佐粧 孝久

OBJECTIVE: Knowledge of footprint anatomy is essential for ankle anterior talofibular ligament repair and reconstruction. We aimed to determine the intra- and inter-rater measurement reliability of the anterior talofibular ligament footprint dimension using three-dimensional MRI. METHODS: MRI images of 20 ankles with intact ligaments, including 11 with a single bundle and nine with double-bundle ligaments, were analyzed. Imaging was performed using a 3.0-Tesla MRI. Isotropic three-dimensional proton density-weighted images with a voxel size of 0.6 mm were obtained. The fibular and talar footprints were manually segmented using image processing software to create three-dimensional ligament footprints. The lengths, widths, and areas of each sample were measured. A certified orthopedic surgeon and a senior orthopedic fellow performed the measurements twice at 6-week intervals. The intra- and inter-rater differences in the measurements were calculated. RESULTS: The length, width, and area of the single-bundle fibular footprint were 8.7 mm, 5.4 mm, and 37.4 mm2, respectively. Those of the talar footprint were 8.4 mm, 4.3 mm, and 30.1 mm2, respectively. The inferior bundle of the double-bundle ligament was significantly smaller than the single and superior bundles (p < 0.001). No differences were observed between intra-rater measurements by either rater, with maximum differences of 0.7 mm, 0.5, and 1.7 mm2, in length, width, and area, respectively. The maximum inter-rater measurement differences were 1.9 mm, 0.5, and 2.4 mm2, respectively. CONCLUSION: Measurements of the anterior talofibular ligament dimensions using three-dimensional MRI were sufficiently reliable. This measurement method provides in vivo quantitative data on ligament footprint anatomy.

BACKGROUND: We aimed to evaluate the intra- and interrater measurement reliability of the lateral ankle ligament attachment locations using three-dimensional magnetic resonance imaging. METHODS: We analysed 54 participants with a mean age of 43 years who underwent three-dimensional ankle magnetic resonance imaging and had normal lateral ligaments. Bony landmarks of the distal fibula, talus, and calcaneus were identified in the reconstructed images. The centers of the anterior talofibular ligament and calcaneofibular ligament attachments were also identified. The distances between the landmarks and attachments were measured. Two raters performed the measurements twice, and intra- and interrater intraclass correlation coefficients were calculated. RESULTS: The intrarater intraclass correlation coefficient values were between 0.71 and 0.96 for the anterior talofibular ligament attachment measurements and between 0.77 and 0.95 for the calcaneofibular ligament attachments. The interrater intraclass correlation coefficient was higher than 0.7, except for the distance between the anterior talofibular ligament superior bundle and fibular obscure tubercle. The fibular attachment of a single-bundle anterior talofibular ligament was located 13.3 mm from the inferior tip and 43% along the anterior edge of the distal fibula. The superior and inferior bundles of the double-bundle ligament were located at 43% and 23%, respectively. The calcaneofibular ligament fibular attachment was 5.5 mm from the inferior tip, at 16% along the anterior edge of the distal fibula. CONCLUSION: The measurements of anterior talofibular ligament and calcaneofibular ligament attachment locations identified on three-dimensional magnetic resonance imaging were sufficiently reliable. This measurement method provides in vivo anatomical data on the lateral ankle ligament anatomy.

OBJECTIVE: To assess articular cartilage degeneration in anterior cruciate ligament (ACL) reconstructed knees as detected by MR T1rho and T2 mapping relative to controls and longitudinally at 3 months and 1 year after ACL reconstruction (ACLR). DESIGN: Twenty-five patients with acute ACL injury were enrolled (13 women and 12 men; mean age 30.8), and 14 healthy controls were selected by sex and age matching. The affected knees of the ACLR participants were imaged using a 3.0T magnetic resonance (MR) scanner 3 months and 1 year after ACLR. Cartilage T1rho and T2 values were quantified for subcompartments in the full-thickness, superficial, and deep layers and were compared with the matched subcompartments of control knees. The influence of concomitant meniscal tears identified using proton density-weighted imaging (PDWI) was also investigated. RESULTS: In the posterior lateral tibia, T1rho and T2 values were significantly higher in ACLR participants at 3 months and slightly decreased at 1-year compared to the control group. T1rho values in the medial compartment exhibited a significant increase at 1-year compared with those of control knees, while T2 showed no significance. In cartilage with medial meniscal tears, the T1rho values in multiple medial subcompartments were significantly higher than those in cartilage without medial meniscal tears, and this alteration was relatively detectable by T1rho. CONCLUSIONS: T1rho and T2 mapping is effective in evaluating cartilage degeneration following ACLR. T1rho may exhibit greater sensitivity for assessing the progression of early degeneration in the medial compartment after ACLR.