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The orthotic management of Foot Drop is often untertaken with an Ankle Foot Orthosis (AFO), sometimes referred to as a splint or brace. These come in two major classes, either stock or custom-made devices. Both types of appliances have advantages and disadvantages to them.
This guide will deal with a subset of Stock AFOs made in fabric.
The major sign of foot drop is an increase in trips and falls. This is due to the inadequate lift of the foot as it swings through before heel strike resulting in the foot pointing down, reducing ground clearance. Often people will notice increased wear on the soles of footwear with worn sections at the toe end of the sole.
In its early stages, people often report a 'foot slap' or audible noise when walking. This is because the muscles that lift the foot are also responsible for controlling the rate at which the foot lowers at heel strike. This can lead to a very audible sound; often, clinicians will keep an ear out for this sound while you walk into the clinic room, as it is a classic sign of muscle weakness. It makes for a very uneven-sounding gait if the foot drop is only on one side.
Foot drop can have many causes
Foot drop is a muscular weakness or paralysis that makes lifting the foot and toes difficult. This can cause poor ground clearance as the leg swings through, making walking difficult. Foot drop is a sign of an underlying problem rather than a condition itself. It can be muscular, caused by nerve damage in the leg, or the result of a brain or spinal injury or a neurological condition.
The main advantage of a fabric AFO is that they are not hard. A regular criticism of plastic or carbon fibre devices is that they are very hard. If not fitting correctly, ‘hard’ splints can rub or prove to be uncomfortable.
Fabric AFOs are generally easier to fit inside shoes or are entirely external to the shoe.
The main advantages of fabric devices are also their main disadvantage in that they are soft. The lack of rigidity can be a compromise causing a decrease in support, and often they don’t provide as much lift as a rigid device.
Rigid devices can also influence the knee and provide increased stability, which is not something a fabric device can achieve.
There are lots of different options and what works best for one person won't work at all for another.
Dictus Flex is a discreet aid that fits shoes with laces for both children and adults. It consists of an ankle strap, a flex rubber band and a fastening device that is mounted in the shoe. The ankle strap is easily attached around the leg with velcro and stays comfortable all day. The ankle strap is made of genuine leather that gets more comfortable with each use. The ankle strap is connected to the fastening device in the shoe through a flex rubber band with two integrated Velcro plates. The flex rubber band provides stable support for the foot and can easily be tightened as much as the user wishes.
Dictus Original is a discreet aid suitable for both children and adults. The band is easily attached around the ankle with velcro and stays comfortable all day. The ankle strap is made of genuine leather that is soft against the skin and gets more comfortable with each use. On the front part of the ankle strap there is a D-ring through which the included soft rubber strap is threaded. It is then attached to the hooks mounted in the shoe's lacing loops. When the user walks with the Dictus band, the foot is automatically lifted by the rubber band.
Unfortunaly a lot of people with foot drop also suffer from hip weakness, in conditions such as MS this is often a problem. This Dictus Hip-foot is designed to help with hip flexor weakness as well as foot drop.
Indications for use
The Textile Drop Foot Orthosis consists of a fabric ankle wrap around the leg just above the ankle, which the elastic section lifts the foot attaches. It is required to be snugly attached to the leg to prevent it from being pulled down by the foot section.
There is a clasp that fits between the laces. While it works best with laces it can also be used in Velcro shoes with more than one strap.
This commonly used style of AFO is good because it can provide a large amount of lift to the foot as the elastic can be pulled to an appropriate tension to lift the foot.
Generally, they are comfortable as there is nothing placed inside the shoe but require suitable footwear to be worn.
The downside to this style of AFO is that you require the hand strength to pull the Velcro tight, and the ankle section can be pulled down in some leg shapes.
The Airmed Textile foot drop orthosis can be worn without footwear with the addition of a plantar band however, this will not provide as much lift as when worn with footwear.
The Foot-Up from Ossur was launched in 2008 and has sold millions of devices around the world. This device has become the go-to description for most elastic devices to aid foot drop.
The split ankle wrap allows for the elastic section to attach the foot section. The foot up attaches to the shoe with a plastic insert which is inserted under the laces.
One downside of the Foot Up is that the elastic tension cannot be adjusted and the elastic clip attachment can be difficult to connect when under tension.
Unlike other fabric supports the Ossur foot up in avalible in two colours Black and Beige.
The Rebound Foot-Up fro Ossur is an upgrade on the original Foot-Up with the addition of the ability to adjust the tension. There have also been cosmetic and comfort-related changes in the design with an improved ankle wrap over the original foot up.
These improvements make the Rebound Foot-Up significantly easier to put on with one hand which can be a great benefit to stroke survivors. It also has the ability to pull off centre allowing it to counter act supination when required.
The Neurodyn foot lift orthosis and Neurodyn Plus Foot lift orthosis are often described like a sock as you pull it onto the foot then tighten it around the leg and ankle with several Velcro straps.
The Neurodyn achieves its dorsiflexion assistance by two elastic straps that cross in a figure of 8 fashion and attach at the back of the leg.
The Neurodyn foot lift also has a lateral strap to reduce supination or inversion of the ankle.
Like some of the other devices featured, the Neurodyn can be worn without footwear.
To get the most of the device, the elasticated straps need to be pulled tight, so patients require good upper limb strength if they are donning the device themselves.
The DynUp is a three-piece brace with a foot and calf wrap which is connected by an elasticated strap to provide foot lift. The strap can come on the inside or outside of the ankle to provide medial or lateral directed force.
Made in soft fabric the DynUp is comfortable to wear and is aimed at a flaccid foot drop with reasonable ankle stability and calf strength.
Fabric AFO’s are highly effective devices in the correct patient group but they are not without compromises.
Generally, the fabric foot drop AFO’s are best in patients with: