What is the recommended preparation and dose for injection to treat Morton's neuroma?

Treatment of Morton's Neuroma with Injection

For Morton's neuroma, a corticosteroid injection is recommended as the first-line injectable treatment, using 1-2 mL of corticosteroid mixed with local anesthetic, administered under ultrasound guidance for optimal placement. 1, 2

Injection Preparation and Technique

Corticosteroid Injection

• Use 1-2 mL of corticosteroid (such as methylprednisolone or triamcinolone) mixed with local anesthetic (lidocaine 1%) 1
• Ultrasound guidance is recommended for precise placement into the affected intermetatarsal space, typically the 3rd or 2nd web space 3
• A plantar approach is generally preferred for better access to the neuroma 4
• Administer as a single injection; multiple injections may be needed over time but should be spaced at least 2-3 weeks apart 1

Alternative Injectable Options

• Alcohol sclerotherapy: 2.5 mL of 70% ethanol under fluoroscopic and electroneurographic guidance has shown up to 82% success rate in one study 5
• This technique requires specialized guidance and may be considered when corticosteroid injections fail 5

Expected Outcomes and Efficacy

• Corticosteroid injections provide moderate short to medium-term pain relief with approximately 50% success at 12 months 1, 2
• A very low adverse event rate has been reported across studies, indicating the treatment is generally safe 1
• Some patients may require surgical intervention if conservative treatment fails; approximately 48.5% of patients in one study eventually requested surgical excision 6

Important Considerations

• The quality of evidence for all non-surgical treatments is generally low, with most studies having small sample sizes and potential for bias 1, 2
• A recent randomized controlled trial found no significant difference between corticosteroid plus local anesthetic versus local anesthetic alone, suggesting the need for further research 6
• Patients should be informed that injections may provide temporary relief but might not be a permanent solution 2

Diagnostic Confirmation Before Treatment

• Confirm diagnosis with appropriate imaging before proceeding with injection therapy 7, 3
• Ultrasound (90% sensitivity) or MRI (93% sensitivity) are recommended for diagnosis confirmation 7, 3
• Clinical correlation during ultrasound examination can help confirm the diagnosis 7

Common Pitfalls to Avoid

• Avoid multiple frequent injections in the same area as this may lead to tissue atrophy 1
• Ensure proper needle placement using image guidance to maximize efficacy and minimize complications 3
• Do not rely solely on injections without addressing contributing factors such as improper footwear 4