Abstract: An intramedullary nail assembly comprises an intramedullary nail component (2) al, the nail component having at least one opening (14, 18) in its wall, and a fixation sleeve which has at least one opening (32) extending through it. One of the fixation sleeve and the nail component has a hollow bore so that the other of the sleeve and the nail component can be fitted within it in a coaxial sliding arrangement, with the openings in the wall of the nail component aligned with the openings in the fixation sleeve. A fixation pin (19) is inserted transversely through the openings in the wall of the nail component and the fixation sleeve when the said openings are aligned. An actuator (50) is used to cause the fixation sleeve to move axially relative to the nail component to cause a fixation pin inserted through the aligned openings in the nail component and the fixation sleeve to be gripped.