Asterisk. With 1 rather bad knee and the other prone to hyper extension, they are worth there weight in gold. Not a single day of pain from riding, which at my age included a couple of what I am sure would have been knee surgery moments. So long as you wear the sleeves that they come with or long bicycle pants they wont chafe, although some wear them with nothing under.
I did not go through insurance when I bought mine, but did have my Dr. write a prescription so I could claim them under the cafeteria plan.