Abstract: An orthopaedic assembly comprises a bone fastener and a head. The bone fastener comprises a shaft with a proximal end and a distal end. The proximal end forms a tip of the bone fastener. A head post is located at the distal end, for mounting a separate head on the bone fastener. The head and the head post are each provided with a respective part of a mount for mounting the head on the head post. The mount comprises an opening in a first lockable part in which a second lockable part of the mount can be admitted. The head is mountable on the head post by moving the head towards the head post and thereby sliding the first lockable part over the second lockable part in a sliding direction, to admit the second lockable part in the opening. The head is lockable in position on the head once the second lockable part is admitted to a predetermined depth into the opening by turning the first lockable part around an axis extending in the sliding direction.

Abstract: An expandable implant (1) implantable in an intra-osseous cavity of a bone comprises an anchoring body (2) having a distal end and a proximal end for anchoring the distal end relative to a part of the bone outside the cavity. An expandable part (4), for in the intra-osseous cavity, is fixated to the anchoring body, e.g. at the distal end. The expandable part comprises a movable piece with a load supporting surface for supporting a wall of the cavity against a load acting on the bone. The movable piece is movable away from the anchoring body in a direction of expansion perpendicular to the longitudinal direction, to bring the load supporting surface from an initial position in a non-expanded state to an expanded position in a expanded state in which the load supporting surface abuts to the wall. A driving part (70) is movable relative to the proximal end of the anchoring body.