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AssigneesThe Royal Institution for the Advancement of Learning/Mcgill University, National Research Council of Canada
InventorsPaul A. Martineau, Louis-Philippe Lefebvre, Edward J. Harvey
Estimating the term…
A bone screw is described which includes a one-piece threaded screw body composed at least partially of a rigid foam. The screw body is headless and includes a bore extending therethrough to define a cannula and thereby providing the screw body with an annular shape defining a radial wall thickness. At least a central portion of the screw body is formed of the rigid foam which defines a matrix having a plurality of inter-connected pores therein. The inter-connected pores are disposed throughout the complete radial wall thickness of the screw body from an outer surface of the screw body to an inner surface thereof within the cannula, such as to permit bone in-growth through the complete radial wall thickness of the annular screw body. The inter-connected pores and the cannula thereby respectively allow bone in-growth through the complete radial wall thickness and the full axial length of the screw body.
A bone screw comprising a one-piece screw body comprised at least partially of a rigid foam and having at least one external thread thereon, the screw body being headless, a bore extending through an axial length of the screw body to define a cannula and providing the screw body with an annular shape having a radial wall thickness, at least a central portion of the screw body being formed of said rigid foam which defines a matrix defining a plurality of inter-connected pores therein having a size of about 30 to about 500 microns, the inter-connected pores being disposed throughout the complete radial wall thickness of the screw body from an outer surface of the screw body to an inner surface thereof within the cannula such as to permit bone in-growth through the complete radial wall thickness of the annular screw body, the inter-connected pores and the cannula thereby respectively allowing bone in-growth through the complete radial wall thickness and the axial length of the screw body.
A compression bone screw for fixation of the scaphoid comprising a leading end, a headless trailing end and at least one external thread therebetween, a bore extending an axial length of the screw between the leading and trailing ends, the bore being radially centered to define an annular screw body having a radial wall thickness, and the screw being formed in one-piece by a porous metallic foam, the porous metallic foam defining a plurality of inter-connected pores therein which are substantially free of material until bone in-growth through the pores occurs, the plurality of inter-connected pores being disposed through the complete radial wall thickness of the bone screw, said bone in-growth being permitted radially through the complete radial wall thickness and axially through the bore.
Dependencies are inferred from the claim text.