Periprosthetic osteolysis and its association with RANKL expression.

Extensive osteolysis adjacent to orthopedic implants is often associated with wear particles of prosthetic material. The activation of the RANKL/RANK/OPG system is considered to be a likely cause of periprosthetic osteolysis leading to implant failure. The aim of this study was to examine the possible correlation between the clinical extent of osteolysis, the number of wear particles and expression of the osteoclastic mediator RANKL (receptor activator of nuclear factor kappa B ligand) in the tissues around aseptically loosened cemented and non-cemented total hip replacements. Periprosthetic tissues were harvested from 59 patients undergoing revision of hip replacement for aseptic loosening. We observed RANKL-positive cells in 23 of our 59 patients, their presence was noted predominantly in tissues with a loosened cemented endoprosthesis. We have found that RANKL is present only in tissues with a large amount of wear debris and predominantly in cases involving loosened cemented implants.