Mortons Neuroma (Interdigital Neuroma)

Last updated 05.03.13

 

Definition

-  Paroxysmal neuralgia from entrapment neuropathy of intermetatarsal nerve

 

Diagram

 

Features

-  Enlargement of nerve sheath of intermetatarsal nerve

-  Usually involves nerve between 3rd & 4th metatarsals at intersection of 2 nerves

-  May also effect nerve between 2nd & 3rd

 

Risk Factors

-  Flat feet

-  High heels, tight shoes, pointy toe boxes

-  Bunions, hammer toes

-  Excessive foot pronation

 

Associated S/S

-  Pain in forefoot

-  Aching, shooting, sharp, burning

-  During or at end of a long run

-  Worse when wearing shoes

-  Improves when rubbed, takin off shoes

-  +/- numbness (may precede pain)

-  Tenderness on palpation of interspace

-  Muddlers sign

 

DDx

-  Foreign body

-  Stress fracture

-  Capsulitis, bursitis

-  Ligament injury

-  Tendon sheath ganglion, nerve sheath tumour

 

Ix

-  US: may confirm Dx

-  +/- MRI

-  X-ray: exclude stress fracture of OA

 

Mx

-  NSAIDs

-  RICE: ice massage

-  Wide shoe toe boxes

-  Loose lacing of forefoot shoe laces

-  Avoid high impact activities

-  Orthotics

-  Injection of LA + corticosteroid: short term relief only

-  Surgery

-  Cryogenic ablation

-  Decompression

-  Neurectomy: 79-93% success rate

 

 

 

References

 

www.sydneyfootsurgery.com.au/interdigital-neuroma.html

www.mayoclinic.com/health/mortons-neuroma/DS00468

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