Prediction of Clinical Prognosis according to Intermetatarsal Distance and Neuroma Size on Ultrasonography in Morton Neuroma: A Prospective Observational Study

Objectives: This study aims to evaluate the clinical importance of intermetatarsal distance, size of neuroma, and proportion of neuroma in the intermetatarsal space in examinations of Morton neuroma using ultrasonography. Methods: Clinical prognosis was observed prospectively after corticosteroid injections in 136 patients with Morton neuroma, and the results were compared with ultrasonographic parameters of intermetatarsal distance, size of neuroma, and proportion of neuroma in the intermetatarsal space. Results: Twenty-one patients (15%) did not respond to corticosteroid injections and underwent surgical treatment for Morton neuroma. Logistic regression analysis and receiver operating characteristic curve analysis showed that the size of the neuroma was the sole predictor of failure of corticosteroid injections (P =.002). No other factors were significant for the prediction of clinical prognosis (P >.05). Conclusions: The size of the neuroma on ultrasonography is the sole predictor of corticosteroid injection failure, while intermetatarsal distance and proportion of neuroma in the intermetatarsal space are not significant when predicting clinical prognosis of Morton neuroma.