Morton's Neuroma Injection

Foot
Equipment & Medications

Equipment

9–14 MHz Linear Probe 25g 1.5″ Needle 5 cc Syringe (lidocaine) 3 cc Syringe (steroid mix) Procedure Tray Ethyl Chloride Spray (optional)

Medications

Lidocaine 1% — 5 cc Kenalog 40 mg/cc — 1 cc Ropivacaine 0.5% — 1 cc
Procedure Steps — Dorsal Approach (preferred)
1

Standard pre-procedure workup: consent, indications, contraindications, allergies, and baseline pain level.

2

Position patient supine with the foot in mild dorsiflexion. Place a rolled towel under the calf to elevate the forefoot slightly.

3

Place the linear probe in the transverse plane over the dorsal forefoot at the level of the metatarsal heads. Identify the intermetatarsal space of interest (most commonly 2nd–3rd or 3rd–4th). The Morton's neuroma appears as a hypoechoic oval mass in the plantar aspect of the interspace, deep to the intermetatarsal ligament. Apply gentle plantar squeeze (Mulder's maneuver) to displace the neuroma dorsally into view.

Morton's neuroma transverse
Click for annotated view
Morton's neuroma long axis
Click for annotated view
4

Mark the needle entry site on the dorsum of the foot, in the interspace between the relevant metatarsals, just proximal to the metatarsal heads. Mark probe position.

5

Prep with betadine or chlorhexidine × 3. Consider ethyl chloride spray for superficial anesthesia — the dorsal foot skin is thin and very sensitive.

6

Place sterile drape and sterile probe cover.

7

Under ultrasound guidance, inject 1% lidocaine superficially using the 25g needle. A small wheal is sufficient — avoid excessive subcutaneous infiltration which can distort anatomy.

8

Advance the 25g needle from dorsal to plantar under real-time ultrasound guidance, targeting the space immediately adjacent to the hypoechoic neuroma. The needle should be positioned at the edge of (not within) the neuroma mass.

Needle approach to neuroma
Click for annotated view
9

Test-inject with 1% lidocaine. Confirm easy flow and perineural distribution of injectate around the neuroma. If resistance is felt, the needle tip may be within the neuroma — retract slightly before injecting.

10

Once correct position is confirmed, exchange for the steroid/ropivacaine syringe and inject 2–3 cc around the neuroma.

11

Remove needle, clean skin with alcohol, and place bandage. Advise the patient that the foot may be numb for 2–4 hours from the ropivacaine — they should avoid walking excessively.

12

Reassess pain level at the end of the appointment and provide patient with a pain log.

Alternative: Plantar Approach

The plantar approach provides direct visualization of the neuroma but requires the patient to be prone or supine with the foot elevated. The dorsal skin is thinner and less tender than the plantar surface; the dorsal approach is generally preferred by most operators.

1

Position patient prone or supine with the foot elevated on a support. The plantar surface faces upward.

2

Place the probe on the plantar surface, imaging the neuroma from below. The neuroma is more superficial from this angle and the needle course is shorter.

3

Proceed as with the dorsal approach. Consider ethyl chloride spray generously — plantar skin is highly sensitive. Advance needle under real-time guidance to the neuroma.

References

  1. Markovic M, Crichton K, Read JW, Lam P, Slater HK. Effectiveness of ultrasound-guided corticosteroid injection in the treatment of Morton's neuroma. Foot Ankle Int. 2008;29(5):483–487.
  2. Ruiz Santiago F, Peces Rama A, Castellano García MDM, et al. Ultrasound-guided therapeutic injection and cryoablation of the interdigital (Morton's) neuroma. Eur Radiol. 2019;29(2):620–627.
  3. Ross AB, Faux SG, Koo K, Park K, Bharat C, Eckstein F. Ultrasound-guided alcohol injection and corticosteroid injection for Morton neuroma. AJR Am J Roentgenol. 2022;218(2):234–240.