CORR Insights®: Does Knee Flexion Influence the Relationship between the Femoral Tunnel and the Lateral Anatomic Structures During ACL Reconstruction?

摘要

Only after decades of studies systematically unraveling the structure and function of the native ACL [5] did orthopaedic surgeons accept anatomic ACL reconstruction as a suitable surgical procedure. Independent drilling of the femoral tunnel, most commonly through an anteromedial portal, consistently positions the tunnel within the anatomic footprint, which better restores the knee kinematics compared to a non-anatomic graft placed through transtibial drilling [8, 9]. While exhaustive research efforts have been made to understand the effects of intercondylar tunnel position on knee kinematics and clinical outcomes following ACL reconstruction, far less is known about the effect of drilling techniques on the position of the lateral structures of the femur relative to the tunnel outlet. Through cadaveric dissection, Laprade and colleagues [10] described the relative positions and sizes of several posterolateral knee structures. More recent studies, utilizing both three-dimensional (3-D) models and cadaveric specimens, investigated tunnel outlet position relative to posterolateral knee structures when drilling was performed through an anteromedial portal [4, 12]. Using angles such as 90°, 110°, 130°, but never exceeding 135° of knee flexion, these studies found that drilling under high knee-flexion angles reduced the risk of violating lateral structures [4, 12]. In another cadaveric in vitro study, Basdekis and colleagues [2] recommended against maximal knee flexion when drilling due to high variability in the maximum flexion angle achieved across specimens, as well as higher tunnel acuity.