External biomechanical devices provide support and stability to the body while aiding or inhibiting movement. Ankle foot orthotics or orthoses (AFOs), in particular, fit around the lower extremities. You may have seen plaster casts, splints or walking boots used for acute ankle and foot injuries. There are many more types of AFOs made with different materials and mechanisms. Whether you need an AFO for a few weeks or the rest of your life, there’s one that can provide the exact amount of protection and flexibility below the knee.
Podiatric specialists have developed new manufacturing technology and materials over the last 10 years. Now AFOs can be 3D printed without making a plaster model and can change shape and function as the patient’s needs change. This article will cover the many purposes AFOs can serve and provide an overview of some of the most common varieties.
What are ankle foot orthotics for?
Ankle foot orthotics serve a range of different purposes to stabilize and support the function of the knee, ankle and foot. They can limit certain types of movement, expand range of motion and provide support for weak muscles. Some patients only need them temporarily while they recover and rehabilitate. Others may need them to support their everyday gait and function. In many cases, ankle foot orthotics help with balance and preventing falls. Sometimes AFOs can be used as night splints to prevent muscle contraction and plantar fasciitis.
What conditions can ankle foot orthotics help treat?
Ankle foot orthotics can help treat almost any condition affecting the lower limbs. They’re used to stabilize the foot and ankle while injuries like fractures and sprains heal. They also help with clearance between the foot and the ground in patients with foot drop. This is a condition that makes it difficult to lift the front part of the foot by flexing the ankle. Foot drop is caused by conditions like stroke, multiple sclerosis, diabetes, peripheral nerve trauma and spinal stenosis.
Ankle foot orthotics can provide support and stability for people with the following conditions:
- Ankle and foot deformities.
- Fractures.
- Cerebrovascular accidents or strokes.
- Peripheral nerve trauma.
- Diabetes.
- Multiple sclerosis.
- Poliomyelitis.
- Spinal cord injuries.
- Spinal stenosis.
How long does someone typically have to wear an ankle foot orthosis?
The length of treatment with ankle foot orthotics depends on the patient’s condition. Again, some patients may only need an AFO for a few weeks or months while they recover. Others may need to wear them indefinitely to correct deformities, assist weak muscles or support everyday function. AFOs can dramatically reduce recovery time for foot and ankle injuries compared to other types of splints. In a study comparing the recovery times of patients with unstable ankle fractures, patients with AFOs recovered in about half the time of patients wearing traditional plaster casts.
How can they be made?
There are several different types of ankle foot orthotics. Some are custom-fitted to the patient and handcrafted, and some are manufactured in a range of sizes. Custom-fitted AFOs can be made using a plaster model of the patient’s lower extremity. Mass-manufactured splints can achieve a snug fit with Velcro straps, inflatable components, cushioned interiors and adjustable dials. Fitting AFOs to patients with open wounds was virtually impossible before 3D printing. Now splints can be custom-made on demand for injuries like compound fractures.
The most common materials used for AFOs today include thermoplastics, carbon fiber, metals, inflatable components, fabric or foam cushions, and kenaf composites. Kenaf is a woody plant related to cotton and okra. Composite materials made of kenaf fibers and resin can be easily molded to create form-fitting shapes with the best strength-to-weight ratio to provide the right amount of support. They’re also sustainable and inexpensive to produce.
Common types of ankle foot orthosis
The traditional plastic AFO comes in several different varieties, both with hinges and without. These provide a lot of joint stability, and they’re an economical option. Plastic AFOs and walking boots are best for temporary use as many of them won’t fit into the patient’s shoes. Different shapes provide varying levels of immobilization, flexibility and support.
Some types of plastic AFOs have similar shapes to the carbon fiber and Swedish AFO. The solid ankle AFO and posterior leaf spring AFO both have one continuous support along the back of the lower leg that curves around the heel and under the foot. Carbon fiber and Swedish AFOs feature an open heel and a much slimmer profile. They’re more expensive and longer lasting than plastic AFOs.
The UD Flex is unique in that it fits around the lower leg and front of the foot, leaving the entire heel open. This allows for maximum ankle flexion. Patients can feel their foot making contact with the ground, which allows for a more natural gait.
The following are just a few of the most common types of ankle foot orthotics available today:
- Solid ankle foot orthosis — Usually made of molded thermoplastic, a solid or rigid AFO wraps around the back, sides and bottom of the lower extremity. It fastens in the front and doesn’t feature any hinges, so it effectively immobilizes the foot and ankle.
- Flexible ankle foot orthosis — Flexible or semi-rigid AFOs can be made of different materials to provide varying amounts of support. They keep the toes lifted for a natural stride. A variation, the posterior leaf spring AFO, has a crease along the centerline of the foot and only comes to the back of the ankle.
- Hinged ankle foot orthosis — Some AFOs have hinges at the ankle to allow the front of the foot to flex forward and backward on a single axis or multiple axes. They may have shells that overlap with a small rivet fastener or more complex metal joints.
- Dynamic ankle foot orthosis — Often made of carbon fiber, dynamic AFOs can either support or inhibit foot and ankle movement in different directions. Some designs store and release energy at the back of the stride for fluid motion without sacrificing support.
- UD Flex — The UD Flex primarily covers the front of the foot with an inverted U-shaped shell and hinges on either side. Because of the open heel, patients can wear the same size shoe as before instead of needing a size bigger for the affected foot. It allows for more plantar flexion than other AFOs and limited dorsiflexion.
- Swedish ankle foot orthosis — This is one of the slimmest and most comfortable AFOs for extended use. It supports the foot with a bit of added stability, so it works for moderately active people with a good amount of muscle strength.
- Articulating ankle foot orthosis — Articulating AFOs are made with hinges, and they can be adjusted with stops as patients make progress with recovery.
- Ground reaction — This type of AFO provides knee support by redirecting pressure with a strap or shell on the front of the shin below the kneecap. These can help patients maintain an upright posture when walking.
- Walking boot — A walking boot covers all sides of the lower leg and foot to provide lots of stability for acute injuries. Inflatable blades and cushioning ensure an even amount of pressure on the patient’s skin, and a curved rocker on the bottom helps them keep an even stride while the ankle’s range of motion is limited.
Biocorrect is your source for handcrafted ankle foot orthoses
Our feet are complex systems made up of many bones, several joints, and sensors for motion and pressure. Each person has a unique gait and feet that bear the weight of the entire body while performing synchronized, fluid movements. If you’ll be wearing an ankle foot orthosis for any amount of time, it’s worth investing in one that’s made just for you.
We’ve elevated custom AFO creation to an art form. A handcrafted Biocorrect orthotic can help correct the smallest misalignments and imbalances in your stride. It can also stabilize your foot and keep you moving while you recover your strength.
Contact us to learn more about the orthotics we offer or to set up an initial evaluation with one of our certified pedorthists.
