Fig. 5

CT-arthrography coronal images (a–d) and axial images (e–h) belonging to four different patients, three of which display different aspects of ligament derangement involving the A-MCL (white arrows). Intact anterior band (A-MCL) of the medial collateral ligament (MCL) complex (a, e and b, f). Widening of the medial aspect of the articular recess, associated to a “bow-shaped” loose A-MCL, with no evidence of fiber tearing, suggestive of ligament laxity (b, f). Thickened and irregular A-MCL, showing a partial-thickness tear (c, g) and a full-thickness tear (d, h); contrast agent progressively spills through the ligament, as fibers are gradually disrupted as a consequence of micro-tearing and damage progresses from a partial to a complete tear