It's like you said "what Ranger does not have trouble with his knees?"
My knees are toast too, (no knee pads were ever used in my era, we just took a knee in rocks / any terrain.
Firstly, physical therapy should help. I think flutter kicks help,
also swimming helps and the ol' mountain bike.
It's the pounding from running and the twisting stress from rucking/ hiking that agravates the knees.
Somedays after a run, simply walking down a flight of stairs is too much for me!
![LOL :lol:](./images/smilies/o_icon_lol.gif)
Don't ignore the pain Ranger, in your line of work you need to be mobile.
I'm no Doctor, just another Ranger with fucked up knees
![LOL :lol:](./images/smilies/o_icon_lol.gif)
Good Luck Bro'.