Combination of anterior tibial and femoral tunnels makes the signal intensity of antero-medial graft higher in double-bundle anterior cruciate ligament reconstruction

Purpose To elucidate whether sagittal graft tunnel affects the signal intensity in anatomical ACL reconstruction (ACLR) and to clarify the prevalence of intercondylar roof impingement. It was hypothesized that if the tunnel apertures are located within the anatomical footprint of ACL, tunnel position would not affect the signal intensity. Methods A total of 132 patients who underwent anatomical double-bundle ACLR (DB-ACLR) using hamstring autograft were recruited. Tunnel position was determined by the quadrant method on three-dimensional computed tomography; the femoral tunnel position was defined as high and low or deep and shallow, while that of the tibial side was defined as anterior and posterior or medial and lateral. Subjects were divided into three groups according to the tertile of % deep-shallow. The signal intensity was evaluated by the region of interest value of the antero-medial bundle (AMB) and postero-lateral bundle on magnetic resonance imaging at 12 months after reconstruction. Linear regression analysis was conducted to elucidate the relationship between the percentage position of each tunnel and the graft signal intensity. Results In the shallow tertile group, AMB signal intensity increased in the anterior position of the tibial tunnel (beta = - 0.34; P = 0.025). In the intermediate and deep tertile groups, the tunnel position did not correlate with the signal intensity. Conclusions A more anterior tibial tunnel position increases AMB signal intensity in shallower femoral tunnel. Conversely, this correlation is attenuated for deeper femoral tunnels. Surgeons should pay attention to sagittal femoral tunnel position to create a more anterior tibial tunnel position.

Automated summary

The study found that in shallower femoral tunnels, an increased anterior tibial tunnel position can lead to an increase in anterior medial bundle signal intensity. However, in intermediate and deep femoral tunnels, tunnel position does not correlate with signal intensity.