Why a 150°C stabilisation treatment
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WHY A 150°C STABILISATION TREATMENT
Crosslinking occurs during radiation (in air or nitrogen) but there is also concomitant formation of free radicals.
25 kGy gamma rays sterilisation results in oxidation both before and after implantation (even if sterilisation occurs in nitrogen). Oxidation causes weakening of the material with a drastic decrease in its mechanical properties.
If after radiation the material is stabilised with heat treatment, free radicals can be eliminated.
Complete elimination of free radicals is achieved only if the temperature rises over 135°C (the melting point of UHMWPE)1.
In this way, the mechanical properties of cross linked and stabilised UHMWPE remain unaltered over time and are, therefore, superior to those of standard UHMWPE, which deteriorate over time1.
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Chiesa, R., Moscatelli, M., Giordano, C., Siccardi, F., Cigada, A., 2004 “Influence of heat treatment on structural, mechanical and wear properties of crosslinked UHMWPE”. Journal of Applied Biomaterials & Biomechanics 2, 20-28. |
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