Morton's Neuroma

Morton's neuroma is a painful condition affecting the ball of the foot.  It is a thickening or benign growth of the nerve in between the third and fourth metatarsal (knuckle) bones of the foot or bases of the third and fourth toes.

The condition was named after Dudley J. Morton, MD who wrote several papers and books about foot problems.  His most well know book entitled, “The Human Foot,” was written in 1935. He theorized that a large number of foot problems were causes by poor distribution of weight bearing pressure across the ball of the foot or the metatarsal bones.  Morton's neuroma is a painful enlargement of the nerve in between the bases of the third and fourth toes that appears to be due to long term excess pressure at the ball of the foot but the exact mechanism of how the growths form has not been proven to this day.

Symptoms of Morton's neuroma include a burning, numb or tingling pain that starts in the ball of the foot but may radiate to the 3rd and 4th toes or sometimes backward toward the arch.  Some patients describe a sensation of a “pebble” in the shoe.  Others relate a sensation of a rolled up sock under the ball of the foot.

Causes of Morton's neuroma are unproven but tend to appear in patients who place excessive pressure on the lessor metatarsal heads, that is, excess pressure under the lessor toe joints as opposed to the big toe joint. Patients with arthritic big toe joints or big toe joints that may have been surgically fused place more pressure on the lessor toe joints and are more likely to have symptoms of Morton's neuroma.  High heels can make the pain of Morton's neuroma worse but do not cause the growth.  Tight shoes can squeeze the bases of the toes together or squeeze the metatarsal heads together increasing the pain. Use of ill fitting shoes is common due to the lack of availability of adequate widths.  Shoe manufacturers are under pressure to make shoes appear sleek which means excess tapering of the front of shoes.

A Morton's neuroma is an inter-metatarsal neuroma between the third and fourth metatarsals.  It is also possible to develop inter metatarsal neuromas in other areas of the ball of the foot with the second most common location being the area between the 2nd and 3rd metatarsals or between the bases of the second and third toe.

Diagnosis of Morton's neuroma or other inter metatarsal neuromas is often initiated by taking the patient history as the type of symptoms listed are fairly characteristic of the disorder.  Radiographs may be used but do not show the neuroma, only bone and joint.  Use of radiographs may be used to rule out other problems such as stress fractures.  MRI may be used to visualize neuromas but often require injection of a contrast material around the neuroma.  The most effective and practical means to examine a neuroma is via diagnostic ultrasound (sonography) as it clearly shows the growths, allowing measurement of neuroma size and shape in the office.

Treatment of Morton's neuroma or inter-metatarsal neuromas include:
Change of shoe gear.  Shoes with wider toe boxes that eliminate lateral pressure on  the metatarsals.?Metatarsal pads.  Elevations placed in shoes to elevate the metatarsals of the nerve growths.?Prescription foot orthotics.  Orthotics designed to shift pressure from the lessor metatarsals to the first metatarsal.  See http://www.footorthotics.pro/ for more information about foot orthotics.  Occasionally, arch supports can aggravate the symptoms of Morton's neuroma as the act of lifting the arch may also shift pressure to the outside of the ball of the foot where the  neuroma is.?Injections. Traditionally, injections containing a local anesthetic and “cortisone” had been used in an attempt to shrink the neuroma.  Sclerosing injections, that is, injections designed to “deaden” the nerve fibers have become more popular in recent years.  Use of sonography has made such injections more accurate and effective.  Overuse of injections, especially those containing “cortisone” can be problematic in that complications such as atrophy of the fatty padding tissue on the ball of the foot and tendon ruptures of the toes can occur.  Injection tend to be more effective when the growths are small so it is important to know their size before starting treatment.  Diagnostic ultrasound (sonography) is the best way to make such measurements.?Radio-frequency ablation or radio-frequency lesioning.  This involves use of a needle, placed in the nerve, which delivers radio waves instead of a drug for the purpose of desensitizing the neuromas. Like other types of injections, this type of treatment works best when the lesions are relatively small.?
Surgical treatment.  Surgical treatment involving removal of Morton's neuromas works best when the lesions are larger as measured by sonography.  The procedure involves use of local anesthetic or local with sedation if performed in a surgery center, an approximately one inch incision on top of the foot, between the 3rd and 4th toes and is the most definitive treatment.  It is an ambulatory procedure generally allowing return to activity in a few days.


For more information on Morton's Neuroma treatment in the San Antonio, TX area, call Ed Davis, DPM, FACFAS. at
(210) 490-3668 today!