An ankle foot orthosis (AFO) as its name implies is a device which is either prefabricated or custom made to hold the foot, ankle and lower leg in proper alignment or at the very least as close to normal as possible. These braces are different than orthotics. To see the difference click here.
These braces are used for a variety of lower extremity problems which include:
adult acquired flatfoot secondary to posterior tibial tendon dysfunction (PTTD)
lateral ankle instability
degenerative joint disease or osteoarthritis of the ankle or rearfoot.
Chronic tendonopathy of the peroneal tendons, which are the tendons, that come down the outside of the ankle and attach into the side of the foot.
Dropfoot due to post CVA (stroke), mild case of Muscular Dystrophy, Charcot Marie Tooth Disease, trauma to the spinal nerves and leg nerves either through an accident or surgery.
The more common prefabricated devices are sold by calf circumference and foot size. It is generally one unit, which extends from the ball of the foot up to the calf. They hold the foot and leg in place with Velcro attachments. Generally they will fit into a casual laced shoe such as a sneaker. They can also be built into special shoes to make walking easier.
Below is a picture of a prefabricated orthosis. (foot drop device)
For problems that involve the alignment of the foot to the ankle such as in degenerative joint changes in the ankle where a better alignment in the ankle joint will relieve pain, a custom device may be required.
In this instance a plaster of paris impression is taken of the foot and ankle in their neutral position, the ideal relationship between the foot, ankle and leg. From this impression the orthosis is fabricated.
While being worn the orthotic holds the foot in its proper alignment relative to the ankle and leg (or a close as humanly possible). This proper alignment should relieve whatever stresses that are being placed on the foot and ankle and allow for more pain free ambulation.
Here is a picture of the Richie brace, possibly the most popular ankle foot orthosis in the field of podiatry. Although smaller than the traditional prefabricated orthosis, it is much more versatile in what it can offer the patient.
As in the case with orthotics,
an AFO only does its job while the patient is wearing it. As soon as it is removed the foot and ankle revert back to their abnormal angular relationship and the factors that caused pain initially are put back into play. So, you might wear the brace for ten hours, come home and take it off and walk around the house barefoot, but you run the risk of undoing all the good that was accomplished through the ten hours of wearing the brace.