Intra-articular injections are sometimes used to relieve pain for people with osteoarthritis. These include injections with corticosteroids, hyaluronan and stem cells. Corticosteroid injections are undertaken to deliver this high dose anti-inflammatory agent within the joint to reduce inflammation of the joint lining (synovium), however, they may not work for everyone in the short term and in some people, repeated injections may be required to sustain symptom control. Hyaluronan injections have been developed to replicate the natural lubricant within the joint with reported benefits, however, its mechanism of action for osteoarthritis is contentious and it can be associated with increased pain in the short term. Stem cells are cells that are capable of developing into different types of tissue. These can be injected into an osteoarthritic joint and this type of therapy has been developed to stimulate regeneration of the tissues, such as cartilage, which consequently can improve symptoms and function and may reduce the need for future joint replacement.