Review Question - QID 211667

You’re called to the emergency department to evaluate a patient with a “knee dislocation." Upon questioning, the patient reports falling on his leg after slipping on a pool deck. After the fall he had a large bulge on the lateral aspect of his knee (Figure F) that went away with the sensation of a large “clunk." On exam, he has a large effusion and tenderness over the medial patellofemoral retinaculum. Ligamentous exam demonstrates normal Lachman and posterior drawer tests and a 3 quadrants of lateral patellar translation at 0 and 30 degrees of knee flexion. Which of the following is most likely to be his knee radiograph in the emergency department?