Tribological studies have shown that the most used couples for hip prostheses consist of metal-on-polyethylene and alumina-on-alumina prostheses. Over time, wear products accumulate in the joint cavity and in the periprosthetic tissues. Although polyethylene and metal are easily identifiable by microscopy in periprosthetic tissues, alumina particles are very difficult to identify.

The fluorescent azo-dye lumogallion was evaluated as a suitable histochemical stain for alumina particles in periprosthetic tissues.

In 28 patients who had a prosthetic revision of an alumina-on-alumina prosthesis, periprosthetic tissues were removed and embedded in paraffin; sections were stained with HPS (for conventional diagnosis) or with lumogallion. Sections were examined for wear particles in light and fluorescence microscopy. Some sections were counter-stained using DAPI for visualization of cell nuclei.

The wear particles of the alumina-alumina prostheses were very difficult to identify on the HPS stained sections; they were clearly evidenced by lumogallion staining with a bright orange fluorescence. The stain revealed large quantities of particles (of the order of several thousand per section). Only two patients had no particles. The staining technique identified numerous particles that were not visible on HPS-stained sections in macrophages, synoviocytes and fibroblasts.

This staining, which has been validated in neuromuscular pathology for the identification of alumina used as a vaccine adjuvant, gave successful results in the present study. Alumina particles are modified when they are phagocytized by macrophages. lumogallion staining easily shows the presence of thousands of wear particles released by alumina-on-alumina prostheses in periprosthetic tissues.

V expert opinion study.