Treatments for foot drop compared


20 August 2019

The study in brief

Foot drop can be treated using two types of device. Functional electrical stimulation (FES) uses small electrical charges to the muscles of the lower leg to force the foot into a more natural position for walking. An ankle-foot orthosis (AFO) is a device made of plastic or carbon fibre that holds the foot and ankle in a correct position to prevent the foot from dropping down during walking.

There’s been very little research comparing the two devices, so this study aimed to compare the effectiveness and relative costs of AFO and FES in people with MS.

Seventy nine people were recruited from seven centres in Scotland and randomly assigned to be fitted with an AFO or an FES. The impact of the device was measured at the start, 3, 6 and 12 months.

The relatively small number of participants and the high drop out rate (38%) made it difficult to draw firm conclusions from the study. Both groups walked faster when wearing their devices at 12 months, with neither of the devices showing a clear advantage over the other. There was no evidence that either device had a therapeutic effect, that is, improved unassisted walking performance. Overall, results suggested that AFO devices were less acceptable to people with MS; the researchers conclude that both the physical and psychological impact of a device needs to be taken into account as both these contribute to someone’s willingness to keep using a device.

The study in more detail

Background

Foot drop is a symptom experienced by some people with multiple sclerosis. It is caused by a disruption in the nerve pathway to and from the brain, which makes it difficult to lift the foot and toes properly when walking.  As a result, your foot tends to catch or drag along the ground, increasing the risk of tripping or falling.  People often change their walking style to compensate for this, leading to extra wear on joints and increasing the effort of walking.

Foot drop can be treated using two types of device. Functional electrical stimulation (FES) uses small electrical charges to the muscles of the lower leg to force the foot into a more natural position for walking. An ankle-foot orthosis (AFO) is a device made of plastic or carbon fibre that holds the foot and ankle in a correct position to prevent the foot from dropping down during walking.

There’s been very little research comparing the two devices, so this study aimed to compare the effectiveness and relative costs of AFO and FES in people with MS.

How this study was carried out

The researchers recruited 79 people with foot drop caused by MS from seven centres in Scotland. Participants were excluded if they had previously used either of the devices.  Participants were randomly assigned to be fitted with a custom-made AFO or with an FES.  They were instructed to gradually increase the wear of their devices over the first 6 weeks. 

The impact of the device on walking was measured at the start, 3, 6, and 12 months.  The main measure of the study was walking speed, calculated from the distance walked in five minutes at the person’s preferred pace.  Additional measures included the amount of oxygen taken up while walking and the time taken to walk 25 feet.  Participants also completed questionnaires to measure the impact of MS and the device on symptoms, quality of life, independence and well-being.

What was found?

Both groups walked faster when wearing their devices at 12 months, with neither of the devices showing greater improvement than the other.  None of the other measures showed a clear, consistent advantage of one device over the other.  There was no evidence from the study that either device had a therapeutic effect ie resulted in an improvement in unassisted walking. 

Over the 12 months, 37 people (38%) dropped out of the study for a variety of reasons.  Although there was no statistically significant difference between the groups, the proportion of drop outs was higher in the AFO group, and most of these because they were unhappy with the device.

The FES group gave significantly higher scores for a questionnaire which assessed the impact of wearing a device on quality of life and sense of well-being (Psychological Impact of Assistive Devices Scale).  This indicated that FES was more acceptable to wearers than AFO.

What does it mean?

The relatively small number of participants completing the study (22 of 43 AFO, 31 of 42 FES) means it is difficult to draw definite conclusions.  Overall, both types of device improved walking speed, although neither device appeared to improve unassisted walking. 

For some people, assistive devices can be viewed as a symbol of disability, a loss of independence and altered self-image.  Some participants in the AFO group reported that wearing their device emphasised their disability and this may have contributed to the higher drop out rate seen in this group, reflected in the lower scores for the psychological impact questionnaire.  The researchers acknowledged that the lower acceptance of the AFO devices may have been caused, at least in part, by the rigid design of the orthosis that was used as a standard across the seven centres; allowing physiotherapists to prescribe an orthosis more suitable for individual participants might have improved acceptance.  However, the researchers point out that both the physical and psychological impact of a device need to be taken into account in clinical studies as both these are important factors for continued use of the device. 

The researchers conclude that despite higher initial costs of FES, it offers value for money as an alternative to the more routinely used ankle-foot orthoses.

Renfrew LM, Paul L, McFadyen A, et al.
The clinical- and cost-effectiveness of functional electrical stimulation and ankle-foot orthoses for foot drop in multiple sclerosis: a multicentre randomized trial.
Clin Rehabil. 2019 Apr 11:269215519842254.
Summary

More about walking problems, orthoses and functional electrical stimulation

Many people with MS have some difficulties with walking but walking problems vary considerably from one person with MS to another. Common difficulties include: unsteadiness on walking or turning, tripping, stumbling, weakness of the leg when weight is on it and difficulty placing the foot on the ground. Other MS symptoms can also make walking more difficult, such as vision problems, balance problems and pain. Having trouble walking can mean people with MS are more vulnerable to tripping and falling. It can also use up more energy, making fatigue worse, and people may alter how they walk to try and compensate for the difficulty they are having. This alteration in walking can result in bad posture which can lead to pain and strains.

If you are experiencing walking difficulties, you can speak to your MS nurse or GP who may refer you to physiotherapy services. The best way forward depends on what is causing the difficulties. Treatment may involve physiotherapy or drug treatments to alleviate specific underlying symptoms such as spasticity or pain.

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