Neuroma (Morton’s neuroma)

If you sometimes feel that you are "walking on a marble," and you have persistent pain in the ball of your foot, you may have a condition called Morton's neuroma. This is a benign tumor of a nerve. Morton's neuroma is not actually a tumor, but a thickening of the tissue that surrounds the digital nerve leading to the toes. It occurs as the nerve passes under the ligament connecting the toe bones (metatarsals) in the forefoot. Morton's neuroma most frequently develops between the third and fourth toes, usually in response to irritation, trauma or excessive pressure. The incidence of Morton's neuroma is 8 to 10 times greater in women than in men.

Normally, there are no outward signs, such as a lump, because this is not really a tumor and the nerve is deep within the foot. The most common symptom is burning pain in the ball of the foot that may radiate into the toes which may intensify with activity or wearing shoes and there may also be numbness in the toes, or an unpleasant feeling in the toes. Runners may feel pain as they push off from the starting block. High-heeled shoes, which put the foot in a similar position to the push-off, can also aggravate the condition. Tight, narrow shoes also aggravate this condition by compressing the toe bones and pinching the nerve. Examination usually reveals a mass that can be felt between the toes and a "click" may occur when pressure is applied between the bones which may replicate the pain. Other conditions will also be excluded by examine and x-rays.

Treatment generally involves changes in footwear with the avoidance of high heels or tight shoes, allowing the bones to spread out and may reduce pressure on the nerve, giving it time to heal, custom or over-the-counter shoe inserts and pads also help relieve irritation by lifting and separating the bones, reducing the pressure on the nerve, and on occasion, and injection of a corticosteroid medication to reduce the swelling and inflammation of the nerve. If conservative treatment does not relieve your symptoms, surgery may be considered. This specifically involves resecting a small portion of the nerve and release the tissue and ligaments overlying the nerve. This procedure can be preformed under ankle block anesthetic (local anesthetic), is done as an outpatient, and involves 2 weeks in a rigid orthopaedic shoe with immediate weight bearing and transition to a regular shoe as soon as swelling allows.

Modified from the AAOS