MRI of anterior cruciate ligament reconstruction

Eleven asymptomatic patients 1-9 months after arthroscopic assisted anterior cruciate ligament (ACL) reconstruction with autogenous semitendinosus and gracilis tendons as a "neoligament" were studied by MR. Each neoligament was clinically intact. Examinations were performed at 1.5 T with T1- and T2-weighted sagittal and oblique spin echo images in the plane of ACL repair. On MR in 9 of the 11 patients (82%) the ACL neoligament appeared as a smooth well-defined band of low signal intensity along its entire course. In two patients (18%) the integrity of the neoligament could not be determined by MR. Ligaments in which integrity could not be determined demonstrated irregularity or a wavy contour, high signal intensity change within the ligament, or discontinuity of the ligament. We conclude that, contrary to previous reports, MR can demonstrate an intact ACL reconstruction.