Isolation, characterization and quantification of polyethylene wear debris from periprosthetic tissues around total joint replacements

Three basic methods of isolation of polyethylene wear particles from periprosthetic tissues (alkaline, acid and enzymatic) were compared. All the three methods had to be significantly modified to obtain pure polyethylene wear particles. For isolation of wear particles the acid method was found to be the most convenient. Purity of isolated wear debris was checked by: scanning electron microscopy (SEM), energy dispersive analysis of X-rays (EDS) and infrared spectroscopy (FTIR). SEM micrographs were used as an input for automated quantitative analysis, i.e. for determination of the total number of wear particles. The reliability of our automated quantification method (called SEMq) was verified on several sets of experiments; relative errors were less than 10%. The first results, obtained by the SEMq method, indicate that the distribution of UHWMPE particles around total joint replacements is quite non-homogenous.