We offer advanced 3D gait analysis and biomechanical assessments in our dedicated state of the art gait laboratory – see www.gaituk.com for more information.
Biomechanical Causes
Why should a patient's walking style (gait) be considered in Morton's neuroma?
In order to manage Morton’s neuroma, it’s important that we understand and treat the mechanical factors that lead to the condition.
Some people can wear high-heeled shoes all day without ever suffering from a neuroma. Others develop the condition whilst hardly ever wearing such footwear. So why is this?
The explanation lies in understanding the structure of the foot through biomechanics and gait analysis. This is why we offer highly advanced gait (walking and running) assessments in our dedicated 3D gait laboratory – one of the most advanced of its kind anywhere in the world today.
A number of treatments, such as injection therapy and cryosurgery, can address the symptoms of Morton’s neuroma. But if the underlying biomechanical cause is not addressed, there is a greater risk that the condition will recur. Morton's neuroma also often develops because of abnormal biomechanical stress through the foot. This can lead to other conditions such as bursitis and arthritis.
These in-depth biomechanical and gait assessments can sometimes avoid the need for surgery altogether and prevent the condition from recurring.
Examples of the many possible biomechanical causes of neuromas and interdigital nerve irritation include:
First metatarsal instability
There are many reasons why the first metatarsal can become unstable. These include abnormal pronation (where the foot arch drops and the ankle collapses excessively when walking or running), bunions, hallux limitus (a stiff big toe joint) and foot hypermobility (double-jointedness).
With an unstable metatarsal, not enough pressure passes through the joint of the big toe. This overloads the adjacent metatarsals and can result in a neuroma forming.
As part of our gait analysis service, we use an advanced method of measuring in-shoe pressure to detect this type of overload. Changing these pressures so they fall within a normal range is a key part of the treatment we can provide.
Lesser toe deformities
Lesser toes (i.e. all toes other than the big toe) can retract due to various and often inherited causes, such as a foot with reduced upward ankle motion (‘ankle equinus’). In this case, the ‘fat pad’ under the ball of the foot moves and the forefoot becomes overloaded, which causes a neuroma to form.
In other cases, underlying conditions such as rheumatoid arthritis may cause the fat pad to move. Specific types of orthoses can encourage the fat pad to sit back under the ball of the foot.
Non-foot related causes
Various abnormalities elsewhere in the body can cause excessive stress on the forefoot, resulting in a neuroma. For example, having legs of different lengths will create greater force on one side over the other.
A difference in leg lengths can also provoke back pain and sciatica, which in turn can agitate the nerves between the toes. A change in the position of the hip, knee or pelvis will alter the way the foot interacts with the ground, which often causes metatarsal instability.
Abnormal pronation
Abnormal pronation occurs when the foot arch remains flat for too long and the ankle collapses into a position, known as ‘eversion’. Typically this results in bulging at the inside of the ankle.
Using our 3D analysis system we can measure such movement very accurately (see an image of our 3D multi-segmental analysis to the right).
We also provide advanced kinetic techniques using our pressure measuring technology to further assess foot function.
Abnormal pronation, which causes the forefoot to become unstable, together with excessive metatarsal movement can provoke a shearing stress on the nerve and lead to the formation of a neuroma.
Specially designed orthoses can help with pronation issues and deal with Morton’s neuroma symptoms. Just as not all reading glasses are the same, the design and sophistication of orthoses vary according to a patient’s needs and the manufacturing method. For this reason, we may still recommend that a patient tries orthoses if they have previously used models that we consider to be inappropriate.
