The Relationship Between Lateral Femoral Anatomic Structures and the Femoral Tunnel Outlet in Anterior Cruciate Ligament Reconstruction Using the Transportal Technique: A 3-Dimensional Simulation Analysis

Abstract

Background: The relationship between the lateral femoral anatomic structures and femoral tunnel outlet according to changes in knee flexion and transverse drill angle during femoral tunnel creation in anterior cruciate ligament (ACL) reconstruction remains unclear. Purpose: To investigate the relationships between the lateral femoral anatomic structures and femoral tunnel outlet according to various knee flexion and transverse drill angles and to determine appropriate angles at which to minimize possible damage to the lateral femoral anatomic structures. Study Design: Controlled laboratory study. Methods: Simulation of ACL reconstruction was conducted using a 3-dimensional reconstructed knee model from the knees of 30 patients. Femoral tunnels were created using combinations of 4 knee flexion and 3 transverse drill angles. Distances between the femoral tunnel outlet and lateral femoral anatomic structures (minimum safe distance, 12 mm), tunnel length, and tunnel wall breakage were assessed. Results: Knee flexion and transverse drill angles independently affected distances between the femoral tunnel outlet and lateral femoral anatomic structures. As knee flexion angle increased, the distance to the lateral collateral ligament, lateral epicondyle, and popliteal tendon decreased, whereas the distance to the lateral head of the gastrocnemius increased (P