T -Mapping Evaluation of Early Cartilage Alteration of Talus for Chronic Lateral Ankle Instability with Isolated Anterior Talofibular Ligament Tear or Combined with Calcaneofibular Ligament Tear

Purpose: To quantitatively evaluate the cartilage alteration of talus for chronic lateral ankle instability (LAI) with isolated anterior talofibular ligament (ATFL) tear and combined ATFL and calcaneofibular ligament (CFL) tear using T -mapping at 3.0T.

Materials And Methods: In all, 27 patients including 17 with isolated ATFL tear and 10 with ATFL+CFL tear, and 21 healthy subjects were recruited. All participants underwent T -mapping scan at 3T and patients completed American Orthopaedic Foot and Ankle Society (AOFAS) scoring. The total talar cartilage (TTC) was segmented into six compartments: medial anterior (MA), medial center (MC), medial posterior (MP), lateral anterior (LA), lateral center (LC), and lateral posterior (LP). The T value of each compartment was measured from T -mapping images. Data were analyzed with one-way analysis of variance (ANOVA), Student's t-test, and Pearson's correlation coefficient.

Results: The T values of MA, MC, MP, TTC in the ATFL group and MA, MC, MP, LC, LP, TTC in the ATFL+CFL group were higher than those in the control group (P < 0.05). Moreover, the T values of MC, MP, LC, and TTC in the ATFL+CFL group were higher than those in the ATFL group (P < 0.05). The T values of MA in both patient groups were negatively correlated with AOFAS scores (r = -0.596, r = -0.690, P < 0.05).

Conclusion: Chronic LAI with ATFL tear had a trend of increasing cartilage T values in talar trochlea, mainly involving medial cartilage compartments. Chronic LAI with ATFL+CFL tear might result in higher T values in a much larger cartilage region than with ATFL tear. MA could be the main cartilage compartment that may affect the patient's clinical symptoms.

Level Of Evidence: 1 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2018;47:69-77.