title: Characterization, quantification, and isolation of aluminum oxide particles on grit blasted titanium aluminum alloy hip implants.
abstract: BACKGROUND
  This study was undertaken to verify whether or not the microstructure of aluminum alloy implants interferes with the characterization and quantification of aluminum inclusions on their surfaces, resulting from grit blasting.
  
  
  METHODS
  Four factory-fresh prostheses were investigated by scanning electron microscopy and X-ray microanalysis. Specimens were cut out of the stems and the cross-sections analyzed. The specimens were etched in hot 25% hydrochloric acid. The hydrochloric acid was subsequently filtered with a 0.2-microm-pore filter. The filters were scanned using electron microscopy and X-ray microanalysis.
  
  
  RESULTS
  Aluminum oxide particles were found on all investigated stems; the diameter of the particles ranged from 4 to 100 microm. One hundred fifty-four particles were counted per mm(2). No particles were seen on the cross-sections of the implants. Scanning electron microscopy of the Millipore filters revealed aluminum oxide particles.
  
  
  CONCLUSIONS
  Remnants of grit blasting were found only on the surfaces; none were observed on cross-sections. We conclude that the microstructure of titanium aluminum alloy does not interfere with the identification and quantification of particles. Particles were identified on the filters by electron microscopy and X-ray microanalysis. Aluminum oxide on the surface of grit-blasted titanium aluminum alloy implants is, in fact, a residue of grit blasting.
authors.affiliation: Department of Orthopedics, Medical University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria. info@hueft-orthopaede.at
authors.forename: Alexander
authors.initials: A
authors.lastname: Grübl
authors.forename: Alexander
authors.initials: A
authors.lastname: Kolb
authors.forename: Georg
authors.initials: G
authors.lastname: Reinisch
authors.forename: Günter
authors.initials: G
authors.lastname: Fafilek
authors.forename: Gobert
authors.initials: G
authors.lastname: Skrbensky
authors.forename: Rainer
authors.initials: R
authors.lastname: Kotz
mesh_terms: D000497:Alloys / Q000737:chemistry*; D000537:Aluminum Oxide / Q000737:chemistry*; D001672:Biocompatible Materials / Q000737:chemistry; D004577:Electron Probe Microanalysis; D006622:Hip Prosthesis; D006801:Humans; D006851:Hydrochloric Acid / Q000737:chemistry; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*
chemical_list: D000497:Alloys; D001672:Biocompatible Materials; D014025:Titanium; D000537:Aluminum Oxide; D006851:Hydrochloric Acid