What are the diagnosis and treatment options for Morton's (Morgan's) neuroma?

Diagnosis and Treatment of Morton's Neuroma

Morton's neuroma is best treated initially with conservative measures including footwear modifications and steroid injections, followed by ultrasound-guided injection therapies before considering surgical neurectomy for refractory cases.

Diagnosis

Clinical Presentation

• Pain in the forefoot, typically between the third and fourth toes or second and third toes 1
• Pain worsens with walking and wearing tight shoes 1
• Sensation of walking on a pebble or having a fold in the sock 1
• Burning, tingling, or numbness in the affected toes 1

Physical Examination

• Tenderness with palpation of the affected web space 1
• Positive Mulder's click (palpable and sometimes audible click when compressing the forefoot while simultaneously squeezing the metatarsal heads together) 1
• Pain with direct pressure between the metatarsal heads 1

Diagnostic Imaging

• MRI can confirm the diagnosis and rule out other pathologies 2
• Ultrasound is useful for visualization during guided injections 3
• Radiographs may be helpful to exclude other causes of forefoot pain 1

Treatment Algorithm

First-Line Treatment: Conservative Management

1. Footwear modifications:

   • Wide toe box shoes 4
   • Low-heeled shoes 4
   • Custom orthoses to offload pressure from the affected intermetatarsal space 4

2. Corticosteroid injections:

   • More effective than footwear modifications alone at 1,6, and 12-month follow-up 4
   • 82% of patients treated with steroid injections had complete or partial relief at 12 months compared to 63% with footwear modifications alone 4
   • Should be performed under ultrasound guidance for accuracy 3

Second-Line Treatment: Advanced Injection Therapies

1. Alcohol sclerosing injections:

   • Success rate of over 82% per single injection when using 2.5mL of 70% ethanol under fluoroscopic and electroneurographic guidance 2
   • May require an average of 1.2 injections for optimal results 2
   • Provides long-term relief with no recurrence observed over 5 years in one study 2

2. Combined approach:

   • A sequential approach of steroid injections followed by alcohol sclerosing injections (if needed) is the most cost-effective treatment strategy 3
   • This approach yields an incremental cost-effectiveness ratio of $4,401.61/QALY compared with no treatment 3

Third-Line Treatment: Surgical Management

• Surgical neurectomy should be considered only after failure of conservative and injection therapies 3, 5
• Can be performed through either dorsal or plantar approach 1
• While surgical treatment shows better outcomes in some studies, it carries risks including:
  • Persistent pain 5
  • Numbness 1
  • Infection 1
  • Wound complications 1

Treatment Effectiveness

• A systematic review found better outcomes with surgical treatment compared to conservative management for refractory cases 5
• However, a cost-effectiveness analysis demonstrated that trying ultrasound-guided injection therapies before proceeding to surgery is more cost-effective 3
• Success rates for different treatments:
  • Steroid injections: 63-82% 4
  • Alcohol injections: >82% 2
  • Combined conservative approaches: 74% probability of being most cost-effective in sensitivity analyses 3

Important Considerations

• Patient selection and proper pre-operative counseling are key to successful outcomes 1
• When the probability of successful alcohol injection drops below 40%, steroid injections alone become the most cost-effective first-line treatment 3
• Some mild pain may persist in athletically active patients even after successful treatment 2
• Regular follow-up is recommended to assess treatment response and consider alternative approaches if needed 4