Before trying Synvisc-One, tell your doctor if you have had an allergic reaction, such as swelling of the face, tongue or throat, respiratory difficulty, rash, itching or hives to SYNVISC or any hyaluronan-based products. Allergic reactions, some which can be potentially severe, have been reported during the use of Synvisc-One. Should not be used in patients with an infected knee joint, skin disease or infection around the area where the injection will be given, and should be used with caution when there is swelling of the legs due to problems with venous stasis or lymphatic drainage.
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. 
Experience is important for the proper performance of joint aspiration and injection procedures. Physicians skilled in arthrocentesis usually have had the opportunity to gain experience with a rheumatologist or other physician who performs many procedures. Each joint has different anatomic landmarks, and novice physicians may need to review a textbook for approaches to an unfamiliar joint. Although arthrocentesis is a simple technique with minimal risk, physicians should have assistance or supervision with their first attempts at any site. Family physicians wanting to perform arthrocentesis on deep joints, such as the hip or vertebral joints, should obtain extensive training in these higher risk procedures. Additional training in arthrocentesis is available from the American Academy of Family Physicians.