EE WAS ASSISTING TO INSTALL LADDER TO #4 ROLL CRUSHER ON THE MAIN FLOOR OF C&S DEPT. STATES THAT TURNED TO STEP AWAY AND FELT HIS KNEE POP. DENIES CATCHING FOOT ON EQUIPMENT. STATES THAT DISCO MFORT WAS NOT BAD AT THE TIME, HOWEVER OVER THE NEXT 24 HOURS HE HAD MARKED SWELLING AND INCREASED DISCOMFORT KNEE WAS TREATED WITH IMMOBILIZER. AND NWB