Synonym: Morton's metatarsalgia, interdigital neuralgia
Risk factors:
(1) repetitive foot trauma
(2) tight or inappropriate shoes (common in women's fashions)
Clinical features:
(1) The patient experiences forefoot pain that may range from
(1a) mild to extreme
(1b) intermittent to constant
(1c) dull and aching to sharp and stabbing
(2) It is most common between the third and fourth metatarsals.
(3) The pain may occur while riding in a car or driving.
(4) The pain may be triggered by pressure on the affected intermetatarsal space.
(5) There may be a loss in the sensory action potential of the affected nerve.
Imaging studies may be performed, especially to exclude metatarsal fractures. The neuroma can be visualized on MRI but the diagnosis is usually made clinically.
There may be fibrosis in the soft tissue surrounding the affected nerve. There may be:
(1) variable loss of myelinated nerve fibers
(2) an increase in collagen in endoneurium
(3) fibrosis of endoneurial blood vessels
There are a variety of management strategies that can be utilized, ranging from conservative (injections or orthotics) to surgery. Surgical resection of the neuroma results in a loss of sensation in the associated toe.