Just getting old (not so gracefully)

My left knee has been acting up again. I don't know why. My kids are out of school, so I haven't even been able to go running, which is what usually triggers my knee pain. I have been icing it and wrapping it and dosing up on glucosamine and ibuprofen. So here is the question of the hour...

If my left knee is causing me so much pain that I can barely make it up and down the stairs, why does my RIGHT knee look like this???

Now I've had unexplained bruising before, but this seems more to me like unexplained massive internal hemorrhaging of the patella (I watch a lot of medical dramas.) This picture doesn't even do it justice. What the heck?!

Is this just a by-product of getting OLD?! Random bruises, joint pain like you wouldn't believe, sluggish metabolism, oh and numbness in my fingers for over a week all because I did some handstands?!