I've found physicians to be very noncommittal - no promises and little advice. FWIW, I have a brand new $700 knee brace that's intended to open up the joint on the medial side (inside) to reduce the bone on bone rub. I've ridden with it a couple of times, but it kind of sucks. I just moved to Thornton, CO, where the roads suck too - lots of traffic and few shoulders. If the fun is gone, I'm not riding.
I didn't want to bore folks with a long story, but I'm in the process of getting the design for my retirement home finalized, with construction to begin next spring. I plan to be the GC and do as much as the skilled work as I can. I'll be driving a 90 mile round trip nearly every day in addition to working on the house. I can't risk a knee replacement in the middle of an 18 month build schedule. After the build, I plan to start building a hot rod. I'd try motorcycles again, but the last time almost resulted in divorce.
Also, a doctor with any ethics won't perform a knee replacement any earlier than necessary, since they don't last forever and two is about the limit. For now, I get injections of this stuff.
http://www.synviscone.com/
Two of my bikes are up for sale (cheap) on craig's list.