Do you have Foot Drop?

If so, read on. This article aims to explain what foot drop is, what causes it and how to recover from it.

Foot drop is one of the most common types of nerve injury to occur in young and middle aged people. It is a common problem for injured bikers and can cause difficulties with walking and getting back on a bike. Fortunately it can be treated with therapy, surgery or prosthetics, and bikes can be easily adapted to enable the biker to safely ride again.

Foot drop is caused by damage to the common peroneal nerve, which is a branch of the sciatic nerve, which comes out of the lower spine. The common peroneal nerve lies on the outside and back of the knee joint. It travels forwards and downwards to supply the muscles and skin on the front and outside of the lower leg with movement and feeling.  It is the proximity of the nerve to the surface and the bone underneath it which makes it vulnerable to damage. In biking accidents it can be damaged when the lower leg bones are broken or dislocated. Or, if the leg is wrenched into an awkward position, the nerve can be overstretched.

When the common peroneal nerve is damaged it may often be missed by doctors in casualty due to more serious injuries which require immediate medical treatment, such as fractures, lacerations or burns. The problem may only be discovered when a plaster of paris is removed or the biker first starts to stand and walk. The exception to this is when the damaged nerve causes nerve pain; for those readers who have experienced nerve pain (or neuropathic pain to give it its proper title) they will agree that the pain is excruciating- like terrible tooth ache magnified 100 times. Neuropathic pain can keep sufferers awake at night and begging for the leg to be amputated. Fortunately there are now effective painkillers specifically for neuropathic pain which can reduce the pain in combination with other medication. Nerve injections are also successful.

However, the main functional problem of common peroneal nerve damage is the inability to move the foot up or outwards from the ankle. This causes the sufferer to adopt a high stepping gait, an asymmetrical posture in standing (the affected leg is held turned outwards and the person leans to the unaffected side) and their balance is significantly affected such that they can easily fall backwards or trip. The feeling in the outer lower leg is reduced or absent causing the skin to be vulnerable to abrasions or burns which may go unnoticed until they become infected.

In day to day life, foot drop can present many practical problems to the sufferer. Obviously their walking will be slower and more effortful such that they cannot walk as far as usual. Their balance is poor so uneven surfaces such as pavements, kerbs or slopes become a challenge which requires a lot of concentration to deal with; sufferers struggle to do anything else at the same time as walking such as talking, carrying bags or holding hands. Falls, trips and twisting or going over on the weak ankle can become part of normal life.

So, what help is available? Usually the first option is to give the sufferer a support for the ankle. These are called ankle-foot orthoses (AFOs for short). This can be a fabric brace to reduce the risk of twisting the ankle, a solid L shaped plastic brace which is worn in the shoe and stops the foot dropping down, or a fabric cuff worn around the ankle with a connecting hook and spring worn in the shoe to lift the foot up. Lightweight graphite AFOs are now available which are very comfortable and easy to wear. However climbing stairs can be awkward and driving/riding can be difficult. AFOs are available “off the shelf” in different sizes or some hospitals offer a custom made service where the person is measured, a cast of their ankle and foot taken and an AFO made to fit them snugly. Sometimes an insert for the shoe to correct the foot position when walking is recommended.

From the medical side of treatment, tests to determine the degree of nerve damage are carried out; these are called nerve conduction tests. If the nerve is not conducting at all, then surgery is offered. This is highly specialised and skilled nerve grafting surgery or tendon transfer surgery. Both have a long rehabilitation period. If the nerve is conducting then recovery may take place naturally and a complete or partial recovery is possible without surgery.

Physiotherapy is usually offered to all foot drop sufferers, whatever the medical or surgical treatment. An assessment is carried out where the amount of ankle movement is measured, balance and walking are observed and the muscles and joints are examined. A classis test for foot drop is to ask the patient to rock back on their heels and measure how far the toes and foot can lift up.

At The Nerve Injury Clinic we assess the nerve activity directly using surface electromyography (SEMG). SEMG involves attaching stick on electrodes to the skin over the weak muscles and asking the person to attempt to move the foot and ankle. We can see the level of nerve activity immediately on the computer screen and this is shown to the patient. This information shapes the physiotherapy offered. If there is reasonable nerve activity then treatment will focus upon strengthening the weak muscles. If there is minimal nerve activity then a muscle stimulator is recommended and we set the patient up with one for daily home use. This will improve the muscle condition and facilitate nerve recovery.

Physiotherapy should always address the abnormal ankle posture, preventing the calf muscles tightening and shortening and re-educating normal balance and walking. Other techniques such as taping the ankle or foot with sports tape (seen in the 2012 Olympics on athletes where brightly coloured tape was used), exercise using bikes or treadmills and upper leg and body strengthening are also useful.

Rehabilitation with a specialist physiotherapist is essential for maximal recovery. There are many complications which can occur as a result of foot drop; these include muscle contractures, pressure sores and pain elsewhere in the body due to compensatory movements (eg leaning to one side, twisting the hip etc). These complications can slow down recovery and can be easily avoided. Recovery can take anywhere between six weeks and three years after injury. However I have treated people many years after their injury and had success in improving their movement, balance anf function.

Peripheral nerve treatment is a fast growing field of surgery, medicine and physiotherapy. Teams of specialist doctors, surgeons, physiotherapists and orthotists are forming around the country whose aim is to help drop foot sufferers. So if you are still suffering with drop foot and want some up to date advice then CONTACT US