Results suggest that small increases in tibial slope do not affect A-P translations or in situ forces in the cruciate ligaments. However, increasing slope causes an anterior shift in tibial resting position that is accentuated under axial loads. This suggests that increasing tibial slope may be beneficial in reducing tibial sag in a PCL-deficient knee, whereas decreasing slope may be protective in an ACL-deficient knee.
The results of the current study suggest that, from a biomechanical point of view, it may be beneficial to reconstruct both bundles of the anterior cruciate ligament to better restore normal anterior tibial translation and combined rotation.
The anterior cruciate ligament (ACL) consists of two major fiber bundles, namely the anteromedial and posterolateral bundle. When the knee is extended, the posterolateral bundle (PL) is tight and the anteromedial (AM) bundle is moderately lax. As the knee is flexed, the femoral attachment of the ACL becomes a more horizontal orientation; causing the AM bundle to tighten and the PL bundle to relax. There is some degree of variability for the femoral origin of the anterome-dial and posterolateral bundle. The anteromedial bundle is located proximal and anterior in the femoral ACL origin (high and deep in the notch when the knee is flexed at 90 degrees ); the posterolateral bundle starts in the distal and posterior aspect of the femoral ACL origin (shallow and low when the knee is flexed at 90 degrees ). In the frontal plane the anteromedial bundle origin is in the 10:30 clock position and the postero-lateral bundle origin in the 9:30 clock position. At the tibial insertion the ACL fans out to form the foot region. The anteromedial bundle insertion is in the anterior part of the tibial ACL footprint, the posterolateral bundle in the posterior part. While the anteromedial bundle is the primary restraint against anterior tibial translation, the posterolateral bundle tends to stabilize the knee near full extension, particularly against rotatory loads.
Recently, the interest in surgical techniques that reconstruct the anteromedial (AM) and the posterolateral (PL) bundles of the anterior cruciate ligament (ACL) has risen. This review focuses on the structural as well as the mechanical properties of the ACL and the anatomical details of the femoral origin, midsubstance, and tibial insertion of AM and PL bundles of the ACL. The terminology of AM and PL bundles is chosen according to the tibial insertion and determined by their functional tensioning pattern throughout knee flexion. Close to extension the AM is moderately loose and the PL is tight. As the knee is flexed, the femoral attachment of the ACL becomes more horizontally oriented, causing the AM bundle to tighten and the PM bundle to loosen up. The ACL has been described to be restraint to anterior tibial displacement and internal tibial rotation. The rotational component might be represented by the PL bundle. The femoral origin has an oval shape with the center of the AM close to over-the-top position and the center of the PL close to the anterior and inferior cartilage margin. Tibial and femoral insertions of the ACL are over 3.5 times larger when compared to the midsubstance and tunnel placement is more challenging because of the limited size of potential grafts selection of tunnel site placement. For reconstruction, both bone-patellar tendon-bone (BPTB) and quadrupled hamstring grafts are used. Structural properties of a 10 mm wide BPTB or quadrupled hamstring graft have been reported to be comparable with those of the native ACL.
This study confirms that proprioceptive and neuromuscular training is appropriate for the prevention of knee and ankle injuries among female European team handball players.
Double-bundle anterior cruciate ligament reconstruction should be performed using anatomical tunnel placement of the anteromedial and posterolateral bundles. Nonanatomical double-bundle reconstruction may fail to show any clinical superiority to single-bundle reconstruction and should be avoided.
At the time of initial fixation, there appears to be a small biomechanical advantage to the second tibial tunnel in the setting of two-bundle anterior cruciate ligament reconstruction.
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