EE STATED THAT HE WAS WALKING BESIDE A MAINTAINCE VEHICLE WHEN HIS RIGHT FOOT SLIPPED ON AN AREA OF SLICK BOTTOM. HE STATED THAT BEFORE HR EGAINED HIS BALANCE HIS RIGHT KNEE HYPEREXTENDED CAUS ING PAIN IN AND AROUND THE RIGHT KNEE. EE MISSEDFIRST SCHEDULED SHIFT ON 8-6-01.