Foot drop (also called drop foot) is a term used to describe the inability to lift one or (rarely) both feet at the ankle. Foot drop is not a disease in and of itself, but a sign of underlying neurological, nerve or muscle dysfunction. A person afflicted with foot drop may drag the top of his foot as he walks, slap it down on the floor or raise his thigh unusually high in order to lift his foot completely off of the ground. Depending on the underlying cause, foot drop may be a temporary or permanent condition.
There are a number of diseases, disorders and injuries that may result in foot drop.
One possible cause of foot drop is physical injury to the nerves or muscles. The most common injury resulting in foot drop is injury to the peroneal nerve, which runs from the spine down to the knee area and supplies the tibialis anterior muscle responsible for lifting the foot. However, physical injury to the lower spine, knee or leg and injury during hip or knee replacement surgery can also cause foot drop.
Foot drop may also be the result of muscle or nerve damage caused by certain diseases and disorders. Diabetic neuropathy (nerve damage), various types of muscular dystrophy and compartment syndrome (a condition that compresses the nerves) may all result in foot drop. Disorders of the brain and spinal cord that cause muscle deterioration or dysfunction like multiple sclerosis, amyotrophic lateral sclerosis (Lou Gehrig’s disease), cerebral palsy, spinal muscular atrophy or others may also result in foot drop.
Foot drop may even be the result of toxins introduced to the body through certain medications like those associated with chemotherapy and those used to treat multiple sclerosis.
If the cause of foot drop is disease or disorder, curing it will often improve or eradicate foot drop. However, if the disease or disorder cannot be treated, the foot drop may be permanent. Permanent foot drop can be managed by a brace or splint placed in the shoe to hold the foot in place and physical therapy to improve walking. And for certain cases, the placement of a nerve stimulator on the peroneal nerve can be used to lift the foot while walking.
In the case of physical injury, surgery is often a successful treatment. However, injury to the peroneal nerve from the upper thigh to the spine is often permanent.