ANALYSIS OF PARTICLES IN ACETABULAR COMPONENTS FROM PATIENTS WITH OSTEOLYSIS

Acetabular polyethylene components were quantitatively analyzed for th e presence of third body particles from 38 consecutively retrieved com ponents. Backscattered electron imaging and correlated energy dispersi ve xray analysis were used for the assessments, Retrievals were divide d into 4 groups based on methods of fixation and metal alloy types: 8 hydroxyapatite coated, 6 cobalt chrome porous coated, 17 titanium poro us coated, and 7 cemented implants were evaluated, The backscattered e lectron imaging data showed that the components from the hydroxyapatit e coated implants had larger particles than did the components from th e cemented group, The hydroxyapatite group had 51 +/- 52 particles per mm(2). The cobalt chrome alloy group had 10 +/- 9 particles per mm(2) , and the titanium alloy group had 9 +/- 16 particles per mm(2). The c emented group had 5 +/- 4 particles per mm(2). The difference between the cement group and the hydroxyapatite group was statistically signif icant. The elemental analysis showed that 70% of the particles in the hydroxyapatite group had calcium and phosphorus elements, Third body p articles likely contribute to particulate generation, The results sugg est that the hydroxyapatite coated components have the potential for p roducing greater amounts of particulate debris, Continued analysis of retrieved components for the presence of the third body particles is r equired.