Implant made of a magnesium alloy and method for the production thereof

Abstract

The invention relates to an implant from a magnesium alloy, in which porosity increases towards the core.

1 . An implant of magnesium die-casting or a magnesium die cast alloy, wherein the implant is porous, at least in portions thereof, and wherein the porosity increases from outside inwardly, at least in portions thereof. 
     
     
         2 . The implant of  claim 1 , wherein at least one surface of the implant is substantially free of open pores. 
     
     
         3 . The implant of  claim 2 , wherein the surface has less than  3  open pores with a diameter of more than 100 μm/cm 2 . 
     
     
         4 . The implant of  claim 1 , wherein the textural structure of the magnesium or magnesium alloy becomes coarser in the inward direction. 
     
     
         5 . The implant of  claim 1 , wherein the degree of porosity in a first region close to the surface is less than 3%. 
     
     
         6 . The implant of  claim 5 , wherein the region close to the surface is defined by a maximum depth of 0.5 mm. 
     
     
         7 . The implant of  claim 1 , wherein the degree of porosity in another region, away from the surface, is more than 3%, preferably more than 5%. 
     
     
         8 . The implant of  claim 7 , wherein the region away from the surface is defined by a depth of more than 0.6 mm. 
     
     
         9 - 11 . (canceled) 
     
     
         12 . The implant of  claim 1 , wherein the implant comprises a magnesium alloy which comprises at least one of the elements Nd, La, Ce, Pr, Sm, and Eu in an amount less than about 0.15% each, and less than about 0.4% in total. 
     
     
         13 . The implant of  claim 1 , wherein the implant comprises a magnesium alloy which comprises at least one of the elements Al, Zn, Si, Mn, Ca, Zr, Li, Sn, Sr, and P in an amount less than about 0.2% each and less than about 0.4% in total. 
     
     
         14 . The implant of  claim 1 , wherein the implant comprises a magnesium alloy comprising at least one of the elements Ag, Au, Cu, Fe, and Ni in an amount less than about 50 ppm each. 
     
     
         15 . The implant of  claim 1 , wherein the implant comprises a magnesium alloy which comprises Be in an amount less than about 4 ppm. 
     
     
         16 . The implant of  claim 1 , wherein the degree of porosity of the implant is about 1 to about 40%. 
     
     
         17 . The implant of  claim 1 , wherein the implant is coated. 
     
     
         18 . The implant of  claim 1 , wherein the implant has a blasted surface. 
     
     
         19 . The implant of  claim 1 , wherein the implant is formed in one piece. 
     
     
         20 . The implant of  claim 1 , wherein the implant is deburred by ignition of an explosion in a drum. 
     
     
         21 . The implant of  claim 1 , wherein the implant is in a form selected from the group consisting of: a screw, a cage, a suture anchor and a suture wound anchor. 
     
     
         22 . A magnesium alloy for the implant of  claim 1 , wherein the magnesium alloy comprises from about 1 to about 9% of Y and from about 0.1 to about 1.5% of other rare earth metals, and wherein the amount of Zn is less than about 0.4%. 
     
     
         23 - 28 . (canceled) 
     
     
         29 . A method for manufacturing the implant of  claim 1 , wherein a magnesium alloy is formed into an implant in a die casting process. 
     
     
         30 . The method of  claim 29 , wherein the magnesium alloy comprises from about 1 to about 9% of Y, and from about 0.1 to about 1.5% of other rare earth metals. 
     
     
         31 . The method of  claim 29 , wherein the pressure under which the melt is compressed in the die during the die cast process is more than about 100 bars. 
     
     
         32 . The method of  claim 29 , wherein a casting temperature is above about 600° C. 
     
     
         33 . The method of  claim 29 , wherein a casting rate more than about 20 cm/s is used. 
     
     
         34 - 39 . (canceled) 
     
     
         40 . The implant of  claim 1 , wherein the implant, or at least portions thereof, comprises a coating which decomposes or dissolves at a temperature above the body temperature. 
     
     
         41 . The method of  claim 29 , wherein the casting temperature is above about 700° C.