Morton's Neuroma Flashcards Preview

Foot and Ankle FRCS > Morton's Neuroma > Flashcards

Flashcards in Morton's Neuroma Deck (11):
1

What is Morton's Neuroma?

  • Compression neuropathy of INTERDIGITAL NERVE

2

Describe its epiemiology?

  • More common in females 9:1
  • Most Frequent between 3rd/4th Metatarsals
  • 2nd most common between 2/3rd Metatarsals

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3

What is the pathology of Morton's Neuroma?

  • Poorly understood
    • COMPRESSION/ Tension around TRANSVERSE INTERDIGITAL LIGAMENT
    • Repeptitive microtrauma
    • Endoneural oedema
    • Excessive bursal tissue
    • All of the above can -> fibrosis

4

What is the anatomy of the plantar nerves to the foot?

  • From the tibial nerve
  • Lateral plantar nerve supplies sole of little, 4th toes and 4/5 and 3/4 webspaces
  • Medial plantar nerve supplies sole of great toe, 1st websapace and 2/3 web space
  • Note the 3rd interspace recieves branches from noth medial and lateral plantar nerves

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5

What webspace has dual nerve supply?

  • Between 3rd/4th Metatarsals- the third webspace

6

What does a patient with Morton's Neuroma present with?

Symptoms

  • Pain- 60% -RADATION TO TOE DISTALLY
  • Pain often DURING PUSH OFF
  • Feelig like a stone on ball of foot
  • PARATHESIA- 40% numbness/ dysesthesia plantar web space

Signs

  • Plantar tenderness with palpation just DISTAL to METATARSAL heads
  • A Mulder's click ( bursa click) may be elicited when squeeze Metatarsals together
  • Metatarsalgia, MTP synovitis or instability must be ruled out

7

What investigations are helpful in DDX Morton's neuroma?

  • Xrays
    • 3 weight bearing views of feet to rule out bony deformity
  • MRI
    • Rule out other pathology
    • not required for diagnosis
  • USS 
    • maybe helpful to evaluate nerve
    • Dependent on size
    • not necessary for diagnosis

 

8

What is the DDx of Morton's Neuroma?

  • MT synovItis
    • can mimic interdigital neuroma
    • Tx of neuroma by steriod injection can exacerbate pathologic ocndition of MTP joint
  • MT instability

9

Describe tx of Morton's Neuroma?

  • Non operative
    • WIDE SHOE BOX, w FIRM SOLE, MT PAD
      • first line of TX
    • CORTICOSTERIOD INJECTION
      • ​Usually dorsal
      • Nerve  is below transverse mt ligament
      • Avoid injecting MTPJ due to risk of iatrogenic instability
  • Operative
    • NEUROMA EXCISION
    • when non op fails
    • ​NEUROMA DECOMPRESSION
      • alternative to resection, esp in adjacent neuroma as excision would -> complete numb toe

10

Describe surgical tx of Morton's Neuroma?

NEUROMA EXCISION

  • dorsal longitudinal incision in central web space incise fascia in line
  • Incise TRANSVERSE METATARSAL LIG to reveal NEUROMA BENEATH
  • EXCISE NEUROMA 2-3CM PROXIMAL to Transverse metatarsal ligament
  • BURY STUMP IN INTRINSICS 

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11

What are the surgical complications?

  • STUMP NEUROMA
    • most common from INADEQUATE RETRACTION  (traction neuritis)
    • tethering of plantar neural branches that prevent retraction following resection
    • INADEQUATE RESECTION ( not proximal enough)
  •  PAINFUL PLANTAR SCAR- 5% increased risk cf dorsal