My mom had osteoarthritis in her knees. She began having problems when she was in her late 70s, and they told her to wait for a knee replacement until it really started to bother her. 10 years later, when it really started to bother her, she asked the doctor about a knee replacement. He told her she was too old (and had some other health problems) for a replacement. Moral of the story, get a knee replacement when you are younger.
The first round of treatment was the Synvisc. The doctor injected the Synvisc with cortisone, with the idea that the cortisone would give immediate relief as the Synvisc took a while to work. He also added a bit of Novocain to stop pain at the injection site. The semiannual Synvisc injections worked for her for about 5 years before becoming ineffective.
Then, they tried the Euflexxa. One injection was incredibly painful for her for about 3 days. She iced it, took pain relievers, and stoically persevered. The results were good for the Euflexxa, as well, and she had some relief from her knee pain for about 3 years. Then, even the Euflexxa became ineffective.
It was only one injection in one knee over the years that was really painful for a few days. In the overall scheme of things, she was pleased with the relief she got from the injections.
She lived until she was 94 and was fond of saying that if she knew she was going to live so long, she would have taken better care of herself when she was younger.