EE WAS REPLACING/REPAIRING A RADIATOR ON A 90TONEUCLID HE TWISTED HIS KNEE WHEN HE WAS STANDING ON THE LADDER OF THE TRK AND STARTED TO DESCEND HE DID NOT SEEK MED ATTENTION UNTIL 5/8/00. HE H AD SURGERY DONE ON 10/14/00. HE WAS NOT PLACED ON ANY RESTRICTED DUTY FROM 5/5/00 THRU 10/14/00