Radiographic measurement of wear in 5 cohorts of patients observed for 5 to 22 years.

Standardized wear measurements using a tablet digitizer were made on long-term serial radiographs for 5 cohorts of total hip replacements to determine any differences in acetabular component polyethylene wear rates. The 5 groups included 4 cemented acetabular component series and 1 cementless acetabular component series. Comparing the rates of linear wear for the 5 groups, 22-mm-head components had similar wear when compared with the 28-mm-head components, both cemented and uncemented, and volumetric wear rates were greater for the cemented 28-mm-head components than for the 22-mm-head components. Although molded 22-mm-head components had less wear than the machined 22-mm-head components, there was no statistically significant difference between the 2. The uncemented metal-backed component with 28-mm-head articulation showed no accelerated wear when compared with the cemented metal-backed components at a shorter 5-year followup. The constant variable in all series was a cemented femoral component.