To him whose feet hurt, everything hurts, said Socrates. Without questioning the wisdom of the ancient philosopher, who among us has not come to the same conclusion?
Individuals suffering from Morton’s neuroma (also known as interdigital perineural fibroma) know precisely how debilitating foot pain can be. Morton’s neuroma involves inflammation and swelling of a nerve that runs between the toes, causing severe pain and numbness in the balls of the feet, usually between the third and fourth toes.
Janet’s neuroma developed after years of wearing tightly fitting high heeled pumps. She first started feeling pain intermittently, particularly toward the end of the day or during extended periods of standing. Eventually, the pain was more constant, and she even noticed it while wearing comfortable shoes. She described it as “like walking on a pebble.” Sometimes she got electrical shock sensations similar to those encountered when hitting the funny bone.
At least in part because of their foot wear, women are five times more likely than men to suffer from Morton’s neuroma. Also at risk are runners, who put repeated impact on the foot; walkers, who push off on the balls of their feet; and persons such as floor and carpet installers who spend extended periods crouching or squatting.
Foot Structure Sets Up Problem
Many, but not all, individuals with Morton’s neuroma have what is known as a “Greek” or “Morton’s” foot, with a relatively short big toe and a longer second toe. About 22 percent of the population have this type of foot structure compared to 69 percent with an “Egyptian” foot (toes tapering down from a large big toe) and 9 percent with a “Giselle” or “peasant” foot (short toes more or less the same length and a wide foot).
Dr. Thomas Morton, who first described Morton’s syndrome in 1876, believed that, over time, persons with this type of foot structure experience a change of weight distribution, putting greater pressure on other bones in the metatarsal arch. Arthritis of the big toe or a bunion–common among long-distance runners and those who wear high-heeled shoes for extended periods–can weaken the big toe, shift the weight even more dramatically and lead to crowding that can pinch the nerve. Other contributing factors include flat feet or feet that pronate or roll inward.
Damage to the nerve is progressive, typically following years of micro-trauma–with the nerve being pinched between bones or subjected to repeated impact. Eventually, the nerve becomes enlarged and chronically irritated.
A neuroma is technically a nerve tumor, but, aside from the pain, it is completely benign. Recent research indicates that in most cases the pain arises not from an actual neuroma but from scar tissue that forms around the irritated nerve.
Prevention and treatment may be as simple as a change of shoes. Appropriate footwear should distribute the weight and pressure evenly across the whole foot rather than on the toes and the balls of the feet. While cushioning is important, it should be balanced against the need for stability.
Running shoes are usually a good choice, especially those with a high and wide toe box and protection against pronation. Inexpensive hiking-style shoes can be even better, offering roominess along with a stable, durable underpinning.
Runners and walkers should be careful to discard wornout shoes promptly. Old shoes not only lose their structure and support but may end up putting more pressure on the forefoot.
If the pain persists, it’s important to get a diagnosis from a foot doctor or your family physician. The most common cause of forefoot pain, particularly in a runner, is a stress fracture of one of the metatarsal bones.
A stress fracture requires at least some period of immobilization. With a neuroma, on the other hand, regular activity may be possible while the pain is treated with a nonsteroidal antiinflammatory such as ibuprofen.
An experienced doctor can usually detect a neuroma simply through a physical examination. The neuroma is often large enough to be visible or felt with the fingers. Squeezing the forefoot area may elicit an audible and painful click.
Pain relief can be obtained through injections of medications such as cortisone or xylocaine–which can also be helpful in diagnosis.
Pads placed inside the shoes may be helpful, in combination with massage, heat or ice therapy. Together, the doctor and patient should work out strategies to relieve daily stress and wear and tear on the feet, particularly in the metatarsal area.
Over the long term, most patients get significant relief from orthotics or shoe inserts that can be custom made to re-distribute weight and correct for biomechanical problems.
Studies have found that orthotics decrease forefoot pressure by 7 to 18 percent along with a significant reduction of pain. Some, although not all, studies have found custom-built orthotics more effective than inserts purchased off the shelf. Custom inserts generally last longer and are more likely to correct individual biomechanical problems such as differences in leg length.
The final treatment option, which is to be undertaken only after all others have failed, is surgery to remove the neuroma. Typically performed on an outpatient basis, the procedure is effective in 95 percent of cases.
Stitches are required, but the patient is usually able to walk without crutches or a cane immediately after the surgery. Recovery is complete after about three weeks. Although the patient may experience permanent numbness between the toes, most find this preferable to the pain they experienced before.
For the other five percent, the aftermath of surgery can be frustrating. Sometimes persisting pain comes from irritation at the cut end of the nerve or “stump neuroma.” This may require an additional surgery. In some cases, the surgery is unsuccessful because the pain originated from something other than a neuroma or there is more than one cause of the pain.
For most persons, the pain of a neuroma may come and go, seeming unbearable for several weeks at a time, then fading for a period of weeks or months. While an athlete may be anxious to get back into action quickly, a conservative approach is safest over the long term.
REFERENCES:
Iliya Beylin, “Effective Approaches to Chronic Foot Pain,” Patient Care, January 15, 2002.
Iliya Beylin, Ira M. Fox and Vijay J. Rajput, “Effective Approaches to Chronic Foot Pain,” Patient Care, January 15, 2002.
Sharon G. Childs, “Diagnosis and Treatment of Interdigital Perineural Fibroma,” Orthopaedic Nursing, November-December, 2002.
Betsy Heidenberger, “Neuroma Prevention,” The Clinic, American Running Association, June, 2001.
Steven J. Levitz, “Prescribing Foot Orthoses: The Authors Review the History, Composition and Application of Orthoses,” (CME) Clinical Podiatry, September, 2002.
Ellen Sobel, “Metatarsalgia: Diagnosis and Management, Etiologies and Differential Diagnoses,” (CME) Clinical Podiatry, March, 2002.
Anne D. Walling, “Morton’s Neuroma,” American Family Physician, September 15, 2000.
