Patent ID: 7776097

Claim:
A prosthetic component for cementless integration into bone comprising two, spaced apart, shells ( 1 , 2 ; 13 , 14 ), wherein a bone facing shell ( 1 ; 13 ) is perforated to allow for rapid bony ingrowth and wherein the perforated bone facing shell ( 1 ) and the other shell ( 2 ) are fitted into each other, wherein the spaced apart shells ( 1 , 2 ) contact each other only at circumferential edges thereof while a continuous gap ( 5 ) left between the spaced apart shells ( 1 , 2 ) freely extends in the area surrounded by the circumferential edges of the shells ( 1 , 2 ; 13 , 14 ) in any direction for bony ingrowth, wherein opposite pairs of circumferential surfaces and opposite pairs of radially extending surfaces at the respective circumferential edges of the two shells contact each other in each pair defining a constant width of the gap in any direction; wherein the thickness of the perforated bone facing shell is in the range from 0.7 to 1.5 mm; and wherein the ratio of the thickness of the perforated bone facing shell to the perforation diameter is between 0.5 and 2.