Foot drop, sometimes called drop foot, is a condition in which the patient has trouble lifting the front portion of the foot during walking, causing that foot to drag along the ground. To counteract this problem, the patient may raise the thigh when walking as if climbing the stairs in order to help the foot clear the floor, a method of walking referred to as steppage gait. Foot drop can occur for a number of neurological, muscular or anatomical reasons and may or may not be permanent.
Foot drop more frequently occurs only in one foot, although sometimes both feet may be affected. The condition is diagnosed through the use of imaging tests, which may include: X-rays, CT or MRI scans, ultrasound or electromyography (EMG).
Causes of Foot Drop
Foot drop may occur at any age as a result of injury or disease process. Common causes of foot drop include compression of the peroneal nerve and neurological or muscular disorders.
Compression of the Peroneal Nerve
The peroneal nerve, a branch of the sciatic nerve that provides sensation and movement to the lower leg, foot and toes, when compressed may result in numbness or pain along the shin or top of the foot, as well as in foot drop. The peroneal nerve may be damaged in any of the following ways:
- Injury during joint replacement surgery
- Injury during spinal surgery
- Accidental or sports injuries
- Immobilization, such as casting
- Excessive weight loss as in anorexia
- Prolonged sitting cross-legged, squatting or kneeling
- Diabetic nerve damage
Several neurological disorders may also contribute to the develop of foot drop. These may include:
- Multiple sclerosis (MS)
- Cerebral palsy
- Charcot-Marie-Tooth disease
- Parkinson's disease
Muscular diseases that cause progressive muscular deterioration may also cause foot drop. Such disorders include:
- Muscular dystrophy (MD)
- Amyotrophic lateral sclerosis (Lou Gehrig's disease)
- Cerebral palsy
Treatment of Foot Drop
There are several treatment options for foot drop. Conservative methods are typically tried first in order to avoid the risks and prolonged recovery period involved in surgery. These treatment methods, which provide support and improve foot position and flexibility include:
- Braces, splints, orthotic or orthopedic shoes
- Physical therapy to increase strength and range of motion
- Nerve stimulation of the peroneal nerve
In situations where the none of the above techniques provide improvement, surgery is considered. There are a few different operations that may be performed to alleviate the condition, depending on its cause. If the peroneal nerve is being compressed, a surgical procedure to eliminate that compression may be performed. This operation can be very effective, especially if the foot drop has developed recently, though the procedure is not useful if the nerve has actually suffered a tear. Another surgery involves grafting a nerve from another part of the body to replace the damaged peroneal nerve. For reasons not yet clear, however, a nerve graft in this area is less successful than one performed elsewhere in the body.
In situations where the foot drop is considered permanent, an operation to fuse the foot and ankle joint, or to transfer tendons from other stronger muscles, may be performed. As with other surgical procedures for foot drop, it is hoped that the operation will improve the patient's gait and stability.