Résumé
Objective To evaluate the angle between the anterior talofibular ligament (ATFL) and posterior talofibular ligament (PTFL) in patients with mechanical ankle instability,so as to find out a new indirect diagnosis method for the chronic ATFL lesion.Methods One hundred subjects were included in this study,among which 50 patients with mechanical ankle instability were assigned to group A and 50 counterparts without it were selected into group B All patients were taken MR Images and the ATFL and PTFL angle at the axial plane was evaluated.The difference between two groups was evaluated.Results The ATFL and PTFL angle increased significantly in group A when compared to group B (82.1° ± 8.0° v.s,74.4° ± 5.9°,P＜0.01).The area under receiver operating characteristic curve (ROC)was 0.874 (P＜0.01),indicating great significance in diagnosing the chronic ATFL tear.Moreover,the angle was 79 degree,showing high sensitivity (0.88) and specificity (0.64) of diagnosing ATFL tear.Conclusion The ATFL and PTFL angle increases significantly in patients with the mechanical instability.Moreover,the possibility of ATFL tear increases when the ATFL and PTFL angle is greater than 79 degree.
Résumé
The lateral ankle ligaments consisted of the anterior talofibular, posterior talofibular and calcaneofibular ligaments. This study was to investigate the dimensions and anatomic variations of these ligaments and correlate with MR images. Sixty seven ankles of Korean adults were used. Among these 37 ankles were only disseted and 30 ankles were dissected after getting MR images. The anterior talofibular ligament consisted of two bands in 72.4%. The length and thickness of this ligament were 20.9mm and 1.8mm, respectively. The widths were 7.0 mm in the upper band and 4.7 mm in the lower band. The talofibular ligament appeared as a hypointense thick band or several lines in MR images. This ligament was observed in 100% of the axial MR sections and 82.8% of the coronal sections. The posterior talofibular ligament showed single thick band in 53.2% while others showed as two bands. The length, width, thickness and the angle between the horizontal plane and the posterior talofibular ligament were 21.8 mm, 7.3 mm, 3.4 mm and 22.6degrees, respectively. In coronal MR images this ligament appeared as a hypointense and heterogeneous thick band between the lateral malleolus and the talus. All anterior and posterior talofibular ligaments were observed in axial MR images with at least one same MR plane showing the two ligaments together. The length, width and thickness of the calcaneofibular ligament were 25.3 mm, 5.2 mm and 2.3 mm, respectively. It was composed of two bands in 8.5%. The angles to the coronal and sagittal planes and this ligament were 20.7degrees(range 5degrees~60degrees) and 27.0degrees(range 7degrees~50degrees), respectively. The calcaneofibular ligament was seen as a hypointense short line or dot depending on the cut plane. It was observed in 72.4% of the axial MR images and in 75.9% of the coronal images but was better imaged in the coronal planes.