The High Arch (Cavus) Foot (Charcot Marie Tooth Disorder)

There are many causes for a high arch foot. In the United States the most common cause for a high arch foot is a form of muscular dystrophy called hereditary sensorimotor neuropathy. Most people recognize this by the more commonly used name of Charcot Marie Tooth Disease. This is a disease of the muscles and the nerves of the legs and occasionally of the hands, in which certain muscles weaken, while others retain their strength. The condition is hereditary and is transmitted as an autosomal dominant condition. This means that statistically, 50% of the offspring will inherit the disorder. This is, however, just a statistic. In some families all of the children develop the condition and in others, none inherit it. The combination of weakness and strength gives rise to a typical pattern of deformity where the arch gets higher and certain muscles weaken, leading to a dropping of the foot. Because the arch is high, the bone under the big toe (called the 1st metatarsal) is very prominent and the toes are curled (called claw toes). The muscles that pull the foot inward (inversion) remain strong, while those that pull the foot outward (eversion) are weak or absent completely. One common problem is the presence of a foot drop. This means that the muscle that pulls the foot upward when walking is weak or paralyzed, leading to a dropping of the foot when walking.

The diagnosis of this condition is fairly straightforward and can be made by an orthopedic surgeon in the office. Nerve tests rarely need to be performed to confirm the diagnosis. The treatment of this condition is varied. It depends on the extent of deformity and the amount of disability the patient is experiencing. The condition occurs both in children and adults. Although the pattern of muscle and nerve damage may be similar through the generations in a family, this is not always the case. Depending upon the symptoms, treatment may include an orthotic arch support, a brace that is worn in the shoe or surgery. The surgical procedures are many and depend upon the underlying deformity and the pattern of muscle loss and weakness. Usually one operation is not enough and a combination of surgeries is performed all at the same time to correct the various deformities. These can be tendon transfers to correct muscle weakness, bone cuts to correct bone deformity and repositioning of the arch of the foot.

These are the appearance of the feet from behind in two patients with a high arch, with the heel twisted inwards. The foot on the left in both patients has already undergone surgical correction and is straight.