All-Epiphyseal Anterior Cruciate Ligament Femoral Tunnel Drilling: Avoiding Injury to the Physis, Lateral Collateral Ligament, Anterolateral Ligament, and Popliteusd - A 3-Dimensional Computed Tomography Study

摘要

Purpose: To investigate the relation of the at-risk structures (distal femoral physis, lateral collateral ligament, anterolateral ligament, popliteus, and articular cartilage) during all-epiphyseal femoral tunnel drilling. A second purpose was 2-fold: (1) to develop recommendations for tunnel placement and orientation that anatomically reconstruct the anterior cruciate ligament (ACL) while minimizing the risk of injury to these at-risk structures, and (2) to allow for maximal tunnel length to increase the amount of graft in the socket to facilitate healing. Methods: Three-dimensional models of 6 skeletally immature knees (aged 711 years) were reconstructed from computed tomography and used to simulate all-epiphyseal femoral tunnels. Tunnels began within the ACL footprint and were directed laterally or anterolaterally, with the goal of avoiding injury to at-risk structures. The spatial relation between the ideal tunnel and these structures was evaluated. Full-length tunnels and partial length condyle sockets were simulated in the models using the same trajectories. Results: An anterolateral tunnel could be placed to avoid direct injury to lateral structures. The safe zone on the anterolateral aspect of the femur was larger than that of a tunnel with a direct lateral trajectory (median 127 mm(2) vs 83 mm(2), P = .028). Anterolateral tunnels were longer than direct lateral tunnels (median 30 mm vs 24 mm, P = .041). Safe angles for anterolateral tunnels were 34 degrees to 40 degrees from the posterior condylar axis; direct lateral tunnels were drilled 4 degrees to 9 degrees from the posterior condylar axis. Sockets could be placed without direct injury to structures at risk with either orientation. Conclusions: An all-epiphyseal ACL femoral tunnel can be placed without causing direct injury to at-risk structures. A tunnel angled anterolaterally from the ACL origin is longer and has a larger safe zone compared with the direct lateral tunnel.