Abstract: A cannula including a hollow cannula body having first and second tubular end portions, a collapsible section interconnecting the end portions, the collapsible section including a plurality of circumferentially spaced arms extending between the end portions, wherein in an extended configuration the arms are substantially aligned with the first and second end portions and in a collapsed configuration the arms deform to extend radially outwardly and a flange extending radially outwardly from the first end portion, so that the arms and flange are spaced apart when the cannula body is in the collapsed configuration, thereby allowing tissue to be sandwiched therebetween to thereby effect a seal between the cannula and the tissue so that the cannula provides an opening through the tissue.

Abstract: A ligament fixation system comprising an expandable screw (11) with an atraumatic thread. The screw is expanded by insertion of an expansion screw (12) into a threaded longitudinal bore of the expandable screw to cause radial expansion of the screw. The system includes an insertion tool (32) having an outer sleeve (33) for insertion of the expandable screw and an inner relatively rotatable member (39) for insertion of the expansion screw. The tool includes a torque gauge. The invention extends to methods of fixing a tendon graft in a bone tunnel.