osteoarthritis
"I have had intermittent knee pain since I was a teenager.  I am now 44 and a few years ago the knee pain began preventing me from running.  I had my first Synvisc-One injection about a year ago.  After reading about the studies online, which show mixed results, I was not expecting this to work but I thought it was worth a try.  The procedure itself was only mildly uncomfortable.  For about a week after my knee felt more irritated than usual...not terrible though.  About a week later..no pain, lasted 4 months. Then the pain returned.  My doc had me wait 6 months, and I had a 2nd injection.  This one irritated my knee for a few weeks and I was afraid it had made it worse but after 3 weeks...pain free.  Again lasted 4 months."