The ACL has two functional bundles — anteromedial (AM) and posterolateral (PL) — with complementary roles. The AM bundle is the primary restraint against anterior tibial translation throughout the range of motion. The PL bundle contributes primarily in extension and provides rotational control. Anatomical single-bundle ACL reconstruction targets the centre of the native footprint to restore combined function.
| Origin | Posterolateral femoral condyle — AM bundle superiorly, PL bundle inferiorly |
|---|---|
| Insertion | Tibial plateau — AM bundle anterior, PL bundle posterolateral to AM |
| Actions | AM bundle: anterior tibial translation restraint at all flexion angles. PL bundle: rotational restraint and extension stability |
|---|
Recognition of the ACL bundle anatomy guides anatomical tunnel placement in reconstruction, positioning the femoral tunnel to restore the native ACL footprint centre and isometry pattern. The native ACL footprint anatomy is identifiable arthroscopically from the lateral wall resident's ridge and bifurcate ridge landmarks.
Single or double-bundle ACL reconstruction using native footprint landmarks to restore anteromedial and posterolateral bundle function.
