FOAMed

40-year-old male is brought by EMS after being struck on his left side while crossing the street by a vehicle at 20 mph. He is visibly uncomfortable, laying on his right side, and refusing to move his left leg. His left lower extremity has an obvious effusion along with localized swelling and tenderness over the lateral aspect of his knee joint. Ligament and meniscal evaluation cannot be completed due to pain on knee exam. There are no signs of neurovascular compromise on exam. What’s the next step in your evaluation and treatment?