Tarsal Coalition
Tarsal Coalition is a condition where
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 progressively flatter as the child gets
older.
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These pictures are of a 16-year-old boy with a tarsal
coalition of one foot. Note how flat the foot is. |
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Symptoms include aching, soreness and fatigue
after exercise and specific soreness and pain in the back of the foot
and heel joint. 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.
The diagnosis of a tarsal coalition can easily be made by a careful
examination of the movement segments of the back of the foot. This
is then confirmed with x-rays. A CAT scan or an MRI will rarely be
needed to confirm the diagnosis.
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These are XRŐs looking at the side of the foot. On the foot on the right, there is no space between the heel bone (calcaneus) and the ankle bone (talus). The space is taken up by abnormal bone, called a coalition. The foot on the left is a normal XR where you can see the space between the calcaneus and the talus, and the one on the right has the coalition circled in red.
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If it cannot be seen
on a plain X-ray, the diagnosis of a tarsal coalition
becomes more obvious using a CAT scan. Note in the scan
here, the normal foot on the right and the bone connection
between the talus and calcaneus on the left. |
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Depending on how uncomfortable or painful the foot is, treatment can
be initiated with a cast, boot or a brace and then followed with orthotic
arch supports. As noted above, the boot or orthotic support will not
ever be curative because the tarsal coalition and the abnormal bone
connection are still present. In order to completely eliminate 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 if associated with a very flat
foot. This is because simply removing the tarsal coalition will not
correct the arch of the foot itself.
The recovery following removal of a tarsal coalition is straightforward.
A removable boot is worn on the foot for six weeks. Walking on the
boot can commence at two weeks during which time, strengthening and
various exercises are done on a regular basis to maintain and improve
the movement and strength and arch of the foot.
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