What is Foot Drop?
The term foot drop describes a condition that presents a limp-like, weak foot that causes difficulty when walking. With foot drop, also interchangeably called drop foot, a person loses the ability to raise the foot at the ankle. The condition causes the person to lift the afflicted foot high to allow the toes to clear the ground; this is known as steppage gait.
Some cases of foot drop are temporary and others are permanent. Causes of foot drop are numerous, but the most common cause is an injury to the peroneal nerve at the top of the calf behind the knee. Other causes of foot drop include multiple sclerosis, Parkinson’s disease, amyotrophic lateral sclerosis (ALS) Lou Gehrig’s disease, and muscular dystrophy. Additional causes include stroke, drug toxicity, diabetes, low back pain, and cauda equine, a compression of the lower bundle of nerves in the spinal cord.
Peroneal nerve palsy is the term used when the nerve at the top of the calf behind the knee is compressed. If the peroneal nerve is injured, it cannot support the tibialis anterior, the muscle which lifts the foot. To diagnose foot drop, a physician will take a complete medical history and may order tests such as magnetic resonance imaging (MRI) or an electromyogram (EMG).
There are shoes and straps that can mimic the natural ankle motion and help patients with foot drop. An ankle-foot orthosis is a brace, generally made of plastic, which supports the ankle and holds the foot and ankle in the correct position. Surgical treatment is also an option and can involve decompression, nerve transfer, or nerve grafting.
A treatment that involves nerve transfer has had promising results if performed within one year of the development of foot drop. The type of surgery that is most effective might be dependent on the location of the injury causing foot drop. When the condition is caused by a knee injury, decompression surgery is also an option.
Damage to a single peripheral nerve is known as mononeuropathy. This damage can be caused by an accident, injury, or physical trauma. Another cause of mononeuropathy is prolonged pressure on a nerve, which happens to some patients confined to a wheelchair or bed. Repetitive motions or cases in which the shock-absorbing discs that lie between the bones in the back are damaged can also cause mononeuropathy.
Written by Cathy Rogers
