Anterior Cruciate Ligament ACL Tear

A 23-year-old collegiate football player presents to the sports medicine clinic one week after an acute non-contact knee injury sustained while pivoting at high speed. He reports an audible pop, immediate collapse, severe pain, and rapid swelling within 2 hours. On examination, he has a positive Lachman test with Grade 2 laxity and soft endpoint, positive anterior drawer test, and positive pivot shift test with clunk. MRI of the knee is obtained. The structure marked **A** in the sagittal T2-weighted image demonstrates discontinuous wavy fibers with high T2 signal at the femoral attachment. Which of the following best describes the primary mechanism of injury in this patient?