I've had both knees replaced about a year apart. Each time I tried to hold off as long as I could with Synvisc injections, and it helped some. Twice on the right knee before it quit working and only worked a little on the left, so in my case I just bought myself 3-6 months delay per knee. I'm glad I tried it because I did not want to schedule surgery until fall when I was mostly done with gardening. Not a long term solution, and I was told you have to wait 3 months after an injection before they will schedule surgery.