Equal Kinematics Between Central Anatomic Single-Bundle and Double-Bundle Anterior Cruciate Ligament Reconstructions

PurposeThe purpose of this study was to compare the kinematics of a central anatomic single-bundle anterior cruciate ligament (ACL) reconstruction with a double-bundle ACL reconstruction by use of hamstring grafts and anatomic tunnel placement.MethodsAnterior tibial translation and rotation were measured with a computer navigation system in 8 pairs of fresh-frozen cadaveric knees by use of a 133-N anterior force, an internal and external torque of 10 Nm, and an anterior force (133 N) combined with an internal rotation torque (10 Nm). Tests were performed at 30° and 60° of flexion with the ACL intact, the ACL transected, and after reconstruction of one side of a pair with either a single or a double-bundle construct.ResultsAt 30° of flexion, cutting the ACL increased anterior translation under an anterior force (P < .0001), an internal rotation torque (P = .02), and a combined anterior force plus internal rotation torque (P = .01). At 60° of flexion, transecting the ACL led to increased anterior translation only when an anterior force was used (P < .0001). Both single- and double-bundle reconstructions restored normal kinematics at 30° and 60° of knee flexion.ConclusionsCentral anatomic single-bundle ACL reconstruction with tunnels centered within the tibial and femoral insertions and double-bundle ACL reconstruction can restore normal anterior translation to the knee under anterior and rotational loads applied at 30° and 60° of flexion.Clinical RelevanceThe primary kinematic effect of an ACL injury is an increase in anterior tibial translation, but there is no significant change in maximum internal or external rotation. Single- and double-bundle ACL reconstructions are equally effective in restoring normal anterior translation to the knee under both anterior and rotational loads.