Viscosupplementation using hyaluronic acid (HA) can reduce joint pain in early to moderate osteoarthritis. HA is a naturally occurring substances that exists in the normal synovial fluid within joints. This fluid acts as a lubricant and also helps to supply nutrients to the articular cartilage. This is the cartilage that enables the joint surfaces to move smoothly over each other. As part of the natural ageing process, joint fluid changes and this is thought to contribute to pain. An HA injection can help to reestablish more normal joint fluid which in turn can help to reduce the symptoms of pain and stiffness.