Abstract: Improved ligament anchor structures and methods for affixing graft ligaments to bone are provided. The ligament anchor assembly includes a sleeve having gripping means for being firmly secured within a bone tunnel and a bore extending therethrough. The graft ligament is secured to an insert sized to pass through the bore in the sleeve. The bore in the sleeve and the external surface of the insert have cooperating asymmetrical teeth formed thereon so that the insert can pass through the sleeve in only one direction. The sleeve is first placed in a bone tunnel and the opposite end of the ligament secured in the corresponding bone, followed by final adjustment of the ligament tension without disturbing the anchors of either end of the graft ligament.