What is foot drop and what causes it?

Foot drop is weakness of ankle and toe dorsiflexion (pulling the foot and toes up) — the muscles that lift the front of the foot. People notice it as a toe catching on stairs or carpet, a slapping sound when the foot lands, or having to lift the knee higher to clear the ground. It is often painless, which is exactly why it gets ignored.

In the lumbar spine it usually means the L5 root. It is most often compressed by a disc herniation or by foraminal narrowing (a tight nerve opening). It can also come from a peroneal nerve compression at the knee. That is a completely different problem with a completely different treatment. The two are separated by examination, not by assumption.

How is foot drop from the back diagnosed?

How is foot drop from a pinched nerve treated?

Where a disc is compressing the root and weakness is progressing, surgical decompression is the right answer. Delay costs recovery. We will say that plainly. We will not offer an injection to avoid the conversation.

Sometimes weakness is mild and stable and the pain is the main problem. Then a targeted transforaminal injection can reduce inflammation around the root. It can buy the natural history time to work. That is a legitimate path. It requires the weakness to be monitored, not assumed stable.

Either way, an ankle-foot orthosis (a brace for the ankle and foot) is worth having early. It prevents the trips and falls that do secondary damage while the root recovers. People are often not offered one because it feels like conceding.

Frequently asked questions

Will my foot drop recover?

Often, when the compression is relieved early and the weakness was not severe or long-lasting. The strongest predictors are how bad it got and how long it lasted. That is the whole argument for not waiting.

How long can I wait?

Progressive weakness should be assessed within days. Stable mild weakness has more room. It needs someone actually re-measuring it rather than asking how it feels.

For the symptoms that cannot wait at all, read when back pain is an emergency.

Is it always from the back?

No. Peroneal nerve compression at the outer knee is a common alternative. It is easy to tell apart on examination. Diabetes and other neuropathies (nerve diseases) can also weaken dorsiflexion, usually more evenly on both sides.

For how a compressed lumbar root weakens the foot, read lumbar radiculopathy.

Does L4 or L5 cause foot drop?

In the lumbar spine, foot drop usually means the L5 root. It is most often squeezed by a disc herniation or by narrowing of the opening the nerve exits through. A clean sign is being unable to walk on your heel on one side. Numbness on the top of the foot and the great toe fits the same L5 pattern.

What are the early signs of foot drop?

Your toe catches on stairs or carpet, your foot slaps when it lands, or you find yourself lifting your knee higher to clear the ground. It is often painless, which is exactly why people ignore it. The problem is weakness in the muscles that lift the front of the foot, and it is on a clock.

Is sudden foot drop an emergency?

Weakness that is getting worse over days should be assessed now, not at the next open appointment. That is because a nerve root under that much pressure can be damaged. If foot drop comes with numbness in the saddle area or any change in bladder or bowel control, go to an emergency department today.

Should I wear a brace for foot drop?

Yes, and early. An ankle-foot orthosis holds the front of the foot up so you stop tripping and falling while the nerve root recovers. Those falls do their own secondary damage. People are often not offered one because it feels like giving in. But it protects you whichever treatment path you take.

An EMG nerve test of the leg helps show whether a weak ankle comes from a nerve root in the back or from a nerve lower in the leg.

Related reading

• Lumbar radiculopathy
• Numbness in the foot
• When back pain is an emergency
• Before you agree to the operation