Graft Inclination Angles in Anterior Cruciate Ligament Reconstruction Vary Depending on Femoral Tunnel Reaming Method: Comparison Among Transtibial, Anteromedial Portal, and Outside-In Retrograde Drilling Techniques

摘要

Purpose: To compare graft coronal and sagittal inclination angles in anterior cruciate ligament (ACL) reconstruction performed by different femoral tunnel drilling techniques with respect to intact native ACL. Methods: In total, 72 patients were prospectively enrolled in the study. The inclusion criteria were complete ACL rupture and patient age between 18 and 55 years. Reconstructions were performed using 4 different femoral tunnel drilling technique: transtibial (TT), anteromedial portal with rigid (AMP-RR) or flexible (AMP-FR) reamer, and outside-in retrograde drilling (OI) techniques. Eighteen patients with intact native ACL were included as controls. Sagittal and coronal graft inclination angles were measured by magnetic resonance imaging 6 months after the procedure by 1 radiologist blinded in regards to the used technique. Results: OI and AMP-FR techniques allowed for the maintenance of native-like ACL inclination in both the sagittal and coronal planes, whereas TT and AMP-RR increased the sagittal angle by a mean of 9.5 degrees (P < .001) and 6.7 degrees (P = .003), respectively, compared with native ACLs. AMP-RR and TT also showed increased sagittal graft inclination compared with AMP-FR (+6.1 degrees, P = .009 and +9.0 degrees, P < .001, respectively) and OI- drilling techniques (+5.5 degrees, P = .024 and +8.4 degrees, P < .001, respectively). No differences were observed among study groups in terms of coronal graft inclination. Conclusions: The study hypothesis was partially confirmed, since OI and AMP-FR techniques, but not AMP-RR, using an independent portal for femoral drilling produce a more anatomic graft inclination on the sagittal plane with respect to TT.