rbon1,
Fourteen years ago, I was (58 yo) training for a half marathon and L knee suddenly swelled like a melon. Long and short, my physician said "get a knee replacement (cartilage was gone, bone-on-bone) and you may be able to continue jogging (not running) or...give it up and live with it" (deal with the underlying arthritis later, in other words). I gave up running completely. Did some PT, without definitive results.

Took glucosamine (see how long ago this was?) and I thought I had achieved some kind of standoff. About 4-5 years after my diagnosis, I tried racquetball and was surprised I had recovered enough to stay with players my age. Even stopped the glucosamine completely, but that's another story. Been playing 3x/week until the present, but now I have to take nsaids. My wife has also been happy I can travel and accompany her on walking tours with the inevitable stairs. And since I race and prep my car myself, I am still limber enough to crawl under and perform major repair on my vehicles. All this time I was aware my R knee was compensating and would eventually run out of cartilage, too. And now I have to pay the piper and have an appointment with my doctor to schedule TKR.

My complaints: increasing difficulty going down stairs (BTW, USA is the most ADA-compliant country, hands down) and knees so noisy loose our spaniel grimaces everytime I get down on the floor to play with her. My apprehensions (other than surgery-related complications): reduced leg ROM and flexibility getting in and out of low cars with race seats; and stair performance no better than what it is, now. What tipped the balance? I bought my current car from a track buddy who underwent TKR with no problems. He's back to an open-wheel racer with a tighter cockpit. I'll take a chance on stairs.

The takeaway: it's been 14 good years with conscious joint management and adjustment of expectations. I read that the TKR age window is 50 - 80, which gets me (and you) farther away from the average with every passing day. I have given activity details to give a better understanding of the recovery and extended level of general activity possible; even with arthritic, or otherwise injured, joints. I am merely sharing, not recommending, since everyone's different and only you know when you will be ready and what relief direction you may choose. I am totally confident that if you decide to put off invasive intervention by more than a couple of years, new and better technology not may, but will, be available. So keep that in mind as well.

Best of luck to you! HTH