Double Bundle ACL Reconstruction: Evaluation of Knee Flexion Angles and Over-the-Top Techniques

Double bundle anterior cruciate ligament reconstruction (DB-ACLR) has recently gained popularity in Europe and Japan. This procedure utilizes two separate tissue grafts to replicate the two functional bundles of the intact anterior cruciate ligament (ACL). Therefore it is believed that the two grafts will be able to restore both the anterior and rotatory laxity to that of an intact knee. However, as in the case of a traditional single bundle ACL reconstruction, there are several variables that can affect the outcome. The knee flexion angle at which each of the two grafts are fixed, is one such variable. Since it is understood that an improper force distribution among the two grafts could lead to the failure one or both of the grafts, it is important to fix the grafts, such that the in situ force of each graft does not exceed that of their respective intact bundle. Therefore, one of the objectives of this thesis is to study if and how the knee flexion angle for graft fixation affects the force distribution of the two grafts in DB-ACLR.A second concern regarding DB-ACLR is related to the complications of drilling a second femoral tunnel. Not only can tunnel placement become more complex, but more problems may also arise in the event of a revision surgery. Therefore, a DB-ACLR procedure that utilizes only a single tibial and femoral tunnel will be investigated. In this procedure, a single femoral tunnel will be created for the PL graft, while the second graft will be fixed on the lateral femoral epicondyle via a staple (fixation protocol PL+OTT). In order to study the effect of the knee flexion angle of graft fixation, as well as the PL+OTT procedure, knee kinematics will be collected for the intact, ACL(-), and reconstructed knees under both a 134 N anterior tibial load, as well as a combined rotatory load of 10 N-m valgus, and 5 N-m internal/external tibial rotation. Lastly, the in situ force of the intact ACL, as well as the intact bundles will be determined, and compared with the in situ force of the grafts