Question: Kansas Subscriber Answer: Here's why: If your physician administered a knee injection during the visit to help alleviate the patient's pain, then appending modifier 25 to the E/M service would be more appropriate. As a therapeutic, "000" day global service, the knee injection is presumed to include some evaluation and management of the patient. You denote that the E/M service done by your physician was above and beyond the usual preoperative care associated with the injection by appending modifier 25 to the E/M code. In this situation, you would report the appropriate E/M code from 99212-99215; the correct knee x-ray code from 73560-73564 (Radiologic examination, knee ...); and 20610 (Arthrocentesis, aspiration and/or injection; major joint or bursa [e.g., shoulder, hip, knee joint, subacromial bursa]) for the knee injection.