How Accurate Are Anatomic Landmarks for Femoral Tunnel Positioning in Anterior Cruciate Ligament Reconstruction? An In Vivo Imaging Analysis Comparing Both Anteromedial Portal and Outside-In Techniques

PurposeTo assess the ability of 2 independent surgical techniques, an inside-out technique and an outside-in technique, using bony landmarks on the femoral wall, to place the anterior cruciate ligament graft anatomically.MethodsA retrospective single-center study was conducted in 2012 and included patients who underwent anterior cruciate ligament reconstruction. Two techniques were used: The lateral condylar wall was visualized from the anterolateral portal and tunnels were drilled “outside-in” in one group, whereas viewing was performed from the anteromedial portal and retrograde drilling (“inside-out”) was performed in the other group. The primary outcome measure was the placement of the tunnel center point on postoperative computed tomography scans with 3-dimensional reconstruction, according to the radiographic quadrant method of Bernard and Hertel. The measurements were compared with optimal placements according to Bird et al. Their reliability was assessed with Spearman (rho) and intraclass correlation coefficients.ResultsForty patients were included, with 20 in each group; the mean age was 29.8 ± 9.6 years, and there were 33 men and 7 women. The interobserver reliability and intraobserver reliability of measurements were good, with a Spearman ρ between 0.46 (P = .002) and 0.93 (P < .001) and an intraclass correlation coefficient between 0.44 (P = .001) and 0.86 (P < .001). The femoral tunnel positions of both techniques were close to the previously published anatomic placements, but there was a significant difference between our results and the theoretical position in proximal-distal measurements (P = .01). There was no difference in the anteroposterior measurements. There was no statistical difference in the accuracy of placement of the femoral tunnel center point between these 2 independent techniques.ConclusionsThe direct arthroscopic visualization of bony landmarks seems sufficient for accurate positioning of the femoral tunnel whatever the drilling technique. This finding is clinically relevant because the routine use of direct measurement techniques or intraoperative radiographs may not be necessary to obtain anatomic tunnel placement.Level of EvidenceLevel IV, case series.