THE EMPLOYEE WAS DESCENDING A 6 FOOT STEP LADDER AND WHEN HIS LEFT FOOT CONTACTED THE BOTTOM STEP IT SLIPPED OFF AND WENT TO THE GROUND. THE EMPLOYEE LOST HIS BALANCE AND TWISTED HIS LEFT KNEE . THE EMPLOYEE HAD SURGERY ON THE LEFT KNEE ON 8/13/03. EMPLOYEE BEGAN LOSING TIME ON 8/13/03.