Q15
Single choice
A70-year-old man presents to urgent care complaining of a painful, swollen left knee. He previously has had no problems with this knee. Three days prior to onset, he went out dancing for 23 hours but recalls no specific injury. Examination of the knee reveals a moderatesized effusion and mild pain with any range of motion. Plain x-ray shows no fracture.
Which of the following is the best next management?