A 72-year-old man injures his right knee in a car accident, and now it is swollen and extremely painful to bend the knee. X-rays of the knee rule out a fracture, and joint fluid aspiration reveals an opaque-colored fluid containing rhomboid crystals with weak-positive birefringence. Which of the following is the most appropriate next step in management?
oral prednisone intravenous antibiotics oral NSAIDs acetaminophen