Comparison of Femoral Tunnel Length and Obliquity Between Transtibial, Anteromedial Portal, and Outside-In Surgical Techniques in Single-Bundle Anterior Cruciate Ligament Reconstruction: A Meta-analysis

PurposeIt is unclear whether femoral tunnel length and obliquity differ after transtibial and independent femoral drilling techniques of anterior cruciate ligament (ACL) reconstruction. This meta-analysis therefore compared femoral tunnel length and obliquity in patients who underwent ACL reconstruction by the transtibial, anteromedial (AM) portal, and outside-in (OI) techniques.MethodsIn accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, all studies comparing femoral tunnel length and obliquity with various measurement tools—from direct measurement to imaging methods such as plain radiography, computed tomography, or magnetic resonance imaging—in patients who underwent reconstruction by the transtibial or independent femoral drilling (AM portal or OI) techniques were included.ResultsFourteen studies were included in the meta-analysis. The femoral tunnel length was 7.8 to 11.0 mm longer (P < .05) and coronal obliquity was 7.5° to 29.1° more vertical (P < .05) with the transtibial technique than with the AM portal or OI technique. Femoral tunnel and graft obliquity in the sagittal plane, however, did not differ significantly (P > .05).ConclusionsACL reconstruction using the AM portal and OI femoral drilling techniques resulted in a shorter length and greater coronal obliquity of the femoral tunnel than did the transtibial technique. However, these 3 femoral drilling techniques resulted in similar obliquities of the femoral tunnel and graft in the sagittal plane.Level of EvidenceLevel III, meta-analysis.