Tension Changes Within the Bundles of Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction at Different Knee Flexion Angles: A Study Using a 3-Dimensional Finite Element Model

초록

Purpose: The aim of this study was to determine the change in length and tension of the reconstructed anterior cruciate ligament (ACL) double bundles at different knee flexion angles by use of a 3-dimensional finite element model. Methods: The right knees of 12 living subjects were scanned with a high-resolution computed tomography scanner at 0 degrees, 45 degrees, 90 degrees, and 135 degrees of knee flexion. Several modeling programs were used to simulate double-bundle ACL reconstruction. A finite element model of each bundle with a tension of 20 N was put into each tunnel followed by fixation of the bundles. The tension and length changes of each bundle at different knee flexion angles were assessed. Results: For the anteromedial bundle, the length decreased gradually between 45 degrees and 90 degrees of knee flexion and then reached a plateau, whereas the length of the posterolateral bundle significantly decreased at 45 degrees and 90 degrees of flexion but then increased at full flexion. The reaction force of the anteromedial graft slightly decreased at 45 degrees and then remained constant between 90 degrees and 135 degrees of knee flexion. The reaction force of the posterolateral bundle at full extension slightly decreased at 45 degrees and 90 degrees of flexion, followed by a rebound increase at 135 degrees. Conclusions: We found that both bundles functioned throughout the arc of flexion with consistency in tension, although their lengths decreased. The 2 ACL grafts did not function in a reciprocal manner, unlike previous descriptions. Clinical Relevance: The data obtained for length and tension versus flexion angle have the potential to suggest the appropriate knee position for graft fixation and tensioning to be near extension in clinical situations.

키워드