Diagnostic value of weight-bearing CT with three-dimensional reconstruction in chronic ankle instability: a comparative study with conventional MRI

OBJECTIVE: This prospective, comparative diagnostic accuracy study was designed to assess the diagnostic value of weight-bearing computed tomography (WBCT) with three-dimensional reconstruction in detecting ligamentous injuries associated with chronic ankle instability (CAI) and to compare its efficacy with that of conventional magnetic resonance imaging (MRI). The goal was to assess the potential of WBCT as a more precise imaging modality to guide clinical decision-making. METHODS: Twenty patients with clinically suspected CAI, recruited between January 2024 and March 2025, underwent both WBCT (Planmed Verity; load equivalent to 100% body weight) and MRI (GE 1.5T; standard imaging protocols). Two senior musculoskeletal radiologists independently evaluated ligament integrity using a blinded protocol. Arthroscopic or intraoperative findings were used as the reference standard. Diagnostic parameters, including sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), were calculated for each method. Interobserver agreement was quantified using the Kappa statistic. RESULTS: WBCT demonstrated significantly higher sensitivity for detecting anterior talofibular ligament (ATFL) injuries compared to MRI (90% vs. 70%, P < 0.05), particularly in cases with osseous abnormalities such as talar dome lesions and syndesmotic widening (P < 0.01). WBCT also yielded superior interobserver agreement (Kappa = 0.82) relative to MRI (Kappa = 0.68). CONCLUSION: WBCT with three-dimensional reconstruction offers enhanced diagnostic accuracy and reproducibility in assessing ATFL injuries, especially in the presence of functional instability or coexisting bony pathology. These findings support the use of WBCT as a complementary modality to MRI in the comprehensive evaluation of CAI.