Foot drop
Encyclopedia
Foot drop is the dropping of the forefoot due to weakness, damage to the peroneal 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. It is characterized by the inability or difficulty in moving the ankle
and toes upward (dorsiflexion
). The severity in foot drop can range from a temporary to permanent condition, depending on the extent of muscle weakness or paralysis. It can occur unilaterally or bilaterally. In walking, while stepping forward, the knees are slightly bent so the front of the foot can be lifted higher than usual to prevent the foot from dragging along the ground. Foot drop can be caused by nerve damage alone. However, it is also caused by muscle or spinal nerve trauma, abnormal anatomy, toxins or disease. Diseases that can cause foot drop include Amyotrophic lateral sclerosis
(ALS or Lou Gehrig's Disease), Parkinson's disease
, muscular dystrophy
, Charcot Marie Tooth disease, and multiple sclerosis
.
Foot drop is characterized by steppage gait
. While walking, people suffering the condition drag their toes along the ground or bend their knees to lift their foot high than usual to avoid the dragging. This serves to raise the foot high enough to prevent the toe from dragging and prevents the slapping. 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.http://sprojects.mmi.mcgill.ca/gait/footdrop/intro.asp
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.
However there are other tests that may help determine diagnosis. These tests include an 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 dorsi flexion. 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 always linked.http://www.mayoclinic.com/health/foot-drop/DS01031
Treated systematically, possible lesion sites causing foot drop include (going from peripheral to central):
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 normal gait cycle is as follows:
The drop foot gait cycle requires more exaggerated phases.
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.
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.
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.
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.
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.
Treatment for some can be as easy as a foot-up ankle support (ankle-foot orthoses). A cuff is placed around the patient's ankle, and a hook is installed under the shoelaces. The hook connects to the ankle cuff and lifts the shoe up when the patient walks.
Ankle
The ankle joint is formed where the foot and the leg meet. The ankle, or talocrural joint, is a synovial hinge joint that connects the distal ends of the tibia and fibula in the lower limb with the proximal end of the talus bone in the foot...
and toes upward (dorsiflexion
Dorsiflexion
Dorsiflexion is the movement which decreases the angle between the dorsum of the foot and the leg, so that the toes are brought closer to the shin. The movement moving in opposite directions is called plantarflexion...
). The severity in foot drop can range from a temporary to permanent condition, depending on the extent of muscle weakness or paralysis. It can occur unilaterally or bilaterally. In walking, while stepping forward, the knees are slightly bent so the front of the foot can be lifted higher than usual to prevent the foot from dragging along the ground. Foot drop can be caused by nerve damage alone. However, it is also caused by muscle or spinal nerve trauma, abnormal anatomy, toxins or disease. Diseases that can cause foot drop include Amyotrophic lateral sclerosis
Amyotrophic lateral sclerosis
Amyotrophic lateral sclerosis , also referred to as Lou Gehrig's disease, is a form of motor neuron disease caused by the degeneration of upper and lower neurons, located in the ventral horn of the spinal cord and the cortical neurons that provide their efferent input...
(ALS or Lou Gehrig's Disease), Parkinson's disease
Parkinson's disease
Parkinson's disease is a degenerative disorder of the central nervous system...
, muscular dystrophy
Muscular dystrophy
Muscular dystrophy is a group of muscle diseases that weaken the musculoskeletal system and hamper locomotion. Muscular dystrophies are characterized by progressive skeletal muscle weakness, defects in muscle proteins, and the death of muscle cells and tissue.In the 1860s, descriptions of boys who...
, Charcot Marie Tooth disease, and multiple sclerosis
Multiple sclerosis
Multiple sclerosis is an inflammatory disease in which the fatty myelin sheaths around the axons of the brain and spinal cord are damaged, leading to demyelination and scarring as well as a broad spectrum of signs and symptoms...
.
Features
Steppage gait
Steppage gait is a form of gait abnormality that is associated with a loss of dorsiflexion.It can be caused by damage to the deep peroneal nerve.-Presentation:Toes point down...
. While walking, people suffering the condition drag their toes along the ground or bend their knees to lift their foot high than usual to avoid the dragging. This serves to raise the foot high enough to prevent the toe from dragging and prevents the slapping. To accommodate the toe drop, the patient may use a characteristic tiptoe walk on the opposite leg, raising the thigh
Thigh
In humans the thigh is the area between the pelvis and the knee. Anatomically, it is part of the lower limb.The single bone in the thigh is called the femur...
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.http://sprojects.mmi.mcgill.ca/gait/footdrop/intro.asp
Patients with painful disorders of sensation (dysesthesia
Dysesthesia
Dysesthesia comes from the Greek word "dys", meaning "not-normal" and "aesthesis", which means "sensation" . It is defined as an unpleasant, abnormal sense of touch, and it may be, or not be, considered as a kind of pain...
) 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.
Epidemiology
In USA, within the course of 2009, there are a total of 1,787 discharges that related to Acquired Ankle-Foot Defect. 348 of the 1,787 patient (about 19.4%) stayed in the hospital for about 2.4 days. Those 2.4 days cost them around $29,756. For patients between the ages 45-64, 626 (roughly 35.05 percent of 1,787) of those patients were discharged. Among the patients between the ages of 45-65, it cost them a total of $38,529 stay for about 2.7 days. For patients of age 65-84, 474 of the patient were discharged. That’s about roughly 26.53% of the patients that were discharged. They stayed a mean of 3.5 days for $37,049. If we were to break down the patients stay further, we can see that about 815 males and 972 females were discharged from the hospital. That is about 45.59% were male and 54.41% were females. The men stayed a mean of 2.6 days for $34,979. For females, they stayed a mean of 2.8 days for $33,765. The standard deviation for errors for the length of stay has a total of 0.1 days. For the standard deviation of errors for discharge has a total for 177 patients. Lastly, for the amount of charges, the mean of the standard error for the total number of discharged patients was roughly $1,918.http://hcupnet.ahrq.gov/HCUPnet.jspDiagnosis
Initial diagnosis often is made during routine physical examination. Such diagnosis can be confirmed by a medical professional such as a physiatrist (or physical therapist), podiatrist, orthopedic spine surgeon or neurosurgeon. A person with foot drop will have difficulty walking on their heels. 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.However there are other tests that may help determine diagnosis. These tests include an MRI, MRN
Magnetic resonance neurography
Magnetic resonance neurography is the direct imaging of nerves in the body by optimizing selectivity for unique MRI water properties of nerves. It is a modification of magnetic resonance imaging. This technique yields a detailed image of a nerve from the resonance signal that arises from in the...
, or EMG
Electromyography
Electromyography is a technique for evaluating and recording the electrical activity produced by skeletal muscles. EMG is performed using an instrument called an electromyograph, to produce a record called an electromyogram. An electromyograph detects the electrical potential generated by muscle...
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 dorsi flexion. The muscles that are used in plantar flexion are innervated by the tibial nerve
Tibial nerve
The tibial nerve is a branch of the sciatic nerve. The tibial nerve passes through the popliteal fossa to pass below the arch of soleus.In the popliteal fossa the nerve gives off branches to gastrocnemius, popliteus, soleus and plantaris muscles, an articular branch to the knee joint, and a...
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 always linked.http://www.mayoclinic.com/health/foot-drop/DS01031
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). Foot drop is rarely the result of a pathology involving the muscles or bones that make up the lower leg. The muscle that is designed to pick up the foot is the anterior tibialis. It is innervated by the common 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. Occasionally, spasticity in the muscles opposite the anterior tibialis 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: 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 drop is different from foot slap, 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, although they often are concurrent.Treated systematically, possible lesion sites causing foot drop include (going from peripheral to central):
- Neuromuscular diseaseNeuromuscular diseaseNeuromuscular disease is a very broad term that encompasses many diseases and ailments that either directly, via intrinsic muscle pathology, or indirectly, via nerve pathology, impair the functioning of the muscles....
; - Peroneal nerve (common, i.e., frequent)—chemical, mechanical, disease;
- Sciatic nerveSciatic nerveThe sciatic nerve is a large nerve fiber in humans and other animals. It begins in the lower back and runs through the buttock and down the lower limb...
—direct trauma, iatrogenic; - Lumbosacral plexusLumbosacral plexusThe anterior divisions of the lumbar nerves, sacral nerves, and coccygeal nerve form the lumbosacral plexus, the first lumbar nerve being frequently joined by a branch from the twelfth thoracic. For descriptive purposes this plexus is usually divided into three parts:* lumbar plexus* sacral plexus*...
; - L5 nerve rootNerve rootA nerve root is the initial segment of a nerve leaving the central nervous system. Types include:* A cranial nerve root, the beginning of one of the twelve pairs leaving the central nervous system from the brain stem or the highest levels of the spinal cord;...
(common, especially in association with pain in back radiating down leg); - Spinal cordSpinal cordThe spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain . The brain and spinal cord together make up the central nervous system...
(rarely causes isolated foot drop)—poliomyelitis, tumor; - BrainBrainThe brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...
(uncommon, but often overlooked)—stroke, TIA, tumor; - GeneticGeneticsGenetics , a discipline of biology, is the science of genes, heredity, and variation in living organisms....
(as in Charcot-Marie-Tooth DiseaseCharcot-Marie-Tooth diseaseCharcot–Marie–Tooth disease- , known also as Morbus Charcot-Marie-Tooth, Charcot-Marie-Tooth neuropathy, hereditary motor and sensory neuropathy , hereditary sensorimotor neuropathy , or peroneal muscular atrophy, is an inherited disorder of nerves that takes different forms...
and hereditary neuropathy with liability to pressure palsies); - Nonorganic;
- 10 Caudia Equina Syndrome. Spinal cord damage caused by nerve impingement due to badly bulging disc.
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.
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 extension 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 times, 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.
Treatment
The underlying disorder must be treated. For example, if a spinal disc herniationSpinal disc herniation
A spinal disc herniation , informally and misleadingly called a "slipped disc", is a medical condition affecting the spine due to trauma, lifting injuries, or idiopathic, in which a tear in the outer, fibrous ring of an intervertebral disc allows the soft, central portion 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.
Non-surgical treatments for spinal stenosis
Spinal stenosis
Lumbar spinal stenosis is a medical condition in which the spinal canal narrows and compresses the spinal cord and nerves at the level of the lumbar vertebra. This is usually due to the common occurrence of spinal degeneration that occurs with aging. It can also sometimes be caused by spinal disc...
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.
Non-surgical treatments for this condition are very similar to the non-surgical methods described above for spinal stenosis. Spinal fusion
Spinal fusion
Spinal fusion, also known as spondylodesis or spondylosyndesis, is a surgical technique used to join two or more vertebrae. Supplementary bone tissue, either from the patient or a donor , is used in conjunction with the body's natural bone growth processes to fuse the vertebrae.Fusing of the...
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
Vertebroplasty
Vertebroplasty and kyphoplasty are similar medical spinal procedure where bone cement is injected through a small hole in the skin into a fractured vertebra with the goal of relieving the pain of vertebral compression fractures...
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.
Functional electrical stimulation
Functional electrical stimulation
Functional electrical stimulation is a technique that uses electrical currents to activate nerves innervating extremities affected by paralysis resulting from spinal cord injury , head injury, stroke and other neurological disorders. FES is primarily used to restore function in people with...
(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.
Treatment for some can be as easy as a foot-up ankle support (ankle-foot orthoses). A cuff is placed around the patient's ankle, and a hook is installed under the shoelaces. The hook connects to the ankle cuff and lifts the shoe up when the patient walks.
See also
- Gait abnormalityGait abnormalityGait abnormality is a deviation from normal walking . Watching a patient walk is the most important part of the neurological examination. Normal gait requires that many systems, including strength, sensation and coordination, function in an integrated fashion...
- Toe walkingToe walkingToe walking refers to a condition where a person walks on his or her toes without putting much weight on the heel or any other part of the foot. Toe-walking in toddlers is common. These children usually adopt a normal walking pattern as they grow older...
- PolymyositisPolymyositisPolymyositis is a type of chronic inflammation of the muscles related to dermatomyositis and inclusion body myositis.-Signs and symptoms:...
- inclusion body myositisInclusion body myositisInclusion body myositis is an inflammatory muscle disease, characterized by slowly progressive weakness and wasting of both distal and proximal muscles, most apparent in the muscles of the arms and legs...
External links
- YouTube video of CMT sufferer
- Walid MS, Ajjan M, Patel N, T Guta: Cellulitis May Present As Foot Drop In A Diabetic Patient: The Internet Journal of Neurology. 2007; Volume 7, Number 1.http://www.ispub.com/ostia/index.php?xmlPrinter=true&xmlFilePath=journals/ijn/vol7n1/cellulitis.xml
- Foot Drop article from Emedicine.com by James W Pritchett, MD, FACS; Margaret A Porembski, MD.
- Foot Drop from the Mayo Clinic.