Viscosupplementation is a procedure in which a thick fluid called hyaluronate is injected into the knee joint. There are no cures for osteoarthritis, so viscosupplementation will not cure osteoarthritis of the knee. However, it is thought that hyaluronate will improve the lubricating properties of the synovial fluid, reduce the pain from osteoarthritis of the knee, improve mobility, and provide a higher and more comfortable level of activity.
People with osteoarthritis of the knee have lower levels of hyaluronic acid in their synovial fluid. What fluid does remain in the joint is often thinner and less effective than the fluid in healthy joints. It is not able to protect the cartilage and bone from grinding and damage as well as it once could. For each dose of a viscosupplement, a doctor injects hyaluronic acid (also called hyaluron or hyaluronate) into the knee joint’s synovial fluid.
The additional hyaluronic acid fills the joint area and increases lubrication in the joint, making movement much easier. Researchers also think that the injection of hyaluronic acid may stimulate the body to produce more of its own hyaluronic acid, which will further cushion the joint and make the effects of the injections last longer.
Viscosupplementation is ideal for people who have mild to moderate OA of the knee. It may be especially useful for people who have not responded to other OA treatments, such as physical therapy, weight loss, pain relievers, and corticosteroid injections.
People with severe OA, especially those who have bone-to-bone contact in their knee joint, will likely not benefit from viscosupplement injections and will instead need more aggressive treatment, such as surgery or joint replacement.
The benefits of viscosupplementation injections are not immediate. Because the injections are given over time, you may begin to feel some benefit after the first injection, but the greatest benefit may not be felt until several weeks or maybe even months after your first injection. The injections may be repeated every six months if you receive a benefit from the initial series of injections.