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.
In many cases, a neuroma may develop as a result of excessive loading on the front of the foot. Sometimes, a patient?s anatomic alignment in the forefoot contributes to the overload. There may be some cases where the neuroma develops spontaneously, for no obvious reason. However, once the nerve is irritated, pressure from walking, and from the adjacent bony prominences (metatarsal heads), as well as from the intermetatarsal ligament that binds the heads together, all may contribute to persistent pain. Repetitive pressure on the nerve causes localized injury with resulting scarring and fibrosis of the nerve. This leads to symptoms in the distribution of the nerve.
If you have a Morton?s neuroma, you may have one or more of these symptoms where the nerve damage is occurring, Tingling, burning, or numbness, pain, a feeling that something is inside the ball of the foot or a feeling that there?s something in the shoe or a sock is bunched up. The progression of a Morton?s neuroma often follows the following pattern. The symptoms begin gradually. At first they occur only occasionally, when wearing narrow-toed shoes or performing certain aggravating activities. The symptoms may go away temporarily by removing the shoe, massaging the foot, or by avoiding aggravating shoes or activities. Over time the symptoms progressively worsen and may persist for several days or weeks. The symptoms become more intense as the neuroma enlarges and the temporary changes in the nerve become permanent.
During the examination, your physician will feel for a palpable mass or a “click” between the bones. He or she will put pressure on the spaces between the toe bones to try to replicate the pain and look for calluses or evidence of stress fractures in the bones that might be the cause of the pain. Range of motion tests will rule out arthritis or joint inflammations. X-rays may be required to rule out a stress fracture or arthritis of the joints that join the toes to the foot.
Non Surgical Treatment
You may be able to treat this problem at home. Avoid wearing tight, pointy, or high-heeled shoes. Choose well-fitted shoes with plenty of room for your toes. Put ice or a cold pack on the area for 10 to 15 minutes at a time. Put a thin cloth between the ice and your skin. Take anti-inflammatory medicines to reduce pain and swelling. These include ibuprofen (such as Advil or Motrin) and naproxen (such as Aleve). Rest your feet when you can. Reduce activities that put pressure on the toes, such as racquet sports or running. Try massaging your foot to relax the muscles around the nerve. If these steps do not relieve your symptoms, your doctor may have you use special pads or devices that spread the toes to keep them from squeezing the nerve. In some cases, a doctor may give a steroid shot to reduce swelling and pain. If these treatments do not help, your doctor may suggest surgery.
Operative treatment of Morton?s neuroma should be entertained only after failure of nonoperative management. Standard operative treatment involves identifying the nerve and cutting (resecting) it proximal to the point where it is irritate/injured. This is usually done through an incision on the top (dorsal) aspect of the foot, although in rare instances, an incision on the sole (plantar) aspect of the foot maybe used. An incision on the sole of the foot works very well, unless an excessive scar forms in which case it can be problematic. 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.
Although the exact causes of neuromas are not completely known, the following preventive steps may help. Make sure your exercise shoes have enough room in the front part of the shoe and that your toes are not excessively compressed. Wear shoes with adequate padding in the ball of the foot. Avoid prolonged time in shoes with a narrow toe box or excessive heel height (greater than two inches).