Results of cemented metal-backed acetabular components - A 10-year-averagefollow-up study

The clinical and radiographic results of 86 primary total hip arthroplastie s performed in 74 patients from 1983 to 1987 with a cemented metal-backed a cetabular component and a cemented collared straight femoral stem with a 32 -mm head were reviewed at a mean follow-up of 10.1 years. Seven patients (9 .2%) underwent acetabular component revision at a mean of 9.0 years after i mplantation; an additional 24 components (31.6%) demonstrated evidence of r adiographic loosening, resulting in a total failure rate of 40.8%. Periacet abular radiolucencies were noted in Charnley zones at the following rates: 34.2% in zone I, 18.4% in zone II, and 27.6% in zone Iii. In addition, 18.4 % and 38.2% of implants demonstrated evidence of migration and excessive po lyethylene wear. Excessively vertical cup placement (>49 degrees inclinatio n) at the time of initial arthroplasty was statistically correlated with po lyethylene wear, implant migration, and fixation failure. A trend of increa sing implant failure was also noted with decreasing polyethylene liner thic kness. Periacetabular cement mantle thickness was not statistically correla ted with subsequent component loosening or failure. Results of Kaplan-Meier survivorship analysis using revision as an endpoint showed 93.6% survivors hip at IO years and 88.4% at 12 years. The mean modified Harris hip scores were 46.9 preoperatively and 81.8 at final follow-up. The significant overa ll rates of radiographic loosening, migration, polyethylene wear, and impla nt revision confirm the suspected trend of increasing failure rates of ceme nted metal-backed acetabular components over time.