Advances in total hip arthroplasty. The metal-backed acetabular component.

Detailed, long-term studies of cemented total hip arthroplasties clearly show that failure of fixation of the acetabular component is a major problem, with a rising incidence and an unusual complexity. By finite element analysis the stress distribution in the human acetabulum before and after total hip arthroplasty was analyzed by three different groups of investigators. Data from all three studies are in agreement that the introduction of cemented acetabular components of high-density polyethylene results in major disturbances of stress distribution, with peak stresses after total hip arthroplasty occurring in the cement, trabecular bone, and medial wall of the acetabulum. The most effective way to reduce these peak stresses in these three critical areas is to use an acetabular component with a metal backing. Long-term follow-up studies of 51 patients who underwent total hip arthroplasty performed by the author during the period from 1971 to 1975 using metal-backed acetabular components confirm the improved fixation that results from use of this design. Both the analytic data of stress distribution and clinical follow-up studies strongly support the use of metal-backed acetabular components in cemented total hip arthroplasty.