The adrenal glands are part of the endocrine system, which regulates hormone levels in the body. They are small, pyramid-shaped glands that rest on the top of each kidney. The adrenal glands produce a hormone called cortisol. Cortisol has many functions but most importantly extra cortisol can be produced to help manage the effects of infection, trauma, and emotional stress. In this instance, otherwise healthy tissue in the knee is seen as infectious and is attacked by the body’s own white blood cells causing a painful inflammation. Sometimes however, even the extra production of cortisol does not adequately control the immune system response. Corticosteroids are drugs that can be inhaled, given orally, topically, or by intravenous or intramuscular injection. They are synthetically-produced hormones that are very similar to cortisol. They block white blood cells from attacking the tissue and decrease the inflammatory-causing substances these immune cells produce. Corticosteroids are frequently used for treatment of inflammatory and autoimmune disorders, such as rheumatoid arthritis, systemic lupus erythematosus, and certain respiratory disorders.