What is hyaluronic acid?

Hyaluronic acid, also known as hyaluronan, is a naturally occurring substance that is a primary element of the extracellular matrix. Although more commonly associated with the skin, hyaluronic acid is a key ingredient found in the fluid that lubricates the joints (synovial fluid) and protects the cells that form articular cartilage. Hyaluronic acid can play an important role in decreasing inflammation as well as regenerating damaged tissues.

Hyaluronic Acid | Manhattan NY

What conditions can be treated with hyaluronic acid?

Hyaluronic acid is an FDA-approved biologic treatment for knee osteoarthritis. When incorporated with water, hyaluronic acid thickens into a gel-like substance that can be directly administered into the knee joint, also known as viscosupplementation. This treatment alternative is often used when conservative therapy is unsuccessful, and the patient has elected to delay or forgo surgery. A recent meta-analysis of the studies for hyaluronic acid effectiveness found improvement in both knee pain and knee function in individuals treated with hyaluronic acid. Dr. Answorth A. Allen, orthopedic surgeon, treats patients in Manhattan, New York City, Westchester, Long Island and surrounding areas, who are experiencing knee osteoarthritis that can be treated with hyaluronic acid.

Are there different treatment options for hyaluronic acid therapy?

There are several commercially available viscosupplementation preparations of hyaluronic acid. Dr. Allen considers the patient’s age, activity level, medical history, and desired outcome when selecting one of the following hyaluronic acid formulas:


Approved by the FDA in 1997, Hyalgan is a gel-like substance consisting of purified natural sodium hyaluronate, known as hyalectin, in a saline solution. The active ingredient is taken from the fleshy growth (comb) on a rooster head. Hyalgan is a series of five injections administered in a single-dose injection procedure.


Is an advanced, patented hyaluronic acid (HA) that uses NASHA technology, (non-animal hyaluronic acid).  It is a highly purified product, manufactured without any animal-sourced materials, ensuring that the risk of contaminants or impurities is close to zero. It is a single injection specifically used to treat symptoms of osteoarthritis.


Also approved by the FDA in 1997, Synvisc (hylan G-F 20) is a hyaluronan derivative created using the gelatinous substances found in a chicken comb. This 2-mm intra-articular injection is delivered in a single-dose injection. In 2009, a new Synvisc product, known as Synvisc-One, was approved by the FDA as a single-dose 6 mm injection. The best results from this viscosupplementation therapy occur when the synovial fluids are removed from the knee cavity prior to the first intra-articular injection.


Is the only non-animal sourced single injection treatment used as a viscosupplementation for treating pain in osteoarthritis (OA) of the knee.  While some viscosupplementation injections are administered in a series of three, Monovisc is administered in a single dose procedure.  It contains the highest amount of hyaluronan available in a single injection and may provide pain relief for up to six months.


The key ingredient in Euflexxa is a synthetic version of hyaluronic acid that has been shown to interrupt the inflammatory processes causing pain and swelling. This synthetic hyaluronan is the first formulation not derived from avian protein as it is extracted from biologically modified bacteria. Euflexxa is administered in a single dose injection. Excessive fluid surrounding the knee is often drained prior to the injection to prevent dilution of the active ingredient with injection. Most patients notice the full benefits of Euflexxa around five weeks after completing the injection series and typically lasts for at least three months.


Similar to Hyalgan, Orthovisc is a high molecular weight solution of purified sodium hyaluronate and saline. The active ingredient in Orthovisc is derived from a non-animal source. Approved by the FDA in 2004, Orthovisc is administered in a single dose injection procedure with benefits lasting as long as six months.

For more information on hyaluronic acid biologic treatments, or to discuss your joint preservation treatment options (for patients under 60) please contact the office of Answorth A. Allen, MD, orthopedic surgeon at the Hospital for Special Surgery (HSS), serving Manhattan, New York City, Westchester, Long Island and surrounding areas.