An acetabular prosthesis system to replace an acetabulum that allows trialing for a shell component, comprising: an acetabular prosthesis; a trial shell operable to be selectively oriented relative said acetabular prosthesis in at least two degrees of freedom, the trial shell including a body having an exterior and an interior, said body defining a track extending between said interior and said exterior and said track extending a length; and a connection mechanism to selectively fix said trial shell relative said acetabular prosthesis; wherein said connection mechanism includes a member that extends through said track, said member having an attachment end and an engagement end; wherein said acetabular prosthesis includes an attachment portion and said attachment end of said member operably engages said attachment portion; wherein said trial shell defines an orientation portion and said engagement end of said member operably engages said orientation portion; wherein said member operably interconnects said trial shell and the acetabular prosthesis allowing a plurality of determined orientations to be created; and said trial shell trials at least one orientation of said trial shell by being selectively fixed in the at least one orientation relative said acetabular prosthesis wherein said member includes a screw having a threaded shank and a head portion; and said attachment portion includes a thread formed in said acetabular prosthesis; wherein said threaded shank and said attachment portion cooperate to draw said head portion against said trial shell such that said head portion applies a force great enough to fix said trial shell in a predetermined orientation. an acetabular prosthesis; a trial shell operable to be selectively oriented relative said acetabular prosthesis in at least two degrees of freedom, the trial shell including a body having an exterior and an interior, said body defining a track extending between said interior and said exterior and said track extending a length; and a connection mechanism to selectively fix said trial shell relative said acetabular prosthesis; wherein said connection mechanism includes a member that extends through said track, said member having an attachment end and an engagement end; wherein said acetabular prosthesis includes an attachment portion and said attachment end of said member operably engages said attachment portion; wherein said trial shell defines an orientation portion and said engagement end of said member operably engages said orientation portion; wherein said member operably interconnects said trial shell and the acetabular prosthesis allowing a plurality of determined orientations to be created; and said trial shell trials at least one orientation of said trial shell by being selectively fixed in the at least one orientation relative said acetabular prosthesis wherein said member includes a screw having a threaded shank and a head portion; and said attachment portion includes a thread formed in said acetabular prosthesis; wherein said threaded shank and said attachment portion cooperate to draw said head portion against said trial shell such that said head portion applies a force great enough to fix said trial shell in a predetermined orientation.