Patent ID: 6036491
Filing Date: 2000-03-14
Classification: A61B,A61C,A61F

Abstract:
An implant having a shaft which has a longitudinal axis, is adapted in use to be embedded in bone tissue and has an outer surface on which is provided a circumferentially-oriented macroroughness,wherein the circumferentially-oriented macroroughness is formed by a series of circumferentially-oriented peaks which are axially spaced-apart by grooves,wherein each circumferentially-oriented peak has first and second flanks and a curved apex which connects the first and second flanks,wherein the first and second flanks of each circumferentially-oriented peak have a bottom radius (r) at the respective adjacent groove and a straight part which extends from the bottom radius to a transition point (P1) between the flank and the curved apex at which a first tangent extends along the straight part,wherein each curved apex has a crest point (P2) at which a second tangent extends parallel to the longitudinal axis of the shaft,wherein the circumferentially-oriented macroroughness has a predetermined height (D), as measured from the crest points on the curved apexes to the grooves,wherein the straight part of each first and second flank is oriented at an angle (v) to a plane which is perpendicular to the longitudinal axis of the shaft, which angle is in the range 10.degree..ltoreq.v.ltoreq.55.degree.,wherein the curved apex of each peak comprises a curved part of a predetermined radius of curvature connecting the transition point on a predetermined one of the associated first and second flanks and the crest point,wherein the curved apex of each peak has an imaginary top radius (R) which connects the transition point on the predetermined associated flank and the crest point, andwherein R>0.4D for the predetermined flanks having 10.degree..ltoreq.v<35.degree. and R>0.2D for the predetermined flanks having 35.ltoreq.v.ltoreq.55.degree..