Full knee extension magnetic resonance imaging for the evaluation of intercondylar roof impingement after anatomical double-bundle anterior cruciate ligament reconstruction

Purpose The purpose of this study was to reveal the relationship between anatomically placed anterior cruciate ligament (ACL) graft and the intercondylar roof using magnetic resonance imaging (MRI). Methods Twenty patients undergoing anatomical doublebundle ACL reconstruction were included in this study. Anatomical double-bundle ACL reconstruction was performed with two femoral tunnels (antero-medial; AM and postero-lateral; PL) and two tibial tunnels. Hamstring autograft was used in all cases. More than 6 months after operation, MRI was performed with full knee extension. The relationship between the graft and the intercondylar roof was evaluated using an axial view of the T2 image at the most distal slice of the intercondylar roof. Qualitative evaluation of the ACL graft was performed with a sagittal view of the T2 image. Tunnel placement was evaluated with three-dimensional computed tomography (3D-CT) and radiographs. The extension angle of the knee was also evaluated with 3D-CT. Results In 12 subjects, the ACL graft touched the roof (Touch group) but no graft deformation was observed. In 8 subjects, no roof–graft contact was observed (Non-touch group). In 1 case, the ACL graft was bowed posteriorly. Signal intensity alteration of the graft was observed in 3 cases. No significant difference in femoral and tibial tunnel placement was observed between the Touch and Non-touch groups. All subjects attained full knee extension. Conclusion Although graft–roof impingement after anatomical double-bundle ACL reconstruction was suspected in some cases after the MRI evaluation, no extension loss in the knee was observed. In these suspected cases of impingement, long-term follow-up will be needed to determine the connection between any potential pathological effects. For the clinical relevance, MRI is an effective tool to determine the status of roof impingement in anatomical double-bundle ACL reconstruction. Level of evidence Case controlled study, Level III.