1.   Tony Angotti crouched so quickly his knees popped.

2.   I could hear the knee pop and I sure could feel it.

3.   Kluwe was trying to slide down to the floor where he was working on a puzzle when he heard his knee pop.

4.   She was a tall, thin, loose-limbed woman, said her mother, and every so often her knee would pop out.

5.   When a jawbone cracked in Carolina and a knee popped on Jacksonville over the weekend, the grisly sounds could be heard by the Dallas Cowboys.

6.   The week after that run, Harris planted his foot on a cut and his knee popped.