Vivo Absorption of Lipids

FTIR nnap collected along the cross-section of an EtO-sterilized acetabular cup, explanted after 4 years in vivo. 

Typical GC/MS analysis of the soluble fraction extracted from a retrieved UHMWPE prosthetic component. 

One question is whether the diffusion phenomenon can affect the mechanical properties of the polymer and to what extent. Recent experimental data, obtained in vitro with model compounds, suggests that modifications of mechanical properties induced by diffusion are quite limited (Turner et al. 2003). 

We are very grateful to Professors Elena Brach del Prever, Maurizio Crova, and Paolo Gallinaro of the Traumatology and Orthopaedics Hospital (CTO) of Torino, Italy, whose interest in research and continuous encouragement has been the foimdation of our work on UHMWPE. 

Amaud R., J.Y. Moisan, and J. Lemaire. 1984. Primary hydroperoxidation in low density polyethylene. Macromolecules 17 332-336. 

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Thermal analyses have been used for over 20 years to characterise heart-valve poppets (silicone elastomer) implanted into humans [29] and to evaluate the in vivo absorption of lipids and related compounds fix)m the body. Important deleterious effects on the implants, observed under in vivo conditions include changes in the hardness and mechanical properties, which appear to be associated with colour changes from white to yellow then brown. Because the thermal curves of the samples extracted from new and unused implants were almost identical, the differences were attributed to materials absorbed into the polymer matrix. Thermal analyses may therefore be useful in understanding the behaviour of these poppets in vivo. Table 1 shows the thermoanalytical data for new and used poppets, with those used poppets differing in terms of the extent extracted materials in vivo. 

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