A morton’s neuroma (or an “inter-digital” neuroma) is found between the toes of the foot, most commonly the third and fourth toes. It can also occur between the metatarsal bones (the long bones in the forefoot). It is basically an entrapped nerve, which becomes inflamed due to constant irritation from the surrounding bony structures.
There are a number of common causes for Morton?s Neuroma, (though the condition can arise spontaneously for reasons still unknown). The Neuroma often occurs in response to irritation, pressure or traumatic injury to one of the digital nerves leading to the toes. A thickening of nerve tissue results as part of the body?s response to the irritation or injury. Abnormal foot movement used to compensate for bunions, hammertoes, flatfeet and other conditions can lead to irritation and development of Morton?s Neuroma. Pronation of the foot may cause the heads of the metatarsal bones to rotate slightly, thereby pinching the nerve running between the metatarsal heads. Chronic pressure or pinching causes the nerve sheath to enlarge, becoming increasingly squeezed, producing worsening pain over time, if not addressed. Morton?s Neuroma can be exacerbated when tight shoes providing little room for the forefoot are worn. Activities which over-pronate the foot (such as walking barefoot in sand) may increase the pain associated with Morton?s Neuroma, as will any high-impact activity, such as jogging.
Neuroma patients occasionally complain of a ?pins and needles? sensation that spreads through their feet, or of a feeling akin to hitting their ?funny bone.? The sensation may be described as similar to an electric shock. Some patients also say that these symptoms, as well as those listed above, will come and go, depending on what they are wearing on their feet, the activity they are doing, or on other external factors.
The diagnosis of interdigital neuroma is usually made by physical examination and review of the patient’s medical history.MRI ad High Definition Ultrasound examination may be useful to confirm the diagnoses however they may still not be 100% reliable. The commonest reason for this is de to natural substances present in between the metatarsal heads and between the fat pad and the intermetatarsal ligament. These natural substances i.e. bursa, fat, capsular thickening and even bony growths, can all be a factor in the impingement process and may need to be surgically cleared.
Non Surgical Treatment
The good news is that the pain can often be relieved fairly easily with the right softer styled orthotic (even in those cases where there is concurrent plantar plate tears and capsulitis!), but its important to remeber that even if your no longer in pain, there is no magic cure to speeding up the healing process so one must take care of their feet for 6-12 weeks. As a rule of thumb a neuroma should always be treated conservatively where possible. This means icing and resting the area, trying to remove the causative factors, and providing postural control and support via metatarsal domes or, if needed, specialised pre-made or custom made orthotics.
About one person in four will not require any surgery for Morton’s neuroma and their symptoms can be controlled with footwear modification and steroid/local anaesthetic injections. Of those who choose to have surgery, about three out of four will have good results with relief of their symptoms. Recurrent or persisting (chronic) symptoms can occur after surgery. Sometimes, decompression of the nerve may have been incomplete or the nerve may just remain ‘irritable’. In those who have had cutting out (resection) of the nerve (neurectomy), a recurrent or ‘stump’ neuroma may develop in any nerve tissue that was left behind. This can sometimes be more painful than the original condition.
Wearing shoes that fit properly and that have plenty of room in the toe area may help prevent Morton’s neuroma.