Foot drop is a weakness or inability in being able to turning the ankle and foot upward, otherwise known as dorsiflexion. Therefore, the foot will hang down. The deep fibular/peroneal nerve innervates the anterior compartment of the leg. Damage to this nerve will lead to the inability for the leg to dorsiflex the foot, therefore causing foot drop. Conditions leading to foot drop may be neurologic, muscular or anatomic in origin, often with significant overlap. The result is an abnormal gait/ walking pattern.
Foot drop is characterized by steppage gait. When the person with foot drop walks, the foot slaps down onto the floor. To accommodate the toe drop, the patient may use a characteristic tiptoe walk on the opposite leg, raising the thigh excessively, as if walking upstairs, while letting the toe drop. This serves to raise the foot high enough to prevent the toe from dragging and prevents the slapping. Other gaits such as a wide outward leg swing (to avoid lifting the thigh excessively or to turn corners in the opposite direction of the affected limb) may also indicate foot drop.
REASONS FOR FOOT DROP
- Neuromuscular disease
- Peroneal nerve (common, i.e., frequent)—chemical, mechanical, disease
- Sciatic nerve—direct trauma, iatrogenic
- Lumbosacral plexus
- L5 nerve root (common, especially in association with pain in back radiating down leg)
- Spinal cord (rarely causes isolated foot drop)—poliomyelitis, tumor
- Brain (uncommon, but often overlooked)—stroke, TIA, tumor
- Genetic (as in Charcot-Marie-Tooth Disease and hereditary neuropathy with liability to pressure palsies)
If the L5 nerve root is involved, the most common cause is a herniated disc. Other causes of foot drop are diabetes, trauma, motor neuron disease (MND), adverse reaction to a drug or alcohol, and multiple sclerosis.
The underlying disorder must be treated. For example, if a spinal disc herniation in the low back is impinging on the nerve that goes to the leg and causing symptoms of foot drop, then the herniated disc should be treated. If the foot drop is the result of a peripheral nerve injury, a window for recovery of 18 months to 2 years is often advised. If it is apparent that no recovery of nerve function takes place, surgical intervention to repair or graft the nerve can be considered, although results from this type of intervention are mixed.
Ankles can be stabilized by lightweight braces available in molded plastics as well as softer materials that use elastic properties to prevent foot drop. Additionally, shoes can be fitted with traditional spring-loaded braces to prevent foot drop while walking. Regular exercise is usually prescribed.
The latest treatments include stimulation of the peroneal nerve, which lifts the foot when you step. Many stroke and multiple sclerosis patients with foot drop have had success with it. Often, individuals with foot drop prefer to use a compensatory technique like steppage gait or hip hiking as opposed to a brace or splint.
I have had excellent results with the Dynamic Richie brace using the dorsiflex assist hinges.
Below are videos of a patient of mine with out the brace and with the brace, notice the right foot how it drags in the first video. Then in the second video with the brace on the foot , there is a normalized gait pattern.