What Causes Mortons Neuroma

Overview

Morton's Neuroma is a common problem in runners, and there are a number of simple fixes you can try before resorting more drastic solutions like sclerosing or surgery. A Morton's Neuroma normally causes a burning pain in the forefoot, just behind the 3rd and 4th toes (sometimes behind the 2nd and 3rd toes). The pain often radiates towards the toes, and sometimes there is numbness rather than pain. The underlying cause is inflammation of the nerve between the bones of the forefoot, often triggered by narrow or tight shoes. I have had good results with the simple fixes described below, and I have had reports of other runners with similar success.

Causes

Although the exact cause for this condition is unclear, a number of factors can contribute to the formation of a neuroma. Biomechanical deformities, such as a high-arched foot or a flat foot, can lead to the formation of a neuroma. These foot types bring on instability around the toe joints, leading to the development of the condition. Trauma can cause damage to the nerve, resulting in inflammation or swelling of the nerve. Improper footwear that causes the toes to be squeezed together is problematic. Avoid high-heeled shoes higher than two inches. Shoes at this height can increase pressure on the forefoot area. Repeated stress, common to many occupations, can create or aggravate a neuroma.

Symptoms

Often, no outward signs (such as a lump or unusual swelling) appear from the condition. Neuroma pain is most often described as a burning discomfort in the forefoot. Aching or sudden shooting pain in the forefoot is also common. All running sports, especially distance running can leave an athlete vulnerable to Morton?s Neuroma, which may appear or flare up in the middle of a run or at the end. The sufferer often has the desire to remove his shoe and rub the afflicted foot. Should the Neuroma be of sufficient size, or if footwear is particularly tight or uncomfortable, the painful condition may be present during normal walking. Numbness in the foot may precede or accompany Neuroma pain.

Diagnosis

Plain x-rays of the foot may demonstrate that one or more of the metatarsals are long (Figure #5). Not uncommonly, the second and/or third metatarsal may be long relative to the third or fourth. This can create a situation where excessive load is occurring in and around the vicinity of the interdigital nerve.

Non Surgical Treatment

In most cases, initial treatment for this condition consists of padding and taping to disperse weight away from the neuroma. If the patient has flatfeet, an arch support is incorporated into footwear. The patient is instructed to wear shoes with wide toe boxes and avoid shoes with high heels. An injection of local anesthetic to relieve pain and a corticosteroid to reduce inflammation may be administered. The patient is advised to return in a week or 2 to monitor progress. If the pain has been relieved, the neuroma is probably small and caused by the structure of the patient's foot and the type of shoes the patient wears. It can be relieved by a custom-fitted orthotic that helps maintain the foot in a better position. Another type of therapy that may be used is alcohol sclerosing injections. In this treatment, the doctor injects a small amount of alcohol in the area of the neuroma area to help harden (sclerose) the nerve and relieve the pain. Injections are given every 7-10 days and, in many cases, 4-7 injections are needed for maximum relief. Please ask your physician for more information regarding this type of treatment.

Surgical Treatment

Operative treatment of Morton?s neuroma should be entertained only after failure of non-operative management. Standard operative treatment involves identifying the nerve and cutting (resecting) it proximal to the point where it is irritated/injured. This is usually done through an incision on the top (dorsal) aspect of the foot, although an incision on the sole (plantar) aspect of the foot can be used. Some physicians will attempt to treat Morton?s neuroma by releasing the intermetatarsal ligament, and freeing the nerve of local scar tissue. This may also be beneficial.