Might be time to adjust your bike fit to suit body changes. It's unlikely our joints will get healthier and stronger with age.
At 61 my hips and knees still seem pretty good but diagnostics this year show deterioration in my neck and both shoulders. I've made lots of little and a few significant adjustments to suit those changes -- reducing reach on the drop bar road bike, switching from flat to riser to albatross bars on the hybrid, changing saddles and positions. Doing more physical therapy but more carefully to minimize joint stress.
Arthritis and osteoporosis run in my family so I'm doing what I can to delay the inevitable. If I'm lucky I'll delay it indefinitely, or at least until I'm finished with this body.