THREE-DIMENSIONAL POROUS STRUCTURES FOR BONE INGROWTH AND METHODS FOR PRODUCING

1 - 19 . (canceled)

20 . A method of producing a porous three-dimensional structure, the method comprising:

depositing and scanning successive layers of metal powder with a beam to form a porous three-dimensional structure comprising a plurality of connected unit cells, wherein each of the connected unit cells includes,

a first structure comprising a plurality of lattice struts arranged such that the first structure is a rhombic dodecahedron, and

a plurality of second structures each formed out of a respective plurality of internal struts within the first structure and a respective number of the lattice struts,

wherein:

the depositing and scanning steps create respective pluralities of openings in the porous three-dimensional structure, the openings defined by the respective number of the lattice struts and the respective plurality of internal struts, each opening of the plurality of pluralities of openings having a window size, and

the depositing and scanning steps define a respective pore size of each second structure, such that for each second structure, a ratio of the respective pore size to each window size is in a range of 1.00 to 2.90.

21 . The method of claim 20 , wherein the porous three-dimensional structure has a porosity between about 50% and about 75%.

22 . The method of claim 20 , further comprising the step of attaching the porous three-dimensional structure to a solid base.

23 . The method of claim 22 , wherein the solid base includes a platform and a stem extending away from the platform, the stem extending through the porous three-dimensional structure.

24 . The method of claim 20 , wherein the ratio is in a range from 1.50 to 1.60.

25 . The method of claim 20 , wherein the ratio is in a range from 1.00 to 1.10.

26 . The method of claim 20 , wherein each of the plurality of second structures is a trigonal trapezohedron.

27 . The method of claim 20 , wherein the plurality of second structures consists of four trigonal trapezohedrons.

28 . The method of claim 20 , wherein each of the plurality of second structures is an octahedron.

29 . A method of producing an orthopaedic prosthetic component, the method comprising:

depositing and scanning successive layers of metal powder with a beam to form a porous three-dimensional structure shaped to be implanted in a patient's body, the porous three-dimensional structure comprising a plurality of unit cells,

wherein each unit cell of the plurality of unit cells comprises a first structure having a first geometry and comprising a plurality of first struts, and a second structure having a second geometry and comprising a plurality of second struts connected to a number of the plurality of first struts to form the second structure, wherein:

the second structure has a pore size,

the number of the plurality of first struts and the plurality of second struts define a plurality of openings in the porous three-dimensional structure, each opening of the plurality of openings having a window size, and

the pore size and the window size of each opening of the plurality of openings defines a ratio of pore size to window size that is in a range of 1.50 to 1.60.

30 . The method of claim 29 , wherein the porous three-dimensional structure has a porosity that is between about 20% and about 95%.

31 . The method of claim 30 , wherein the porous three-dimensional structure has a porosity that is between about 50% and about 75%.

32 . The method of claim 29 , wherein the first structure is a rhombic dodecahedron.

33 . The method of claim 32 , wherein the second structure is a trigonal trapezohedron.

34 . The method of claim 29 , wherein the second structure is a trigonal trapezohedron.

35 . The method of claim 29 , wherein the first struts define an average first strut length, and at least some of the first struts have respective lengths that are different than the average first strut length and within 50% to 150% of the average first strut length.

36 . A method of producing an orthopaedic prosthetic component, the method comprising:

depositing and scanning successive layers of metal powder with a beam to form a porous three-dimensional structure shaped to be implanted in a patient's body, the porous three-dimensional structure comprising a plurality of connected unit cells,

wherein at least one unit cell of the plurality of unit cells includes:

a first structure comprising a plurality of lattice struts, and

a plurality of second structures formed out of a respective plurality of internal struts within the first structure and a respective number of the lattice struts,

wherein the lattice struts define an average lattice strut length, and at least some of the lattice struts define respective lengths that are modified to be different than the average lattice strut length and within 50% to 150% of the average lattice strut length, wherein the lattice struts are arranged such that the first structure approximates a rhombic dodecahedron.

37 . The method of claim 36 , wherein:

the respective number of the lattice struts and the respective plurality of internal struts of the second structures define respective pluralities of openings in the porous three-dimensional structure, each opening of the plurality of openings having a window size,

each second structure has a respective internal volume that, in turn, has a respective pore size, and

for each second structure, a ratio of the respective pore size to each window size is in a range of 1.00 to 2.90.

37 . The method of claim 36 , wherein the porous three-dimensional structure has a porosity between about 50% and about 75%.

38 . The method of claim 36 , further comprising a solid base, wherein the porous three-dimensional structure is attached to the solid base.

39 . The method of claim 36 , wherein the respective lengths of the at least some of the lattice struts are within 75% to 125% of the average lattice strut length.