Hyaluronan
"As a 64 yr old female I was having severe pain and stiffness in both knees due to advanced osteoarthritis. Ortho doc recommended a series of 4 weekly Orthovisc injections in both knees.  For me, the shots were very painful. There was no improvement until after the 3rd week. I am now 1 wk. post the 4th and final shots and have greatly decreased pain. I now can exercise regularly without pain. The only difficulty I still have is walking up and down stairs. I highly recommended the orthovisc injection treatment."