CHARCOT MARIE TOOTH FOOT DEFORMITY
Charcot Marie Tooth Generally affects the lower extremity in more advanced cases. For more information in general on CMT click here: National Institutes of Health. For foot information read here:
But first here is what we can do to help control the effects of CMT on the feet. Below is a classic picture of a charcot marie tooth foot. The patients generally come in with an extremely high arch that is thought to be caused by an imbalance of muscles secondary to a nerve disease. the muscles on the outside of the foot that pull the foot foot outward into whats called pronation weaken. The muscles on the inside of the foot that pull up the arch and turn the foot inward ( called supination) overpower the outside muscles ( peroneal muscles, there are two of them , the peroneus longus and peroneus brevis ) hence raising the arch. See the picture below.
Now take a look at the image below, the heel is inverted ( the arrow points to the inside of the arch, we call that the medial side ). So as the arch increses in height the heel goes into an inverted position called a varus heel, this makes for an unstable foot during walking which makes the patient prone to ankle sprains.
By understanding the above pictures and the reasons for those deformities to happen you will understand the surgical procedures we use to fix the foot.
We need to cut some bone out of the middle of the foot in the shape of a wedge taking more from the top, this will lower the arch architecture. This procedure is called the Cole Osteotomy.
Then we need to address the heel varus position, this is done by a wedge taken from the outside of the heel bone - calcaneus. This is called the Dwyer Osteotomy and puts the heel straighter in relation to the ground.
Lastly to correct the muscle imbalance we perform either a posterior tibial tendon transfer or an anterior tibial tendon transfer to balance the muscles forces.
Now in cases of deformity AND severe arthritis to the foot joints, in those cases we fuse the joints with a procedure called a triple arthrodesis. the procedures mentioned before are joint sparing meaning that the function of the joints is left intact, the fusion (arthrodesis) removes the joints and their motion.