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.
A Morton's neuroma commonly occurs due to repetitive weight bearing activity (such as walking or running) particularly when combined with tight fitting shoes or excessive pronation of the feet (i.e. "flat-feet"). The condition is also more common in patients with an unstable forefoot allowing excessive movement between the metatarsal bones. A Morton's neuroma can also occur due to certain foot deformities, trauma to the foot, or the presence of a ganglion or inflamed bursa in the region which may place compressive forces on the nerve.
Symptoms typically include pain, often with pins and needles on one side of a toe and the adjacent side of the next toe. Pain is made worse by forefoot weight bearing and can also be reproduced by squeezing the forefoot to further compress the nerve. Pressing in between the third and forth metatarsals for example with a pen can also trigger symptoms.
Based on the physical examination, your doctor usually can diagnose a Morton's neuroma without additional testing. A foot X-ray may be ordered to make sure that there isn't a stress fracture, but it will not show the actual neuroma. If the diagnosis is in doubt, your doctor may request magnetic resonance imaging (MRI) of the foot.
Non Surgical Treatment
Relief of symptoms can often start by having a good pair of well fitting shoes fitted to your feet ensuring that the shoes don't squeeze your foot together. Once footwear is addressed patients may require a small pre-metatarsal pad to be positioned onto the insole of the shoe to help lift and separate the bones in the forefoot to alleviate the pressure on the nerve. If the patients foot structure and mechanics is found to be a contributing cause, a custom made orthotic is usually the most convenient and effective way to manage the problem. Sometimes an injection of local anaesthetic and steroid is recommended to assist in settling acute symptoms.
If pain persists with conservative care, surgery may be an appropriate option. The common digitial nerve is cut and the Mortons neuroma removed. This will result is numbness along the inside of the toes affected, and there is a small chance the end of the nerve will form a Stump Neuroma. Approximately 75% of people receive symptom resolution for Mortons Neuroma with conservative care.