My last blog entry served as a bit of an introduction into the topic of AFOs. (If you didn’t read it, here is your chance). By way of quick review, AFO is an abbreviation that stands for “Ankle Foot Orthosis”.  Orthosis is the more formal term for a brace.

The number 1 most common reason for someone to wear an AFO is because they have a condition known as “Foot drop (or drop foot)”. Foot drop happens when there is weakness in a muscle group called the “Dorsiflexors”. These muscles run along the front of your lower leg and ankle. They are responsible for the action of lifting your toes up. The muscles in the Dorsiflexor group include the Anterior Tibialis, the Peroneus Tertius and the Extensors of the Toes.

Foot drop muscles

Sometimes when a person has foot drop, the Dorsiflexor muscles themselves are weak, but most frequently it is actually the nerve that runs to these muscles that isn’t functioning properly. Because it is so often a nerve problem, foot drop occurs many times in people who have had a stroke, brain injury or multiple sclerosis. It also common in people who are born with cerebral palsy, muscular dystrophy, CMT, or many other conditions. Foot drop can also be the result of a back or leg injury.

All of these Dorsiflexor muscles are controlled by a nerve called the “Common Peroneal Nerve”. This nerve is actually an extension of the Sciatic nerve which branches off the spinal cord at the lower back and runs all the way down through the leg. If this nerve is damaged at any point, there is a very good chance that the signals will be disrupted and some leg and ankle weakness will occur as a result.

Nerves of Foot Drop

Drop foot can range from mild weakness to complete paralysis of the effected muscle groups. People with mild foot drop sometimes only notice it when they are tired at the end of a long day. Many times mild cases of drop foot go unnoticed until the person begins to realize that they are tripping and falling more frequently than usual, especially on uneven surfaces.

Those with more severe drop foot usually walk with a very distinctive gait called a “steppage gait”. This is where the person picks their knees up especially high in order to allow their foot to swing forward without snagging on the ground. When the foot is placed down on the ground it usually hits with a slapping noise as the toes uncontrollably flap onto the floor.

Here is a little video demonstration:

 

 

The job of an AFO for someone with drop foot is to keep the toes from dragging while the person walks, and also to slow down the slapping motion as the foot is planted on the ground. A whole multitude of devices have been invented to do this task.

Very mild drop foot can be treated with devices like this:

mild foot drop options

More complicated cases of drop foot sometimes require custom molded AFOs with a variety of features. Here is a little photo gallery of typical drop foot AFOs:

Foot drop AFOs

Custom foot drop AFOs like these are made by Orthotists and Pedorthists. They are typically made from a cast of the patient’s leg. The AFO is then designed and fabricated exactly to the specifications of each individual patient. Custom AFOs usually work very well (if the person making it did a good job), but they have several draw-backs: It takes a long time to make them, they are super expensive and because they are made so precisely, they have to be adjusted and fine-tuned frequently to ensure that they fit correctly. If the AFO was made for a child, constant changes have to be made to accommodate growth. Even adults tend to lose and gain weight over the course of the years. These changes can jeopardize the fit of the AFO. A poorly fitting AFO is not as effective as it should be and it can even be dangerous because it could lead to falls or it could cause a sore on the skin.

Because of these complications, new solutions to foot drop are beginning to flood into the market. My personal favorite development is carbon graphite AFOs. These AFOs are lightweight and strong. They are low profile because they don’t have to include bulky joints like the old fashioned plastic AFOs. Many models of this type of AFO can be purchased completely ready to wear. This eliminates the long process of taking molds of the patient’s feet and making the AFOs from scratch. Many patients use a custom foot orthotic in addition to the carbon graphite AFOs in order to ensure total comfort and appropriate support.

The reason carbon graphite AFOs are so cool is that the material is springy which means that it provides energy return. This allows the person wearing the AFO to walk with a very smooth and natural gait. Some people are even able to run marathons, hike, bike, etc with the use of this type of AFO. Can you tell that I am excited about this technology? Here are some cool videos of people using a few of the more common carbon graphite AFOs:

 

 

before:

 

after:

one more:

 

 

These are just some examples of the new solutions to the problem of foot drop. I think that carbon graphite AFOs are the wave of the future. I am very interested in watching the evolution of the AFO as patients become more thoroughly informed about their treatment choices. Patients now have access to huge amounts of information in all sorts of formats (including possibly, dare we say – this blog). They can then use these facts and concepts to educate their caregivers and voice their opinions and preferences. This is great! It means that more and more people get to take advantage of the cutting-edge technology choices. This process then drives improvements and encourages the development of even newer and better AFOs. How exciting!

Walk well.

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