Are you taking Glucosamaine?
My dad swore by Joint Flex (I think that was the name)
My dad was pinned by a tow-motor against a guard rail when he was 46 years old (in 1990) - the tow-motor crushed his knee - the only thing that was left was his patella. He was immobilized for about 10 weeks while worker's comp decided when they wanted to fix it. He had the total knee put in that was cement-less so he wasn't able to bend it right away. He had to keep it immobilized for several weeks and by the time he was allowed to bend it - it wouldn't bend. He had to be knocked out and the dr had to manually bend it himself. It was a long road for him but he went back to working and trucking, and farming full time. He finally had it revised in 2004. And then only the pad in b/n the joint needed replaced. He is now 63 (almost 64) and he farms, still drives truck, snowmobiles, and does just about everything the dr told him NOT to do. He's fallen off ladders, off the back of wagons and trucks and got his shirt caught in the power take off of the tractor while standing on top of a silo with no one around.(that was scary) Plus he's had 2 back surgeries.
Walking behind a mower on a golf course wouldn't be easy on your knee for certain - I'm assuming the ground is rather 'smooth' so at least you HOPEFULLY wouldn't step in a hole! yikes And I'm sure you have more miles on it than some just b/c of that.
If you aren't taking glucosamaine try that while you are waiting to get into your dr. It won't be a cure-all but hopefully it will help.
good luck!