Morton's neuroma

• Morton's neuroma:

  • Benign fibrotic thickening of nerve running between metatarsals in foot
  • Most commonly in the 3rd intermetatarsal space
  • Usually diagnosed between ages 40-60 years
  • More common in women
  • Caused by biomechanics of the foot causing compression and irritation to the nerve during movement
• Risk factors:

  • Pes cavus - high arched feet
  • Tight/ill fitting shoes
  • Repetitive heavy impact on the feet e.g. running, dancing
• Symptoms:

  • Pain at front of foot at location of lesion - most commonly 3rd intermetatarsal space
  • Pain whilst walking, exacerbated by increased activity or particular footwear, relieved by removal of footwear and massaging foot/toes
  • Sensation of having a pebble or lump under the metatarsal region when walking
  • Sharp stabbing, burning or tingling sensation in the distribution of affected nerve
• Examination:

  • Pain on applying pressure to affected inter-metatarsophalangeal space
  • May also be loss of sensation in affected toe/s
  • Special tests e.g. Mulders clock - compression of the metatarsal heads produces a palpable click due to displacement of the neuroma (squeeze foot)
• Investigations:

  • Only needed if diagnosis uncertain
  • Bloods to rule out other conditions e.g. osteomyelitis, gout, inflammatory arthritis
  • Imaging - ultrasound or MRI
• Management:

  1. Initial - comfortable flat shoes, metatarsal pad, avoid impact activities, analgesia e.g. NSAIDs
  2. Persist for >3 months - orthotist for metatarsal dome orthotic
  3. Refer for specialist treatment - corticosteroid injections, guided alcohol injections (causes sclerosis and shrinks nerve), surgery to reduce nerve size and relieve pressure from surrounding structures