Funny you'd say that! I'm in the boat I have really bad knees for my age, largely a genetic thing. My dad was one of 7 siblings not to get his replaced before 60ish and that's only because he didn't bother to, he was half crippled for the last few years of his life. I have a medical phobia and fear of needles that would put Manny Pacquiao to utter shame, I was told I had osteoarthritis in my knees but had a few things recommended before I actually need injections, and they have really been helping fingers crossed.
Stretch religiously! try folding a towel really tightly and kneeling with in under the joints for one Master. Never do any serious exercise without warming up and stretching before and after, especially if it's in cold weather. Never EVER run on pavement, some people can handle it but it's fucking brutal if you have joint problems. Take glucosamine, eat lots of green veggies and omega 3's along with that.