Some sources claim that entrapment of the plantar nerve because of compression between the metatarsal heads, as originally proposed by Morton, is highly unlikely, because the plantar nerve is on the plantar side of the transverse metatarsal ligament and thus does not come in contact with the metatarsal heads. It is more likely that the transverse metatarsal ligament is the cause of the entrapment. Despite the name, the condition was first correctly described by a chiropodist named Durlacher, and although it is labeled a “neuroma”, many sources do not consider it a true tumor, but rather a perineural fibroma (fibrous tissue formation around nerve tissue).
Although in many areas of medicine, it?s easy to pinpoint the exact source of a problem (the way a specific germ causes a certain illness with recognizable symptoms), neuromas are harder to categorize. While there isn?t really one exact cause, podiatric physicians tend to agree that a neuroma can occur in response to the irritation of a nerve by one or more factors. Abnormality in foot function or foot mechanics: In other words, a foot that doesn?t move the way science thinks it should. In general, this means a pronated foot (one with an excessive rolling motion when the patient is walking, running or doing any kind of activity), because it causes excessive strain on the nerve. If you are not certain whether or not this is a problem for you, ask your podiatric physician, who will be able to examine your feet, as well as the wear pattern on your shoe, and give you an answer. Foot mechanics, and problems with them, tend to run in families, so if you know that a relative has had foot pain similar to yours, be sure to mention it.
Pain is usually increased by forefoot weight bearing activities (such as running), with narrow-fitting footwear, or with high heeled shoes. It is usually painful to firmly touch the affected region and, in chronic cases, pain and sometimes an audible click, may be heard when squeezing the foot and toes together with the hand. Often a localized area of swelling may be evident at the site of injury.
The doctor will ask about your symptoms and medical history. A physical exam will be done. Initial diagnosis of Morton’s neuroma is based on your description of the type and location of pain and discomfort in the foot. The diagnosis will be confirmed by a physical exam of the foot, including checking for mechanical abnormalities in the foot, squeezing the side of the foot, which will usually cause pain when Morton’s neuroma is present. Examination of your shoes to check for excess wear in parts of the shoe, check to see whether the shoes are too tight. Imaging tests evaluate the foot and surrounding structures. This may be done with X-ray, MRI scan, Ultrasound. Injections of local anesthetic can also be used for diagnosis.
Non Surgical Treatment
Initial treatment for Morton?s Neuroma may include non-prescription anti-inflammatory medications to reduce pain and swelling. These may consist of standard analgesics such as aspirin and ibuprofen (Advil, Motrin, others). Massaging the painful region three times daily with ice. Change of footwear. Avoid tight shoes, high heels or any footwear that seems to irritate the condition. Low heeled shoes with softer soles are preferable. Arch supports and foot pads to help reduce pressure on the nerve. In some cases, a physician may prescribe a customized shoe insert, molded to fit the contours of the patient?s foot. Reducing activities causing stress to the foot, including jogging, dancing, aerobic activity or any high impact movements of the foot. Injections of a corticosteroid medication to reduce the swelling and inflammation of the nerve and reduce pain. Occasionally other substances may be injected in order to ?ablate? the Neuroma. (The overuse of injected steroids is to be avoided however, as side effects, including weight gain and high blood pressure can result.)
Surgical treatment has provided relief in some cases while poor results and surgical complications have resulted in other cases. It is believed that ligament weakness, as opposed to the pinching of nerves in the foot, may be to blame for recurrent pain in these situations. For reasons which are not fully understood, the incidence of Morton?s Neuroma is 8 to 10 times greater in women than in men.