AFTER WORKING A 12-HOUR SHIFT, EE WITH PRE-EXISTING KNEE CONDITION WAS DESCENDING A FLIGHT OF STAIRS TO GO HOME. ABOUT 2/3 OF THE WAY DOWN THE STAIRS, THE INDIVIDUAL FELT A SHARP PAIN IN THE BAD KNEE WHICH CAUSED THE EE TO TWIST RIGHT ANKLE AND BREAK A SMALL BONE IN THE RIGHT FOOT.