Comparison of Inside-Out and Outside-In Methods of Femoral Tunnel Preparation in Anterior Cruciate Ligament (ACL) Reconstruction Using 3D-CT.

Introduction Anterior cruciate ligament (ACL) reconstruction techniques continue to evolve and the need to address the more anatomical femoral tunnel placement of the graft is critical, and in our study, we assessed the placement of femoral tunnel via transportal and retrograde drilling techniques. Material and methods Sixty patients where n=31 for retrograde, n=29 for transportal were assessed via CT knee for the femoral tunnel aperture on the intercondylar ridge via high low and deep shallow direction ratio and interpreted accordingly. Results In our study, the femoral tunnel done via transportal method (n=29) has a deep shallow ratio range of 22%-47% and mean of 31.9±6.5, and graft is anatomical in 79%. The femoral tunnel done via the retrograde method (n=31) has a deep shallow depth ratio range of 11%-41% with a mean of 27.5±6.5 and graft is anatomical in 77% of the study group and the p-value means the ratio is 0.01 (significant). The femoral tunnel done via transportal method (n=29) has a high low ratio range of 19%-45% and mean of 32.9±6.3 and graft is anatomical in 72%. The femoral tunnel done via the retrograde method (n=31) has a deep shallow depth ratio range of 20%-38% with a mean of 33.9±4.1 and graft is anatomical in 94% of the study group with a p-value mean ratio being 0.51 (insignificant). Conclusion Watch out for the femoral tunnel placement in a deep shallow direction while going for standard transportal technique and high low direction while performing retrograde technique.