Okay, you've said this a few times. I didn't see others telling you to go back to the max rearward position. It's not for everyone. It does feel strange at first. Especially if you are just coming from flat pedals where you may have been doing more pushing with your toes. I'm sure most of us have our cleats somewhere between the fore and rearward limit.

There isn't one perfect magical position where everyone must put their cleats. For me, I've moved my cleats around as I've gotten use to different things. Mostly they have over the years moved toward the rear of the shoe. Maybe in a few years of getting use to using cleats you can re-visit moving your cleats back just to see if it does anything positive for your performance.

But with knees hurting, you have more important issues to get taken care of and that is more likely the angle of your shoe, heel in or heel out along with the possibility you might need shims or wedges..