Effects of chitosan addition to self-setting bone cement.

The Cementek is a self-setting bone cement composed of a solid phase and a liquid phase. After mixing these two phases, it sets in situ to form an hydroxyapatite (HAp) as the only end product. It is difficult to introduce a new component into this cement without modifying the final product and its mechanical properties. In order to improve the mechanical properties of the Cementek, a natural polymer (chitosan) was added in the initial formulation. Two types of chitosan were added into the Cementek, at various concentration, in either the liquid or the solid phase. The effects of chitosan addition on the properties of the self-setting bone cement are examined. The different composites were characterized by the determination of the setting time, the chemical transformation by X-ray diffraction and mechanical tests. The chemical transformations were not affected by the addition of chitosan neither in the liquid nor in the solid phase. The maturation towards HAp appeared to be complete for all the composites. The setting time was decreased by the addition of chitosan in the solid phase. However the setting time value of each composite remained compatible with a practical use in situ. This study shows that the maturation mode of the samples directly affects the mechanical properties of the obtained composites. The sterilization of the cement with chitosan has been studied.