Well this is from the heart - LITERALLY... I have tried to reason with this and I have had an epiphany. My various prescriptions have screwed my knees for life. I have a few ideas to partially solve this but my specialist really sucks....
I am now on my fourth or fifth drug to lower my pressure. They did not work out as they all have side affects. Yes they did lower the pressure - individully they horribly affect the ability to hike...
There is something called fuzzy arthritis. Caused by drugs. Check out your side affects and look for gout and pain in knees and stuff. Won't happen right away...
don't skimp on the meds but if your hiking drops from 15-30 to .5 miles.... yea there's your sign.
Why do I know this... Well I stopped for a week; my knee came back a little.... go figure.
I am not a doc - but there is something clearly there.
Consult your doc.