Morton's interdigital neuroma: a clinical review of its etiology, treatment, and results.

Morton's neuroma is most likely a mechanically induced degenerative neuropathy which has a strong predilection for the third common digital nerve in middle-aged women. The excessive motion between the third and fourth metatarsals, the tethered third common digital nerve in the third web space, the third and fourth metatarsal heads flanking the third common digital nerve, the stout third transverse intermetatarsal ligament overlying the third common digital nerve, and excessive weightbearing stress on the forefoot, particularly by wearing pointed and high-heeled shoes, can collectively produce microdamage to the third common digital nerve. If allowed to continue for a long period of time, this can become manifested microscopically by nerve fiber degeneration and excessive intraneural and juxtaneural reparative fibrous tissue formation resulting in a significantly enlarged nerve. Such enlargement can create further trauma, and therefore become even more symptomatic. When nonsurgical means fail to relieve patient's symptoms, surgical removal of this offending neuroma through a dorsal approach can produce dramatic relief of symptoms. In addition, when a painful recurring Morton's neuroma does not respond to conservative treatments, removal of this lesion through a plantar approach can provide lasting relief.