title: No effect of hydroxyapatite particles in phagocytosable sizes on implant fixation: an experimental study in dogs.
abstract: The influence of wear debris on bone healing around orthopedic implants is debated. Hydroxyapatite (HA) particles and polyethylene (PE) particles have been shown to have a negative effect on osteoblast cultures in vitro. The present study investigated the in vivo effects of HA and PE particles on the mechanical fixation and gap healing around experimental HA implants. Nonloaded implants (n = 30) were inserted bilaterally into the proximal tibia of 15 dogs with a 2-mm gap to the bone. The peri-implant gap was either (1) empty (n = 6) or filled with (2) hyaluronic acid (n = 8), (3) hyaluronic acid and HA particles (n = 8), or (4) hyaluronic acid and PE particles (n = 8). After 4 weeks, the animals were killed. The implant interface was evaluated by pushout testing until failure and by histomorphometry. Both HA and PE particles were found to be phagocytosed by macrophage-like cells in the interfacial tissue. HA particles were also integrated in newly formed bone. We found no negative effect of the particulate material on mechanical fixation of the implants or on bone formation around the implants.
authors.affiliation: Orthopedic Research Laboratory, Aarhus University Hospital, Norrebrogade 44, Building 1A, DK-8000, Aarhus C, Denmark. ole_rahbek@hotmail.com
authors.forename: O
authors.initials: O
authors.lastname: Rahbek
authors.forename: S
authors.initials: S
authors.lastname: Kold
authors.forename: K
authors.initials: K
authors.lastname: Bendix
authors.forename: S
authors.initials: S
authors.lastname: Overgaard
authors.forename: K
authors.initials: K
authors.lastname: Soballe
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001672:Biocompatible Materials / Q000494:pharmacology*; D001861:Bone Regeneration / Q000187:drug effects / Q000502:physiology; D004285:Dogs; D017886:Durapatite / Q000494:pharmacology*; D006820:Hyaluronic Acid / Q000378:metabolism; D008855:Microscopy, Electron, Scanning; D010587:Phagocytosis / Q000187:drug effects*; D020959:Polyethylene / Q000378:metabolism; D019736:Prostheses and Implants
chemical_list: D001672:Biocompatible Materials; D020959:Polyethylene; D006820:Hyaluronic Acid; D017886:Durapatite