A radiological study after anterior cruciate ligament reconstruction

Disruption of the anterior cruciate ligament is a common injury, often resulting in functional instability. Currently, arthroscopic anterior cruciate ligament (ACL) reconstruction using the central third bone-patellar tendon-bone graft is a common surgical procedure. The purpose of this study was to evaluate the postoperative structural remodeling in the ligament following ACL reconstruction over time by X-ray and magnetic resonance imaging (MRI).

We performed arthroscopic ACL reconstruction with central third bone-patellar tendon-bone autograft for 27 patients (14 males, 13 females, mean 27.2 years old) between October 1995 and January 1999. All patients were examined post-operatively at 3, 6, 12, and 18 months by X-ray to evaluate the sequential change of the tibia bone tunnel and by MRI to monitor the sequential signal changes in the recipient and donor sites.

The MRI showed an increased signal at the patellar tendon (donor site) at 3 and 6 months and decreased signal after 1 year. The signal of ACL graft from MRI remained increased after operation. On AP, lateral view of X-ray, the diameter at the joint site of the tunnel was larger than at the bone plug site. Pearson correlation method revealed that the diameter of the bone tunnel expanding at the joint site was statistically greater than that at the bone plug site (p < 0.05). The difference between the bone tunnel diameter at the bone plug site and the joint site was not statistically correlated with the distance between them (by linear regression method, p = 0.77).

We concluded that the windshield wiper effect could not be the only factor inducing the enlargement of the bone tunnel, based on our results. The signal change of patellar tendon was more obvious than that of the bone-patellar tendon-bone graft.