93 - Acetabular Revision: Uncemented Hemispheric Components

Abstract

Revision of the acetabular component of a total hip arthroplasty poses a unique set of challenges for the reconstructive surgeon. A full appreciation of the etiology for the revision will assist in the preoperative planning and execution of an appropriate acetabular reconstruction. There are several etiologies for revision of the acetabular component, including polyethylene wear with or without osteolysis, aseptic loosening, mechanical failure, recurrent dislocation, acetabular component malposition, and septic loosening. The challenges of acetabular revision are related to loss of bone stock, alteration of the hip center, and the need to achieve stability of the prosthesis. The aims of revision are to reconstitute acetabular deficits with the primary goal of recreating the anatomy and biomechanics of the physiologic joint while achieving stable fixation. Over the past 30 years, a cementless hemispheric component has become the preferred technique for the majority of acetabular revisions. Paramount to revision success is that the implant has initial stability to promote bone ingrowth and remodeling of the acetabulum in order to ensure long-term viability of the arthroplasty. Implant stability is directly related to the characteristics of the acetabular bone deficits, which determines the specifics of the reconstruction process. A standard porous cementless hemispheric shell secured with multiple screws is the implant of choice when there is at least 50% host-bone contact. The introduction of ultraporous metal surfaces with superior bone ingrowth capability has further increased the capabilities of cementless hemispheric acetabular shells.