CMT Guide

Q: Q: With my current braces I try to get to a faster walking speed, and I have trouble sometimes as there is a hesitation when my foot tries to roll over. Why is this?

A: It can be because: there is not enough energy loading, and consequently not enough energy released by your brace. if your brace has a full length footplate, and you have strong quadriceps muscles, you will not be able to bend your metatarsals enough. In addition, a full length footplate with a person who has good quadriceps, causes a tremendous amount of floor reaction. Floor reaction used in bracing systems is generally done for the purpose of creating an extension force at the knee, and preventing the knee from buckling. This is not a desirable force system to use with a person who has good quadriceps.

As you are currently researching bracing for CMT, you will have many questions. We will try and address the most common ones here.

Charcot-Marie-Tooth

Guide for Orthotics:

At Ortho Rehab Designs we carefully evaluate your specific mechanical profile. We are American Board Certified in Orthotics and Prosthetics. We stress that if you are to be treated by an orthotist for CMT that they should be board certified in the discipline of Orthotics. We feel this is essential in order for basic standards to be met. We will work with your physician or physical therapist in order to ascertain muscle strengths and physical profiles that will help in the design of your orthosis. We pride ourselves in listening to the needs of each patient. Each device is designed for that specific patient’s needs and physical mechanical profile. Our approach is straightforward and honest. We will always be attentive to your needs and goals.

Regression to CMT

If you were just recently diagnosed with CMT, you might be very concerned about what to expect. As the disease progresses, muscular atrophy and weakness become apparent in the peroneal nerve muscles and toe extensors. Subsequently, the disease may advance to involve the tibialis anterior muscles, in which case there is a bilateral drop foot gait.

CMT Q&A

Q: I have a high steppage gait. Will this disappear with braces?

A: Yes, but only if you are braced in proper alignment.

Q: I feel off-balance in my current AFO's. Why is this?

A: It is generally due to a poor fit, or poor fit in conjunction with poor alignment.

Q: I feel extremely tired after walking a long distance, is this related to my braces?

A: This is a strong indicator that you are not getting the benefits from an energy return system. Or you might be walking with gait compensations that are causing early fatigue.

Q: With my current brace I am getting severe pain in my foot from the footplate. Why is this?

A: Generally, this is due to poor mold rectifications. Some practitioners overcorrect, or there simply might not be any correction at all. This is something that needs to be checked.

Q: What are floor reaction forces?

A: The reaction from the floor as an object, such as a ball or a foot, or a braced limb, strikes it.

Q: With my current braces I try to get to a faster walking speed, and I have trouble sometimes as there is a hesitation when my foot tries to roll over. Why is this?

A: It can be because:

1. there is not enough energy loading, and consequently not enough energy released by your brace.

if your brace has a full length footplate, and you have strong quadriceps muscles, you will not be able to bend your metatarsals enough. In addition, a full length footplate with a person who has good quadriceps, causes a tremendous amount of floor reaction. Floor reaction used in bracing systems is generally done for the purpose of creating an extension force at the knee, and preventing the knee from buckling. This is not a desirable force system to use with a person who has good quadriceps.

Q: How fast should I be walking?

A: The average human walking speed is 3.0 miles per hour.

Types of CMT

The following is just a brief outline to help you to become more familiar with what you have. If you know the type you have when you call us or send in a videotape for assessment, we will automatically know what to look for in your correction system:

CMT Type 1

CMT Type 2

What is deformity?

There are two categories of deformity:

The fixed deformity Fixed deformities are also known as contractures. They are essentially rigid malalignments of joints. They can be a result of prolonged malalignment of joints which prevent the normal range of motion of that joint. Management for fixed deformity is quite difficult orthotically. Any kind of prevention of further deformity can be controlled with the proper orthotic system using the proper corrective force systems. Sometimes over long periods of time, orthoses can loosen up fixed deformities to a degree.

The dynamic deformity The dynamic deformity consists of a non-fixed malalignment of the joints. This is the result of an imbalance of the muscle’s tendonous pull. This is the category that most people with CMT fall under. Most of the time this can be easily corrected with the proper molding, mold rectification, and an appropriate carbon graphite device to maintain corrected joint alignment.

Goals for CMT

Prevent further deformity

Improve limb function

Correct any deformity already present

Balance and Stability

The broader the supporting area…the greater the stability becomes. Greater stability equals greater balance.

Whenever I receive e-mails or phone calls from CMT’ers, usually someone says “my balance is getting worse”, or “will these braces help with my balance”. Yes, they do help restore balance. They do this by correcting and stabilizing the deviations in joint alignment. But how is balance achieved? It is achieved through forces that stabilize segments of the body.

What is stability in bracing?

Stability: the broader the supporting area… the greater the stability becomes. Greater stability equals greater balance.

Through careful mechanical design of the orthosis, stability is achieved by two essential things:

The alignment of the orthosis
The mechanical design of the footplate
(the aspect that you bear weight on).

Through proper brace design and reduction of gait deviations, better balance and stability is attainable for you.

Designing the orthosis with stability brings your center of gravity to a more normal position statically (standing). This directly translates to better balance while walking. In order to maintain balance in standing and walking, the body’s center of gravity needs to be in the appropriate location. These laws of physics apply to all things that require stability in remaining upright (including animals, buildings, bridges, etc).

Correction vs. Overcorrection

With CMT, we want to correct your foot as much as possible. What does this mean? This means within the tolerances that meet acceptable standards. We do not want to correct your foot beyond what your body can tolerate. As practitioners, we must realize our limits and your limits as well. We will work with you to properly design your orthosis, so that you can wear it comfortably with maximal correction. Silicone allows greater tolerance to correction and greater comfort. At the very least the primary goal of any orthosis is to prevent any further deformity.

Once this is done new alignment can be put in place and better balance develops as a result. If you can take care of number one, and in addition take care of numbers two and three, and put all three equations together: the patient will experience improved alignment which is an improved structural outcome. This equals enhanced balance and usually results in an increased velocity or walking speed.