Foot drop

Foot drop
Foot drop
	Shown here, the right foot drops due to paralysis of the tibialis anterior muscle, while the left foot demonstrates normal lifting abilities.
Specialty	Neurology

Last updated February 16, 2024

A patient recovering from surgery to treat foot drop, with limited plantar and dorsiflexion.

Foot drop is a gait abnormality in which the dropping of the forefoot happens due to weakness, irritation or damage to the deep fibular nerve (deep peroneal), including the sciatic nerve, or paralysis of the muscles in the anterior portion of the lower leg. It is usually a symptom of a greater problem, not a disease in itself. Foot drop is characterized by inability or impaired ability to raise the toes or raise the foot from the ankle (dorsiflexion). Foot drop may be temporary or permanent, depending on the extent of muscle weakness or paralysis and it can occur in one or both feet. In walking, the raised leg is slightly bent at the knee to prevent the foot from dragging along the ground.

Foot drop can be caused by nerve damage alone or by muscle or spinal cord trauma, abnormal anatomy, toxins, or disease. Toxins include organophosphate compounds which have been used as pesticides and as chemical agents in warfare. The poison can lead to further damage to the body such as a neurodegenerative disorder called organophosphorus induced delayed polyneuropathy. This disorder causes loss of function of the motor and sensory neural pathways. In this case, foot drop could be the result of paralysis due to neurological dysfunction. Diseases that can cause foot drop include trauma to the posterolateral neck of fibula, stroke,^[1]^[2]^[3]^[4] amyotrophic lateral sclerosis, muscular dystrophy, poliomyelitis, Charcot–Marie–Tooth disease, multiple sclerosis, cerebral palsy, hereditary spastic paraplegia, Guillain–Barré syndrome, Welander distal myopathy, Friedreich's ataxia and chronic compartment syndrome. It may also occur as a result of hip replacement surgery or knee ligament reconstruction surgery.

Signs and symptoms

Mild steppage gait after treatment for foot drop

Foot drop is characterized by steppage gait.^[5] While walking, people suffering the condition drag their toes along the ground or bend their knees to lift their foot higher than usual to avoid the dragging.^[6] This serves to raise the foot high enough to prevent the toe from dragging and prevents the slapping.^[7]^[8] 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. 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.^[9]

Patients with painful disorders of sensation (dysesthesia) of the soles of the feet may have a similar gait but do not have foot drop. Because of the extreme pain evoked by even the slightest pressure on the feet, the patient walks as if walking barefoot on hot sand.^{[ citation needed ]}

Human lower leg anatomy Gray437.png — Human lower leg anatomy

Pathophysiology

The causes of foot drop, as for all causes of neurological lesions, should be approached using a localization-focused approach before etiologies are considered. Most of the time, foot drop is the result of neurological disorder; only rarely is the muscle diseased or nonfunctional. The source for the neurological impairment can be central (spinal cord or brain) or peripheral (nerves located connecting from the spinal cord to an end-site muscle or sensory receptor).^{[ citation needed ]}

Foot drop is rarely the result of a pathology involving the muscles or bones that make up the lower leg. The anterior tibialis is the muscle that picks up the foot. Although the anterior tibialis plays a major role in dorsiflexion, it is assisted by the fibularis tertius, extensor digitorum longus and the extensor hallucis longus. If the drop foot is caused by neurological disorder all of these muscles could be affected because they are all innervated by the deep fibular (peroneal) nerve, which branches from the sciatic nerve. The sciatic nerve exits the lumbar plexus with its root arising from the fifth lumbar nerve space.^{[ citation needed ]}

Occasionally, spasticity in the muscles opposite the anterior tibialis, the gastrocnemius and soleus, exists in the presence of foot drop, making the pathology much more complex than foot drop. Isolated foot drop is usually a flaccid condition. There are gradations of weakness that can be seen with foot drop, as follows according to MRC:^{[ citation needed ]}

0 = complete paralysis,
1 = flicker of contraction,
2 = contraction with gravity eliminated alone,
3 = contraction against gravity alone,
4 = contraction against gravity and some resistance, and
5 = contraction against powerful resistance (normal power).

foot slap is a heel strike abnormality, which is the audible slapping of the foot to the floor with each step that occurs when the foot first hits the floor on each step. Sometimes it is not visible and the diagnosis is done by actually hearing the slap.

Treated systematically, possible lesion sites causing foot drop include (going from peripheral to central):

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);
Cauda equina syndrome, which is caused by impingement of the nerve roots within the spinal canal distal to the end of the spinal cord;
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);
Nonorganic causes, e.g. as part of a functional neurological symptom disorder.

If the L5 nerve root is involved, the most common cause is a herniated disc. Other causes of foot drop are diabetes (due to generalized peripheral neuropathy), trauma, motor neuron disease (MND), adverse reaction to a drug or alcohol, and multiple sclerosis.^{[ citation needed ]}

Gait cycle

Drop foot and foot drop are interchangeable terms that describe an abnormal neuromuscular disorder that affects the patient's ability to raise their foot at the ankle. Drop foot is further characterized by an inability to point the toes toward the body (dorsiflexion) or move the foot at the ankle inward or outward. Therefore, the normal gait cycle is affected by the drop foot syndrome.

The normal gait cycle is as follows:

Swing phase (SW): The period of time when the foot is not in contact with the ground. In those cases where the foot never leaves the ground (foot drag), it can be defined as the phase when all portions of the foot are in forward motion.
Initial contact (IC): The point in the gait cycle when the foot initially makes contact with the ground; this represents the beginning of the stance phase. It is suggested that heel strike not be a term used in clinical gait analysis as in many circumstances initial contact is not made with the heel. Suggestion: Should use foot strike.
Terminal contact (TC): The point in the gait cycle when the foot leaves the ground: this represents the end of the stance phase or beginning of the swing phase. Also referred to as foot off. Toe-off should not be used in situations where the toe is not the last part of the foot to leave the ground.

The drop foot gait cycle requires more exaggerated phases.

Drop foot SW: If the foot in motion happens to be the affected foot, there will be greater flexion at the knee to accommodate the inability to dorsiflex. This increase in knee flexion will cause a stair-climbing movement.
Drop foot IC: Initial contact of the foot that is in motion will not have normal heel-toe foot strike. Instead, the foot may either slap the ground or the entire foot may be planted on the ground all at once.
Drop foot TC: Terminal contact that is observed in patients that have drop foot is quite different. Since patients tend to have weakness in the affected foot, they may not have the ability to support their body weight. Often, a walker or cane will be used to assist in this aspect.

Drop Foot is the inability to dorsiflex, evert, or invert the foot. So when looking at the Gait cycle, the part of the gait cycle that involves most dorsiflexion action would be Heel Contact of the foot at 10% of Gait Cycle, and the entire swing phase, or 60-100% of the Gait Cycle. This is also known as Gait Abnormalities.^{[ citation needed ]}

Diagnosis

Initial diagnosis often is made during routine physical examination. Such diagnosis can be confirmed by a medical professional such as a physiatrist, neurologist, orthopedic surgeon or neurosurgeon. A person with foot drop will have difficulty walking on his or her heels because they will be unable to lift the front of the foot (balls and toes) off the ground. Therefore, a simple test of asking the patient to dorsiflex may determine diagnosis of the problem. This is measured on a 0-5 scale that observes mobility. The lowest point, 0, will determine complete paralysis and the highest point, 5, will determine complete mobility.^{[ citation needed ]}

There are other tests that may help determine the underlying etiology for this diagnosis. Such tests may include MRI, MRN, or EMG to assess the surrounding areas of damaged nerves and the damaged nerves themselves, respectively. The nerve that communicates to the muscles that lift the foot is the peroneal nerve. This nerve innervates the anterior muscles of the leg that are used during dorsiflexion of the ankle. The muscles that are used in plantar flexion are innervated by the tibial nerve and often develop tightness in the presence of foot drop. The muscles that keep the ankle from supination (as from an ankle sprain) are also innervated by the peroneal nerve, and it is not uncommon to find weakness in this area as well. Paraesthesia in the lower leg, particularly on the top of the foot and ankle, also can accompany foot drop, although it is not in all instances.

A common yoga kneeling exercise, the Varjrasana has, under the name "yoga foot drop", been linked to foot drop.^[10]^[11]

Treatment

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.^{[ citation needed ]}

Non-surgical treatments for spinal stenosis include a suitable exercise program developed by a physical therapist, activity modification (avoiding activities that cause advanced symptoms of spinal stenosis), epidural injections, and anti-inflammatory medications like ibuprofen or aspirin. If necessary, a decompression surgery that is minimally destructive of normal structures may be used to treat spinal stenosis.^{[ citation needed ]}

Non-surgical treatments for this condition are very similar to the non-surgical methods described above for spinal stenosis. Spinal fusion surgery may be required to treat this condition, with many patients improving their function and experiencing less pain.

Nearly half of all vertebral fractures occur without any significant back pain. If pain medication, progressive activity, or a brace or support does not help with the fracture, two minimally invasive procedures - vertebroplasty or kyphoplasty - may be options.

Ankles can be stabilized by lightweight orthoses, 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.^{[ citation needed ]}

Functional electrical stimulation (FES) is a technique that uses electrical currents to activate nerves innervating extremities affected by paralysis resulting from spinal cord injury (SCI), head injury, stroke and other neurological disorders. FES is primarily used to restore function in people with disabilities. It is sometimes referred to as neuromuscular electrical stimulation (NMES) 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.

FES is applied to lower extremities for improving functional walking in stroke patients; for the correction of foot drop. They have benefited patients by improving gait speed, muscle strength and other functions.^[12]

Treatment for some can be as easy as an underside L-shaped foot-up ankle support (ankle-foot orthoses). Another method uses a cuff placed around the patient's ankle, and a topside spring and hook installed under the shoelaces. The hook connects to the ankle cuff and lifts the shoe up when the patient walks.

Both these techniques show significant improvement on usage.^[12]

Identification of a suspect in a murder case

In December 2021, police in Toronto, Canada said they were looking for a person with a distinctive gait as a suspect in the murder of Barry Sherman and Honey Sherman. Medical professionals quoted by the Toronto Star said that the distinctive gait could be caused by foot drop.^[13]

Related Research Articles

Charcot–Marie–Tooth disease (CMT) is a hereditary motor and sensory neuropathy of the peripheral nervous system characterized by progressive loss of muscle tissue and touch sensation across various parts of the body. This disease is the most commonly inherited neurological disorder, affecting about one in 2,500 people. It is named after those who classically described it: the Frenchman Jean-Martin Charcot (1825–1893), his pupil Pierre Marie (1853–1940), and the Briton Howard Henry Tooth (1856–1925).

Transverse myelitis (TM) is a rare neurological condition wherein the spinal cord is inflamed. The adjective transverse implies that the spinal inflammation (myelitis) extends horizontally throughout the cross section of the spinal cord; the terms partial transverse myelitis and partial myelitis are sometimes used to specify inflammation that affects only part of the width of the spinal cord. TM is characterized by weakness and numbness of the limbs, deficits in sensation and motor skills, dysfunctional urethral and anal sphincter activities, and dysfunction of the autonomic nervous system that can lead to episodes of high blood pressure. Signs and symptoms vary according to the affected level of the spinal cord. The underlying cause of TM is unknown. The spinal cord inflammation seen in TM has been associated with various infections, immune system disorders, or damage to nerve fibers, by loss of myelin. As opposed to leukomyelitis which affects only the white matter, it affects the entire cross-section of the spinal cord. Decreased electrical conductivity in the nervous system can result.

<span class="mw-page-title-main">Human leg</span> Lower extremity or limb of the human body (foot, lower leg, thigh and hip)

The leg is the entire lower limb of the human body, including the foot, thigh or sometimes even the hip or buttock region. The major bones of the leg are the femur, tibia, and adjacent fibula. The thigh is between the hip and knee, while the calf (rear) and shin (front) are between the knee and foot.

Spasticity is a feature of altered skeletal muscle performance with a combination of paralysis, increased tendon reflex activity, and hypertonia. It is also colloquially referred to as an unusual "tightness", stiffness, or "pull" of muscles.

The sciatic nerve, also called the ischiadic nerve, is a large nerve in humans and other vertebrate animals which is the largest branch of the sacral plexus and runs alongside the hip joint and down the lower limb. It is the longest and widest single nerve in the human body, going from the top of the leg to the foot on the posterior aspect. The sciatic nerve has no cutaneous branches for the thigh. This nerve provides the connection to the nervous system for the skin of the lateral leg and the whole foot, the muscles of the back of the thigh, and those of the leg and foot. It is derived from spinal nerves L4 to S3. It contains fibers from both the anterior and posterior divisions of the lumbosacral plexus.

The ankle jerk reflex, also known as the Achilles reflex, occurs when the Achilles tendon is tapped while the foot is dorsiflexed. It is a type of stretch reflex that tests the function of the gastrocnemius muscle and the nerve that supplies it. A positive result would be the jerking of the foot towards its plantar surface. Being a deep tendon reflex, it is monosynaptic. It is also a stretch reflex. These are monosynaptic spinal segmental reflexes. When they are intact, integrity of the following is confirmed: cutaneous innervation, motor supply, and cortical input to the corresponding spinal segment.

The plantar reflex is a reflex elicited when the sole of the foot is stimulated with a blunt instrument. The reflex can take one of two forms. In healthy adults, the plantar reflex causes a downward response of the hallux (flexion). An upward response (extension) of the hallux is known as the Babinski response or Babinski sign, named after the neurologist Joseph Babinski. The presence of the Babinski sign can identify disease of the spinal cord and brain in adults, and also exists as a primitive reflex in infants.

Clonus is a set of involuntary and rhythmic muscular contractions and relaxations. Clonus is a sign of certain neurological conditions, particularly associated with upper motor neuron lesions involving descending motor pathways, and in many cases is accompanied by spasticity. Unlike small spontaneous twitches known as fasciculations, clonus causes large motions that are usually initiated by a reflex. Studies have shown clonus beat frequency to range from three to eight Hz on average, and may last a few seconds to several minutes depending on the patient’s condition.

Functional electrical stimulation (FES) is a technique that uses low-energy electrical pulses to artificially generate body movements in individuals who have been paralyzed due to injury to the central nervous system. More specifically, FES can be used to generate muscle contraction in otherwise paralyzed limbs to produce functions such as grasping, walking, bladder voiding and standing. This technology was originally used to develop neuroprostheses that were implemented to permanently substitute impaired functions in individuals with spinal cord injury (SCI), head injury, stroke and other neurological disorders. In other words, a person would use the device each time he or she wanted to generate a desired function. FES is sometimes also referred to as neuromuscular electrical stimulation (NMES).

A gait is a manner of limb movements made during locomotion. Human gaits are the various ways in which humans can move, either naturally or as a result of specialized training. Human gait is defined as bipedal forward propulsion of the center of gravity of the human body, in which there are sinuous movements of different segments of the body with little energy spent. Varied gaits are characterized by differences such as limb movement patterns, overall velocity, forces, kinetic and potential energy cycles, and changes in contact with the ground.

<span class="mw-page-title-main">Peroneal nerve paralysis</span> Medical condition

Peroneal nerve paralysis is a paralysis on common fibular nerve that affects patient’s ability to lift the foot at the ankle. The condition was named after Friedrich Albert von Zenker. Peroneal nerve paralysis usually leads to neuromuscular disorder, peroneal nerve injury, or foot drop which can be symptoms of more serious disorders such as nerve compression. The origin of peroneal nerve palsy has been reported to be associated with musculoskeletal injury or isolated nerve traction and compression. Also it has been reported to be mass lesions and metabolic syndromes. Peroneal nerve is most commonly interrupted at the knee and possibly at the joint of hip and ankle. Most studies reported that about 30% of peroneal nerve palsy is followed from knee dislocations.

Astasis is a lack of motor coordination marked by an inability to stand, walk or even sit without assistance due to disruption of muscle coordination.

The common fibular nerve is a nerve in the lower leg that provides sensation over the posterolateral part of the leg and the knee joint. It divides at the knee into two terminal branches: the superficial fibular nerve and deep fibular nerve, which innervate the muscles of the lateral and anterior compartments of the leg respectively. When the common fibular nerve is damaged or compressed, foot drop can ensue.

Toe walking refers to a condition where a person walks on their toes without putting much or any weight on the heel or any other part of the foot. This term also includes the inability to connect one's foot fully to the ground while in the standing phase of the walking cycle. Toe walking in toddlers is common. Children who toe walk as toddlers commonly adopt a heel-toe walking pattern as they grow older. If a child continues to walk on their toes past the age of three, or cannot get their heels to the ground at all, they should be evaluated by a health professional who is experienced in assessing children's walking.

Steppage gait is a form of gait abnormality characterised by foot drop or ankle equinus due to loss of dorsiflexion. The foot hangs with the toes pointing down, causing the toes to scrape the ground while walking, requiring someone to lift the leg higher than normal when walking.

<span class="mw-page-title-main">Orthotics</span> Medical specialty that focuses on the building and designing of artificial legs

Orthotics is a medical specialty that focuses on the design and application of orthoses, sometimes known as braces or calipers. An orthosis is "an externally applied device used to influence the structural and functional characteristics of the neuromuscular and skeletal systems." Orthotists are professionals who specialize in designing these braces.

Alternating hemiplegia is a form of hemiplegia that has an ipsilateral cranial nerve palsies and contralateral hemiplegia or hemiparesis of extremities of the body. The disorder is characterized by recurrent episodes of paralysis on one side of the body. There are multiple forms of alternating hemiplegia, Weber's syndrome, middle alternating hemiplegia, and inferior alternating hemiplegia. This type of syndrome can result from a unilateral lesion in the brainstem affecting both upper motor neurons and lower motor neurons. The muscles that would receive signals from these damaged upper motor neurons result in spastic paralysis. With a lesion in the brainstem, this affects the majority of limb and trunk muscles on the contralateral side due to the upper motor neurons decussation after the brainstem. The cranial nerves and cranial nerve nuclei are also located in the brainstem making them susceptible to damage from a brainstem lesion. Cranial nerves III (Oculomotor), VI (Abducens), and XII (Hypoglossal) are most often associated with this syndrome given their close proximity with the pyramidal tract, the location which upper motor neurons are in on their way to the spinal cord. Damages to these structures produce the ipsilateral presentation of paralysis or palsy due to the lack of cranial nerve decussation before innervating their target muscles. The paralysis may be brief or it may last for several days, many times the episodes will resolve after sleep. Some common symptoms of alternating hemiplegia are mental impairment, gait and balance difficulties, excessive sweating and changes in body temperature.

Neuromechanics is an interdisciplinary field that combines biomechanics and neuroscience to understand how the nervous system interacts with the skeletal and muscular systems to enable animals to move. In a motor task, like reaching for an object, neural commands are sent to motor neurons to activate a set of muscles, called muscle synergies. Given which muscles are activated and how they are connected to the skeleton, there will be a corresponding and specific movement of the body. In addition to participating in reflexes, neuromechanical process may also be shaped through motor adaptation and learning.

Proportional myoelectric control can be used to activate robotic lower limb exoskeletons. A proportional myoelectric control system utilizes a microcontroller or computer that inputs electromyography (EMG) signals from sensors on the leg muscle(s) and then activates the corresponding joint actuator(s) proportionally to the EMG signal.

Cutaneous, superficial, or skin reflexes, are activated by skin receptors and play a valuable role in locomotion, providing quick responses to unexpected environmental challenges. They have been shown to be important in responses to obstacles or stumbling, in preparing for visually challenging terrain, and for assistance in making adjustments when instability is introduced. In addition to the role in normal locomotion, cutaneous reflexes are being studied for their potential in enhancing rehabilitation therapy (physiotherapy) for people with gait abnormalities.

References

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↑ Stewart, John D. (2008-06-01). "Foot drop: where, why and what to do?". Practical Neurology. 8 (3): 158–169. doi:10.1136/jnnp.2008.149393. ISSN 1474-7758. PMID 18502948. S2CID 28002732.
↑ Pittock, S. J.; Moore, A. P.; Hardiman, O.; Ehler, E.; Kovac, M.; Bojakowski, J.; Khawaja, I. al; Brozman, M.; Kaňovský, P.; Skorometz, A.; Slawek, J.; Reichel, G.; Stenner, A.; Timerbaeva, S.; Stelmasiak, Z. (2003). "A Double-Blind Randomised Placebo-Controlled Evaluation of Three Doses of Botulinum Toxin Type A (Dysport®) in the Treatment of Spastic Equinovarus Deformity after Stroke". Cerebrovascular Diseases. 15 (4): 289–300. doi:10.1159/000069495. ISSN 1015-9770. PMID 12686794. S2CID 29635400.
↑ Gao, Ying; Gang, Xiaochao; Yuan, Yue; Yin, Kai; Gong, Xiaoyan (2022-10-07). "Efficacy and safety of acupuncture in the treatment of foot drop in post-stroke: A protocol for systematic review and meta-analysis". Medicine. 101 (40): e30994. doi:10.1097/MD.0000000000030994. PMC 9542557 . PMID 36221406.
↑ "Definition of Steppage gait". MedicineNet, Inc. Archived from the original on 7 August 2012. Retrieved 23 March 2013.
↑ "Walking abnormalities". MedlinePlus. Archived from the original on 23 March 2013. Retrieved 23 March 2013.
↑ "high stepping gait". GPnotebook. Archived from the original on 12 February 2012. Retrieved 23 March 2013.
↑ Mayo Clinic staff. "Foot drop". Mayo Clinic. Archived from the original on 7 March 2013. Retrieved 23 March 2013.
↑ http://www.painontopoffoottalk.com Archived 2014-02-25 at the Wayback Machine
↑ Joseph Chusid (August 9, 1971). "Yoga Foot Drop". JAMA: The Journal of the American Medical Association. 271 (6): 827–828. doi:10.1001/jama.1971.03190060065025.
↑ William J. Broad (January 5, 2012). "How Yoga Can Wreck Your Body". The New York Times Magazine. Archived from the original on August 22, 2012. Retrieved August 29, 2012.
1 2 Alnajjar, Fady; Zaier, Riadh; Khalid, Sumayya; Gochoo, Munkhjargal (2020-12-28). "Trends and Technologies in Rehabilitation of Foot Drop: A Systematic Review". Expert Review of Medical Devices. 18 (1): 31–46. doi:10.1080/17434440.2021.1857729. ISSN 1743-4440. PMID 33249938. S2CID 227234568.
↑ Donovan, Kevin (2021-12-14). "The inside story of how Toronto police zeroed in the Sherman murder 'suspect' with the odd gait". Toronto Star. ISSN 0319-0781 . Retrieved 2021-12-15.