A medical that is implantable into a human or animal body or being an augmentation device for strengthening human or animal hard tissue for subsequent implantation of a separate implant. The device includes a sheath element suitable of being brought into contact, during a surgical operation, with live hard tissue and/or with hard tissue replacement material. The sheath element has a, for example, generally elongate shape and a longitudinal bore defining a longitudinal opening reaching from a proximal end of the sheath element into a distal direction, and a plurality of holes in a wall of the opening. Further, the device includes a liquefiable element that is insertable or inserted in the longitudinal opening and at least partly liquefiable by the impact of energy impinging from the proximal side.