Corticosteroid injection for Morton's neuroma with or without ultrasound guidance: a randomised controlled trial.

AIMS: The objective of this double-blind randomised controlled trial was to assess whether ultrasound guidance improved the efficacy of corticosteroid injections for Morton's neuroma (MN).

PATIENTS AND METHODS: In all, 50 feet (40 patients) were recruited for this study but five feet were excluded due to the patients declining further participation. The mean age of the remaining 36 patients (45 feet) was 57.8 years (standard deviation (sd) 12.9) with a female preponderance (33F:12M). All patients were followed-up for 12 months. Treatment was randomised to an ultrasound guided (Group A) or non-ultrasound guided (Group B) injection of 40 mg triamcinolone acetonide and 2 ml 1% lignocaine, following ultrasound confirmation of the diagnosis.

RESULTS: The mean visual analogue score for pain improved significantly in both groups (Group A - from 64 mm, sd 25 mm to 29 mm, sd 27; Group B - from 69 mm, sd 23 mm to 37 mm, sd 25) with no statistical difference between them at all time-points. The failure rate within 12 months of treatment was 11/23 (48%) and 12/22 (55%) in Groups A and B, respectively (p = 0.458). The improvement in Manchester Oxford Foot Questionnaire Index and patient satisfaction favoured Group A in the short-term (three months) that almost reached statistical significance (p = 0.059 and 0.066 respectively). However, this difference was not observed beyond three months.

CONCLUSION: This study has shown that ultrasound guidance did not demonstrably improve the efficacy of corticosteroid injections in patients with MN.

TAKE HOME MESSAGE: In the presence of a clear diagnosis of MN, a trained clinician who understands the forefoot anatomy may perform an injection without ultrasound guidance with good and safe results.