What is foot drop, and can it be treated?

What does foot drop look like?

The muscles at the front of the shin lift the foot upwards as the leg swings forward. When they are weak, the toes point down and scrape the floor, which makes tripping more likely. People compensate by lifting the knee higher than usual, swinging the leg out to the side or hitching the hip. The foot may also slap down with each step instead of landing heel first.

Foot drop can affect one or both legs and may be constant or appear only when tired. It is often noticed first on stairs, kerbs or uneven ground, or as a pattern of catching the same shoe.

What causes foot drop?

Causes fall into two broad groups. Central causes affect the brain or spinal cord, such as stroke, multiple sclerosis, cerebral palsy or spinal cord injury. In these conditions the foot muscles may also be stiff because of spasticity, particularly the calf muscles that pull the foot down.

Peripheral causes affect the nerves after they leave the spine. The most common is compression of the common peroneal (fibular) nerve where it wraps around the bone just below the outside of the knee, which can happen after prolonged leg crossing, squatting, a tight plaster cast, rapid weight loss or a knee injury. A slipped disc in the lower back pressing on the L5 nerve root can also cause foot drop, often with back or leg pain. Diabetes and other conditions that damage nerves are further causes.

How is the cause found?

A doctor examines strength, sensation, reflexes and muscle tone in the legs and back. The pattern usually points to the level of the problem: weakness limited to lifting the foot and turning it outward, with numbness over the top of the foot, suggests the peroneal nerve, while weakness plus back pain and a particular pattern of numbness suggests a nerve root in the spine.

Nerve conduction studies and electromyography measure how well the nerve and muscle are working and help show where the damage is and how severe it is. Imaging of the brain, spine or knee may be needed depending on the findings.

How is foot drop treated?

The underlying cause is treated where possible, for example removing pressure on the nerve, adjusting a cast or managing a disc problem. Where a disc is pressing on a nerve root and there is progressive weakness or pain that does not settle, a specialist may discuss surgery 3.

For the walking problem itself, an ankle-foot orthosis, a light plastic or carbon brace worn inside the shoe, holds the foot up during the swing phase and reduces tripping. Guidelines recommend ankle-foot orthoses for people with foot drop after a stroke 2. Functional electrical stimulation uses a small device and skin electrodes to stimulate the nerve at the moment the foot needs to lift; UK guidance considers it safe and effective enough for use in foot drop caused by conditions of the brain or spinal cord 1.

Which exercises help?

Exercises aim to strengthen the muscles that lift the foot, stretch the calf, and improve balance and walking pattern. Examples include lifting the foot against light resistance, heel walking with support, calf stretches on a step, and practising stepping over small obstacles. A physiotherapist adapts these to how much muscle activity is present.

When there is no active movement yet, electrical stimulation during exercise can help activate the muscles. Stretching remains important because a tight calf makes foot drop worse and can lead to a fixed ankle position.

Will foot drop get better?

Recovery depends on the cause. Foot drop from compression of the peroneal nerve often improves over several months once the pressure is removed, because the nerve can regrow slowly. After a stroke, the ankle muscles may regain activity with rehabilitation, although some people continue to need a brace for longer walks.

In progressive conditions such as multiple sclerosis, foot drop may fluctuate, and devices are reviewed as needs change. Sudden foot drop together with back pain, numbness around the genitals or buttocks, or new problems controlling the bladder or bowel needs emergency assessment.

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