EE WAS GETTING OUT OF A PICKUP TRUCK. WHEN HE WENT TO STEP ONTO THE GROUND, HE STEPPED ONTO THE EDGE OF THE SIDEWALK AND TWISTED HIS LEFT KNEE. BETWEEN THE EDGE OF THE SIDEWALK AND ACTUAL GROU ND LEVEL, THERE WAS A 3"" DIFFERENCE IN ELEVATION. DID NOT GOT OFF WORK UNTIL 11-14-01.