SLIPPED ON WET CONCRETE, DID NOT BOTHER HIM WHILE AT WORK. HE WENT ON VACATION, RETURNED TO WORK, IT WAS BOTHERING HIM SLIGHTLY BUT HE IGNORED IT. FINALLY ON 9-1 HE REPORTED IT TO MANAGEMENT. WE SENT HIM TO A DOCTOR. DOCTOR DID XRAY DID NOT FIND ANYTHING. HE CONTINUED TO WORK. DOCTOR SENT FOR MRI. MRI DETERMINED TORN LIGAMENT REQUIRING SURGERY.