[Size and shape of commercially available polyethylene particles for in-vitro and in-vivo-experiments].
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.
von Knoch
M
M
Klinik und Poliklinik für Orthopädie, Universität Duisburg-Essen. mariusvonknoch@yahoo.com
Sprecher
C
C
Barden
B
B
Saxler
G
G
Löer
F
F
Wimmer
M
M
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
D001672:Biocompatible Materials; D020959:Polyethylene