Diagnostic tools to evaluate ankle instability caused by a deltoid ligament rupture in patients with supination-external rotation ankle fractures: A systematic review and meta-analysis

AIM: Supination-external rotation (SER) ankle fractures account for the majority of ankle fractures and can be divided into stable or unstable fractures, based on the state of the deltoid ligament. The objective of this review was to appraise the available literature concerning diagnostic tools to evaluate deltoid ligament integrity in patients with SER-type ankle fractures.

METHODS: A comprehensive literature search of Pubmed and Embase was performed up to December 2020. The outcome measures were sensitivity, specificity and positive and negative predictive value of the diagnostic tools. A meta-analysis was performed to obtain an overview of sensitivity, specificity and area under the curve (AUC). The methodological quality of the articles was evaluated using Quality Assessment of Diagnostic Accuracy Studies.

RESULTS: A total of 12 studies investigating tools for deltoid ligament rupture in patients with SER-type ankle fractures were included. The present study found sensitivity (and specificity) ranges of 0.20-0.90 (and 0.38-0.97) for clinical features, Magnetic Resonance Imaging (MRI) 0.57-0.85 (and 0.81-1.00), ultrasonography 1.00 (and 0.89-1.00), Malleolar Medial Fleck Sign (MMFS) 0.25 (and 0.99), conventional ankle mortise radiography 0.33-0.57 (and 0.60-0.94), gravity stress radiography 0.71-1.00 (and 0.72-0.88) and manual stress ankle radiography 0.65-1.00 (and 0.00-0.77). The largest AUC was found for ultrasonography, followed by MMFS, gravity stress radiography and MRI.

CONCLUSION: Ultrasonography and gravity stress radiography seem the most accurate diagnostic tools to evaluate deltoid ligament integrity. To strengthen this conclusion, future research should use an identical reference test to ensure comparability of results. Nevertheless, present study is of high value to close the knowledge gap about which presently available diagnostic tool is to be preferred to evaluate deltoid ligament integrity in patients with SER-type ankle fractures.