The underlying mechanism often involves a rapid change in direction, sudden stop, landing after a jump, or direct contact to the knee.[1] It is more common in athletes, particularly those who participate in alpine skiing, football (soccer), American football, or basketball.[1][2] Diagnosis is typically made by physical examination and is sometimes supported by magnetic resonance imaging (MRI).[1] Physical examination will often show tenderness around the knee joint, reduced range of motion of the knee, and increased looseness of the joint.[6]