failure of segmentation of the primitive mesenchyme during embryonic development. This leads to a persistent bridge of bone, cartilage, or fibrous tissue between adjacent tarsal bones 2 10 11 13 14.
• Onset: Although the coalition is present at birth, symptoms often emerge only after ossification occurs in late childhood or adolescence 2 6.

Genetic Factors

• Inheritance: There is strong evidence for an autosomal dominant inheritance pattern with reduced penetrance in many cases, meaning the condition can run in families but doesn't always manifest 3 10 11.
• Syndromes: Coalitions can also be part of broader congenital syndromes affecting limb development 11.

Acquired Causes

• Trauma: Repeated injury or fractures involving the tarsal bones can rarely result in abnormal fusion as part of the healing process 3 12.
• Arthritis/Inflammation: Chronic inflammatory diseases or infections of the foot joints may also lead to acquired coalitions, though this is much less common compared to congenital cases 3 12.

Treatment of Tarsal Coalition

Treatment strategies for tarsal coalition are evolving, with a strong emphasis on conservative methods first and surgery reserved for persistent cases. The choice of treatment depends on the type, location, severity of symptoms, and the impact on daily life.

Approach	Key Features	Indication	Source(s)
Conservative	Rest, immobilization, orthotics, NSAIDs	First-line, mild cases	1 2 3 5 16
Surgical Resection	Removal of coalition, restore motion	Failed conservative tx	1 2 4 5 15 17
Arthrodesis	Fusion of joints, salvage procedure	Advanced/failed cases	2 3 5 14 15
Imaging-Guided	CT/MRI for planning	All surgical cases	7 8 9 15

Table 4: Treatment Overview

Conservative (Non-Operative) Treatment

• Approach: The mainstay for initial management includes rest, casting or boot immobilization, activity modification, custom orthotics, and anti-inflammatory medications 1 2 3 5 16.
• Effectiveness: Nonoperative treatment can relieve pain and prevent surgery in a significant proportion of patients, especially in milder cases or calcaneonavicular coalitions. For example, 79% of calcaneonavicular and 62% of talocalcaneal coalitions in one study did not require surgery after conservative treatment 16.
• Duration: A trial of at least 6 months is generally recommended before considering surgery 2 4 5.

Surgical Resection

• Indication: Reserved for cases where conservative management fails and the patient continues to experience significant pain or loss of function 1 2 4 5.
• Procedure: The coalition is surgically removed to restore joint motion. In calcaneonavicular coalitions, interposition of tissue (e.g., muscle or fat graft) is often performed to reduce recurrence risk 5 13 17.
• Outcomes: Surgery is generally successful, with pooled success rates of 80–81% for both talocalcaneal and calcaneonavicular coalitions. Arthroscopic (minimally invasive) approaches show similar or better results compared to open surgery 17.
• Risks: Complication and recurrence rates are relatively low (4–6%), but careful patient selection and surgical planning are crucial 17.

Arthrodesis (Joint Fusion)

• Indication: This is a salvage procedure for advanced cases, such as those with extensive coalitions, multiple coalitions, or secondary arthritis, as well as when resection fails 2 3 5 14 15.
• Types: Subtalar or triple arthrodesis may be performed, depending on the joints involved and the extent of degeneration 14 15.
• Goal: The aim is to relieve pain and provide stability, at the cost of losing some foot motion.

The Role of Imaging in Treatment Planning

• CT and MRI: Advanced imaging is essential to determine the type, location, and extent of the coalition, as well as any degenerative changes, which inform both the feasibility and approach of surgery 7 8 9 15.
• Preoperative Planning: Identifying coexisting coalitions and associated deformities is critical for avoiding surgical pitfalls and optimizing outcomes 4 5 7.

Conclusion

Tarsal coalition is a complex foot condition with implications for pain, mobility, and overall quality of life. Early recognition and a thoughtful, staged approach to management can make a substantial difference in outcomes. Here’s a summary of the main points:

• Symptoms: Most often present as activity-related hindfoot pain, stiffness, recurrent sprains, and sometimes rigid flatfoot.
• Types: Calcaneonavicular and talocalcaneal coalitions are the most common, with rarer types involving other tarsal bones.
• Causes: Primarily congenital due to failure of bone segmentation, with a strong genetic component; acquired causes are rare.
• Treatment: Starts with conservative management; surgery (resection) is reserved for persistent cases, with fusion as a last resort. Advanced imaging guides both diagnosis and treatment planning.

By staying alert to the signs and understanding the latest evidence-based strategies, clinicians and patients alike can achieve the best possible outcomes in managing tarsal coalition.