One of the common problems seen in children and adolescents who have CMT in the 10 to 16-year-old age group, and in young adults, is a cavo-varus foot where there is a high arch and patients walk on the outer border of the foot. All of the pressure goes through the heel and the outer side of the foot, resulting in calluses on the outer border and heel. With time, the big toe on the inner side drops down creating a lot of pressure on the ball of the foot. As the people we see become older, the toes tend to claw resulting in calluses on the knuckles of the toes.
Patients present with the following problems:
1. Cosmetic - Children and teenagers do not like the appearance of their feet.
2. Painful calluses on the outer side of the foot, the heel of the foot and the ball of the foot.
3. A tight painful band in the sole of the foot stretching from the heel to the ball of the foot. This is known as a contracted plantar fascia.
A number of surgical procedures have been performed in the past to correct this problem. This consisted of soft tissue releases and bony operations.
Soft tissue releases consisted of releasing the tight band in the sole of the foot, lengthening of tendons and transfer of muscles (plantar fascia release).
Bony operations consisted of correcting and fusing the deformed joints, a procedure called triple arthrodesis, and phalangeal fusions where the toes were all fused in the straight position.
An alternate procedure, especially in the adolescent and young adult, is to cut the bones and realign the bones without fusing them. This is called an osteotomy. The toe joints still have to be fused. (This fusing is called an interphalangeal arthrodesis.) This procedure preserves mobility in the foot as the joints are not fused.
One muscle that stays strong for many years is a muscle on the inner side of the foot called the tibialis posterior. When all other muscles are weak, this muscle acts as a deforming force pulling the foot inwards. This muscle should always be transferred to the upper middle part of the foot to help to pull the foot up. This is a posterior tibial tendon transfer to the dorsum of the foot through the interosseous membrane.