An ACL injury typically presents with which combination of findings?

• A. Fever and warmth around the knee
• B. Knee pain with instability, swelling, and a popping sound after an acute twisting injury
• C. Ankle swelling
• D. Shoulder pain

Answer: (B)

An ACL tear is classically seen after a sudden pivot or twist with the foot planted. The ACL prevents the tibia from sliding forward, so tearing it causes knee instability or a sense that the knee could “give way.” Bleeding into the joint from the injury leads to quick swelling (effusion) within hours, and many patients report a popping sensation at the moment of injury. So the combination of knee pain with instability, rapid swelling, and a popping sound after an acute twisting injury best fits an ACL tear. Fever and warmth around the knee would point to infection, ankle swelling involves a different joint, and shoulder pain is unrelated.