A surgical file instrument comprising a file, file guide, an outer split casing, a motion converter converting rotary motion to reciprocal motion and file assembly. The file assembly consists of an angular shaped elongated tube fairing into a generally flat portion defining the guide for the blade of the file, a complementary shaped file and a plastic rod insert having a lumen for the file and a lumen defining a passage for flowing a fluid to the surgical site. The motion converter consists of a planetary gear system connected to the battery powered motor that rotates a platen which in turn drives a cam and cam follower fitted into the cam slot for driving a drum for producing rectilinear motion. The file assembly is attached to the drum for reciprocating the file blade for use in a medical procedure for removing bone or a portion thereof.