by providing more coverage to the head of the femoral stem in a preferred anatomical orientation this results in the axis 46 of the open end of adaptor 14 being inclined at the angle u2202 with polar axis 44 of outer shell 12 referring to fig6 and 7 there is shown the adaptor 14 and the outer shell 12 prior to assembly within the cup system 10 in the preferred embodiment outer shell 12 includes a polar hole 22 with threads 60 to receive coupling screw 18 and a plurality of typical holes 62 adapted to receive bone screws not shown which are used to mount outer shell 12 within the natural acetabulum fewer than all both fig4 and 7 show the flanges straps or wings which are used as additional attachment element for attaching shell or cage 12 to the bone surrounding the acetabulum preferably wings or straps 30 are flexible or ductile enough to be deformed by the surgeon as best seen in fig3 the inner surface of the preferred outer shell or cage 12 includes the tapered surface 42 which extends around the circumference of the inner cavity 20 thereof as discussed above tapered surface 42 can include an auxiliary attachment means such as a groove 42 a so that a bearing insert may be coupled directly to the outer cage 12 without the use of.