Cartilaginous intra-articular bodies float freely within the synovial fluid, which they require for nutrition and growth. Progressive enlargement and ossification occur with time. If they remain free, they continue to grow larger and more calcified. In severe cases, they may occupy the entire joint space or penetrate to adjacent tissues. Alternately, they can deposit in the synovial lining, reestablish a blood supply, and become replaced by bone. On occasion, synovial reattachment can lead to complete reabsorption of the cartilage fragment.
SYNVISC (hylan g-f 20) is a gel-like mixture that is made up of hylan A fluid, hylan B gel, and salt water. Hylan A and hylan B are made from a substance called hyaluronan (pronounced hy-al-u-ROE-nan), also known as sodium hyaluronate that comes from chicken combs. Hyaluronan is a natural substance found in the body and is present in very high amounts in joints. The body's own hyaluronan acts like a lubricant and a shock absorber in the joint and is needed for the joint to work properly. Osteoarthritis (pronounced os-TE-o-ar-THRI-tis) (OA) is a type of arthritis that involves the wearing down of cartilage (the protective covering on the ends of your bones). In OA, there may not be enough hyaluronan, and there may be a decrease in the quality of the hyaluronan in the joint. SYNVISC (hylan g-f 20) comes in syringes containing 2 mL (half a teaspoon) of product. SYNVISC (hylan g-f 20) is injected directly into your knee.
In medicine , a joint injection ( intra-articular injection ) is a procedure used in the treatment of inflammatory joint conditions , such as rheumatoid arthritis , psoriatic arthritis , gout , tendinitis , bursitis , Carpal Tunnel Syndrome ,  and occasionally osteoarthritis .   A hypodermic needle is injected into the affected joint where it delivers a dose of any one of many anti-inflammatory agents, the most common of which are corticosteroids . Hyaluronic acid , because of its high viscosity , is sometimes used to replace bursa fluids.  The technique may be used to also withdraw excess fluid from the joint.