Employee was moving a ladder to reach a area that needed to be patched. Vac truck hose was in the floor in the area I was working in. I stepped backwards & tripped over the hose, fell down & hit a rock laying in floor with my left ankle. Employee didn't go to the doctor until later and was advised on 12-4-2012 the ankle was broken and would need to have surgery on 12-7-2012.