Navigated ACL reconstruction and lateral tenodesis

Although in recent years many studies demonstrated that reconstruction of the Anterior Cruciate ligament (ACl) restored functional knee stability in most cases, several studies have now shown that normal knee joint kinematics are not restored, with the pivot shift phenomenon remaining in many cases. More recently anatomical reconstruction of the ACl with double-bundle gracilis and semitendinosus tendon grafts, reproducing the Antero Medial (AM) and poster lateral (pl) bundles, have been proposed to produce a better biomechanical outcome, especially during rotatory loads. Computerassisted ACl reconstruction has been used because it could be very effective in evaluating the global performance of the reconstructed knee, being able to calculate very accurately the anteroposterior (Ap) displacement and the internal rotation (IR) and external rotation (ER) of the tibia with respect to the femur. Introduction In a first study (1) we compared single (n= 20; group A) and double (n= 20; group B) bundle ACl reconstruction “in vivo” and we find that both techniques significantly reduced Ap displacement and IR and ER of the tibia with respect to preoperative ACl–deficient condition (p<0.05). Comparing groups, no differences in Ap tibial displacement and IR and ER of the tibia were found (Ap: 3.7 mm and 5.2 mm, p=0.06; IR: 16.3° and 16.6°, p=0.09; ER: 15.7° and 15.1°, p=0.72) in group A and B respectively. on the basis of these results we concluded that the hypothesis that addition of the posterolateral bundle to the anteromedial bundle is able to reduce internal rotation of the tibia at different degrees of knee flexion is not confirmed and so the effective role of the anatomical double-bundle procedure in better restoring knee kinematics should be questioned in an in vivo model. However many methods of tenodesing the lateral aspect of the tibia to the femur to reduce IR of the tibia and minimize anterior translation of the tibia relative to the femur as a backup for intraarticular reconstruction, have been also suggested. So the goal of our second study was to evaluate the effect, on the IR of the tibia, of a lateral reconstruction in addition to a standard single bundle ACl reconstruction as compared with an anatomic double bundle ACl reconstruction (2). Both surgical techniques reduced significantly Ap displacement, IR and ER of the tibia respect to pre-operative ACl deficient condition (p<0.05). Comparing the single bundle reconstruction after the addition of the lateral tenodesis and the double bundle reconstruction no differences in Ap tibial displacement and in ER of tibia were found (p=0.90 and 0.15, respectively) while a significant reduction in IR of the tibia was found in group A after the addition of the lateral tenodesis respect to the group B after the addition of the pl bundle (p=0.0001).