Tarsal coalition is a fusion or sticking together of the tarsal bones in the foot. The tarsals are 7 bones located at the back of the foot. It is a congenital disease meaning you are born with it. Midfoot pain may appear in adolescents with this condition, but symptoms may not show until later in some people.
- Symptoms include pain in the midfoot area in adolescents, which is usually felt after hard training or activity.
- Sometimes the condition becomes obvious after an ankle sprain when the pain does not appear to get any better.
- Other signs include the arch of the foot collapsing with reduced movement at the ankle joint. The athlete may walk with a limp complaining of stiffness in the foot and ankle.
- Symptoms usually do not appear until the bones have started to mature, between the ages of 10 and 16. However, some people will not display any symptoms until later on in life, possibly if they start to exercise or suffer an ankle sprain.
- The athlete may complain of symptoms of tarsal tunnel syndrome which can be caused by an unknown coalition of the tarsal bones.
- Diagnosis is made after a thorough examination with a full medical history. An X-ray may show up an osseous coalition and an MRI may show up a fibrous one.
What causes tarsal coalition?
The bones involved are the Calcaneus, Talus, Navicular, Cuboid, and the three Cuneiform bones. The most common joints to be affected are the calcaneonavicular joint between the Calcaneus and the Navicular, and the talocalcaneal joint between the Talus and the Calcaneus.
It usually affects adolescents as the fibrous or cartilaginous joints between the bones ossify (turn to bone) and harden. This causes a decreased range of motion in the rearfoot causing strain on the ankle joint. Tarsal coalition can occasionally develop in later life due to an infection or arthritis in the joints, or an ankle injury.
After diagnosis, the foot may be placed in a cast or walking boot to allow proper rest to reduce the pain and inflammation. After this period biomechanical problems should be corrected. This may require insoles or orthotics. Exercises to improve mobility may also be advised. Corticosteroid injections are sometimes also recommended.
If conservative treatment fails, surgery for tarsal coalition may be required. Surgery may be used to either excise or remove the excess bone growth, or to completely fuse the two joints together.