The knee is a common joint that is injected. It is recommended that patients limit their weight bearing activity for 1 - 2 days after an injection so as to give it the best chance to succeed. Overuse in the first 6 hours after injection can actually aggravate the arthritis because local anesthetic is typically combined with the steroid and patients may be putting too much stress on their arthritic joint.
Recommendations vary, but most physicians will avoid injecting a single joint more than 3 times in a year. For example, you could have your left knee injected two times a year and your right knee injected two times.
There are several choices of steroid that can be used and is typically dependent on physician preference (e.g. Depo-Medrol, Aristospan, Kenalog and Celestone). Patients often feel better in the exam room, but may notice as the anesthetic wears off, it may take up to 10 days to see that benefit again.
Potential side effects include increased pain or swelling of the joint in the first 24 hours. Swelling, redness or increased pain after 24 hours may signal a joint infection. This is a rare adverse effect but needs immediate attention. In more superficial areas, such as "trigger injections" used for localized muscle pain, the skin may thin, or in dark skinned patients, may develop a lightening or hypopigmentation. Other potential but rare adverse effects include, but are not limited to tendon rupture and damage to the bone.
Local injection into the muscle (buttocks) or a course of oral corticosteroids can provide a "systemic" (i.e. all over the body effect). It is less helpful when a specific joint or area is involved. If repeated frequently, it can increase the risk of developing some of the common adverse effects one sees from taking oral steroids, including osteoporosis and cataracts.
Answer provided by Scott J. Zashin, M.D., clinical assistant professor at University of Texas Southwestern Medical School, Division of Rheumatology, in Dallas, Texas. Dr. Zashin is also an attending physician at Presbyterian Hospitals of Dallas and Plano. He is a fellow of the American College of Physicians and the American College of Rheumatology and a member of the American Medical Association. Dr. Zashin is author of Arthritis Without Pain - The Miracle Of Anti-TNF Blockers. The book is a must-have for anyone on one of the biologic drugs (Enbrel, Remicade, Humira) or considering the biologic drugs. Read my review of the book.