- Discussion:
    - ACL tears most often occur during football and basketball in younger patients, and occur most often from skiing injuries in older patients;
    - substantial anterior tibial shear forces that stress ACL are produced from quadriceps contraction, esp in 0-30 deg of extension;
    - typically, the ACL is torn in a noncontact deceleration situation that produces a valgus twisting injury;
            - this usually occurs when the athlete lands on the leg and quickly pivots in the opposite direction. (see pivot shift)
    - mechanisms reported as possibly able to disrupt ACL w/ minimal injury to other structures are:
            - extension or hyperextension
            - marked internal rotation of tibia on femur (may be most important);
            - pure deceleration
            - valgus position

Noninjured Knees of Patients With Noncontact ACL Injuries Display Higher Average Anterior and Internal Rotational Knee Laxity Compared With Healthy Knees of a Noninjured Population.

Association of noncontact ACL injury with presence and thickness of a bony ridge on the anteromedial aspect of the femoral intercondylar notch. 

Bone Contusion and Associated Meniscal and Medial Collateral Ligament Injury in Patients with Anterior Cruciate Ligament Rupture

An Association of Lateral Knee Sagittal Anatomic Factors with Non-Contact ACL Injury: Sex or Geometry

What Strains the Anterior Cruciate Ligament During a Pivot Landing?

Risk assessment for anterior cruciate ligament injury

Does Limited Internal Femoral Rotation Increase Peak Anterior Cruciate Ligament Strain During a Simulated Pivot Landing?