Drive your hips through.

Once the bar reaches your knees, drive your hips forward aggressively to meet it.
Drive the hips
HIPS FORWARD, BAR UP
HIPS FORWARD, BAR UP
Juggernaut
Remember to drive your hips as soon as it hits your knees. Don't wait. If you wait, you're gonna arch.
Elite FTS
What we want to achieve with an ideal and optimal deadlift lockout is when you feel the bar reach the bottom of your knee, then the athlete will begin driving the hips through to meet the bar at lockout. So as the bar rises, the hip comes forward and they meet at the top. Rather than pulling the bar up and back into the hip, we want the bar to move in a straight line throughout the lift.
Juggernaut
OPEN THE BOOK
OPEN THE BOOK
Squat University
When you get to [your knees] pull it in and squeeze your butt. So you're keeping [the bar] closer [to your body] so it changes how long you got to pull it and it doesn't keep your hips high.
Super Training
As soon as the bar hits the middle of your kneecap, you should be driving your hips forward as hard as possible and flexing your butt.
Neversate