MR Evaluation of Human Anterior Cruciate Ligament Autograft on Oblique Axial Imaging

PURPOSE: The purpose was to observe the changing MR appearance of stable anterior cruciate ligament (ACL) grafts on oblique axial images. METHOD: Fifty-five knees in 44 patients were studied with MRI 1-54 months after arthroscopic ACL reconstruction with double-looped autogenous semitendinosus and gracilis tendons. Knees with poor stability were excluded from this study. Examinations were performed at 0.2 T with SE proton density and T2-weighted sagittal and oblique axial images. RESULTS: High signal intensity areas covered the grafts 1-3 months after surgery. The high signal subsequently extended into the intertendinous bundles. The entire graft gradually became a low signal intensity bundle again after 12 months. Grafts were classified by their appearance on the oblique axial images. CONCLUSION: We conclude that high signal intensity can be seen within stable ACL grafts.