title: Response of human osteoblasts exposed to wear particles generated at the interface of total hip stems and bone cement.
abstract: Aseptic loosening of total hip replacement is mainly caused by wear particles. Abrasive wear occurs at articulating surfaces or as a consequence of micro-motions at the interface between femoral stem and bone cement. Direct impact of wear particles on osteolysis, the remodeling of the bone stock and a directly affected function of osteoblasts was described. The present study examined the response of human osteoblasts exposed to different wear particles, which were generated in a test device providing oscillating micro-motions at the interface between femoral stem and standard bone cement. Characterization of released particles was performed by quantifying the size distribution and the metal content of the wear debris. Human osteoblasts were incubated with particles obtained from hip stems with different material compositions (Ti-6Al-7Nb and Co-28Cr-6Mo) and rough and smooth surface finishings combined with standard bone cement (Palacos(R) R) containing zirconium oxide particles. Commercially pure titanium particles (cp-Ti) and particulate zirconium oxide (ZrO(2)) were used for comparative analyses. The results revealed significant (p < 0.05) reduction of the cell viability after exposure to higher concentration of metallic particles, particularly from Co-based alloys. In contrast, ZrO(2) alone showed significantly less adverse effects on the cells. When increasing metallic particle concentrations massive inhibition was also observed in the release of cytokines including interleukine-6 (IL-6) and interleukine-8 (IL-8), but the expression of Procollagen I and the cell viability showed the highest reduction after exposure to Co-based alloy particles from rough stems.
authors.affiliation: Orthopädische Klinik und Poliklinik, Universität Rostock, Rostock, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Lenz
authors.forename: Wolfram
authors.initials: W
authors.lastname: Mittelmeier
authors.forename: Doris
authors.initials: D
authors.lastname: Hansmann
authors.forename: Regina
authors.initials: R
authors.lastname: Brem
authors.forename: Peter
authors.initials: P
authors.lastname: Diehl
authors.forename: Andreas
authors.initials: A
authors.lastname: Fritsche
authors.forename: Rainer
authors.initials: R
authors.lastname: Bader
mesh_terms: D001843:Bone Cements / Q000494:pharmacology*; D002470:Cell Survival / Q000187:drug effects; D024042:Collagen Type I / Q000096:biosynthesis; D016207:Cytokines / Q000096:biosynthesis; D006622:Hip Prosthesis; D006801:Humans; D010006:Osteoblasts / Q000166:cytology* / Q000187:drug effects*; D010316:Particle Size; D019904:Polymethyl Methacrylate / Q000494:pharmacology; D013997:Time Factors
chemical_list: D001843:Bone Cements; D024042:Collagen Type I; D016207:Cytokines; D019904:Polymethyl Methacrylate