Which history finding is typically reported at the time of an ACL injury?

Which history finding is typically reported at the time of an ACL injury?

• A. Sport participation that involves cutting, pivoting, or landing from a jump
• B. Hearing a \"pop\"
• C. Immediate effusion within 12 hours after injury
• D. Feeling of instability/giving way with 2 or more ADLs

Answer: (B)

Hearing a pop at the moment of injury is the hallmark history finding for an ACL tear. This audible event occurs when the ligament fibers rupture during a pivot, sudden change in direction, or awkward landing, and it is what patients commonly report right as the injury happens. Right after, many experience knee swelling from bleeding into the joint, which typically becomes more noticeable within hours, not necessarily instantly. The idea of “giving way” or instability can be reported as well, but that symptom often develops as the knee becomes weakened and painful, rather than being the immediate event itself. The option describing the activity involved is related to how ACL injuries occur but does not describe what the patient experiences at the exact moment of tearing.

Hearing a pop at the moment of injury is the hallmark history finding for an ACL tear. This audible event occurs when the ligament fibers rupture during a pivot, sudden change in direction, or awkward landing, and it is what patients commonly report right as the injury happens. Right after, many experience knee swelling from bleeding into the joint, which typically becomes more noticeable within hours, not necessarily instantly. The idea of “giving way” or instability can be reported as well, but that symptom often develops as the knee becomes weakened and painful, rather than being the immediate event itself. The option describing the activity involved is related to how ACL injuries occur but does not describe what the patient experiences at the exact moment of tearing.