Interdigital neuroma (sometimes called a Morton’s neuroma) is the medical term for a painful growth in the forefoot. The pain is most commonly felt between the third and fourth toes but can also occur in the area between the second and third toes.
The most common cause of pain is thought to be irritation on the nerve. The chronic nerve irritation is believed to cause the nerve to scar and thicken, creating the neuroma. Many foot surgeons feel that the problem may arise because the metatarsal bones squeeze in on the nerve, and the ligament that joins the two bones irritates, or entraps, the nerve. Entrapment of the nerve that is in the space between the toes is thought to lead to the chronic irritation and pain you are experiencing.
The pain occurs most often in the ball of the foot when weight is placed on the foot. Many people with this condition report feeling a painful catching sensation while walking, and many report sharp pains that radiate out to the two toes where the nerve ends. There may be swelling between the toes or a sensation similar to having a rock in the shoe. This can feel like electric shocks, similar to hitting the funny bone of the elbow. Although it’s not life-threatening, this condition can be very disabling.
Treatment usually begins with changes in shoe wear. Sometimes simply moving to a wider shoe will reduce or eliminate the symptoms. A firm, crepe-soled shoe may help. The firm sole decreases the amount of stretch in the forefoot as the affected person takes a step. This lessens the degree of irritation on the nerve.
A special metatarsal pad can also be placed within the shoe under the ball of the foot. It sounds like this is what you are trying out now. The pad is designed to spread the metatarsals apart and take pressure off the neuroma. These simple changes to your footwear may allow you to resume normal walking immediately. But with the continued pain you are reporting, you may want to try cutting back more on activities for several weeks to allow the inflammation and pain to subside.
Other treatments directed to the painful area can help control pain and swelling. Examples include ultrasound, moist heat, and soft-tissue massage administered by a physical therapist. Physical therapy sessions sometimes include iontophoresis, which uses a mild electrical current to push anti-inflammatory medicine to the sore area. This treatment is especially helpful for patients who can’t tolerate injections. For those who can handle an injection, a combination of lidocaine and cortisone into the area may help temporarily relieve symptoms.