Early Structural Results After Anatomic Triple Bundle Anterior Cruciate Ligament Reconstruction Validated by Tunnel Location, Graft Orientation, and Static Anteroposterior Tibia-Femur Relationship

Abstract

To elucidate how closely the structural characteristics of the anterior cruciate ligament (ACL) grafts after anatomic triple bundle (ATB) reconstruction resembled those of the normal ACL. From 2012 to 2016, patients who underwent primary ATB ACL reconstruction using hamstring tendon autografts and the same number of healthy control subjects were included. Using magnetic resonance imaging (MRI) taken at 6months postoperatively, ACL graft orientation was evaluated by the angles against the tibial plateau measured in the sagittal and oblique coronal planes at the anteromedial and posterolateral portions (ACL-tibial plateau angle [ATA]). For factors affecting the graft orientation, the static tibiofemoral relationship was evaluated by anteroposterior tibial translocation (APTT) in the identical MRI using a previously established method, and tunnel locations were evaluated using the quadrant method. To test equivalence, the widely used two one-sided test procedure was performed, with the equivalence margins of 5° and 3mm for ATA and APTT, respectively. Thirty-five patients were enrolled for each group. ATAs were not significantly different, and the 95% confidence interval (CI) of these differences was within 5° (sagittal: P= .211 [95% CI,-2.9 to 0.6]; oblique coronal ATA for the anteromedial and posterolateral portions: P= .269 [95% CI,-1.9 to 0.5] and P= .456 [95% CI,-2.1 to 0.9], respectively). The difference in APTT was neither statistically nor clinically significant (P= .114; 95% CI,-2.0 to 0.2). These data suggest that ACL grafts using the ATB technique achieved a graft orientation equivalent to that of the normal ACL, with an equivalent postoperative anteroposterior tibiofemoral relationship in the static MRI. Thus, the ATB ACL reconstruction technique with the presented tunnel locations produced grafts that were similar to the native ACL in orientation. Level III, case-control study.