ELECTRICIAN USED THE ON-BOARD MANLIFT TO GET OFF A HYDRAULIC POWER SHOVEL. WHEN HE STEPPED OUT OF THE MANLIFT TO THE GROUND HE HEARD A ""POP"" IN HIS RIGHT KNEE AND COULDN'T PUT WEIGHT ON IT. TH E MANLIFT WAS ONLY 4""-6"" OFF OF THE GROUND AND THE TERRAIN WAS GOOD. HE RECENTLY BEGAN PHYSICAL THERAPY.