title: Migration of polyethylene particles around stable implants in an animal model.
abstract: The aim of this study was to test the hypothesis that a tight seal between bone and implant will eliminate the avenue of particle migration around stable implants. Three types of implants were used in rabbits (polished press-fit Ti-6Al-4V or plasma-sprayed hydroxyapatite [HA]-coated Ti-6Al-4V) or doughy stage polymethyl methacrylate (PMMA). Implants were placed in the condylar notch. Each animal received an intra-articular injection of high density polyethylene (PE) particles (10(8) in 0.4 mL; mean size 4.7 microns) at 4 and 6 weeks postoperatively. Eight weeks postoperatively, peri-implant tissues were examined for PE particles and osteolysis. In all cases, intracellular PE particles were seen at the bone-implant interface and within marrow. No osteolysis was observed. Bone apposition was determined by computerized image analysis. There was no significant difference in the percentage of bone apposition (+/- SD) among the three groups of implants: Ti-6Al-4V (68% +/- 19%), HA-coated Ti-6Al-4V (70% +/- 10%), and PMMA (59% +/- 12%). These results indicate that a polished Ti-6Al-4V surface is as effective as PMMA or HA coating in limiting migration of PE particles around stable osseointegrated implants in rabbits.
authors.affiliation: Skeletech, Inc., Bothell, WA 98021, USA.
authors.forename: P A
authors.initials: PA
authors.lastname: Lalor
authors.forename: R
authors.initials: R
authors.lastname: Namba
authors.forename: S L
authors.initials: SL
authors.lastname: Mitchell
authors.forename: J
authors.initials: J
authors.lastname: Bearcroff
authors.forename: N
authors.initials: N
authors.lastname: Beals
authors.forename: C B
authors.initials: CB
authors.lastname: Sledge
authors.forename: M
authors.initials: M
authors.lastname: Spector
mesh_terms: D000497:Alloys; D000818:Animals; D004195:Disease Models, Animal; D005548:Foreign-Body Migration / Q000473:pathology / Q000517:prevention & control*; D020007:Implants, Experimental / Q000009:adverse effects*; D007720:Knee Prosthesis / Q000009:adverse effects*; D010014:Osteolysis / Q000209:etiology / Q000473:pathology; D010316:Particle Size; D020959:Polyethylene / Q000009:adverse effects*; D011817:Rabbits; D014025:Titanium
chemical_list: D000497:Alloys; D020959:Polyethylene; D014025:Titanium