If you have osteoarthritis in your knee , you might be able to get injections of hyaluronic acid. These are also known as hyaluronan injections. Hyaluronan injections are used to keep joints moving and reduce pain, especially when other treatments haven’t worked. Hyaluronic acid is naturally found inside many joints in your body in the synovial fluid. In a healthy joint, synovial fluid works as a lubricant, allowing the cartilage covering the ends of your joints to glide against one another. This keeps your joints healthy and moving freely. It’s thought that injections of hyaluronic acid could help to lubricate joints where the cartilage has been roughened by osteoarthritis and may even help regeneration of the cartilage.