Rollback of the femoral condyle in anatomical double-bundle anterior cruciate ligament reconstruction.

Abstract

The purpose of this study was to evaluate rollback of the femoral condyle in anatomical double-bundle anterior cruciate ligament reconstruction (ACL). Twenty-two subjects who underwent anatomical double-bundle ACL reconstruction were included in this study. More than 6 months after surgery, lateral radiographic imaging of the knee was performed with active full knee flexion. The most posterior tibiofemoral contact point was measured for evaluation of femoral rollback (rollback ratio). Flexion angle was also measured using the same radiograph, and the correlation between rollback and flexion angle was analyzed. As a control, radiographs of the healthy contralateral knees were evaluated. For clinical evaluation, side-to-side difference in anterior tibial translation (ATT) and pivot shift test were analyzed approximately 1 year after surgery. The rollback ratios of the operated knees and the healthy contralateral knees were 28.7 ± 6.6 and 29.7 ± 6.7%, respectively, from the posterior edge of the tibia. No significant difference in rollback was observed. The flexion angles of the operated knees and the healthy contralateral knees were 136 ± 11° and 140 ± 9°, respectively. No significant difference in knee flexion angle was observed. Significant correlation between femoral rollback and knee flexion angle was observed. The side-to-side difference in ATT was 0.7 mm, and no cases of positive pivot shift were observed. Anatomical double-bundle ACL reconstruction can restore normal femoral rollback in active full knee flexion. For clinical relevance, knees with anatomical double-bundle ACL reconstruction can flex with normal kinematics at the end of knee flexion angle. III.