Diagnostic value of measuring the talofibular space using stress sonography in chronic lateral ankle instability

Abstract

Objectives: To investigate the diagnostic value of measuring the talofibular space using stress sonography for chronic lateral ankle instability (CLAI).

Materials & methods: We recruited patients who were clinically diagnosed with CLAI between October 2018 and December 2019 (CLAI group). A control group of healthy volunteers was also included for this study. Both groups underwent a preliminary stress sonographic examination. First, the ultrasonic characteristics of the anterior talofibular ligament (ATFL), including length, thickness, relaxation, calcification, and rupture, were observed using conventional sonography. Second, the talofibular space at the passive neutral position (D1) and maximum varus position (D2) was measured (by stress sonographic images), and the difference (ΔD = D1-D2) between them was determined. Third, the parameters of the two groups were statistically compared. Finally, receiver operating characteristic (ROC) curves and area under the curve (AUC) analyses were performed for parameters with significant differences.

Results: The CLAI group comprised 60 patients, yielding data on 60 ankles, whereas the control group comprised 35 participants, yielding data for 70 ankles. Differences in D1, D2, and ΔD of the talofibular space between the two groups were significant, with ΔD proving to be the best diagnostic indicator (P < 0.001). Its AUC, optimal cutoff value, sensitivity, and specificity were 0.922, 0.11 cm, 73 %, and 94 %, respectively, followed by D2 (0.850, 0.47 cm, 67 %, and 94 %, respectively; P < 0.001) and D1 (0.635, 0.47 cm, 67 %, and 94 %, respectively; P = 0.006).

Conclusion: Measurement of talofibular space in stress sonography is a valuable diagnostic indicator for CLAI, especially the ΔD between the neutral and stress position.

Keywords: Ankle; Diagnosis; Musculoskeletal sonography.