A Morton's neuroma, or interdigital neuroma, is a painful condition which involves a nerve on the plantar aspect (bottom) of the foot. Occasionally a neuroma develops following a bruising injury to the sole of the foot, such as might be caused by jumping onto a rock or other objects, but in general, the origin of the condition is unknown.
Anything that causes compression or irritation of the nerve can lead to the development of a neuroma. One of the most common offenders is wearing shoes that have a tapered toe box, or high-heeled shoes that cause the toes to be forced into the toe box. People with certain foot deformities - bunions, hammertoes, flatfeet, or more flexible feet - are at higher risk for developing a neuroma. Other potential causes are activities that involve repetitive irritation to the ball of the foot, such as running or court sports. An injury or other type of trauma to the area may also lead to a neuroma.
A Morton's neuroma causes a "burning" sharp pain and numbness on the bottom of the foot in the involved area, and this pain and numbness can radiate to the nearby toes. The pain is usually increased by walking or when the ball of the foot is squeezed together and decreased with massaging. It may force a person to stop walking or to limp from the pain.
The diagnosis of a Morton's neuroma can usually be made by the doctor when the history of pain suggests it and the examination elicits the symptoms. The foot is generally tender when the involved area is compressed and symptoms of pain and sometimes tingling can be elicited when the sides of the foot are squeezed. Magnetic resonance imaging (MRI) or ultrasound testing can be used to confirm the diagnosis if necessary.
Non Surgical Treatment
Orthotics and corticosteroid injections are widely used conservative treatments for Morton?s neuroma. In addition to traditional orthotic arch supports, a small foam or fabric pad may be positioned under the space between the two affected metatarsals, immediately behind the bone ends. This pad helps to splay the metatarsal bones and create more space for the nerve so as to relieve pressure and irritation. It may however also elicit mild uncomfortable sensations of its own, such as the feeling of having an awkward object under one's foot. Corticosteroid injections can relieve inflammation in some patients and help to end the symptoms. For some patients, however, the inflammation and pain recur after some weeks or months, and corticosteroids can only be used a limited number of times because they cause progressive degeneration of ligamentous and tendinous tissues.
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.