Acetabular cup assembly with selective bearing face orientation

Claim 1

An acetabular cup assembly capable of being implanted in stages so as to enable preliminary ascertainment and adjustment of position during implant and prior to commitment to a completed implanted position, said acetabular cup assembly comprising: a shell component having an outer surface for enabling permanent implant of the shell component at an implanted position, an upper top, a lower opening and an inner cavity extending into the shell component upwardly from the lower opening; a bearing insert for placement within the cavity of the shell component by movement of the bearing insert in an axial direction into the cavity, the bearing insert being initially movable into a preliminary axial position within the shell component and subsequently movable axially upwardly beyond the preliminary axial position into a fully-seated axial position within the shell component, the bearing insert having a bearing face extending transverse to said axial direction; an alignment and securing arrangement for aligning and securing the bearing insert within the shell component, said alignment and securing arrangement including first alignment and securing means carried by the shell component and second alignment and securing means carried by the bearing insert, the first and second alignment and securing means being generally complementary to one another for engagement when the bearing insert is in either of the preliminary and fully-seated axial positions; the alignment and securing means including alignment and securing elements, the number and circumferential location of the alignment and securing elements being such that the bearing insert may be placed within the cavity in any selected one of a plurality of circumferential positions relative to the shell component for selective orientation of the bearing face relative to the shell component; the alignment and securing elements including preliminary alignment means engagable upon placement of the bearing insert at the preliminary axial position for retaining the bearing insert at a preliminary circumferential position, relative to the shell component, wherein the bearing face is located at an initial selected orientation, the preliminary alignment means enabling holding of the bearing insert at the preliminary axial position for ascertainment of the circumferential position of the bearing insert and the concomitant orientation of the bearing face, and enabling selective withdrawal of the bearing insert from the preliminary axial position for circumferential repositioning of the bearing insert and concomitant reorientation of the bearing face to a selected final orientation corresponding to a predetermined appropriate orientation, final alignment means engagable upon placement of the bearing insert at the fully-seated axial position for aligning the bearing insert at a final circumferential position, wherein the bearing face is at the selected final orientation, relative to the shell component, and locking means engagable in response to placement of the bearing insert at the fully-seated axial position for locking the bearing insert at the fully-seated axial position with a capturing force great enough to capture the bearing insert at the fully-seated axial position within the shell component, with the bearing face at the selected final orientation relative to the implanted position of the shell component, for permanent service in the acetabular cup assembly.