Foot drop

What is foot drop?

Foot drop is when you find it difficult to lift the front part of your foot and toes, because of weakness or paralysis in the muscles that raise them. It's not a condition in its own right, it's a sign of an underlying problem, which could be in your muscles, nerves, brain or spinal cord.

Foot drop usually affects one foot, though it can affect both, depending on the cause. It can be temporary or long-term (chronic).

What are the symptoms of foot drop?

The main symptom is difficulty lifting the front of your foot and toes, so your foot or toes may drag or scuff along the ground as you walk.

To avoid dragging your toes, you might:

• lift your knee higher than usual, almost like climbing stairs (sometimes called a steppage gait)
• notice your foot slapping down onto the floor with each step.

You may also notice:

• numbness, tingling or a burning feeling, often down the outer side of your calf and onto the top of your foot
• a higher risk of tripping or falling.

If a problem in your lower back is the cause, you might also have back pain, or find it hard to bend your knee or straighten your leg.

What are the causes of foot drop and who is at risk?

The most common cause is an injury to, or compression of, a nerve. This is usually either:

• the peroneal nerve – a nerve that runs from behind your knee down to your foot and controls the muscles that lift it, often compressed around the knee
• a pinched nerve in your lower back lumbar radiculopathy – this can happen when the space where a nerve root leaves your spine narrows, for example due to spinal stenosis, bone spurs, a slipped disc or spondylosis (wear and tear in the spine).

Other causes and risk factors include:

• sports injuries, or fractures and dislocations around the knee or ankle
• crossing your legs, or kneeling or squatting for long periods, such as in some manual jobs
• wearing a leg cast, being on bed rest, or losing weight quickly
• peripheral neuropathy (nerve damage) caused by diabetes
• hip or knee replacement surgery
• not moving for a long time, for example during a hospital stay
• rarely, a tumour or cyst pressing on the nerve, or an inflammatory condition such as rheumatoid arthritis or lupus.

Less commonly, foot drop is caused by a condition affecting your muscles, nerves, brain or spinal cord, such as:

• muscular dystrophy, spinal muscular atrophy or motor neurone disease
• Charcot-Marie-Tooth disease, an inherited nerve condition affecting around 1 in 2,500 people
• stroke, cerebral palsy, Parkinson's disease or multiple sclerosis.

In children, foot drop can also follow a traumatic injury to the peroneal nerve, such as a knee dislocation, severe ankle sprain, fracture or surgical injury.

Rarely, it can be caused by compartment syndrome, a dangerous build-up of pressure in the leg after severe trauma that stops blood reaching the muscles and nerves.

Are there different types of foot drop?

Foot drop can affect one foot (unilateral) or both feet (bilateral), depending on the underlying cause.

Some people also have what's known as fatigable foot drop. This means your ankle works normally to begin with, but weakens the more you use it, so the problem becomes more noticeable over a longer walk.

Does foot drop get worse over time?

This depends on the underlying cause. Foot drop from a temporary nerve injury, such as compression or inflammation, often improves as the nerve heals.

Foot drop caused by a progressive condition, such as multiple sclerosis, can start with just occasional catching of the foot or difficulty lifting the toes on one side, and gradually progress to little or no ability to lift the toes and ankle at all.

You can get a rough idea of whether you have foot drop by sitting or standing with your feet flat on the floor, keeping your heels planted, and lifting your toes upward on each side in turn. If one side is harder to lift, or doesn't move at all, this could be a sign of foot drop. Repeating this 10 to 20 times on each side can also show whether the weakness gets worse with repeated use.

How is foot drop diagnosed?

A GP or specialist will examine your leg and foot, and watch the way you walk. This can show reduced muscle strength or wasting, and difficulty lifting your foot and toes.

You may be referred for further tests, which can include:

• imaging, such as an X-ray, ultrasound or CT scan, to check for damage or compression
• an MRI scan, to look more closely at the nerve itself
• a blood sugar test, to check for diabetes
• nerve conduction studies and electromyography (EMG), tests that check how well your nerves and muscles are working and can help pinpoint where the problem lies.

How is foot drop treated?

Non-surgical treatment

• Physiotherapy or occupational therapy: This is to stretch and strengthen the muscles in your leg and foot and help you walk more easily
• A brace, splint or shoe insert: This is often called an ankle-foot orthosis (AFO), and it holds your foot and ankle in a more natural position
• Electrical stimulation: This is where a small device uses electrical signals to help your nerves work – it can be especially helpful after a stroke or with multiple sclerosis, and for long-term use, the electrodes can sometimes be implanted under your skin during an operation.

Surgical treatment

Surgery is usually considered if the cause is permanent, if nerve damage is severe, or if other treatments haven't helped. Options include:

• Nerve repair: This means reconnecting the two ends of a damaged nerve directly, or using a nerve graft if the gap is too large
• Nerve decompression: This involves relieving pressure on a nerve that's being compressed
• Nerve or tendon transfer: This uses a working nerve or tendon from elsewhere in your body to replace the affected one
• Ankle fusion (also called arthrodesis): This fixes the ankle and foot bones together and is usually a last resort, since it stops all movement at the ankle joint.

If the underlying cause can be treated, foot drop may improve or go away completely. If it's caused by a long-term condition, such as a neurodegenerative disease, foot drop is often permanent, though treatment can still help you walk more safely and comfortably.

When should I see a doctor?

See a GP if you find it difficult to lift the front of your foot and toes, or if you notice your toes dragging on the ground when you walk.

Getting it checked matters. If foot drop isn't treated, it can lead to a loss of mobility and function, and sometimes chronic pain that affects your quality of life.

Get urgent medical help if you develop foot drop together with severe pain, swelling and tight, tense skin in your leg after a significant injury, as this can be a sign of a dangerous condition affecting the blood supply to your leg (compartment syndrome).