This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Thigh, Knee,Leg,Foot & Ankle injuries, Subject name: Orthopaedics
A 22-year-old male basketball player presents with a swollen, painful left knee. He was on a fast break and as he began to jump for an alley-oop, he felt his knee give out and he collapsed to the floor. What is the most likely diagnosis 
Select and explain. 
A. Patello-femoral dislocation, B. Anterior cruciate ligament injury, C. Medial collateral ligament injury, D. Posterior cruciate ligament injury
B: Anterior cruciate ligament injury
Answer: B: Anterior cruciate ligament injury 
Explanation: The history provided describes a noncontact injury to the knee during an acceleration-deceleration/pivoting move with the patient experiencing a feeling of giving way in his knee. The player quickly accumulates a knee effusion and has significant pain. These findings are characteristic descriptions of an ACL injury. The Lachman test is diagnostic for this injury, and an MRI would confirm the diagnosis.