Tarsal coalition
A tarsal coalition is an abnormal connection between two or more bones of the foot that forms during development before birth. It can limit foot mobility and cause pain, rigid flatfoot or repeated ankle sprains. Although it may cause no symptoms for years, it usually shows up in late childhood or adolescence, when the connection between the bones becomes stiffer.
- Typical age
- 8–16 years
- Also known as
- Tarsal bar · Calcaneonavicular coalition · Talocalcaneal coalition
What it is
The tarsal bones form the back and middle of the foot and allow it to adapt to the ground when walking, running and playing sport. For the foot to work properly, these bones need to sit correctly in relation to each other and be able to move against one another.
Sometimes, during development in the womb, two tarsal bones do not separate completely. This leaves an abnormal connection, called a tarsal coalition, which may be made of fibrous tissue, cartilage or bone. The condition is congenital, although it does not always cause symptoms in the first years of life.
The most common coalitions are the calcaneonavicular coalition, between the calcaneus and the navicular, and the talocalcaneal coalition, between the talus and the calcaneus. A coalition can gradually limit hindfoot movement and alter the normal mechanics of walking.
It is estimated that about 1% of people may have a tarsal coalition, although many are never diagnosed because they cause no discomfort. In children who do develop symptoms, they usually appear between 8 and 16 years of age, as the connection matures and ossifies. It can affect one foot or both.
The right diagnosis and treatment can relieve symptoms and improve foot function.
Signs parents may notice
Symptoms vary depending on the location and size of the coalition. The most common are:
- Flatfoot that does not correct when standing on tiptoe: the arch stays flat and the hindfoot does not regain its normal movement.
- Pain in the foot or around the ankle: especially when walking, running or doing sport.
- Stiff foot: difficulty moving the hindfoot or walking on uneven ground.
- Repeated ankle sprains: these may happen because the foot loses some of its ability to adapt to the ground.
- Limping or difficulty doing sport: the child may avoid running, jumping or activities they used to do without difficulty.
- Muscle spasm: in some cases, the muscles on the outside of the leg go into spasm and change the position of the foot.
Not every child has all of these symptoms. A rigid flatfoot, especially with pain or recurrent sprains, should raise the possibility of a tarsal coalition.
When to see a specialist
It is advisable to ask for an assessment by a paediatric orthopaedic specialist when the child has:
- Persistent pain in the foot or ankle.
- Flatfoot that does not regain its shape when standing on tiptoe.
- Stiffness or limited movement of the hindfoot.
- Repeated ankle sprains.
- A limp or difficulty walking, running or doing sport.
When is it urgent?
Most tarsal coalitions are not a medical emergency. However, sudden severe pain, being unable to put weight on the foot, or fever with redness or marked swelling require urgent medical assessment to rule out other causes.
How it is diagnosed
Diagnosis requires a clinical examination and imaging tests to identify the coalition, find out how extensive it is and assess any associated deformity.
Clinical examination
The specialist looks at the shape of the foot when standing, the height of the arch, hindfoot movement and whether the heel valgus corrects when the child stands on tiptoe. Gait, ankle movement, possible muscle spasm and the location of the pain are also assessed.
X-rays
X-rays of the foot, usually taken standing, show the alignment of the bones and can reveal signs suggesting a coalition. Depending on their type and location, some coalitions can be hard to see on plain X-rays.
Computed tomography (CT)
CT shows the bone anatomy in detail, defines the location and extent of the coalition and allows assessment of the joints involved. It is particularly useful for planning surgery when there is a bony connection.
Magnetic resonance imaging (MRI)
MRI can identify fibrous or cartilaginous coalitions and shows soft tissues, cartilage and any associated changes, without ionising radiation.
The choice of tests depends on the examination and clinical suspicion. Not every patient needs all of them.
Treatment
Treatment depends on how severe the symptoms are, the location and size of the coalition, the patient’s age, the degree of deformity and the condition of the neighbouring joints. Not all coalitions need surgery: when they cause no pain or functional limitation, clinical follow-up may be enough.
Non-surgical treatment
The aim of non-surgical treatment is to relieve pain, reduce overload on the affected area and improve foot function.
It may include:
- Temporary activity modification: reducing high-impact activities that trigger pain, such as running and jumping, for a few weeks.
- Insoles and footwear changes: these may improve comfort and spread the load, although they do not remove the abnormal connection between the bones.
- Temporary immobilisation: for patients with significant pain, an orthopaedic boot or cast may be used for a limited period to reduce irritation.
- Medication: pain relief or anti-inflammatory medicines when prescribed by the doctor.
- Physiotherapy: this can help restore function and treat associated muscle spasm, adapted to the available range of movement.
If symptoms persist or return despite these measures, surgery should be considered.
Surgical treatment
Surgery is considered when there is persistent pain, functional limitation or difficulty with everyday activities despite appropriate non-surgical treatment.
The technique is chosen individually according to the anatomy of the coalition and the condition of the joints.
1. Resection of the tarsal coalition
This involves removing the abnormal connection between the bones to restore or improve hindfoot movement and relieve pain. In some cases, tissue is placed between the resected surfaces to reduce the risk of them joining again.
Resection may be indicated for selected calcaneonavicular or talocalcaneal coalitions, provided the characteristics of the coalition and the condition of the joints allow their function to be preserved.
2. Correction of the associated flatfoot
Removing the coalition does not always correct the foot deformity. If there is marked hindfoot valgus or a structural flatfoot that contributes to the pain, reconstructive procedures such as calcaneal osteotomies or other bone realignment techniques may also be needed.
3. Arthrodesis in selected cases
For extensive coalitions, severe deformities or situations with degenerative joint damage, arthrodesis may need to be considered. This procedure fuses one or more joints in a controlled way to relieve pain and improve alignment, at the cost of reduced movement in the fused joints.
The operation is usually done under general anaesthesia, with a pain relief plan adapted to the patient. Depending on the technique, the child’s age and hospital protocols, it may require a hospital stay or be done as day surgery. The decision is made individually for each child.
Outlook and recovery
Recovery depends on the surgical technique, the location of the coalition and whether an associated deformity needs to be corrected.
- First weeks: pain is controlled and the foot is protected in a cast or boot, depending on the operation.
- Weight-bearing: after surgery it may be necessary to avoid putting weight on the foot for several weeks. When weight-bearing can begin depends on the stability of the reconstruction and on bone healing.
- Back to school: many children can return once pain is under control and they can get around safely, even on crutches if needed. After complex procedures, returning may take longer.
- Physiotherapy and functional recovery: once the surgeon gives the go-ahead, movement, strength and walking are gradually recovered.
- Back to sport: this usually takes several months and should be allowed once clinical recovery and, where relevant, X-ray healing are adequate.
Follow-up checks pain, movement, foot alignment and, when an osteotomy has been performed, bone healing.
In many carefully selected patients, surgery relieves pain and improves function. However, full recovery can take several months and results depend on the characteristics of each coalition.
Dr. Laura Corominas Francés, a specialist in paediatric orthopaedics and paediatric foot and ankle, assesses foot deformities, including rigid flatfoot associated with tarsal coalitions. The aim is to identify the cause of the symptoms and offer individual treatment, from non-surgical measures to resection of the coalition and reconstruction of the foot when indicated.
This page is for general information and does not replace an assessment by a specialist. If you are worried about your child's foot, talk to their paediatrician or book an appointment.