EE WAS WORKING WITH CO-WORKERS TO STRING DRIP TUBE ON A ""RIPPED"" PAD SECTION. AFTER CUTTING THE DRIP TUBE TO LENGTH, HE SQUATTED DOWN TO PICK UP THE LOOSE ENDS OF THE TUBE TO PULL THEM INTO PO SITION. AS HE SQUATTED HE FELT HIS LEFT KNEE ""LOCK UP"" AND FELT A SHARP PAIN IN THE KNEE.