Injectable acrylic bone cements for vertebroplasty based on a radiopaque hydroxyapatite. Formulation and rheological behaviour.

The utilization of injectable acrylic bone cement is crucial to the outcome of vertebroplasty and kyphoplasty. However, only a few cements that are in clinical use today are formulated specifically for use in these procedures and even these formulations are not regarded as "ideal" injectable bone cements. The aim of this work is to prepare bioactive bone cements by adding strontium hydroxyapatite (SrHA) to a cement formulation based on polymethylmethacrylate. Thus, the cement combines the immediate mechanical support given by the setting of the acrylic matrix with optimum radiopacity and bioactivity due to the incorporation of the SrHA. Formulations of bioactive cement were prepared with 10 and 20 wt% of SrHA as synthesised and after a surface treatment with the monomer. Cements loaded with treated particles showed an enhancement of their handling properties, and hence, an improvement on their rheological behaviour, injectabilities and compressive parameters. Further experiments were also carried out to determine their bioactivity and biocompatibility and results appear in other publication.