An AFO, or ankle-foot orthosis, is a brace worn on the lower leg and foot that stabilizes the ankle, supports the foot during walking, and prevents the foot from dragging on the ground. It runs from just below the knee down to the foot, fitting inside a shoe, and is one of the most commonly prescribed orthotic devices in rehabilitation medicine.
AFOs work by maintaining proper alignment between your ankle and foot. During normal walking, your foot needs to clear the ground as it swings forward, then land heel-first before rolling smoothly to your toes. When injury or neurological conditions disrupt this process, an AFO steps in to keep the foot positioned correctly through each phase of your stride.
How an AFO Changes the Way You Walk
Walking involves a surprisingly precise sequence of movements at the ankle. When your foot first contacts the ground, it should be in a roughly neutral position, not pointed downward. From there, your shin tilts forward over your foot in a controlled way, allowing your knee to bend slightly and your body to progress smoothly. When any part of this chain breaks down, the effects ripple through your entire leg.
People who need an AFO often have excessive downward pointing of the foot (called plantar flexion) when they step. This forces the shinbone backward instead of allowing it to tilt forward naturally, which can cause the knee to snap into a hyperextended position. Over time, this puts enormous strain on the knee joint and makes walking exhausting.
An AFO corrects this by holding the ankle closer to a neutral angle. Research on patients with brain injuries found that wearing an articulated AFO reduced the abnormal downward foot position at initial contact, shifted the shin into a more vertical alignment, and significantly reduced knee hyperextension during standing phases of walking. The brace essentially restores the mechanical chain that allows your body weight to transfer smoothly from heel to toe.
Conditions That Lead to AFO Use
The most common reason someone ends up in an AFO is foot drop, a condition where you can’t lift the front part of your foot. Foot drop isn’t a disease on its own but rather a symptom caused by nerve damage, muscle weakness, or brain and spinal cord conditions. It can make you trip over your own toes or develop an exaggerated high-stepping gait to compensate.
Stroke is one of the leading reasons adults are prescribed an AFO. When a stroke damages the brain areas controlling leg movement, one side of the body often loses the ability to control the ankle properly. A rehabilitation study of stroke survivors found that those using an AFO improved their walking speed from 0.4 meters per second at admission to 0.51 meters per second at discharge, compared to just 0.45 meters per second without the brace. Nearly 31% of AFO users achieved a clinically meaningful improvement in walking speed, compared to only 8% of those walking without one.
Cerebral palsy is the most common reason children wear AFOs. Because CP affects muscle tone and motor control from early in life, bracing plays an important role in supporting functional walking patterns and preventing joint deformities as children grow. Other conditions that frequently call for an AFO include multiple sclerosis, peripheral neuropathy, spinal cord injuries, and certain muscular dystrophies.
Types of AFO Braces
Not all AFOs do the same thing. The type prescribed depends on how much control your ankle needs and how much natural movement you still have.
- Solid AFOs provide maximum control by locking the ankle in place, preventing both upward and downward foot movement. These are typically used when someone has severe spasticity or very little muscle control, since the rigid structure does most of the work of stabilizing the ankle.
- Hinged AFOs include a joint at the ankle that blocks the foot from pointing downward but allows upward movement (dorsiflexion). This design permits a more natural walking pattern because the shin can still tilt forward over the foot during stance. Research in children with cerebral palsy found that hinged AFOs improved gross motor function more than solid AFOs, likely because they allow the wearer to use whatever ankle movement they still have.
- Posterior leaf spring AFOs are thin, flexible braces that provide a spring-like assist to push off during walking. They’re the lightest and least restrictive option, best suited for people who mainly need help with toe clearance but still have decent ankle stability.
Despite their differences, both solid and hinged AFOs have been shown to increase stride length, reduce the number of steps taken per minute, and decrease excessive downward foot positioning compared to walking without any brace.
Materials: Plastic vs. Carbon Fiber
Most AFOs are made from thermoplastic, a type of rigid plastic that can be heated and molded to the shape of your leg. These are the standard workhorses of the AFO world: durable, relatively affordable, and easy to adjust.
Carbon fiber AFOs are lighter and thinner, with a reputation for storing and releasing energy during walking, which can make each step feel less effortful. However, a 2024 study comparing carbon fiber and plastic AFOs in chronic stroke patients found no significant difference in energy cost between the two materials. Both types reduced the energy needed for walking by about 15% compared to walking without a brace. The practical takeaway: carbon fiber may feel sleeker and lighter on the leg, but the functional benefits for walking efficiency are similar to standard plastic in many cases.
Custom-Molded vs. Prefabricated
AFOs come in two broad categories. Custom-molded versions are made from a plaster cast or 3D scan of your leg, producing a brace shaped precisely to your anatomy. Prefabricated (off-the-shelf) versions come in standard sizes and are adjusted to fit.
Custom AFOs are generally prescribed when someone has significant deformity, unusual leg shape, severe spasticity, or needs very specific control over ankle position. They take longer to produce and cost more, but the fit is far more precise. Prefabricated options work well for milder cases, temporary use after surgery, or situations where a quick solution is needed while waiting for a custom device. Your orthotist will determine which approach makes sense based on the severity and nature of your condition.
AFOs for Children
Pediatric AFOs face a unique challenge: kids grow. A brace that fits perfectly at age four may be too small six months later, so pediatric orthotics need to balance precise correction with some room for growth.
For children with cerebral palsy, AFOs provide meaningful improvements in functional balance. A study of children with hemiplegic CP (affecting one side of the body) found that both solid and hinged AFOs significantly improved balance compared to walking without a brace. The choice between hinged and solid designs in children often depends on the level of spasticity and how much voluntary ankle control the child has. Hinged designs tend to promote more natural walking patterns by allowing some free movement, while solid designs offer more stability for children with less muscle control.
Bracing in children is almost always combined with physical therapy. The AFO provides the mechanical support, while therapy builds the strength, coordination, and motor patterns that maximize what the child can do.
Living With an AFO: Shoes and Daily Wear
One of the most practical challenges of wearing an AFO is finding shoes that fit over it. A standard shoe usually won’t accommodate the added bulk of a brace, so you’ll need footwear with specific features.
Look for shoes with extra depth and width to fit the orthotic without cramping your toes. Removable insoles are helpful because you can take them out to create more interior space. Wide-opening closures make a big difference in getting your braced foot into the shoe. Velcro straps, zippers (especially wrap-around styles), and elastic laces all make the process easier than trying to force a braced foot into a lace-up sneaker. Several brands now design shoes specifically for AFO users, with openings that fold down or unzip completely so you can slide the brace in without a struggle.
Wearing an AFO typically requires shoes one to two sizes larger than your usual size on the braced foot. Some people wear mismatched shoe sizes, buying one regular shoe and one larger, though not all retailers accommodate this. Your orthotist can recommend specific brands and styles that work well with your particular brace design.
Emerging Smart AFO Technology
A newer generation of AFOs incorporates sensors and adjustable resistance into the brace itself. One device currently in clinical trials, the Biomotum Ambulo, features adjustable spring settings and footplate sensors that provide real-time biofeedback during walking. The device tracks gait data and sets progressive goals based on the individual’s walking pattern, essentially turning the brace into both a support device and a rehabilitation tool. This type of technology is being tested in children with cerebral palsy, with the goal of using the brace not just to support walking but to actively train better movement patterns over time.