I flew several times back and forth between France and the US (AF, KLM, AA, Delta), and despite people reclining in front of me, it never hurt my knees, ever, and I'm not small by any measure. Reclining the seat hardly affects the leg room because the frame of the seat is fixed, otherwise reclining would make the tray on the back to recline with it, which it doesn't.
At any rate, if your knees are at tray level, you should pick exit row seats in the first place. Or alley seats and putting your legs in the alley like I've done more than once.
What did happen once and really pissed me off is that once the guy in front of me reclined his seat while we were eating, which bumped my glass and spilled apple juice on my tray and myself. If he had asked before I would have warned him or I could have moved my glass, but noooo. Personally, I only recline when people start sleeping, in particular if the person behind me reclined his/her seat.