Updated: Nov 13, 2022
Bracing in Charcot Marie Tooth Disease is A Bottoms-Up Approach with The Goal of Improving Mobility, Minimizing Trips & Falls, and Maximizing Quality of Life for the CMTer
"There is no “CMT Orthosis” that will work for all patients with CMT. Within CMT as a diagnosis, there can be many, many varied presentations, each of which might require different approaches and orthosis designs." --Alicia Baxter CPO, University of Michigan Orthotics and Prosthetics Center
Why AFOs? Well, first, what is AFO? AFO is mentioned a lot within the CMT realm, but what is it? AFO is an acronym for Ankle Foot Orthosis, and is pronounced A-F-O as standalone letters. Alright, then, what’s an orthosis? Orthosis is the mechanical correction of limb deformities or support of weak musculature by use of external mechanical bracing. So, by definition, an AFO is a mechanical device that is used to correct deformities of the foot and ankle. Some devices are used only for feet. These would be considered a foot orthosis. Any device that crosses the level of the ankle joint but stops below the knee is considered an AFO. As such, an ankle brace is also an AFO. There are some who also need knee bracing incorporated into their device. This device would be called a KAFO, for, as you guessed it, Knee Ankle Foot Orthosis. This article, however, focuses on AFOs. So, why, again, AFOs?
The Nuts & Bolts
Foot weakness and instability, plus ankle weakness and instability are exceedingly common in Charcot Marie Tooth disease. Progressive changes in the structure and alignment of the feet and ankles are common. However, the issues that are caused by the feet & ankle weakness and instability are as varied as the individual CMTer is unique. There are some commonalities across the spectrum though, because of the overall disease process.
Standing and walking on the edges of the feet is very common in CMT. As this becomes the normal foot and ankle posture for the CMTer, the knees are forced to pitch in the opposite direction that the ankles pitch. In turn, this causes the hips to pitch, yet, again, in the opposite direction (opposite to the knees, but the same direction of the ankles). Because nothing with the human body is or happens perfectly symmetrical side-to-side, this action may cause the pelvis to shift/tilt to one side. This shifted pelvis can give the perception of one leg being disproportionately shorter than the other. Mechanically, as a result of a mechanical process, rather than anatomically, it is functionally shorter. The human body tries to compensate, and in turn, the lower back shifts.
As the lower back (the lumbar spine) shifts to compensate for the legs, ankles, and feet being sketchy, the middle back (thoracic spine) shifts; and, then, the neck (cervical spine) shifts. A CMTer’s body is constantly working overtime just to maintain central and core neutral balance and centerline, and it all starts with the feet being out-of-neutral and the ankles shaky. When the foundation is shaky, and the feet and ankles are the foundation, all dependencies suffer.
So, What’s Happening?
There is a common and underappreciated presentation with CMT. This presentation is a dysfunction with proprioception. Proprioception is, essentially, knowing where our limbs are in space without looking at them. This is fundamental, as are many other things, to maintaining balance. Proprioception is often disrupted and reduced by CMT. We talked earlier about the weakening and mechanical changes that occur in CMT, but this decreased proprioception means CMT also causes sensation and balance disturbances. Throw in some of this proprioception deficiency on top of whack feet and ankles, and the Tibialis Anterior muscles, which control the feet, become unbalanced side-to-side and front-to-back, making them have to work even harder to maintain upright balance. This muscle imbalance can be easily visualized.
Whether you are already in AFOs, or they are being entertained for you for the first time, this quick exercise will show exactly how your muscles are working to maintain balance. Tap a couple of helpers. You must have help. Do not do this by yourself. Period. The end. This is not open for debate. One of your helpers is somebody who can help steady you. The other is for making a quick video with their phone. Throw on a pair of shorts, don’t put on socks, and you’re ready to go. For comparison, have a non-CMTer do the same exercise afterwards, and make a video of what their lower leg muscles are doing. The results will be strikingly different.
With your helper at your side, and your camera person at the ready, stand bare-footed, and in a normal standing orientation. You don’t have to do anything special. Now, raise both arms so that they’re level across your shoulders and pointing straight out. You have probably done this several times with your neurologist.
As you look straight ahead, close your eyes, and just stand there. Your camera person should be recording what your lower legs, ankles, feet, and toes are doing. It’s best if they are filming you either from in front or behind you. You’ll most likely start to sway after just a couple of seconds. Your helper is there, at your side, to catch you if you sway too much. It only takes a few seconds of video footage to capture how everything is working, so you only need to do this for a few seconds. Again, do not try this alone, and do not do this so long that you fall. Do not hurt yourself while trying this. If you don’t have help, the risk to falling is not worth it, and I cannot stress this enough. Don’t do this by yourself.
You probably didn’t feel what is going on while doing this short exercise. If you didn’t, it’s because it is your normal – you’re used to it. If you do feel what’s going on, you’re more in-tune than most. The video that was made will show that the muscles of your lower legs are in constant activation as they are trying to compensate for you not knowing where your limbs are in space. These muscles are just some of the muscles that are working overtime to keep the feet solidly planted. Keeping feet solidly planted in CMT is challenging for the body, to put it mildly. This is also a significant reason why the muscles of the lower legs get so fatigued and crampy for a CMTer. These muscles are always overworking, and they are overworking in addition to being weakened directly by CMT. AFOs can help to manage these issues. But, how? I’m glad you asked.
Enough with The Wobbulations
The primary goal of AFOs for a CMTer is to achieve a solid foundation via mechanical assistance to achieve a neutral foot posture thereby achieving an ideal weight distribution across the structure of the foot while also achieving an ideal heal-to-toe strike pattern when walking. Posture used here is not referring to sitting, standing, and walking with a straight back posture, as used to be drilled into us as a child. Rather, I use it here to refer specifically to how the feet function to support the body at rest and when in motion. As equally important, another primary objective is to stabilize the ankle both to prevent rolling the ankle and to prevent foot-drop (more on this in a moment). If the ankle is left alone to remain wobbly, then anything that is done to provide for foot neutrality is done in vain. Likewise, if an attempt is made to stabilize the ankle, but achieving a neutral foot posture is ignored, the work is for naught. The two go hand-in-hand. Once foot neutral posture and ankle stabilization is achieved, what happens? Well, there’s a domino-effect.
Once the feet are held neutral and the ankles are stabilized, the body’s central alignment is more, well, central. Starting at the bottom—the foundation, and working upward through each joint, everything becomes more equally loaded and balanced. As an example, if you stand on the lateral (outside) edges of your feet, thereby stepping on the outside edges and rolling in as you walk, just as I do, your knees, like mine, are improperly loaded and pitch inwards. All of the ankle wobbulations (I made that word up, but you can use it all you like) cause the knees to also wobbulate. In turn, the hips wobbulate. When AFOs achieve a neutral foot posture and successfully stabilize the ankles, knee and hip wobbulations are minimized, and the AFOs, as a secondary process, achieve a more equal and balanced joint loading above the level of the AFOs. This benefit carries all the way up and through the spine, and all of those joints that were out of whack are now aligned how they should have been all along. Another benefit in the causative domino-effect is the potential for pain mitigation.
There’s no question that there can be an insane amount of pain with CMT. The reasons for this are many. Part of the pain problem is caused by the feet and ankle issues that we’ve discussed. By using AFOs to manage these mechanical issues however, the pain that is caused by these issues has an opportunity to be reduced and maybe even controlled. I can speak to this from personal experience. My AFOs have significantly reduced my overall lower extremities pain level.
My Magic Shoes Rock!
I wear Allard BlueROCKER© AFOs, bilaterally. I wear custom orthotic inserts with them. Together, the appliances are my AFO system. My orthotic inserts are the mechanism by which my feet achieve a neutral posture. The BlueROCKERs©, together with my orthotic inserts, stabilize my ankles, and they manage another common CMT issue: the prolific trip-inducing bilateral foot-drop. My foot-drop is controlled via the rigid ankle of the BlueROCKERs©. This AFO has been a game-changer for me. What is foot-drop, though? Let me explain.
Foot-drop is a condition where the front of the foot doesn’t fully “pick up” as you take a step while walking. If you visualize the mechanical process of walking, one foot is out in front and the other is trailing behind. When you move forward the foot that is trailing behind to take the next step, as the foot leaves the ground, a “normal” foot will “pick up” the front of the foot, tipping the toes upward as it swings through to be in position to take the next step. In “normal” walking, the foot will strike down on the heel, followed by the toes in a normal heel-to-toe rocking mechanical movement. Visualizing that same step again, but adding in foot-drop, rather than the foot properly picking up and tipping the front of the foot upwards, muscle weakness causes the front of the foot to drop downward. Often, with foot-drop, the toes will catch and cause a stumble, and sometimes a full trip and fall. AFOs can be used to correct for this by limiting the drop motion of the front of the foot, and sometimes eliminating the drop motion, depending on individual needs, and depending on the system that is selected to meet those needs.
The orthotic inserts and the rigid ankle of the BlueROCKERs© work together, as a system, to mitigate my ankle wobbulations and to achieve a controlled heel-to-toe strike pattern while walking. This AFO system also achieves a more stable and solid foundation for supporting my body. Accomplishing this causes my muscles to not have to work as hard to maintain balance. Also, my AFO system achieves a more stable and balanced loading of my knees, hips, and spine. In so doing, my pain from mobility is reduced. This is an outcome measure that doesn’t get enough emphasis.
Understanding the Biomechanics of CMT is Vital
BlueROCKERs© with custom orthotic inserts work very well for me. I have worn this system for more than ten years. It took almost ten years to land in what I now use. The first orthotist I had did their best, but they didn’t fully appreciate the mechanics of how my CMT affected me. As such, early attempts were not successful. Of course, AFO technology then was nowhere near what it is now, twenty years later. The orthotist who put me in BlueROCKERs© with orthotics was amazing with CMT. The orthotist I now have, Alicia Foster CPO, at University of Michigan Orthotics and Prosthetics Center, who is also on the staff of the University of Michigan CMTA Center of Excellence, is an authority on AFOs and bracing in CMT.
Alicia kept me in my system, and she stepped it up with how she makes my orthotic inserts. The one time I tried to suggest that I wanted a different AFO system, she stopped me and explained why what I had was perfect for me and my needs, and why the different system would have hindered my function more. This is why it is critically important for the orthotist to study how the CMTer moves, to study where the deficiencies are, and to make decisions based upon the individual CMTer’s unique needs. She determined that my system was optimal for me, that the system was achieving what I needed, and was so doing efficiently. You know what? She was right. However, my system may not be perfect for you. Only your orthotist, in working with you and your physician, as a team, can determine what your unique needs are.
When a CMTer is meeting with an orthotist for AFO selection, Alicia says, “It’s important for patients to know that, while it is valuable to know about many different types of devices we have in our proverbial toolbox to treat different patients, there is not one device that works for “CMT” in and of itself. There is no “CMT Orthosis” that will work for all patients with CMT. Within CMT as a diagnosis, there can be many, many varied presentations, each of which might require different approaches and orthosis designs. There are some support groups on social media that are so valuable for “meeting” other patients with CMT and it is great to learn and share all the different devices that work for each other. But, just remember that each device type and design is determined by taking into account:
Your specific clinical presentation (i.e. your range of motion at each joint, your strength of those joints in various planes of motion, and your level of impairment/frequency of falls).
The environment in which you live and work (i.e. Do you have to traverse stairs? Uneven terrain? Multiple flooring types in either of those places? Do you live alone or have assistance either from a partner or caregiver?)
Your hobbies or activities you’d like to return to.
Then, once we’ve determined these needs, we can determine which type of orthosis design will likely work best for you. Within the design, we consider the available componentry, materials, and the properties of each. We strive to give patients the most motion and function while also keeping them safe and stable enough so their fall risk is minimized and stability is maximized while not “over-bracing” which could also have negative effects. It’s really the Goldilocks principle we use every day to give each person their optimal level of function and quality of life!”
Having the right system for the individual is essential. Having an orthotist who understands the needs of the CMTer is just as essential. As Alicia explained, there are so many variables that have to be considered for the individual CMTer, that there really is no one-device-fits-all. The AFO needs have to be tailored to individual needs if outcome expectations are to be maximized.
With all the good that can come from wearing the correct AFO system, and there are a lot of systems out there, are there any downsides? For me, the short answer is no. Only good things come from wearing the proper AFOs. However, there are a few things that bear discussion for anybody who is new to AFOs, or who is about to be new to AFOs.
Just for Kicks
The biggest hurdle to overcome is footwear. Finding footwear that your AFOs will fit inside of is challenging at best. Finding footwear that is fashionable is even more difficult, especially if your job has a business attire requirement. On the other side of that, finding footwear that meets safety compliance for industrial, construction, skilled trades, etc. is as equally difficult. In the US, laws allow for accommodations so that AFOs can be worn in the workplace along with whatever footwear accommodates the AFOs, but this doesn’t solve the hassle of finding footwear that you like and fits the AFOs. For me, personally, footwear for my AFOs isn’t a big deal. Options are limited, but I’m a guy, and society is far more forgiving to me than to women. The website, Trend-Able, can be an invaluable resource for overcoming this footwear hurdle.
My shoe size is a 9 ½ EEE without my AFOs. With my AFOs, I need a 10 ½ EEEE with a very tall toe box (the toe box, as you can probably picture, is the area of the shoe where the toes sit). My orthotic inserts add overall height, and the AFOs add width, especially from the strut. A 10 ½ EEEE is not a typical off-the-shelf size. If it is on the shelf, the toe box typically isn’t tall enough. However, a specialty shoe store will typically carry the size in something with a tall toe box. There are some online resources, too. Any 10 ½ EEEE I’ve gotten from New Balance© has a tall enough toe box. I currently wear Skechers© hiking shoes (not boots). I can easily get away with any style that fits. Not everybody can though.
Your footwear needs when in your AFOs could very well be different than mine. You could require something that is larger than a one-size and one-width increase. You may not need something that much larger. The AFO system you require for your individual needs might even have the shoes incorporated into the system. The variables are many. Just as my footwear experience is unique to me, yours, too, will be unique to you. Another foreseeable issue that might be experienced is short-term soreness, joint pain, and lower back pain at first, especially if you’re brand new to AFOs.
Patience and Communication is Paramount
If you have just gotten into your first set of AFOs, it is reasonable to expect that things are going to hurt at first. This should subside as you get used to them. If you follow your orthotist’s break-in instructions to the letter, this soreness and pain will be minimized. While the AFOs need to be broken-in, the break-in period is more for your body to adjust to what your AFOs are doing. The same applies to the seasoned AFO pro. What causes this soreness and pain though?
We’ve discussed in great detail how the body is affected by the poor foot posture, wobbulating ankles, knees, and hips that is a result of the disease process of CMT. Especially if you’ve never worn AFOs, your body is used to all of these bad mechanical processes that are your normal. These processes have taken a toll on you, too. Now, throw on some AFO’s that are going to tweak your foot into a neutral posture, that are going to minimize the side-to-side flexion that your ankles normally do, and is possibly going to help manage any foot-drop you might have going on, and your body is not going to know how to act at first, and things are going to be thrown out from what your normal alignment is. If you follow your orthotist’s break-in instructions to the letter, these impacts will be minimized, and you’ll be realizing the benefits of your AFOs in no time.
There is a rare occasion that the AFOs you are put in just aren’t the right system for you. While this is rare, it can happen. This happened far more often twenty years ago than it happens in present day. Keeping an open communication with your orthotist is paramount to working through these kinds of issues. Often, the orthotist can make adjustments and/or modifications to your hardware so that the system does for you what it’s designed to do. Communication is paramount. Tossing them in the corner because they hurt, rather than discussing your concerns with your orthotist will not get you the benefit you need and deserve.
Alicia reminds us to, "Try to not get discouraged. Most orthotists (if they’re in it for the right reasons) would rather you tell them when something is wrong because they want to help you; and they can’t help you if you don’t tell them what’s wrong. There are all KINDS of things they can do to improve the comfort and fit of your system and you are just as much a part of your medical team as your doctors and your orthotist.” And, if you break an AFO, and this does happen, an orthotist actually likes this – it means you’re wearing them. Don't be afraid of your AFOs!
Why AFOs? Proper AFOs can dramatically improve mobility and ambulatory stability. The sooner the feet are maintained in a neutral posture, the more benefit the ankles, knees, hips, and spine will have. A drawback to myself not receiving a diagnosis until I was in my late twenties was that I didn’t have anything to help maintain neutral foot posture, even though I had a clear need for assistive devices from an early age. Because I wasn’t in any device for so long, my ankles, knees, hips, and lower back have suffered progressive joint changes that, had there been intervention years prior, may not have occurred. It should not have taken receiving a diagnosis for something to have been thought of. I am grateful to now have my AFOs, and I can’t imagine life without them.
As with all things CMT, nothing is easy. There is only complexity. The biomechanics of CMT are especially complex. Working with somebody who understands this complexity and who has an astute eye to mechanical detail can change a CMTers life. It did mine, and it can yours as well.