I believe my knees have gotten stronger over the years, and more used to the work I put them to--something to be grateful there!
But though the pain has eased much over time, they still manifest effects. I cannot sit still for very long without the knees having to shift position. I'm sure I annoy people when I sit near them on a couch. Constantly stretching, bending, twisting. It's the only way to keep them comfortable.
I think the biggest thing I have to be grateful for is that though the knees can hurt, they work! Though there is pain there is also strength, functionality, and capability--which is worth any pain considering the alternative.
I am grateful that there are so many "knees scriptures" that I can find reassurance in and great symbolism from.
Isaiah 35: 3
Strengthen ye the weak hands, and confirm the feeble knees.
Thy words have upholden him that was falling, and thou hast strengthened the feeble knees.
Doctrine and Covenants 81:5
Wherefore, be faithful; stand in the office which I have appointed unto you; succor the weak, lift up the hands which hang down, and strengthen the feeble knees.
They are weak, but they make me strong.