Evaluation of amorphous magnesium phosphate (AMP) based non-exothermic orthopedic cements

What is it about?

This paper reports for the first time the development of a biodegradable, non-exothermic, self-setting orthopedic cement composition based on amorphous magnesium phosphate (AMP). The occurrence of undesirable exothermic reactions was avoided through using AMP as the solid precursor. The phenomenon of self-setting with optimum rheology is achieved by incorporating a water soluble biocompatible/biodegradable polymer, polyvinyl alcohol (PVA). Additionally, PVA enables a controlled growth of the final phase via a biomimetic process. The AMP powder was synthesized using a precipitation method. The powder, when in contact with the aqueous PVA solution, forms a putty resulting in a nanocrystalline magnesium phosphate phase of cattiite. The as-prepared cement compositions were evaluated for setting times, exothermicity, compressive strength, biodegradation, and microstructural features before and after soaking in SBF, and in vitro cytocompatibility. Since cattiite is relatively unexplored in the literature, a first time evaluation reveals that it is cytocompatible, just like the other phases in the MgO–P2O5 (Mg–P) system. The cement composition prepared with 15% PVA in an aqueous medium achieved clinically relevant setting times, mechanical properties, and biodegradation. Simulated body fluid (SBF) soaking resulted in coating of bobierrite onto the cement particle surfaces.

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Why is it important?

The review of the previous work clearly identifies several advanced signatures of this paper as reiterated in the paper. It describes an alternate strategy of addressing the exothermicity issue in a self-setting, orthopedic cement composition. The first signature is the ease of using AMP as the starting material as opposed to ACP. This material when, mixed with an aqueous solution of PVA, sets within an appropriate clinical time frame with enough strength and appropriate biodegradability and without exothermicity. As opposed to all of the previous reports, the compositions do not need a high temper ature exposure to ensure crystallinity of the reactants.