Which signs on-field may indicate an ACL injury and require medical evaluation?

• A. A loud pop at injury, rapid swelling, instability, and pain
• B. Immediate full weight-bearing without pain
• C. No swelling or instability, but mild soreness only
• D. Pain that subsides within minutes with normal gait

Answer: (A)

On-field ACL injuries typically present with a loud pop at the moment of injury, rapid swelling inside the knee, a sense that the knee is unstable or gives way, and significant pain. This combination is strongly associated with an ACL tear, so those signs together rightly indicate a need for medical evaluation to confirm the diagnosis and plan treatment.

If someone can bear weight immediately without pain, that’s less consistent with a major ligament tear. No swelling or instability with only mild soreness suggests a minor issue or strain rather than an ACL rupture. Pain that fades quickly and a normal gait point away from a serious ACL injury.