Retrieved ceramic total knee prosthesis in clinical use for 23 years

According to knee simulator test results in the 1970s', the total decrease in thickness of the UHMWPE tibial tray in combination with ceramic femoral component [F-Comp] was less than one tenth of that in combination with metal [1]. These advantages led to the development of a total knee prosthesis [TKP] with alumina ceramics. In this study, we report the wear surface observation, the clinical wear and the oxidation of the retrieved TKP, which was implanted in 1979, and retrieved in 2002. This TKP consisted of an alumina ceramic F-Comp and a UHMWPE tray combined with an alumina ceramic tibial component. Alumina F-Comp did not have any scratches on the surface. The UHMWPE tray had obvious deformation and scratches. The liner wear rate of the tray was 37 μm/year and the volumetric wear rate was 18.8 mm³/year. The oxidation indexes were 0.6 in the unworn area, 1.2 in the worn area and 0.2 in the inner area. SEM observations of the F-Comp demonstrated no scratches or pits. In contrast, many scratches were clearly observed on the UHMWPE tray. However, higher magnification observations did not demonstrate severe wear, which was shown in the wear analysis of a metallic F-Comp. The low wear rate and mild wear pattern demonstrate that ceramic F-Comp reduced UHMWPE wear.