What is foot drop?
Foot drop is a muscular weakness or paralysis which makes it
difficult to lift the front part of your foot and toes. This can cause you to
drag your foot on the ground, 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 such as Multiple Sclerosis / Parkinson’s. (NationalFoot Drop Society)
What nerve controls lifting the foot?
The common peroneal nerve controls the muscle tibialis anterior, which, if damaged or compressed, can cause foot drop. Interruption of any part of the nerve from the back around the lumbar vertebrae L4 to the muscle can lead to its development.
What are the signs and symptoms of foot drop?
The classic sign of a foot drop is increased trips and falls. This is due to the inadequate lift of the foot as it swings through before heel strike. This results in the foot being pointed 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.
Some people will report a 'foot slap' in its early stages. The muscles that lift the foot are also responsible for controlling the rate the foot lowers after the heel strikes the ground. 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.
Causes of Foot drop
There are several causes for footdrop
- Trauma to the common peroneal nerve
- Multiple Sclerosis (MS)
- Charcot Marie Tooth (CMT)
- Nerve impingement in the back
- Guillain–Barré syndrome
- Cerebral palsy (CP)
- Muscular dystrophy
- Spinal cord injury
Managing foot drop
The orthotic management of Foot Drop is often achieved 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.
Stock AFO / Splints
As the name suggests, they are ordered from stock and are standard in design They come ready-made often to just a shoe size. Usually the main advantage of a stock orthosis is the price; they are cheaper than having something made to measure. There are numerous designs of foot drop splints on the market, all of which have positives and negatives. The main disadvantage of a stock orthosis is that they may not fit the foot and leg correctly as they are a standard size.
Stock splints are available in most materials from plastic to carbon fibre and are aimed at various activity levels and weakness.
Custom AFO / Splints
Again as the name suggests these are custom made devices. They are often made from either plaster casts of the leg or 3d Scans. They are more expensive but for the extra money you can get exactly what is required for your condition. While on paper you would think that custom made devices are automatically better than stock devices but that is not always the case, often a stock device is the better option for a low profile device when there is minimal deformity present.
Custom splints are generally required when a person either does not fit into a stock device due to deformity or the aim of the device is too complex for a stock device to meet the objective.
Examples of such Orthotics devices include
Stock DevicesElasticated fabric braces like the Prim Airmed. This splint wraps around the ankle and has a hook section that attaches in the shoes around the lace or velcro fastening. It uses an adjustable elastic section to provide lift of the foot when walking.
The Neurodyn Foot lift Orthoses is a sock designed brace which uses a figure of 8 elasticated strap arrangement to aid foot lift. This splint also has an additional strap on the outside ankle to pull the foot straight and reduce ankle inversion.
Stock or off the shelf Ankle Foot orthoses (AFO) are often made in plastic. This is a classic design often called a swedish AFO or Supralite AFO. They come in standard sizes generally Small to X-Large with the footplate needing trimmed to fit if it is too long.
Carbon Fibre ankle foot orthoses come in various designs and sizes from a number of suppliers. Carbon fibre is light weight and can provide energy return to give a spring when walking. There are numerous different stock Carbon fibre splints which are generally go by your shoe size. They range from rigid to help with knee control to flexible when minimal support is required.
Custom made devices
Custom made Ankle foot orthoses are made to casts of the leg and are individually designed to meet the clinical need of the person.
Splints can also be custom made in carbon fibre to provide increased support or energy return over stock carbon devices. These are made to casts of the leg and are designed on an individual basis going on clinical need and anticipated activity they are to be worn with.
Custom Made PLS Style Carbon AFO
Custom Hinged Carbon AFO
3d Printed AFO's
A newer development is 3d printed splints these can offer an number of benefits over traditional plastic AFOs for foot drop. They can be thinner and have areas of stiffness which would be difficult to produce in a traditional plastic splint. Crispin Orthotics is one of the leading designers of 3d Printed Orthotic devices. Generally they are made to 3d Scans of the leg however occasional a cast is required and that will depend on the condition. Another major advantage of a 3d Printed AFO is that it is repeatable and when a new one is required it can just be printed again.
3d Printed AFO
There are also hybrid designed splints. These utilise stock of kits to make a device to help with foot drop. A good example of this is the Turbomed Xtern; it is made from a kit but is customised to fit you and your footwear.
Below knee Iron with backstops
Below knee caliper or Irons can also be classed as a hybrid design as they require footwear to be adapted with sockets to hold the caliper.
These are just some of the options available and our expert clinicians can assist you in finding the right device for you. We are not linked to any one supplier so can offer the best solution to you.
We have a number of articles on the treatment options