An Ankle Foot Orthosis (AFO) is an external support device that encompasses the lower leg, ankle, and foot. Its primary function is to provide stability, support, and proper alignment. AFOs are worn to assist with movement and enhance overall stability during activities like walking or standing, acting as a supportive aid for various foot and ankle conditions.
How AFO Braces Provide Support
AFO braces function by applying external forces to the lower limb, which helps to control and guide ankle and foot movement. This control can limit excessive motion, such as plantarflexion (pointing the toes down) or side-to-side ankle movement, while sometimes preserving dorsiflexion (lifting the foot). By stabilizing the ankle and subtalar joints, an AFO reduces abnormal motion, contributing to improved balance and decreased risk of falling.
The device helps to maintain the foot and ankle in a more neutral position, which can improve a person’s gait pattern. For individuals with muscle weakness or paralysis, an AFO can provide the necessary support to increase foot clearance during walking, preventing the foot from dragging and allowing for a more proper heel strike. This promotes safer and more efficient mobility.
Common Reasons for AFO Braces
AFO braces are prescribed for various medical conditions affecting foot and ankle function. A common reason is foot drop, where individuals struggle to lift the front part of their foot, often caused by nerve damage or muscle weakness from conditions like stroke, multiple sclerosis, or peripheral nerve injury. The brace helps to stabilize the foot and ankle, preventing it from dragging during walking and improving gait.
AFOs also provide support for neurological disorders such as cerebral palsy, spina bifida, muscular dystrophy, and spinal cord injuries, where muscle weakness or high muscle tone can impair movement and cause instability. For individuals experiencing severe ankle instability, arthritis, or recovering from ankle sprains or fractures, AFOs offer support and stability to promote healing and reduce the risk of re-injury. Additionally, they can be used to alleviate pain and provide arch support for conditions like plantar fasciitis.
Types of AFO Braces
AFO braces come in various designs, tailored to specific needs.
Solid AFOs
Solid AFOs are rigid structures that offer extensive support by completely immobilizing the ankle joint in all planes of movement. These are often used when significant control over foot and ankle movement is necessary, such as in cases of severe instability or excessive pronation of the foot.
Articulated or Hinged AFOs
Articulated or hinged AFOs incorporate a joint at the ankle, allowing for some controlled movement, typically dorsiflexion, while still limiting plantarflexion. This design can be beneficial for individuals who require control but also need some ankle flexibility for activities like walking, and they are often used for conditions like adult-acquired flatfoot.
Posterior Leaf Spring AFOs
Posterior leaf spring AFOs are more flexible and lightweight, characterized by a thin band of plastic that runs up the back of the leg. They primarily assist with foot drop by helping to lift the foot during gait.
Ground Reaction AFOs
Ground reaction AFOs are designed to influence knee extension and stability by applying an anterior force at the knee. They are often used for individuals with quadriceps weakness or knee buckling.
AFOs are commonly made from thermoplastic materials like polypropylene, which can be custom-molded, or from carbon fiber, which offers a lightweight, dynamic, and semi-flexible option that can provide energy return during walking.
Wearing and Caring for an AFO Brace
Proper fitting and consistent use are important for the effectiveness of an AFO brace. When first wearing an AFO, a gradual break-in period is often recommended, starting with a few hours a day and slowly increasing wear time as comfort allows. It is important to always wear a clean, wrinkle-free sock that extends above the top edge of the brace to reduce friction and absorb perspiration, helping to protect the skin.
Appropriate footwear is also necessary; lace-up athletic shoes with removable insoles and added depth are often recommended. Shoes may need to be a half-size larger than usual to accommodate the brace. Daily skin checks are important, especially for individuals with reduced sensation, to monitor for any redness, irritation, or pressure areas that persist for more than 20-30 minutes after removing the brace, which should prompt a consultation with an orthotist for adjustments. For cleaning, the AFO can typically be wiped with a damp cloth and mild soap, then air-dried, avoiding extreme heat which can warp the material.