A neuroma develops when a nerve is compressed, injured or pinched, causing swelling and pain. A neuroma in the area between the third and fourth toes, or between the second and third toes, is known as a Morton?s neuroma. Morton?s neuroma causes sharp, burning pain and numbness in the toes and foot. You may feel like you?ve stepped on a tiny hot coal and can?t get rid of it. At the same time, you?ll have the disconcerting experience of not being able to feel your toes. Sometimes the nerve tissue becomes so thickened you can feel or see a lump.
A Morton?s Neuroma are a result of complex biomechanical changes that occur in your feet. There are a number of theories as to the exact cause of the scarring and thickening, but it basically boils down to overload of the tissue structure. The body lays down scar tissue to try to protect the overloaded structure. Tight-fitting shoes may exacerbate a Morton?s Neuroma. Shoes such as high heels and shoes with tight toe boxes (eg womens fashion shoes and cowboy boots) are particularly damaging to the toes. These shoes have a sloping foot bed and a narrow toe box. The slope causes the front of the foot to bear your weight. The angle of the toe box then squeezes your toes together. Footwear is not the only cause of a Morton?s Neuroma. Injuries to the foot can also be a factor in developing the condition by changing your foot biomechanics. Poor foot arch control leading to flat feet or foot overpronation does make you biomechanically susceptible to a neuroma.
The most common symptom of Morton’s neuroma is localized pain in the interspace between the third and fourth toes. It can be sharp or dull, and is worsened by wearing shoes and by walking. Pain usually is less severe when the foot is not bearing weight.
Negative signs include no obvious deformities, erythema, signs of inflammation, or limitation of movement. Direct pressure between the metatarsal heads will replicate the symptoms, as will compression of the forefoot between the finger and thumb so as to compress the transverse arch of the foot. This is referred to as Mulder?s Sign. There are other causes of pain in the forefoot. Too often all forefoot pain is categorized as neuroma. Other conditions to consider are capsulitis, which is an inflammation of ligaments that surrounds two bones, at the level of the joint. In this case, it would be the ligaments that attach the phalanx (bone of the toe) to the metatarsal bone. Inflammation from this condition will put pressure on an otherwise healthy nerve and give neuroma-type symptoms. Additionally, an intermetatarsal bursitis between the third and fourth metatarsal bones will also give neuroma-type symptoms because it too puts pressure on the nerve. Freiberg’s disease, which is an osteochondritis of the metatarsal head, causes pain on weight bearing or compression.
Non Surgical Treatment
Most non-operative treatment is usually successful, although it can take a while to figure out what combination of non-operative treatment works best for each individual patient. Non-operative treatment may include the use of comfort shoe wear. The use of a metatarsal pad to decrease the load through the involved area of the plantar forefoot. A period of activity modification to decrease or eliminate activities, which maybe exacerbating the patient?s symptoms. For example, avoiding long periods of standing or other activities that result in significant repetitive loading to the forefoot can be very helpful. Wearing high heels should be avoided. Local corticosteroid injections can help decrease inflammation associated with the nerve. However, this does not necessarily address the underlying loading forces that maybe causing the injury to the nerve in the first place. It has been proposed that an alcohol injection in and around the nerve will cause a controlled death to the nerve and subsequently eliminate symptoms from the nerve. In theory, this may be helpful. In practice, adequate prospective studies have not demonstrated the benefit of this procedure above and beyond the other standard non-operative treatments available. In addition there is the concern that the alcohol will cause excessive scarring and death of other important structures in the area.
When medications or other treatments do not work, podiatric surgery may be required. The most common surgical procedure for treating Morton?s neuroma is a neurectomy, in which part of the nerve tissue is removed. Although this procedure effectively removes the original neuroma, sometimes scar tissue known as a stump neuroma forms at the site of the incision. This may result in tingling, numbness, or pain following surgery. Surgery is effective in relieving or reducing symptoms for Morton?s neuroma patients in about 75% to 85% of all cases. Occasionally, minimally invasive radio frequency ablation is also used to treat Morton’s neuroma.
Wearing shoes that fit properly and that have plenty of room in the toe area may help prevent Morton’s neuroma.