Viscosupplementation refers to the injection of a gel-like fluid called hyaluronic acid into the joint. Hyaluronan is a natural substance present in the joint fluid that assists in lubrication. It allows smooth movement of the cartilage covered articulating surfaces of the joint. With arthritis the level of hyaluronic acid decreases. By adding hyaluronic acid to  an arthritis joint, the theory is that this will help with movement and pain.

These injections are indicated in the management of knee osteoarthritis that has not responded to non-surgical treatment options such as pain medications, physical therapy and corticosteroid injections. The hyaluronic acid preparation is injected directly into the joint to replenish the diminished synovial fluid, thereby enhancing its lubricating properties. A single dose or a total of three separate doses over several weeks, may be required for optimum benefit.

Some patients may experience mild pain, swelling, warmth and redness at the injection site for up to 48 hours. Headache and joint stiffness may also occur in some cases. Ice packs and an analgesic may be used, if required, to ease the discomfort. Any strenuous activity such as jogging or tennis should be completely avoided for 48 hours to a week after the injection and should be resumed only after consultation with your doctor.

Recent research has not found viscosupplementation injections to reduce pain or improve function, however some patient report pain relief with the injections.

Please note: Immediately consult your doctor if you develop fever or the pain and swelling fail to resolve after 48 hours following the injection.

Viscosupplementation - AAOS link