Drop Foot

Definition / Symptoms

Drop foot (also known as dropped foot, foot drop or floppy foot) refers to a weakening of those muscles that allow the ankle and toes to flex, causing difficulty in moving the ankle and toes upwards (dorsiflexion). This causes the individual to drag their toes while walking and to compensate by bending the knee and hip to lift the foot higher than usual, to prevent it from catching on the ground during the swing phase.

Symptoms/causes

While drop foot is a neuromuscular disorder that affects the nerves and muscles, it is not actually a disease in itself, but rather a symptom of some other medical problem.

If drop foot is caused by an injury or nerve damage, recovery is often possible. However, if it's caused by permanent nerve damage or a progressive neurological condition, such as multiple sclerosis, it will be a lifelong symptom to manage.

 

Risk Factors

The immediate risk factors involve tripping and falling. Clearly, this is to be avoided particularly in the older population that has a higher risk of further injuries, such as fractures.

Medium- to long-term risks of leaving drop foot untreated are problems related to the skeletal system. They involve pain in the forefoot, the collapse of the midfoot, hip and knee alignment problems and postural problems, which can cause back pain.

Complications and related diseases

Drop foot can lead to many other orthopaedic problems if left untreated. These can include metatarsalgia; flat foot; tightness in the calf and Achilles tendon; and hyperextension of the knee.

It will also make walking more difficult. Often patients complain of having to constantly look at the floor while walking, which is tiring. This can lead to postural problems such as a Kyphotic Posture.

 

Tests and Diagnosis

Assessment for drop foot requires a full biomechanical assessment. This includes: assessing joint ranges of movement; joint stability; muscle strength; standing posture and alignment; and a gait/walking assessment.

Orthotic Treatments

There are many different types of orthoses that can be used to treat drop foot. Some are very simple and purely deal with the drop foot. These can include some elasticated supports and the 'foot-up' device. 

Some are more advanced and will require a bespoke or made-to-measure device. These tend to involve an ankle foot orthoses (AFO), of which there are many different types depending on the exact biomechanical requirement. Different materials, such as plastic and carbon fibre offer different solutions. The basic aim of each design will be to control the foot drop during the swing phase part of the gait cycle and ensure that any initial contact with the ground occurs with heel contact. The bespoke options will also be designed to control the medial/lateral stability of the ankle, and ensure that the lower leg is prepositioned during the stance phase to allow as normal a gait pattern as possible.

Also, in some cases where the cause of the rrop foot is an upper motor neurone problem, Functional Electronic Stimulation (FES) may be recommended.

Choosing the correct orthosis is essential. Although some devices appear to resolve the short-term risk factors, such as tripping, they do not prevent the longer-term risks of orthopaedic damage.

At LOC, we will make sure you understand what your orthosis will and won’t do, and ensure that you receive the most appropriate orthosis for your particular condition. 

Further information / Reading / Links

NHS website

Wikipedia

 

FAQs:

An AFO is an Ankle Foot Orthosis which as the name would suggest encompasses the ankle and foot. The objective is to control the position and movement of the ankle. AFOs are used to support weak limbs; they can also be used to immobilise the ankle and lower leg to correct foot drop. When set up correctly they can also have a great influence on the knee and hip joints. They are the most commonly used Orthoses.

The length of time that one needs to wear an AFO very much depends on the condition being treated. If it is a long-term condition like cerebral palsy or post-polio syndrome it is likely to be years as the condition cannot be cured. Your orthotist will advise you.

A patient’s comfort in their AFO is vital for compliance with the prescribed wearing regime.

So there are a number of steps the orthotist should take to ensure a comfortable fit: the patient’s heel should fit fully into the heel cup without excess space, the contours of the plantar surface of the AFO should match the patient’s foot, for children there needs to be up to half an inch growth room in the toe shelf length. At LOC we use our Gait Laboratories at our Kingston and Manchester clinics to fine-tune our bespoke orthotics.

A GRAFO is used to control instabilities in the lower limb by maintaining proper alignment of limbs and controlling their motion. It reaches around to the front of the knee extending down to the ankle. It works by altering a patient’s limb presentation to displace load and impact as well as offering further control to the knee.

The cost of an AFO is dependent on the type of AFO that has been prescribed and the material that it has been made with. Carbon fibre will be more expensive than metal or plastic for example. LOC’s bespoke AFOs cost can be found on our Orthotic Prices page.

The ability to drive while wearing an AFO is dependent on the condition being treated and the orthosis that has been prescribed. If wearing a hinged AFO, for example, you will be able to drive, but if wearing a knee brace, you won’t. Your orthotist will advise you.

The most flexible type of AFO is a Dynamic Ankle Foot Orthosis (DAFO).  It is thin and provides flexible support to the foot and ankle.

Both normal AFOs and DAFOs improve static balance (eg: while standing). Research among MS sufferers suggests that DAFOs aided balance while walking more than AFOs.

The simple answer is: yes they can. However one has to be sensible and look for wide-fitting trousers/jeans preferably of light and thin material.

Typically an AFO is stiff and rigid whereas a DAFO is thin, flexible and wraps around the patient’s entire foot. A DAFO provides support but also allows some range of normal movement.

A Supra Malleolar Orthosis SMO gets its name from the part of the body it encompasses. Thus an SMO supports the leg just above the ankle bone or malleoli. It allows dorsiflexion and plantar flexion(toes up and toes down) but eliminates mediolateral movement.

It typically takes a few weeks but is slightly dependent on the chosen materials and current availability.

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