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Morton's neuroma; Morton's entrapment; intergidital or intermetatarsal neuroma

Etiology: - running - tight shoes, high heels - bunion - hammertoe - high arched feet Epidemiology: 1) uncommon 2) women affected 4-fold more often than men [3] Pathology: 1) repetitive microtrauma of the common digital nerves 2) cycle of inflammation, accumulation of perineural fibrosis, & enlargement of neurilemma 3) nerve entrapment [8] Clinical manifestations: 1) burning pain at the 2nd or 3rd web space between the toes 2) pain may radiate to the tips of the involved toes 3) unilateral in most cases 4) most commonly in the web space between the 3rd & 4th toes but may be found in the 2nd web space 5) tenderness to palpation at the involved webspace 6) symptoms reproduced by compression of the involved metatarsals 7) weight-bearing exacerbates symptoms - runners may feel pain as they push off from the starting block 8) removal of shoes may relieve symptoms 9) generally, not palpable 10) pain may be described as cramping [3] or walking on pebbles [1] Radiology: - X-ray of foot may show widening of the metatarsal space - magnetic resonance imaging (MRI) for soft tissue visualization Differential diagnosis: - metatarsalgia Management: 1) metatarsal pads to spread the metatarsal heads & decompress the nerve 2) injection of glucocorticoid & local anesthetic a) effective for some patients [5] b) multiple injections may be needed (see joint injection) 3) surgery involves resection of a small portion of involved nerve or release of tissue around the nerve 4) common plantar digital nerve decompression [8]

Related

metatarsalgia (forefoot pain) Morton's foot

General

neuroma entrapment neuropathy; nerve entrapment syndrome; pinched nerve

References

  1. Medical Knowledge Self Assessment Program (MKSAP) 11, 16, 18. American College of Physicians, Philadelphia 1998, 2012, 2018.
  2. UCLA Intensive Course in Geriatric Medicine & Board Review, Marina Del Ray, CA, Sept 12-15, 2001
  3. Geriatrics Review Syllabus, American Geriatrics Society, 5th edition, 2002-2004 - Geriatric Review Syllabus, 8th edition (GRS8) Durso SC and Sullivan GN (eds) American Geriatrics Society, 2013
  4. Wu KK. Morton neuroma and metatarsalgia. Curr Opin Rheumatol. 2000 Mar;12(2):131-42. PMID: 10751016
  5. Thomson CE et al. Methylprednisolone injections for the treatment of Morton neuroma: A patient-blinded randomized trial. J Bone Joint Surg Am 2013 May 1; 95:790. PMID: 23636185 http://jbjs.org/article.aspx?articleid=1679101
  6. Adams WR 2nd. Morton's neuroma. Clin Podiatr Med Surg. 2010 Oct;27(4):535-45 PMID: 20934103
  7. Thomson CE, Gibson JN, Martin D. Interventions for the treatment of Morton's neuroma. Cochrane Database Syst Rev. 2004;(3):CD003118. Review. PMID: 15266472
  8. Barrett SL, Woolley M Managing Morton's Entrapment Practical Pain Management. Sept 2, 2011 http://www.practicalpainmanagement.com/pain/other/managing-morton-entrapment
  9. Morton's Neuroma American Academy of Orthopaedic Surgeons http://orthoinfo.aaos.org/topic.cfm?topic=A00158