Guidelines from the American College of Rheumatology conditionally recommend the use of intra-articular corticosteroid injections for treatment of knee osteoarthritis. 51 The duration of pain relief is one to two weeks in most trials, with a few showing improvements lasting three to four weeks. 60 – 63 Research uniformly supports the safety of intra-articular corticosteroid injections for treatment of knee osteoarthritis; however, these studies are limited by lack of histologic data and poor long-term follow-up. 64 A Cochrane review found weak evidence for the use of corticosteroid injections for the treatment of knee rheumatoid arthritis. 52
In 2014, Dr. George Habib who has authored many studies trying to find out if, how, and when a cortisone injection into the knee has side-effects throughout the body, found that injection of the glucosteroid methylprednisolone acetate disrupted the hypothalamic-pituitary-adrenal axis in 25% of subject patients receiving the injection for knee osteoarthritis. These were patients who first failed to respond to nonsteroidal anti-inflammatory medications and physical therapy. The disruption was transient, lasting 2 – 4 weeks after the injection.