Can Foot Injury Cause Morton's Neuroma?
Yes, foot injury can cause Morton's neuroma through repetitive microtrauma or direct nerve compression, though it is not a true neuroma but rather a mechanically-induced degenerative neuropathy with perineural fibrosis. 1, 2, 3
Mechanism of Development After Injury
Morton's neuroma develops as a secondary change following entrapment or repeated microtrauma to the common digital nerve, most commonly affecting the third webspace of the foot. 1 The condition represents fibrosis of the nerve tissue rather than true neuromatous growth, occurring when pressure or repetitive irritation causes thickening of the digital nerve. 3
Post-traumatic development is well-documented, with case reports demonstrating bilateral Morton's neuroma formation after fingertip amputation and multiple revision surgeries, suggesting that inadequate primary treatment and high pressure from surrounding soft tissue can trigger neuroma formation. 4
The pathophysiology involves mechanically-induced degenerative neuropathy where chronic compression or trauma leads to proliferative fibrosis of perineural tissue. 2, 3
Clinical Presentation After Injury
Following foot trauma, patients typically develop:
Burning or shooting pain in the webspace that extends to the toes, often described as the sensation of walking on a pebble. 5
Pain while walking or weight-bearing, particularly exacerbated by tight or high-heeled shoes. 1
Symptoms that impact quality of life and weight-bearing activities. 5
Diagnostic Approach Post-Injury
Start with weight-bearing foot radiographs to evaluate foot deformity and exclude other causes of webspace pain such as osteoarthritis, Freiberg's infraction, and stress fractures. 6, 1
After negative or equivocal radiographs:
Proceed to ultrasound or MRI, which are the preferred imaging modalities with high sensitivity (ultrasound: 90%, MRI: 93%) for detecting Morton's neuroma. 7, 6
Ultrasound has the advantage of allowing clinical correlation during examination and dynamic assessment. 7, 6
Physical examination should include palpation of the web spaces and Mulder's test (compression test of the affected webspace), which is quite specific for diagnosis. 1, 2
Important Clinical Caveat
If local corticosteroid injection is not temporally effective for diagnosis and treatment, surgical treatment is not indicated. 1 This diagnostic injection serves dual purposes and helps confirm the diagnosis before considering more invasive interventions.
The evidence clearly supports that trauma—whether acute injury or repetitive microtrauma—can precipitate Morton's neuroma development through mechanical nerve injury and subsequent perineural fibrosis. 1, 2, 4, 3