How often cortisone injections are given varies based on the reason for the injection. This is determined on a case-by-case basis by the health care practitioner. If a single cortisone injection is curative, then further injections are unnecessary. Sometimes, a series of injections might be necessary; for example, cortisone injections for a trigger finger may be given every three weeks, to a maximum of three times in one affected finger. In other instances, such as knee osteoarthritis, a second cortisone injection may be given approximately three months after the first injection, but the injections are not generally continued on a regular basis.
Experience is important for the proper performance of joint aspiration and injection procedures. Physicians skilled in arthrocentesis usually have had the opportunity to gain experience with a rheumatologist or other physician who performs many procedures. Each joint has different anatomic landmarks, and novice physicians may need to review a textbook for approaches to an unfamiliar joint. Although arthrocentesis is a simple technique with minimal risk, physicians should have assistance or supervision with their first attempts at any site. Family physicians wanting to perform arthrocentesis on deep joints, such as the hip or vertebral joints, should obtain extensive training in these higher risk procedures. Additional training in arthrocentesis is available from the American Academy of Family Physicians.