Tarsal Coalition

What is a tarsal coalition?

A tarsal coalition is an abnormal connection between two of the bones in the back of the foot. The bones are joined by bone, cartilage or fibrous tissue rather than separated by a normal joint, which restricts movement and changes how the foot functions.

Coalitions are present from birth but often only become symptomatic in later childhood or adolescence, as the affected tissue stiffens and the foot starts to feel the consequences. The most common types involve specific pairs of bones in the hindfoot.

Coalitions are an important and sometimes underrecognised cause of persistent foot pain in adolescents. They're also a recognised cause of recurrent ankle sprains in young people.

What does it feel like?

Symptoms typically appear in late childhood or adolescence. Common features include:

• Pain in the foot or ankle, particularly with activity

• Recurrent ankle sprains or a feeling of weakness

• Stiffness in the foot, often with reduced side-to-side motion

• Spasm of the muscles on the outer side of the foot in some cases

• A flat foot that doesn't form an arch properly

Symptoms can be mistaken for other conditions, particularly recurrent ankle sprains or simple flat feet. The lack of motion in the back of the foot is the key clue when present.

How is it diagnosed?

Examination findings — particularly restricted hindfoot motion — raise the suspicion. Confirmation typically requires imaging.

X-rays may show some types of coalition, but CT and MRI are often more revealing. CT shows bony coalitions clearly; MRI better demonstrates fibrous or cartilaginous bridges and can also show secondary changes from the abnormal mechanics.

It's important to get a clear picture of which bones are involved and how, because this influences treatment options.

What are the treatment options?

Initial treatment is usually non-surgical — rest from aggravating activities, orthotic support, physiotherapy and sometimes a period of immobilisation. Many tarsal coalitions can be managed this way, particularly when symptoms are mild or moderate.

When non-surgical management isn't enough, surgical options include resection of the coalition (removing the abnormal bridge) or, in some cases, fusion procedures. The right approach depends on the type, location and the broader picture. Nev will work through this with you and your child at your consultation.

When should you get it checked?

Seek a specialist assessment if:

• Your child has persistent foot or ankle pain in their teens

• There are recurrent ankle sprains without a clear cause

• The foot feels stiff or movements are limited

• Pain is interfering with sport or daily activity

• Flat feet are persistent and symptomatic

Tarsal coalitions benefit from being identified — without the right diagnosis, treatment is often misdirected. A proper assessment opens up the options that actually address the underlying problem.