Tarsal coalition is a condition in which one or more bones are abnormally joined together (fused or coalesced) in the back of the foot. Normal development of any joint requires that the bones on either side of the joint move freely.
A child born with tarsal coalition has bones that do not develop normally because the joint and its cartilage lining never fully develop. For this reason, the two bones that are involved in the coalition are stuck together and the foot does not move in and out (inversion and eversion) adequately. As the foot develops, the child and family will notice that the foot is flat and often getting progress
Symptoms of tarsal coalition include:
• Aching, soreness and fatigue after exercise
• Specific soreness and pain in the back of the foot and heel joint
The diagnosis of a tarsal coalition can be made easily by a careful examination of the movement segments of the back of the foot. A tarsal coalition diagnosis then is confirmed with x-rays. A CAT scan or an MRI rarely is needed to confirm the diagnosis.
Depending on how uncomfortable or painful the foot is, tarsal coalition treatment can be initiated with a cast, boot or a brace and then followed with orthotic arch supports. When symptoms from tarsal coalition begin, they can be quieted down by immobilizing the foot in a cast or a boot. This does not treat the underlying problem of the coalition but it does help temporarily with the symptoms of pain and soreness.
Occasionally, the use of a cast for a few months will be sufficient as treatment and once the cast is removed the symptoms dissipate. While the symptoms of the coalition may be improved, the coalition remains, and the foot continues to be stiff. For this reason, once a coalition is diagnosed, it is unusual that the use of the cast immobilization is the only form of treatment.
In order to completely eliminate tarsal coalition symptoms and improve the movement in the back of the foot, surgery is required. The surgery is designed to remove the tarsal coalition and improve the inversion and eversion movement of the foot. Once this is done, most children are able to resume full athletic activity.
There are times when removal of the tarsal coalition cannot completely correct the deformity. For these children, additional surgery may be necessary, particularly if the tarsal coalition is associated with a very flat foot. This is because simply removing the tarsal coalition will not correct the arch of the foot itself.