During certain activities, particularly weight-bearing activities (e.g. walking or running) a compressive force, is sometimes placed on the interdigital nerves and surrounding soft tissue, between the metatarsal bones (this is often the case with tight fitting shoes or in patients with flat feet). If this force is repetitive enough and beyond what the nerve and soft tissue can withstand, swelling to the nerve and soft tissue may occur. This may result in pain, tenderness, pins and needles or numbness in the forefoot or toes. When this happens, the condition is known as a Morton’s neuroma.
Various factors have been implicated in the precipitation of Morton’s neuroma. Morton’s neuroma is known to develop as a result of chronic nerve stress and irritation, particularly with excessive toe dorsiflexion. Poorly fitting and constricting shoes (ie, small toe box) or shoes with heel lifts often contribute to Morton’s neuroma. Women who wear high-heeled shoes for a number of years or men who are required to wear constrictive shoe gear are at risk. A biomechanical theory of causation involves the mechanics of the foot and ankle. For instance, individuals with tight gastrocnemius-soleus muscles or who excessively pronate the foot may compensate by dorsiflexion of the metatarsals subsequently irritating of the interdigital nerve. Certain activities carry increased risk of excessive toe dorsiflexion, such as prolonged walking, running, squatting, and demi-pointe position in ballet.
Patients with a Morton’s neuroma typically experience a sharp, shooting or burning pain, usually at the base of the forefoot or toes, which radiates into the two affected toes. Sometimes the pain may also radiate into the foot. The pain is often associated with the presence of pins and needles and numbness.
X-rays of your affected foot will not show a neuroma, as neuromas are made up of soft tissue. X-rays may be helpful, however, in helping rule in osteoarthritis or a stress fracture as the cause of your symptoms. Ultrasonography and MRI are sometimes used to help diagnose neuromas, although they are often ineffective. The clinical diagnosis by a foot care expert with experience treating this health problem is usually the most effective way to diagnose neuromas. Your podiatrist will attempt to duplicate your neuroma symptoms by pressing on the involved nerve at various points, and he or she may try to cause a clicking of your nerve that indicates nerve enlargement.
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.)
Majority of publications including peer review journal articles, surgical technique description and textbooks promote surgical excision as a gold standard treatment. Surgical excision is described as the most definitive mode of treatment for symptomatic Morton?s neuroma with reported success rates varying between 79% and 93%. Various surgical techniques are described, essentially categorised as dorsal versus plantar incision approaches. Beyond this the commonest technical variation described as influencing the outcome of surgery involves burying and anchoring transacted nerve into soft tissue such as muscle.