Tarsal Coalition in Adults: When Childhood Foot Fusion Causes Adult Pain and Flatfoot

🩺 Medical Review: This article was written and reviewed by Dr. Thomas Biernacki, DPM, board-qualified podiatric surgeon at Balance Foot & Ankle Specialists. Last updated April 2026.

Quick Answer: Tarsal coalition in adults is an abnormal bone, cartilage, or fibrous connection between two or more tarsal (rearfoot) bones that restricts normal motion and causes progressive pain, stiffness, and flatfoot deformity. While most coalitions form before birth, many aren’t diagnosed until adulthood when compensatory mechanisms fail and symptoms emerge. Treatment ranges from custom orthotics and activity modification to surgical resection or fusion depending on coalition type, size, and arthritis involvement.

If you’ve been told you have a tarsal coalition as an adult, you may feel confused — this is typically described as a childhood condition. The reality is that many tarsal coalitions go undiagnosed for decades, only becoming symptomatic when the foot can no longer compensate for the restricted motion. Understanding your specific coalition type and treatment options is essential for making informed decisions about your care.

Table of Contents

• What Is Tarsal Coalition?
• Types of Tarsal Coalition
• Calcaneonavicular Coalition
• Talocalcaneal Coalition
• Why Symptoms Appear in Adulthood
• Symptoms of Adult Tarsal Coalition
• Diagnosis and Imaging
• Conservative Treatment Options
• Custom Orthotics for Tarsal Coalition
• Physical Therapy and Exercises
• Injection Therapy Options
• Surgical Resection of Tarsal Coalition
• Triple Arthrodesis for Severe Cases
• Recovery After Coalition Surgery
• Living with Tarsal Coalition Long-Term
• Recommended Products
• Complete Support Kit
• Most Common Mistake
• Warning Signs
• FAQ
• Sources
• Video

What Is Tarsal Coalition?

Tarsal coalition is an abnormal connection between two or more of the seven tarsal bones in the rearfoot and midfoot. This connection can be made of bone (synostosis), cartilage (synchondrosis), or fibrous tissue (syndesmosis). The coalition restricts or eliminates normal motion between the affected joints, forcing other joints and soft tissues to compensate. These coalitions form during fetal development when the bones fail to completely separate, occurring in approximately 1-2% of the population. Bilateral coalitions occur in about 50% of cases, meaning both feet are often affected.

Types of Tarsal Coalition

The two most common types account for approximately 90% of all tarsal coalitions. Calcaneonavicular coalition connects the calcaneus (heel bone) to the navicular bone across the midfoot, comprising about 53% of cases. Talocalcaneal coalition connects the talus to the calcaneus at the subtalar joint, comprising about 37% of cases. Less common coalitions include calcaneocuboid, talonavicular, and cubonavicular varieties. The type of coalition significantly influences both symptoms and treatment options because each affects different joints and motion planes.

Calcaneonavicular Coalition in Adults

Calcaneonavicular coalition creates a bridge or bar between the anterior process of the calcaneus and the lateral aspect of the navicular. In adults, this coalition is often identified on oblique foot X-rays as the classic “anteater nose” sign where the elongated anterior calcaneal process resembles an anteater’s snout. This coalition primarily restricts midfoot motion and is generally more amenable to surgical resection than talocalcaneal coalitions. Adults with calcaneonavicular coalition typically present with lateral midfoot pain that worsens with activity and improves with rest. The coalition may be fibrous or cartilaginous in younger adults but often progresses to complete bony fusion over time.

Talocalcaneal Coalition in Adults

Talocalcaneal coalition occurs at the middle facet of the subtalar joint, connecting the sustentaculum tali of the calcaneus to the talus. This coalition restricts subtalar joint motion — the joint responsible for foot inversion and eversion on uneven ground. CT scan is the gold standard for diagnosis because X-rays often miss this coalition. The “C sign” on lateral X-ray, where a continuous C-shaped density connects the talus dome to the sustentaculum, suggests the diagnosis but isn’t always present. Talocalcaneal coalition tends to cause more significant flatfoot deformity and peroneal muscle spasm than calcaneonavicular coalition because it directly restricts the subtalar joint’s ability to adapt to terrain.

Why Symptoms Appear in Adulthood

Many adults with tarsal coalition were asymptomatic for decades because their bodies compensated effectively. Several factors trigger symptom onset in adulthood. Weight gain increases load through already-stressed compensatory joints. Decreased tissue elasticity with aging reduces the ability of surrounding joints to absorb abnormal forces. Activity changes such as starting a new exercise program expose biomechanical limitations. Previous ankle sprains may destabilize joints that were compensating for the coalition. Progressive osteoarthritis develops in adjacent joints that have been overworked for years. A fibrous or cartilaginous coalition may gradually ossify (convert to bone), eliminating any remaining motion. Understanding these triggers helps explain why a condition present since birth can suddenly become painful at age 35, 45, or beyond.

Symptoms of Adult Tarsal Coalition

Adult tarsal coalition symptoms develop gradually and often mimic other foot conditions, leading to delayed diagnosis. Deep, aching rearfoot or midfoot pain that worsens with prolonged standing and walking is the hallmark symptom. Stiffness is pronounced, particularly on uneven terrain where the restricted joint cannot adapt. Recurrent ankle sprains occur because the rigid rearfoot forces the ankle to compensate for lost subtalar motion. Peroneal muscle spasm causes lateral ankle tightness and cramping as the peroneal tendons guard against inversion that the coalition prevents. Progressive flatfoot deformity develops as compensatory mechanisms fail. Fatigue and leg cramping occur because muscles work overtime to compensate for restricted joint motion. Pain is typically worse after activity and improves with rest, distinguishing it from inflammatory conditions that are worse with morning stiffness.

Diagnosis and Imaging for Tarsal Coalition

Accurate diagnosis of adult tarsal coalition requires a combination of clinical examination and advanced imaging. Physical examination reveals limited or absent subtalar joint motion — the inability to invert and evert the rearfoot is a critical finding. Forced inversion often reproduces peroneal spasm. Weight-bearing X-rays show flatfoot deformity and may reveal the “anteater nose” sign for calcaneonavicular coalition or the “C sign” for talocalcaneal coalition. CT scan is essential for definitive diagnosis, clearly showing the location, size, and composition of the coalition. MRI is valuable for detecting fibrous coalitions that CT may underestimate and for assessing adjacent joint cartilage health. MRI also identifies bone marrow edema indicating active stress at the coalition site, which helps guide treatment decisions.

Conservative Treatment Options for Tarsal Coalition

Conservative treatment is the first approach for adult tarsal coalition, particularly when arthritis is minimal. The goal is to reduce stress on the coalition and compensatory joints while maintaining function. Activity modification avoids high-impact activities that stress the restricted joints — swimming, cycling, and elliptical training are excellent alternatives. A short course of walking boot immobilization (2-4 weeks) during acute flare-ups reduces inflammation. Nonsteroidal anti-inflammatory medications manage pain and inflammation during symptomatic periods. Ice application after activity reduces post-exercise swelling. Weight management reduces mechanical stress through the coalition and compensatory joints. Supportive footwear with motion control features reduces the demand on the restricted subtalar joint.

Custom Orthotics for Tarsal Coalition

Physical Therapy and Exercises for Tarsal Coalition

Physical therapy for tarsal coalition focuses on strengthening the muscles that support the arch and ankle while improving mobility in adjacent joints. Peroneal muscle stretching addresses the protective spasm that commonly accompanies tarsal coalition. Intrinsic foot muscle strengthening through towel curls, marble pickups, and short foot exercises improves dynamic arch support. Ankle strengthening with resistance bands builds stability that compensates for the rigid rearfoot. Balance and proprioception training on wobble boards teaches the body to adapt to uneven surfaces despite limited subtalar motion. Calf stretching maintains Achilles flexibility, which is critical because a tight Achilles dramatically increases stress through the midfoot and rearfoot. Avoid exercises that force subtalar joint motion beyond its available range, as this creates pain without benefit.

Injection Therapy Options for Tarsal Coalition

Injection therapy can provide diagnostic information and therapeutic relief for adult tarsal coalition. Corticosteroid injections at the coalition site or in adjacent inflamed joints can reduce inflammation and pain for weeks to months. These injections also serve a diagnostic purpose — if pain resolves with injection into a specific location, it confirms that area as the primary pain generator. Image-guided injection (ultrasound or fluoroscopy) improves accuracy for targeting the coalition interface. However, repeated corticosteroid injections are limited due to potential cartilage and tissue damage. Some specialists are exploring platelet-rich plasma (PRP) injections for coalition-related arthritis in adjacent joints, though evidence is still emerging. Injection therapy works best as part of a comprehensive treatment plan that includes orthotics and physical therapy rather than as a standalone solution.

Surgical Resection of Tarsal Coalition

Surgical resection involves removing the coalition bar and interposing fat, muscle, or bone wax to prevent regrowth. This procedure aims to restore motion to the affected joint while eliminating the pain source. Calcaneonavicular coalition resection has excellent results in adults when the coalition comprises less than 50% of the joint surface and adjacent joints are free of arthritis. The success rate for calcaneonavicular resection in selected patients ranges from 85-95%. Talocalcaneal coalition resection is more technically demanding and has somewhat lower success rates (70-85%) because the subtalar joint is deeper and the coalition often involves more of the joint surface. Key factors predicting surgical success include coalition size (smaller is better), absence of adjacent arthritis, and maintained hindfoot alignment. Resection is less predictable in adults over 50 or those with significant degenerative changes.

Triple Arthrodesis for Severe Cases

When tarsal coalition has caused significant arthritis in the subtalar, talonavicular, and calcaneocuboid joints, triple arthrodesis may be the best option. This procedure fuses all three rearfoot joints, eliminating the arthritic pain sources while correcting flatfoot deformity. Triple arthrodesis is typically reserved for adults with advanced arthritis where resection alone won’t address the degenerative changes. The procedure provides reliable pain relief and deformity correction but eliminates all rearfoot motion. Recovery takes 3-4 months to full weight-bearing and 6-12 months for maximum improvement. Despite eliminating rearfoot motion, most patients report significant improvement in function and pain compared to their pre-surgical state because they were already functioning with minimal motion due to the coalition and arthritis. Proper orthotic support with PowerStep Pinnacle Maxx insoles is essential after triple arthrodesis to protect the midfoot joints.

Recovery After Coalition Surgery

Recovery differs significantly between resection and fusion procedures. After coalition resection, patients are typically non-weight-bearing for 2-3 weeks, then progressive weight-bearing in a boot for 4-6 weeks, with return to regular footwear with PowerStep Pinnacle insoles by weeks 6-8. Physical therapy starts early to maximize the restored motion. After triple arthrodesis, non-weight-bearing lasts 6-8 weeks, followed by progressive weight-bearing in a boot for another 4-6 weeks. Full recovery takes 4-6 months. During both recovery pathways, swelling management with DASS compression sleeves and pain relief with Doctor Hoy’s Pain Relief Gel support comfortable healing.

Living with Tarsal Coalition Long-Term

Whether managed conservatively or surgically, tarsal coalition requires ongoing attention to foot health. Daily orthotic use is non-negotiable — the biomechanical abnormality persists even after successful treatment. Regular low-impact exercise maintains strength and flexibility without overloading the affected joints. Weight management reduces mechanical stress through the rearfoot complex. Proper footwear with motion control features supports the restricted or surgically altered joint mechanics. Annual podiatric evaluation monitors for progressive changes in foot structure and function. Many adults with tarsal coalition live active, pain-free lives once properly diagnosed and treated — the key is understanding that this is a structural condition requiring permanent biomechanical support rather than a temporary injury that fully heals.

Recommended Products for Tarsal Coalition Management

Managing tarsal coalition effectively requires the right combination of support, compression, and pain relief products. These are the products I recommend to my tarsal coalition patients based on years of treating this condition.

PowerStep Pinnacle Maxx Orthotic Insoles

Most adult tarsal coalition patients have rigid or semi-rigid flatfoot deformity that requires maximum support. PowerStep Pinnacle Maxx orthotic insoles provide the firmest arch support and motion control in the PowerStep lineup — exactly what a coalition foot needs. The angled heel platform prevents excessive pronation that overloads the restricted rearfoot joints, while the reinforced arch shell supports the medial longitudinal arch that tends to collapse. I consider PowerStep Pinnacle Maxx insoles the single most important non-surgical intervention for tarsal coalition because they reduce the compensatory strain that causes pain.

PowerStep Pinnacle Orthotic Insoles

For coalition patients with preserved partial motion or milder flatfoot deformity, PowerStep Pinnacle orthotic insoles provide balanced arch support with more cushioning flexibility. The semi-rigid arch shell supports without over-restricting, and the double-layer cushioning absorbs impact forces that would otherwise transfer through the rigid rearfoot. PowerStep Pinnacle insoles work especially well for patients recovering from coalition resection surgery who need support while regaining motion. Having both PowerStep models allows patients to match support level to daily activities.

Doctor Hoy’s Natural Pain Relief Gel

Deep rearfoot pain from tarsal coalition responds well to topical menthol-based therapy. Doctor Hoy’s Natural Pain Relief Gel penetrates to the deep tissue level where coalition pain originates. Doctor Hoy’s gel is particularly effective when applied after prolonged walking or exercise when the compensatory joints are most inflamed. Many of my tarsal coalition patients keep Doctor Hoy’s pain relief gel in their work bag for midday application when their feet start aching from standing.

Doctor Hoy’s Arnica Boost Recovery Cream

Chronic inflammation at the coalition site and adjacent joints responds to regular arnica therapy. Doctor Hoy’s Arnica Boost Recovery Cream combines arnica montana with menthol for dual anti-inflammatory and analgesic effect. Doctor Hoy’s arnica cream works particularly well as a nightly application, addressing the cumulative inflammation from daily weight-bearing. Post-surgical patients benefit from Doctor Hoy’s arnica cream once incisions are healed to manage residual swelling during rehabilitation.

DASS Original Dynamic Ankle Stabilizing System

The DASS Original Dynamic Ankle Stabilizing System provides graduated compression from ankle to midfoot that addresses the chronic swelling common in tarsal coalition. DASS compression sleeves also provide proprioceptive feedback that helps the ankle compensate for the restricted subtalar joint motion. This is especially important during activities on uneven terrain where the coalition limits the foot’s ability to adapt. DASS sleeves are an essential daily wear for coalition patients — the compression reduces fatigue, controls swelling, and improves stability throughout the day.

FLAT SOCKS

For coalition patients who need minimal bulk inside their shoes, FLAT SOCKS provide a thin moisture-wicking interface that works perfectly over orthotics. FLAT SOCKS prevent the friction and bunching that standard socks create when combined with orthotic insoles inside supportive shoes. For tarsal coalition patients who wear orthotics daily, FLAT SOCKS ensure comfortable all-day wear without adding bulk that changes shoe fit.

Complete Tarsal Coalition Support Kit

🏥 Dr. Biernacki’s Tarsal Coalition Support Kit:

For comprehensive tarsal coalition management, I recommend combining these products:

• PowerStep Pinnacle Maxx Insoles — maximum arch support and motion control for rigid flatfoot
• PowerStep Pinnacle Insoles — balanced support for lighter activities and post-resection recovery
• Doctor Hoy’s Pain Relief Gel — natural topical pain management for deep rearfoot pain
• Doctor Hoy’s Arnica Boost Cream — chronic inflammation reduction
• DASS Compression Sleeves — graduated compression and proprioceptive support
• FLAT SOCKS — thin orthotic-friendly interface

This combination addresses the three pillars of coalition management: biomechanical support, inflammation control, and joint stabilization.

The Most Common Tarsal Coalition Mistake

🔑 Key Takeaway: I treated a 41-year-old West Bloomfield man who had been seeing multiple doctors for 4 years for recurrent ankle sprains and chronic rearfoot pain. He’d been diagnosed with “weak ankles,” chronic ankle instability, and posterior tibial tendinitis — treated with ankle braces, physical therapy, and steroid injections with minimal improvement. A CT scan in our office immediately revealed a large talocalcaneal coalition that was the root cause of everything: the restricted subtalar motion caused his recurrent sprains, the compensatory strain caused his tendon pain, and no amount of ankle bracing could fix a bone bridge. After coalition resection and proper rehabilitation with PowerStep Pinnacle Maxx insoles and DASS compression, his “4-year mystery” resolved in 3 months. Tarsal coalition is one of the most under-diagnosed conditions in adult podiatry — if rearfoot pain and stiffness don’t respond to standard treatment, always get a CT scan.

Warning Signs with Tarsal Coalition

⚠️ Seek immediate podiatric evaluation if you experience any of these warning signs with tarsal coalition:

1. Progressive flatfoot deformity — worsening arch collapse indicates the coalition is causing structural deterioration requiring intervention
2. Recurrent ankle sprains despite treatment — may indicate undiagnosed coalition restricting protective subtalar motion
3. Peroneal muscle cramping and lateral ankle pain — classic coalition sign often misdiagnosed as tendinitis
4. Inability to walk on uneven surfaces — restricted rearfoot motion prevents normal terrain adaptation
5. Pain that worsens despite orthotics and physical therapy — may indicate progressive ossification of the coalition
6. Sudden increase in pain after years of stability — could indicate adjacent joint arthritis developing from chronic compensation
7. Bilateral foot stiffness and pain — coalitions are bilateral in 50% of cases, both feet may need evaluation
8. Numbness or tingling in the foot — altered biomechanics can compress nerves, particularly the tarsal tunnel

Frequently Asked Questions About Tarsal Coalition in Adults

Can tarsal coalition develop in adulthood or is it always congenital?

Tarsal coalition is always congenital — it forms during fetal development. However, it’s frequently not diagnosed until adulthood because many people compensate effectively for decades. The condition doesn’t develop in adulthood, but symptoms often first appear in adults when compensatory mechanisms fail due to aging, weight gain, injury, or progressive ossification of a previously fibrous coalition. If you’re diagnosed as an adult, the coalition has been present since birth.

Do I need surgery for tarsal coalition?

Not all adult tarsal coalitions require surgery. Many patients manage successfully with PowerStep Pinnacle Maxx insoles, physical therapy, activity modification, and DASS compression sleeves. Surgery is recommended when conservative treatment fails after 3-6 months, when pain significantly limits daily activities, or when progressive deformity is occurring. The type of surgery depends on the coalition type, size, and presence of arthritis.

Will I be able to run or play sports with tarsal coalition?

Many adults with tarsal coalition participate in sports and exercise with proper management. Low-impact activities like swimming, cycling, and elliptical training are excellent options. Running on flat, even surfaces is possible for many patients with orthotic support. After successful coalition resection, athletic function often improves significantly as restored motion allows more normal biomechanics. The key is matching activity level to your specific coalition type and remaining joint motion.

Should I get my children checked if I have tarsal coalition?

Yes. Tarsal coalition has a genetic component, and first-degree relatives have a higher risk. Children of parents with tarsal coalition should be evaluated if they develop foot pain, flatfoot deformity, limited ankle motion, or recurrent ankle sprains — especially during the adolescent growth spurt (ages 12-16) when fibrous coalitions often begin to ossify. Early detection allows for more treatment options and better outcomes.

What’s the difference between tarsal coalition resection and fusion?

Resection removes the coalition bar to restore joint motion, while fusion (arthrodesis) permanently eliminates motion by joining bones together. Resection is preferred when the coalition is small, no significant arthritis exists, and restored motion is the goal. Fusion is chosen when arthritis is advanced, the coalition is too large for successful resection, or resection has previously failed. Both procedures reliably reduce pain, but they achieve it through opposite strategies — restoring motion versus eliminating it.

Sources

1. Lemley F, Berlet G, Hill K, Philbin T, Isaac B, Lee T. Current concepts review: tarsal coalition. Foot Ankle Int. 2006;27(12):1163-1169.
2. Luhmann SJ, Schoenecker PL. Symptomatic talocalcaneal coalition resection: indications and results. J Pediatr Orthop. 1998;18(6):748-754.
3. Cass AD, Camasta CA. A review of tarsal coalition and pes planovalgus: clinical examination, diagnostic imaging, and surgical planning. J Foot Ankle Surg. 2010;49(3):274-293.
4. Kernbach KJ. Tarsal coalition: etiology, diagnosis, imaging, and stigmata. Clin Podiatr Med Surg. 2010;27(1):105-117.
5. Mosca VS, Bevan WP. Talocalcaneal tarsal coalitions and the calcaneal lengthening osteotomy: the role of deformity correction. J Bone Joint Surg Am. 2012;94(17):1584-1594.

Watch: Understanding Tarsal Coalition in Adults

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