I've had cortisone injections in both my wrist and my foot. The injection in my foot hurt like h*ll to the point I thought I was going to pass out and fall off the table. The injection site in my foot was extremely painful for about 24hours following the dreaded injection but after that my foot felt great.

The three injections I had in my wrist worked equally as well and were given without any pain. However, the relief only lasted about 6 - 8 weeks with each at which time the pain and discomfort returned and seemed to be worse than before the injection. I finally saw a chiropractor who worked on my wrist for about 8 weeks and I've been relatively pain free for over a year.

I hope your knee feels better soon.