Should the webspaces be a review area for Mortons neuroma on computed tomographies performed for metatarsalgia?

Morton's neuroma-bursal complex (MNBC) is a common cause of metatarsalgia which is usually investigated with ultrasound. Patients presenting with metatarsalgia may also have computed tomography (CT) as part of their investigation to look for alternative causes such as stress fracture. Although CT is considered to be of most use in assessing the bones in this scenario, the soft tissues can also be reviewed. This study analyses whether MNBC can reliably be detected on CT in patients presenting with metatarsalgia.

43 cases were identified on the Radiology Information System where both CT and ultrasound had been undertaken to assess for metatarsalgia. Two blinded consultant musculoskeletal radiologists retrospectively reviewed the CTs to determine the presence or absence of MNBC and this was compared to the ultrasound reports.

There was a mean sensitivity of 45.5% and mean specificity of 62.5%. Mean accuracy was 52.3% and Youden's index was 0.080. There was fair agreement between the two reviewers with Cohen's κ of 0.62.

Sensitivity and specificity of CT for MNBC are poor. CT should not be used as an isolated modality to make a definite diagnosis regarding the presence or absence of a MNBC.