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

Purpose It 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. Methods In 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. Results Fourteen 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). Conclusions ACL 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 Evidence Level III, meta-analysis.