The fibular collateral ligament can be visualized in its entire course in the coronal plane suggesting anterior translation of the lateral tibia relative to the femur.
This is confirmed in the sagittal plane: the posterolateral tibia is approx 9 mm anterior to a vertical line tangent to the posterior lateral femoral condyle , the PCL is more vertical distally , and there is a mild bi-concavity of the sulcus terminalis that could represent an old kissing contusion (soft call).
The mid ACL is irregular , compatible w/ partial tear, more specifically, the anteromedial bundle , which helps stabilize against rotational load, and likely posterolateral.
Knowledge of the 2 anatomic bundles of the ACL is important for better stratifying partial tears for potential selective-bundle ACL reconstructions because single-bundle reconstructions restore anteroposterior tibial translation, but not tibial rotation.
This case has not yet been confirmed arthroscopically.
1 Casagranda et al. Normal Appearance and Complications of Double-Bundle and Selective-Bundle Anterior Cruciate Ligament Reconstructions Using Optimal MRI Techniques. AJR:192, May 2009.
Study description: MRI LOWER EXTREMITY JOINT W/O CONTRAST - RIGHT