THE EE WAS REMOVING AN OXYGEN BOTTLE FROM THE RACK, WHICH HAD A 20"" SNOW DRIFT IN FRONT OF IT.THE BOTTLE SHIFTED AS HE REMOVED IT, CAUSING HIMTO TWIST HIS KNEE. THE EE DID NOT SEEK MEDICAL ATTENTION UNTIL 1-04-02. AT THAT TIME IT WAS DETERMINED THERE WAS TORN CARTILAGE. SURGERY IS TENTATIVELY SCHEDULED FOR 1-10-02.