The impact of femoral head surface roughness on wear of gamma-irradiation sterilized (3 MRad in nitrogen crosslinked) and nonsterilized (not crosslinked) UHNWPE acetabular cups has been evaluated. Gravimetric wear testing was performed in a hip joint simulator for 2x106 cycles. CoCrMo heads were used with different surface roughness (Ra=15 nm and Ra=400 nm). The surface roughness after wear test was unchanged for the roughened heads, whereas the initially smooth heads showed a few scratches. The roughened heads increased the wear of the acetabular cups 2-fold. The gamma-irradiated cups tested against rough heads underwent the highest wear. The absorption of water was highest for the gamma-irradiated cups (0,0204% compared to 0,0031% after 85 days). Raman spectroscopy showed small but significant crystallinity changes in the wear zone, where the gamma-irradiated cups with the most extensive abrasion increased in crystallinity, whereas the nonsterilized cups underwent a crystallinity decrease.

Effect of head surface roughness and sterilization on wear of UHMWPE acetabular cups

TADDEI, PAOLA;FAGNANO, CONCEZIO;M. Viceconti
2009

Abstract

The impact of femoral head surface roughness on wear of gamma-irradiation sterilized (3 MRad in nitrogen crosslinked) and nonsterilized (not crosslinked) UHNWPE acetabular cups has been evaluated. Gravimetric wear testing was performed in a hip joint simulator for 2x106 cycles. CoCrMo heads were used with different surface roughness (Ra=15 nm and Ra=400 nm). The surface roughness after wear test was unchanged for the roughened heads, whereas the initially smooth heads showed a few scratches. The roughened heads increased the wear of the acetabular cups 2-fold. The gamma-irradiated cups tested against rough heads underwent the highest wear. The absorption of water was highest for the gamma-irradiated cups (0,0204% compared to 0,0031% after 85 days). Raman spectroscopy showed small but significant crystallinity changes in the wear zone, where the gamma-irradiated cups with the most extensive abrasion increased in crystallinity, whereas the nonsterilized cups underwent a crystallinity decrease.
A. Jedenmalm; S. Affatato; P. Taddei; W. Leardini; U.W. Geddel; C. Fagnano; M. Viceconti
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/79871
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