Bone on bone diagnosis was 14 months ago. My knees still click when I twist them, but there has been zero pain for last 8-9 months. Regular walking (30 minutes 4-5 times a week) is what I am doing. Only medication worth mentioning is baby aspirin (80 mg) on alternate days. But I take it to prevent heart attack, not for knee particularly. There is history of heart attacks on both my parents side. I will
celebrate my 78th birthday this month, never had heart attacks, strokes or arthritis..yet..knock on wood. Totally pain free for several months.
As for knee surgery, if pain comes back and is chronic, only then I will opt for knee replacement. Keeping weight down and exercise is what I prefer.
78 and heart attack history probably not a good candidate for the operation. I had my op at 64 and actually waited too long and ended up with nerve damage. 71 now and doing well except for bouts of numbness.
Good luck & God Bless You