Abstract 30

IS IT BETTER TO BE HOT?
MECHANICAL PROPERTIES OF BONE CEMENTS AT VARYING CURING TEMPERATURES

SMITHAM P, Micheal D, Leong A, Pelletier M, Butler A, Nielsen G, Bruce W, Walsh WR

Orthopaedic Research Laboratories, University of New South Wales, Sydney, Australia

It has been suggested that warming femoral prosthesis prior to implantation may reduce cement porosity and hence reduce cement microfractures and potentially improve long-term results. This study investigates the effects of temperature during curing of different bone cements.

Four cements (CMW1, Endurance, Palacos R-40, Simplex) were tested following ASTM F451-99 standards. The cements were placed into four preheated moulds at 18ºC, 37ºC, 40ºC and 50ºC respectively following mixing, and allowed to cure at these temperatures for 1 hour and the final 23 hours at 18ºC. Faxitron radiographics, apparent density, ultrasonic modulus and compression testing were performed for each cement at each temperature (n=25 per group). Additional samples were used to assess micro and macroporosity with micro Computer Tomography (µCT).

Whilst some of the cements were indeed influenced by the temperature during curing this was not universal across all cements and temperatures. In general, increasing the temperature during the initial one hour of curing increased the mechanical properties due to a reduction in porosity and increase in density. CMW1 and Endurance were more susceptible to temperature changes with respect to changes in physical and mechanical properties.

Heating femoral stems prior to cementing to influence polymerisation and interface bonding opens a number of questions regarding the effect of temperature, implant material, surface roughness and cement type. This study revealed temperature is an important factor but may not be transferable across different cements as their compositions vary.

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