Summary

This study provides valuable quantitative information regarding the ligament dimension and signal intensity pre- and postoperatively.

Abstract

Purpose

Anterior talofibular ligament (ATFL) injury is well recognized in chronic ankle instability patients. On magnetic resonance imaging (MRI), injured ATFL may appear disrupted, thickened, heterogeneous, or attenuated in signal intensity and may be abnormal in contour. The purpose was to quantitatively evaluate and characterize the dimension and signal intensity of ATFL using 3.0T MRI in the mechanical ankle instability group pre- and postoperatively.

Methods

A total of 97 participants were recruited retrospectively in this study, including 56 with mechanical chronic ankle instability (CAI group) and 41 without ankle instability (Control group). All the subjects accepted MRI preoperatively. Among the 56 CAI patients, 25 patients, who accepted modified Broström repair of ATFL, underwent a MRI scan at follow-up. The ATFL dimension (length and width) and signal/noise ratio (SNR) were measured based on MRI images. The results of the MRI studies were then compared between groups.

Results

The CAI group had a significantly higher ATFL length (p = 0.03) or ATFL width (p < 0.001) compared with the control group. The mean SNR value of the CAI group was significantly higher than that of the control group (p = 0.006). Furthermore, the mean SNR value of the ATFL after repair surgery (11.2 ± 3.4) was significantly lower than that of the ATFL before surgery (8.4 ± 2.4) (p < 0.001). However, no significant change of ATFL length or ATFL width were observed after repair surgery.

Conclusions

CAI ankles had a higher ATFL length or width as well as higher signal intensity compared with stable ankles. After repair surgery, the mean SNR value of the ATFL decreased, indicating the relaxed ATFL becomes tight postoperatively.