Foot drop

Foot drop is a muscular weakness or paralysis that makes it difficult to lift the front part of your foot and toes.

It's also sometimes called drop foot, and can cause you to drag your foot on the ground when you walk.

Foot drop is a sign of an underlying problem rather than a condition itself. This could be muscular, caused by nerve damage in the leg, or the result of a brain or spinal injury.

Foot drop usually only affects one foot, but both feet may be affected, depending on the cause. It can be temporary or permanent.

What causes foot drop?

Foot drop is the result of weakness or paralysis of the muscles that lift the front part of your foot. This can be caused by a number of underlying problems, which are described below.

Muscle weakness

Muscular dystrophy is a group of inherited genetic conditions that cause gradual muscle weakness and can sometimes lead to foot drop.

Foot drop can also be caused by other muscle wasting conditions, such as spinal muscular atrophy or motor neurone disease.

Peripheral nerve problems or neuropathy

Foot drop is often caused by compression (squashing) of the nerve that controls the muscles that lift the foot.

Sometimes, nerves around the knee or lower spine can become trapped. The nerves in the leg can also be injured or damaged during hip replacement or knee replacement surgery.

Foot drop can sometimes be caused by nerve damage linked to diabetes (known as a neuropathy).

Inherited conditions that cause peripheral nerve damage and muscle weakness, such as Charcot-Marie-Tooth disease, can also sometimes lead to foot drop.

Brain and spinal cord disorders

Foot drop can also be caused by conditions that affect the brain or spinal cord, such as:

• stroke
• cerebral palsy
• multiple sclerosis

Diagnosing foot drop

Foot drop is often diagnosed during a physical examination. Your GP will look at the way you walk and examine your leg muscles.

In some cases, imaging tests, such as an X-ray, ultrasound scan or computerised tomography (CT) scan, may be required.

Nerve conduction tests may be recommended to help locate where the affected nerve is damaged.

Electromyography, where electrodes are inserted into the muscle fibres to record the muscles' electrical activity, may also be carried out at the same time.

Managing foot drop

If you have foot drop, you'll find it difficult to lift the front part of your foot off the ground. This means you'll have a tendency to scuff your toes along the ground, increasing your risk of falls. To prevent this, you may lift your foot higher than usual when walking.

Recovery depends on the cause of foot drop and how long you've had it. In some cases it can be permanent.

Making small changes in your home, such as removing clutter and using non-slip rugs and mats, can help prevent falls. There are also measures you can take to help stabilise your foot and improve your walking ability.

These measures include:

• physiotherapy – to strengthen your foot, ankle and lower leg muscles
• wearing an ankle-foot orthosis – to hold your foot in a normal position
• electrical nerve stimulation – in certain cases it can help lift the foot
• surgery – an operation to fuse the ankle or foot bones may be possible in severe or long-term cases

Some of these treatments are discussed in more detail below.

Ankle-foot orthosis

An ankle-foot orthosis (AFO) is worn on the lower part of the leg to help control the ankle and foot. It holds your foot and ankle in a straightened position to improve your walking.

If your GP thinks an AFO will help, they'll refer you for an assessment with an orthotist (a specialist who measures and prescribes orthoses).

Wearing a close-fitting sock between your skin and the AFO will ensure comfort and help prevent rubbing. Your footwear should be fitted around the orthosis.

Lace-up shoes or those with Velcro fastenings are recommended for use with AFOs because they're easy to adjust. Shoes with a removable inlay are also useful because they provide extra room. High-heeled shoes should be avoided.

It's important to break your orthosis in slowly. Once broken in, wear it as much as possible while walking because it will help you walk more efficiently and keep you stable.

Electrical nerve stimulation

In some cases, an electrical stimulation device, similar to a TENS machine, can be used to improve walking ability. It can help you walk faster, with less effort and more confidence.

Two self-adhesive electrode patches are placed on the skin. One is placed close to the nerve supplying the muscle and the other over the centre of the muscle. Leads connect the electrodes to a battery-operated stimulator, which is the size of a pack of cards and is worn on a belt or kept in a pocket.

The stimulator produces electrical impulses that stimulate the nerves to contract (shorten) the affected muscles. The stimulator is triggered by a sensor in the shoe and is activated every time your heel leaves the ground as you walk.

If your GP or consultant thinks you'll benefit from using an electrical stimulation device, you'll be referred to an orthopaedic foot and ankle surgeon for an assessment. You may then be referred to a specialist unit to try the device and assess its suitabilty.

For long-term use, it may be possible to have an operation to implant the electrodes under your skin. The procedure involves positioning the electrodes over the affected nerve while you're under general anaesthetic.

The National Institute for Health and Care Excellence (NICE) advises that electrical stimulation can be used to treat people with foot drop caused by damage to the brain or spinal cord, provided:

• the person understands what's involved and agrees to the treatment
• the results of the procedure are closely monitored

Read the NICE guidance about Functional electrical stimulation for drop foot of central neurological origin.

Surgery

Surgery may be an option in severe or long-term cases of foot drop that have caused permanent movement loss from muscle paralysis.

The procedure usually involves transferring a tendon from the stronger leg muscles to the muscle that should be pulling your ankle upwards.

Another type of surgery involves fusing the foot or ankle bones to help stabilise the ankle.

Speak to your GP or orthopaedic foot and ankle specialist if you're thinking about having surgery for foot drop. They'll be able to give you more information about the available procedures and any associated pros and cons.