EE WAS EXITING CAT 16G GRADER. WHEN HE REACHED THE GROUND LEVEL WITH HIS RIGHT LEG, HIS LEFT LEG- WHICH WAS STILL ON THE STEP - SWUNG UNDER THE GRADER AND HE STRAINED HIS LEFT KNEE. INJURY REP ORTED 9/13/2002 EVALUATED AND RELEASED. RESTRICTIONS AFTER 9/19/02. AMEND AT REQUEST OF MSHA FIELD OFFICE.