Hyaluronic Acid
A naturally occurring substance found in synovial fluid that gives it its thick, gel-like consistency and lubricating properties. Also used as an injection treatment for joint pain.
Extended Definition
Hyaluronic acid (HA), also known as hyaluronan, is a naturally occurring polysaccharide (complex sugar molecule) found throughout the human body. In joints, it’s a key component of synovial fluid, responsible for the fluid’s viscosity and ability to lubricate and cushion joint surfaces.
In healthy joints, hyaluronic acid molecules form long chains that trap water, creating a thick, gel-like substance. This unique structure allows synovial fluid to act as both a lubricant during slow movements and a shock absorber during rapid, high-impact activities. However, in osteoarthritic joints, the concentration and quality of hyaluronic acid decreases, leading to thinner, less protective synovial fluid.
Medical-grade hyaluronic acid used in injections is typically derived from bacterial fermentation or rooster combs. These products come in different molecular weights—high molecular weight HA tends to provide longer-lasting effects, while lower molecular weight HA may penetrate tissues more easily. Brands like Synvisc, Hyalgan, and Euflexxa each have different molecular weight formulations, which may affect their effectiveness and duration of relief for different patients.
Related Terms
More Treatments Terms
View allCorticosteroid
A powerful anti-inflammatory medication similar to cortisol (a hormone naturally produced by the body) that can be injected into joints to quickly reduce swelling and pain.
Molecular Weight
The size of a molecule measured in daltons. In hyaluronic acid products, molecular weight affects how thick and long-lasting the injection is, with higher molecular weight typically providing longer relief.
NSAID
Non-Steroidal Anti-Inflammatory Drug - a type of medication that reduces pain, inflammation, and fever by blocking enzymes that produce inflammatory chemicals in the body.
Nerve Block
An injection of anesthetic near specific nerves to temporarily block pain signals. Used for diagnosis, pain relief, or before surgery. Effects last hours to months depending on medication used.
Orthotic
A custom or prefabricated device worn to support, align, or correct joint and limb function. For knee arthritis, includes braces, shoe inserts, and wedged insoles that reduce joint stress.