SLR - August 2017 - Michelle L. Dole

Corticosteroid Injection for Morton's Neuroma with or Without Ultrasound Guidance: A Randomized Controlled Trial

Reference: Mahadevan D, Attwal M, Bhatt R, Bhatia M. Corticosteroid Injection for Morton's Neuroma with or Without Ultrasound Guidance: A Randomized Controlled Trial. Bone Joint J. 2016. Apr;98–B(4):498–503.

Scientific Literature Review

Reviewed By: Michelle L. Dole, DPM
Residency Program: Hennepin County Medical Center, Minneapolis, MN

Podiatric Relevance: Podiatric surgeons commonly perform corticosteroid injections to treat Morton’s neuroma. However, the utility of ultrasound-guided injections has been debated in the literature. This study evaluates whether ultrasound guidance improves the effectiveness of corticosteroid injection for Morton’s neuroma.

Methods: This double-blinded randomized controlled trial evaluated patients with Morton’s neuroma treated by a single foot and ankle surgeon. Patients were included if they had a clinical diagnosis of Morton’s neuroma with duration greater than six months, a positive thumb-index-finger web space squeeze test and ultrasound evidence of neuroma. Patients were randomly assigned to treatment with corticosteroid injection under ultrasound guidance or corticosteroid injection without ultrasound guidance. One radiologist performed all injections in a dorsal-to-plantar fashion with an ultrasound transducer positioned plantarly at the neuroma site. A sham ultrasound was performed in the control group. Patients and investigators were blinded to the treatment randomization. Patient outcomes were recorded at three, six and twelve months after treatment. The visual analogue scale (VAS) was used as the primary outcome measure. Investigators also evaluated the Manchester-Oxford Foot Questionnaire Index, patient satisfaction and failure of treatment (need for repeat injection or neuroma excision).

Results: Twenty-three feet were treated with ultrasound-guided injection and 22 feet with nonultrasound-guided injection. Three months after injection, the mean VAS score decreased by 55 percent in the ultrasound-guided injection group and by 46 percent in the nonultrasound-guided injection group. Both groups had a significant reduction in VAS scores, but the difference between groups was not statistically significant. Both groups had significantly improved Manchester-Oxford Foot Questionnaire Index scores. This score favored the ultrasound-guided injection group at three months, but no difference between groups was seen at twelve months. Similarly, patient satisfaction was higher in the ultrasound-guided group at three months although not statistically significant. Twelve months after treatment, 11/23 patients in the ultrasound-guided group and 12/22 patients in the nonultrasound-guided injection group had failed treatment.

Conclusions: This study demonstrates the initial efficacy of corticosteroid injection for Morton’s neuroma, as both groups showed improved VAS and Manchester-Oxford Foot Questionnaire Index scores, as well as high initial patient satisfaction. However, the efficacy of injection did not improve with use of ultrasound. Ultrasound guidance increases costs, patient wait times and provider workload, so its benefit needs to be significant in order to support its use in the clinical setting. This study shows little value in using ultrasound to perform routine injections for Morton’s neuroma. It also demonstrates a high overall failure rate of corticosteroid injection within twelve months, with many patients requesting repeat injections or surgical excision. It is important for providers to recognize that while corticosteroid injections may be beneficial for treatment of Morton’s neuroma initially, their efficacy may be limited and may decrease over time.

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