Mortons Neuroma Causes

Overview

Morton’s metatarsalgia is a condition associated with a painful neuroma* on the digital nerve causing pain in the foot. Charcterised by perineural fibrosis and nerve degeneration due to repetitive irritation, is thought to be due to irritation of the digital nerve caused by repeated trauma, ischemia or entrapment of the nerve, occurs most frequently in women aged 40-50 who wear high-heeled, pointed-toe shoes. The neuroma occurs at the level of the metatarsal necks. The common digital nerve to the third/fourth metatarsal spaces is most often affected, although other interspaces can be involved.

Causes

Occupational hazards. Individuals whose jobs place undue stress on their forefeet (with or without wearing improper footwear) are among those who complain of neuromas. Podiatric physicians report that individuals who work on ladders, or who perform activities on their knees (such as doing landscaping, carpeting, flooring, or other work on the ground) are at risk for this problem, too, since these activities cause stress to the nerve near the ball of the foot. Those who engage in high-impact activities that bring repetitive trauma to the foot (running, aerobics, etc.) have a better than average chance of developing a neuroma at the site of a previous injury. To put it more simply, if you have sustained a previous injury to your foot (a sprain, stress fracture, etc.), that area of your foot will be more prone to neuroma development than an area that has not been injured. However, sports injuries aren?t automatically a ticket to neuromas. Trauma caused by other forms of injury to the foot (dropping heavy objects, for example) can also cause a neuroma to develop at the site of the previous injury. Much though we hate to say it, sometimes neuromas just develop and nobody knows why. The patient doesn?t have a previous injury, is wearing properly fitted shoes, and doesn?t stress his/her feet with any specific activity but the neuroma develops anyway. It is important to remember that some of the factors listed above can work alone, or in combination with each other, to contribute to the formation of neuroma.

Symptoms

Symptoms of interdigital neuroma typically manifest as a sharp, burning or tingling sensation in the forefoot. The pain radiates toward the lesser toes and is aggravated by shoe wear. The pain is relieved when the shoe is removed and the forefoot is massaged. Sometimes the symptoms involve specific toes.

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

Initial treatment for Morton?s Neuroma may include non-prescription anti-inflammatory medications to reduce pain and swelling. These may consist of standard analgesics such as aspirin and ibuprofen (Advil, Motrin, others). Massaging the painful region three times daily with ice. Change of footwear. Avoid tight shoes, high heels or any footwear that seems to irritate the condition. Low heeled shoes with softer soles are preferable. Arch supports and foot pads to help reduce pressure on the nerve. In some cases, a physician may prescribe a customized shoe insert, molded to fit the contours of the patient?s foot. Reducing activities causing stress to the foot, including jogging, dancing, aerobic activity or any high impact movements of the foot. Injections of a corticosteroid medication to reduce the swelling and inflammation of the nerve and reduce pain. Occasionally other substances may be injected in order to ?ablate? the Neuroma. (The overuse of injected steroids is to be avoided however, as side effects, including weight gain and high blood pressure can result.)

Surgical Treatment

Surgical treatment has provided relief in some cases while poor results and surgical complications have resulted in other cases. It is believed that ligament weakness, as opposed to the pinching of nerves in the foot, may be to blame for recurrent pain in these situations. For reasons which are not fully understood, the incidence of Morton?s Neuroma is 8 to 10 times greater in women than in men.

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