Causes
Foot drop is caused by weakness or paralysis of the muscles involved in lifting the front part of the foot. Causes of foot drop might include:

Nerve injury. The most common cause of foot drop is compression of a nerve in your leg that controls the muscles involved in lifting the foot (peroneal nerve). This nerve can also be injured during hip or knee replacement surgery, which may cause foot drop.

A nerve root injury — "pinched nerve" — in the spine can also cause foot drop. People who have diabetes are more susceptible to nerve disorders, which are associated with foot drop.

Muscle or nerve disorders. Various forms of muscular dystrophy, an inherited disease that causes progressive muscle weakness, can contribute to foot drop. So can other disorders, such as polio or Charcot-Marie-Tooth disease.

Brain and spinal cord disorders. Disorders that affect the spinal cord or brain — such as amyotrophic lateral sclerosis (ALS), multiple sclerosis or stroke — may cause foot drop.