Review Question - QID 103449

A 55-year-old man presents to the emergency department with right knee pain. He woke last night with sudden-onset, sharp, 10/10 non-radiating pain in his right knee. He denies recent trauma and he has no known medical problems. He denies tobacco use and will often drink 6-8 beers or spirits on weekend nights. His temperature is 98.6°F (37.0°C), pulse is 90/min, blood pressure is 140/90 mmHg, respirations are 16/min, and oxygen saturation is 97% on room air. Physical exam reveals an erythematous, edematous right knee. Passive extension of the knee is limited by pain. Synovial fluid aspiration is performed and sent for analysis, which reveals 20,000 leukocytes/mm^3, and no organisms visualized. Microscopic examination of synovial fluid is shown in Figure A. Which of the following is the most likely diagnosis?