On 4/30/07, employee was washing hauler tire, when he slipped on the concrete slab and twisted his right knee. He did not wish to see a doctor until 11/19/07. At that time the doctor diagnosed strained knee ligaments and place his knee in a brace. No restrictive duty was issued. EE had surgery on knee 2/15/08. He returned to full duty on 3/31/08.