Magnetic resonance evaluation of remodeling process in patellar tendon graft.

Several studies have shown the accuracy of magnetic resonance imaging in evaluating the reconstructed anterior cruciate ligament. The purpose of the current study was to clarify the clinical usefulness of magnetic resonance imaging for evaluating the reconstructed anterior cruciate ligament in comparison with using arthroscopy. Sixty-nine patients who had an anterior cruciate ligament reconstruction using a bone-tendon-bone autograft were examined by magnetic resonance imaging and arthroscopy an average of 12 months after surgery. There were 41 males and 28 females with an average age of 25.9 years (range, 15-66 years). The interval from surgery to the magnetic resonance imaging or arthroscopic evaluation was a mean of 12 months (range, 4-32 months). The magnetic resonance imaging findings of the reconstructed anterior cruciate ligament were classified as either high, intermediate, or low intensity. The arthroscopic findings also were classified as either graft impingement at the intercondylar notch or no impingement. In the 47 anterior cruciate ligament grafts that were not impinged, the signal intensity remained low and did not increase during second-look arthroscopy. In contrast, 22 anterior cruciate ligament grafts that were impinged showed an increased signal intensity in the distal area of the graft at the time of the second-look arthroscopy. Furthermore, no significant correlation was observed between the presence of a high signal intensity and postoperative instability. The high signal intensity of the anterior cruciate ligament graft on magnetic resonance imaging was found to be caused by graft impingement. These findings therefore show a clear association between graft impingement and the subsequent appearance of the graft on magnetic resonance imaging.