Review Question - QID 218712

A 6-year-old girl is brought to an urgent care by her mother while on a beach vacation because she won't put weight on her right knee. The knee is mildly swollen and she cries when the knee is passively ranged beyond 20° of flexion. Radiographs show no acute osseous pathology, she is afebrile with a temperature of 37.5° C, and laboratory studies reveal a white blood cell count (WBC) of 10,500/mm3, an erythrocyte sedimentation rate (ESR) of 22 mm/hr, and a CRP of 1.0 mg/dL. Based on a Kocher criteria score of 1/4 in this patient, which of the following statements is most true about the best next step in her care?