Foot drop in MS
Fact-checked by Foot drop is a common symptom of multiple sclerosis (MS) in which the front of the foot cannot be adequately lifted during walking. This can make walking more difficult, increase the risk of falls, and make day-to-day movement more tiring.
While it is often a long-lasting condition, treatments and supportive strategies can help people experiencing this symptom to maintain their mobility and independence.
In MS, the immune system erroneously attacks healthy parts of the brain and spinal cord, disrupting nerve communication. When the nerve pathways that control voluntary movement are damaged, the signals that activate the ankle and leg muscles may not travel correctly, leading to MS foot drop.
When walking, people normally lift their toes as their leg swings forward, allowing the heel to strike the ground first. With foot drop, however, it is difficult to lift the front of the foot at the correct angle when walking, so the toes point downward, causing them to catch or drag on the ground instead. This increases a person’s risk of tripping and falling, especially on uneven surfaces.
Some people with MS try to compensate for a dropped foot by lifting the knee higher when walking, as if they were constantly climbing stairs. However, this altered movement increases fatigue and may contribute to back or hip pain.
What causes foot drop?
Walking requires precise communication between the nervous system and the muscles of the lower leg.
For example: During a normal step, the nervous system instructs key muscles, mainly the tibialis anterior muscle, to contract. This lifts the front part of the foot, allowing the foot to clear the ground as the leg swings forward.
In MS, inflammatory damage to the brain and spinal cord can disrupt these signals. Foot drop occurs when the communication between the nervous system and the tibialis anterior muscle is affected. The result is a weak or inactive muscle that cannot lift the foot to the appropriate angle.
While this is the primary cause of foot drop in MS, other MS symptoms may also cause or exacerbate foot drop:
- Altered sensations: Sensations such as numbness or tingling can affect a person’s ability to feel the floor or sense limb positioning.
- Muscle spasticity: Muscle stiffness or tightness can make it more difficult to control the legs and feet.
- Fatigue: Worse fatigue, if it builds up during the day, can make it harder to lift the foot later in the day or during longer walks.
While foot drop is widely described as a common MS symptom, its exact prevalence is not well established.
Early signs of foot drop in MS
Foot drop often becomes noticeable through changes in a person’s walking patterns. Common early signs of foot drop in MS include:
- trouble lifting the toes while walking
- dragging the front of the foot
- tripping or stumbling more often
- needing to lift the knee higher than usual to avoid dragging the foot
Foot drop isn’t constant for everyone, and some people may only notice these issues at certain times, such as when they are fatigued, after walking for extended periods, or when overheated. It can also occur in one or both feet.
Patients should seek medical care if they notice these changes or if walking feels harder than usual. A neurologist or physical therapist an diagnose foot drop during a physical exam. The clinician will observe how a person walks and check the leg and foot muscles for signs of weakness.
In some cases, imaging tests such as X-rays, ultrasounds, or MRI scans may also be ordered to aid in diagnosing foot drop.
How is foot drop treated?
Foot drop in MS often cannot be fully reversed, but the symptom can usually be managed with treatment and lifestyle modifications. Finding the right approach for each person may involve some trial and error.
Some treatment options that may be considered include:
- Physical therapy: Strengthening and stretching exercises can improve mobility and help compensate for weakness or spasticity that contributes to foot drop.
- Occupational therapy: An occupational therapist can help patients develop strategies to make daily activities easier, recommend home adaptations, and demonstrate how to use mobility tools effectively.
- Ankle-foot orthosis (AFO): Orthotic braces or splints, which can be purchased off-the-shelf in a store or custom-made, hold the foot and ankle in a neutral or slightly lifted position to prevent the foot from dropping down during walking.
- Functional electrical stimulation (FES): An FES is a small device that delivers electrical pulses to the peroneal nerve, which innervates the tibialis anterior and other muscles in the lower leg, prompting the correct muscles to contract during each step.
While AFO and FES can both be effective in improving mobility, the choice between them depends on several factors.
On one hand, a leg brace for MS foot drop is typically less expensive and easier to use than electrical stimulation devices. On the other hand, FES enables the active use of muscles to produce a more natural walking pattern, without the need for a brace. Importantly, though, FES may not be effective if the targeted nerves are too severely damaged.
In cases where these conservative management approaches don’t work, and there is severe ankle weakness due to MS, surgery to fuse the ankle and foot bones may be considered, although this is rare in MS.
Tips for avoiding falls
To reduce the risk of tripping and falling, people with foot drop can take several practical steps:
- Optimize the home environment: Walking paths around the home should be clear of items that could be tripped over, such as electrical cords, throw rugs, or other clutter. Ensuring good lighting throughout the house can also make obstacles easier to spot.
- Wear appropriate footwear: Well-fitting and comfortable shoes that stay secured on the feet can help support the feet and leg muscles and make it easier to move around.
- Use a “scan and plan” strategy: Before starting to walk, it can help to look ahead and plan the safest route. Once moving, people should take their time and stay aware of their surroundings to avoid hazards.
- Use assistive devices: If recommended by a healthcare provider, mobility aids such as canes, walking sticks, or walkers can provide added stability and support. Handrails should also be used when going up or down stairs.
Multiple Sclerosis News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.
