title: [Size and shape of commercially available polyethylene particles for in-vitro and in-vivo-experiments].
abstract: OBJECTIVE
  The longevity of total hip arthroplasty is sometimes limited by osteolysis and aseptic loosening. Aseptic loosening may be caused by the biologic reaction to polyethylene wear particles. Particles of less than 1 micro m diameter are of particular importance. These particles are not easily available for experimental use.
  
  
  METHODS
  We performed a morphologic analysis of commercially available, very small polyethylene particles (Ceridust(R)) in order to determine the specific size distribution. We measured 1 978 particles. Size analysis was performed using an electron microscope. Particle size was described as the equivalent circle diameter (ECD). Particle morphology was described as feret ratio. In addition, Ceridust(R) particles were compared to different particles stemming from a hip simulator experiment.
  
  
  RESULTS
  More than 35 % of the particles were less than 1 micro m in size. The particle size was 1.75 micro m +/- 1.43 micro m (median 1.42 micro m). The minimum was 0.06 micro m, the maximum was 11.06 micro m. The feret ratio was 0.58 +/- 0.17 (median 0.63). The minimum was 0.07, the maximum was 0.93. The majority of Ceridust(R) particles had a rough surface. Compared to polyethylene particles stemming from a hip simulator experiment, Ceridust(R) particles had a rougher surface, were less longitudinal, and had a more even size distribution.
  
  
  CONCLUSIONS
  The pure, commercially available polyethylene particles analyzed here are suitable for in vitro and in vivo experiments due to their easy availability, minor costs, and large fraction of very small particles.
authors.affiliation: Klinik und Poliklinik für Orthopädie, Universität Duisburg-Essen. mariusvonknoch@yahoo.com
authors.forename: M
authors.initials: M
authors.lastname: von Knoch
authors.forename: C
authors.initials: C
authors.lastname: Sprecher
authors.forename: B
authors.initials: B
authors.lastname: Barden
authors.forename: G
authors.initials: G
authors.lastname: Saxler
authors.forename: F
authors.initials: F
authors.lastname: Löer
authors.forename: M
authors.initials: M
authors.lastname: Wimmer
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D019544:Equipment Failure Analysis / Q000295:instrumentation* / Q000379:methods*; D008422:Materials Testing / Q000379:methods*; D008863:Microspheres; D010316:Particle Size; D020959:Polyethylene / Q000032:analysis* / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D001672:Biocompatible Materials; D020959:Polyethylene