Overview
Morton neuromas are focal areas of symptomatic perineural fibrosis around a plantar digital nerve of the foot. The abnormality is non-neoplastic and does not represent a true neuroma. It may more correctly be known as Morton?s metatarsalgia. The condition is thought to be due to chronic entrapment of the nerve by the intermetatarsal ligament. It most often occurs in middle-aged individuals and is many times more common in women than men. Approximately 30% of asymptomatic middle-aged persons have the radiological pathologic findings of a Morton?s neuroma.
Causes
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.
Symptoms
Morton?s neuroma is a progressive condition which means the symptoms typically get worse over time. Initially people often complain of a tingling or numbness at the base of their toes, typically in the space between the third and fourth toes, or, less commonly , between the second and third toes, which feels a bit like pins and needles. Over time the pain progresses and can feel like a stabbing or burning sensation in the ball of the foot under the toes. Some describe it as feeling as if they are standing on a stone. Normally the pain will get worse when you wear tight fitting shoes. Doing exercise that impacts on the foot such as jogging can also make the symptoms worse. The extent of the pain varies from person to person but in some cases it can be so intense that every step can feel acutely painful.
Diagnosis
Patients with classic Morton?s neuroma symptoms will have pain with pressure at the base of the involved toes (either between the 2nd and 3rd toes, or between the 3rd and 4th toes). In addition, squeezing the front of the foot together can exacerbate symptoms. As well, they may have numbness on the sides of one toe and the adjacent toe as this corresponds with the distribution of the involved nerve.
Non Surgical Treatment
In developing a treatment plan, your foot and ankle surgeon will first determine how long you?ve had the neuroma and evaluate its stage of development. Treatment approaches vary according to the severity of the problem. For mild to moderate neuromas, treatment options may include Padding techniques provide support for the metatarsal arch, thereby lessening the pressure on the nerve and decreasing the compression when walking. Placing an icepack on the affected area helps reduce swelling. Custom orthotic devices provided by your foot and ankle surgeon provide the support needed to reduce pressure and compression on the nerve. Activities that put repetitive pressure on the neuroma should be avoided until the condition improves. Wear shoes with a wide toe box and avoid narrow-toed shoes or shoes with high heels. Oral nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, may be recommended to reduce pain and inflammation. Treatment may include injections of cortisone, local anesthetics or other agents.
Surgical Treatment
When conservative measures are unsuccessful, surgery can be a good choice in the treatment of Morton’s neuroma. The operation for Morton’s neuroma does not require an overnight hospital stay. The anesthetic used is an ankle block, which completely numbs the foot during the surgery. The physician removes the neuroma from an incision made on the top of the foot between the involved metatarsal heads. The nerve to the interspace is exposed and cut next to the metatarsal heads.
Prevention
Wearing shoes that fit properly and that have plenty of room in the toe area may help prevent Morton’s neuroma.
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