A radially expandable sheath is provided having a substantially closed distal end with at least two sidewalls extending proximally therefrom and defining a central lumen. Each sidewall can have a substantially concave outer surface adapted to seat a graft member, and each side wall is at least partially separated by a longitudinally oriented slot that extends from a proximal end along a substantial length of each sidewall. The slot preferably terminates at a position just proximal to the distal end. The device can also include a sheath expander that is adapted to be disposed in the central lumen of the radially expandable sheath and that is configured to flex the sidewalls to radially expand the sheath so as to fix a graft member within a bone tunnel.