Identification of wear particles of joint prostheses in tissues using laser microprobe mass analysis (LAMMA)]

The definite identification of wear particles from joint prostheses is of great importance for the development of joint replacement, as the type and quantity of different wear particles gives information on the wear resistance of implant materials. From the types of prostheses nowadays in use polyethylene wear of the sockets, bone cement wear, metallic and ceramic wear can be generated. Whereas polyethylene wear can be easily identified by its bright luminescence in polarized light and its characteristic configuration, the distinction of the small granular wear particles of the bone cement, metal and ceramic by light microscope is difficult. The laser microprobe mass analysis (LAMMA) is a method, which allows the analysis of single light microscopically detectable wear particles in tissues. Not only contrast medium particles of the bone cements (zirconium oxide or barium sulfate) but also metallic and aluminum oxide particles could be definitely identified within the pseudocapsules as well as in regional lymph nodes by LAMMA-analysis, whereby the bone cement wear predominated. In addition, the distinction between organic substances (as blood degradation products), which may appear similar to wear particles in configuration and colour, and the foreign material is also possible with this method.