The invention relates to a device 1, in particular for insertion into the medullary cavity of a fractured tubular bone, comprising at least one outer element 2 which comprises at least one expandable section 3, 4, at least one inner element 12 which is at least partially disposed within the outer element 2 and at least one operating means 13 which is operable to force the expandable section 3, 4 from an unexpanded state to an expanded state. The operating means 13 is coupled with the expandable section 3, 4 such that the operating means 13 is further operable to force the expandable section 3, 4 from the expanded state to the unexpanded state. Thus, the operating means 13 is operatively coupled to the inner element 12 for reversibly expanding the expandable sections 3, 4. To this end, nut-like tip piece 6 acts as a coupling means that interacts with the inner element 12 so as to provide an operative connection between the inner element 12 and the expandable sections 3, 4.
