An attachment device for attaching a bone plate to a bone having a medullary canal is provided. The attachment device comprises a central portion having a recess to accommodate the bone plate and at least two lateral fixation support members projecting from the central portion. The lateral fixation support members are arranged on opposite sides of the central portion, wherein each lateral fixation support member comprises a hole extending through the lateral fixation support member and are adapted to accommodate a fixation element therethrough to fix the attachment device to bone. The angles of the hole axes of the holes are different with respect to a perpendicular bisector of the centers of the holes and the hole axes lie outside of the medullary canal.
