My arthritic right knee has been holding up very well indeed since that last round of Synvisc injections in August. Very happy with the results. I'm sure I'll need more of that stuff eventually, but if I can get away with one round of shots annually or less (the previous round of shots held off the cranky knee syndrome for almost 18 months), that would be stellar. I'm riding pretty hard and the knee is really putting up with all that very nicely. Typical successful Synvisc results are 6-12 months of relief from arthritic knee conditions, if you get 12+ months it's working very well for you.
I also take a daily Glucosamine/Chondroitin supplement, which really does seem to help too.