Review Question - QID 218180

A 66-year-old homemaker presents 3 weeks after an elective total knee arthroplasty with a red, inflamed, and painful knee, and the findings shown in Figure A. She notes that she did fall and scrape her knee on the pavement when getting into her car while leaving the hospital after surgery. She had minimal pain initially and didn't think about it again until it started to swell and become painful last week after a bout of diverticulitis that resolved with a course of antibiotics. On exam in the office, she has a mild extensor lag with an appreciable effusion and a small healing wound adjacent to her incision with surrounding ecchymosis. Which of the following is the next best step in management?