Summary

Intra-operative tibial tunnel communication would not result in the posterior shift of the AMB graft and affect the bone-tendon healing of the AMB graft in the DB ACL reconstruction.

Abstract

Background

Tibial tunnel communication is not a rare complication after double-bundle anterior cruciate ligament (DB ACL) reconstruction. There is a concern that the tibial tunnel communication results in the posterior shift of the anteromedial bundle (AMB) graft with poor bone-tendon healing.

Purpose

To compare the bone-tendon healing and the location of the AMB graft at the tibial tunnel aperture between the DB ACL reconstruction with and without tibial tunnel communication.

Methods

One-hundred seven patients who underwent DB ACL reconstruction with a minimum one-year follow-up were included in this study. Tunnel communication was determined with a bird’s-eye view of the tibial surface on 3D-CT images at 1-week after surgery. On MRI six months after surgery, the bone-tendon healing and the location of the AMB graft were examined by evaluating the anterior half of the fibrous interzone (FIZ) in the AMB tibial tunnel at the articular surface level. For evaluating the bone-tendon healing, the intensity of FIZ on axial proton density-weighted images with fat suppression was evaluated according to the classification of Silva and Sampaio, in which FIZ signal intensity was classified as grade 0 if similar to the patellar tendon, grade 1 if similar to skeletal muscle, grade 2 if greater than muscle but less than fluid, and grade 3 if similar to joint fluid. The location of the AMB graft was examined by measuring the width of the FIZ at the most anterior part of the AMB tunnel. The clinical outcome was evaluated at the final follow-up with a side-to-side difference of KT-2000, Lysholm score, Tegner activity score, and IKDC objective form. Statistical analyses were performed using the Mann-Whitney U test and the chi-square test.

Results

Forty-five knees had tibial tunnel communication (Group C), whereas 62 knees did not have tunnel communication (Group NC). Demographic data between Group C and NC were not significantly different except for sex and the AMB graft diameter. Signal intensity grades of the FIZ were not significantly different between the C and NC groups (p=0.554). The mean width of the anterior FIZ in group C (0.90mm) was not significantly different from that in group NC (0.98mm) (p=0.404). The side-to-side difference of KT-2000 was not significantly different between group C (1.5±1.8 mm) and group NC (0.9±3.0 mm) (p=0.076). There was no significant difference in the clinical outcome, including Lysholm score (p=0.522), Tegner activity score (p=0.355), and IKDC objective form (p=0.321) between the two groups.

Conclusion

The present study suggested that intra-operative tibial tunnel communication would not result in the posterior shift of the AMB graft and affect the bone-tendon healing of the AMB graft in the DB ACL reconstruction.