Synvisc One is an osteoarthritis treatment that contains hylan, a natural found in the synovial fluid of the joints. When injected directly into the joints, Synvisc One acts as a replacement for synovial fluid. The therapeutic effect of this treatment is achieved through viscosupplementation, a process in which the rheological and physiological state of arthritic joint tissues are reestablished. This increases mobility of the joint through decreased pain and inflammation.