Today's run was pretty much the exact same as yesterday's--same time of day, same route, same weather, same sweaty shorts (okay, not that last one). I guess I wore different shoes, too.
I'm still worried about my knee, but based on experience more than anything. I do seem to fell better when I run outside, though. I think the variations in stride help my knee, and you just can't get those on a treadmill. Of course, now that it's getting so cold I'm going to have to start worrying about protecting my knees from the cold.