A head-to-head comparison of high-frequency ultrasound and magnetic resonance imaging for preoperative assessment of ATFL tears and concomitant CFL injuries.

BACKGROUND: This study aims to comparatively evaluate the diagnostic performance of high-frequency ultrasound (HFUS) and magnetic resonance imaging (MRI) in the assessment of anterior talofibular ligament (ATFL) injuries, particularly in the context of associated concomitant injuries. By analyzing sensitivity, specificity, accuracy, and inter-modality agreement, we seek to determine the relative clinical utility of these two imaging modalities for comprehensive evaluation of lateral ankle instability and multi-structure involvement. METHODS: A retrospective, single-center study was conducted on clinical data from 123 surgically treated patients suspected of ATFL ankle injuries who presented to our hospital between May 2015 and June 2025. All patients underwent both HFUS and MRI examinations prior to surgery. Surgical findings were used as the reference standard to compare the diagnostic performance of HFUS and MRI in assessing the severity of acute ATFL injuries. The diagnostic efficacy of HFUS and MRI for ATFL injuries was evaluated using receiver operating characteristic (ROC) curve analysis. RESULTS: In grading ATFL injuries, HFUS demonstrated significantly higher diagnostic accuracy compared to MRI (90.24% vs. 78.05%, p < 0.01). The AUC for detecting complete ATFL tears was also markedly superior for HFUS (0.938, 95% CI: 0.898-0.975) compared to MRI (0.857, 95% CI: 0.792-0.917). However, in detecting concomitant calcaneofibular ligament (CFL) injuries, MRI demonstrated substantially higher sensitivity (95.83%, 95% CI: 91.67-99.00) than HFUS (63.54%, 95% CI: 53.69-72.00), highlighting its superior performance in identifying combined ATFL-CFL injuries. CONCLUSION: HFUS demonstrates better diagnostic performance for preoperative grading of ATFL tear severity, whereas MRI shows moderate diagnostic capability in detecting concomitant CFL injuries in the setting of combined lateral ankle ligament trauma. These findings support a complementary imaging strategy, with HFUS as a useful initial tool for ATFL assessment and MRI reserved for comprehensive evaluation when concomitant CFL or other pathologies are suspected.