Effect of Femoral Tunnel Location on Outcomes after Anatomic Single Bundle Anterior Cruciate Ligament Reconstruction

Abstract Background Anterior cruciate ligament (ACL) reconstruction technique has continued to evolve over time. From the early 1990s, orthopedic surgeons performed arthroscopic ACL reconstruction using a transtibial technique. However, latter studies demonstrated that the transtibial technique is unable to locate the femoral tunnel (FT) in the native ACL femoral footprint and results in unsatisfactory clinical outcomes. Subsequently, anatomical ACL reconstruction using the tibial tunnel independent technique became the most utilized technique for FT placement at the anatomical footprint. Aim of the Work to compare clinical outcomes and graft failure after anatomical single-bundle ACLR with FT placed at different positions. Patients and Methods We performed a comprehensive literature search of the following databases from their inception dates to July 2024: PubMed, Cochrane Central Register of Controlled Trials [CENTRAL], and Web of Science. Searches were carried out in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses). The full search strategy is (anterior cruciate ligament [MeSH Terms] OR ACL[Title/Abstract]) AND (femoral tunnel[Title/Abstract] OR femoral aperture[Title/Abstract]) Results This systematic review compared the outcomes of femoral tunnel (FT) positions in anatomical single-bundle ACL reconstruction using tibial independent (TI) techniques. Seven studies involving 1,051 patients were included, comparing anteromedial bundle (AMB) with posterolateral (PLB) and central positions. While there were no significant differences in patient-reported outcomes or sagittal knee laxity between AMB and other positions, a subclinical difference of 3-4 points in Lysholm and IKDC scores favored AMB. Rotational stability was assessed clinically without instrumental evaluation, and the lack of long-term follow-up limited conclusions on complications like osteoarthritis (OA). The Lachman and pivot-shift tests were used to assess knee stability, focusing on grade 0 as normal to avoid controversy over mild grade 1 findings. Despite the limited quality of included studies, this review provides a comprehensive analysis, highlighting the need for higher-quality trials in the future. The review is the first to specifically compare FT positions in anatomical ACL reconstruction using TI techniques, contrasting with previous studies that often compared anatomical with non- anatomical placements, particularly when using the transtibial (TT) approach. The search was extensive but limited to English-language studies, potentially introducing publication bias. Conclusion Placement of FT at AMB position likely reduces the risk of failure/revision than placement at the central position. Placement of FT at AMB position achieved better anterior stability than placement at either the PLB or the central position with subclinical difference. These is no evidence of difference in patient-reported outcomes and rotational stability by pivot shift test between the three FT positions.