Titanium Alloy Expandable Interference Screws Expandable titanium interference screw, made of ASTM-F136 titanium alloy raw material with a superior and unique design, consists of four expandable  winged main shaft screws and internal expansion pin. Compared to standard interference screws, this implant provides the best and most superior contribution to the bone-tendon attachment by ensuring perfect surface contact as long as the length of the screw. 1,3mm-large expansion created by the internal expansion pin of the screw ensures that all exterior surface of the screw –as long as the length of the screw- puts a pressure on the bone tunnel surfaces together with the tendon and this creates excellent attachment.