This is a condition characterised by compression of the common peroneal nerve. This results in weakness when using the foot. This is sometimes referred to as foot drop.
Foot drop is a condition, in which a person has difficulty lifting the front part of the foot. When a person with a foot drop walks, he might have to drag his foot on the ground. Foot drop is a neurological problem that can result from damage to the common peroneal nerve or injury to the L5 nerve. The nerve around the head of the fibula at the knee joint is compressed, leading to the condition. There might also be a history of trauma or fracture of the fibula in the patient.
The patient usually presents with the symptoms of pain or numbness at the top and lateral aspects of the foot. Other symptoms include weakness in the foot. In case of enhanced weakness, the patients might have a high stepping pattern of walking, and might drag the foot on the floor. Due to numbness in the foot, the patient would walk by raising their thighs as though they were climbing stairs. Careful clinical evaluation is required to differentiate it from a foot drop resulting from L5 nerve compression.
When the muscle involved in lifting the front part of the foot gets weakened or paralyzed, it leads to the problem of foot drop. Some other reason which might cause foot drop include:
Various forms of muscular dystrophyies that cause progressive muscle weakness can lead to foot drop. These dystrophies can also cause other disorders such as polio or charcot marie tooth disease.
Compression of the nerve in the leg that assists in lifting of the foot is the most common cause of foot drop. This nerve sometimes also gets injured during hip or knee replacement surgery. A pinched nerve in the spine can also cause foot drop. People suffering from diabetes are more prone to a nerve disorder, associated with foot drop.
Diseases such as amyotrophic lateral sclerosis and multiple sclerosis affect the brain and spinal cord. This can also lead to other neurological disorders and foot drop.
The below mentioned factors can lead to foot drop in patients:
If there is suspicion of common peroneal neuropathy, a confirmatory diagnosis is required. Careful clinical evaluation and neurological examination is required to differentiate it from a weakness resulting from an L5 nerve injury.
This is confirmed by performing a nerve conduction study or tests such as CT scan, X-rays, ultrasound, magnetic resonance imaging and EMG. These tests will confirm the compression of the common peroneal nerve at the knee joint.
Other diagnostic tests conducted may include MRI scans of the spine and knee and possibly x rays to look for fractures.
Treatment options range from physical therapy, splint, braces to surgical treatment. Surgically decompressing the common peroneal nerve is an effective method of treatment when the weakness is the result of a nerve compression or tumour. This decompresses the nerve, which in turn helps to improve foot movement. For non compressive causes such a diabetic neuropathies, the treatment is supportive. The main component is physiotherapy, splinting and exercises.
Exercise should be included in a person’s routine. Stretching exercise is required to improve the patient’s way of walking, range of motion of the knee and strengthen the leg muscle.
Braces and splint are used to immobilise the injured area for healing. In foot drop braces are put on the ankle and foot area and splints are fit into the shoe to immobilise the foot.
Having a regular exercise routine help in the prevention of foot drop. Exercises can include: ankle adduction, ankle dorsiflexion, assisted toe raise, heel raise, toe raise, ankle aversion, ankle inversion, hip rotation, single-leg stands.