Fabrication and Characterizations of Metallic Mg Containing PMMA-Based Partially Degradable Composite Bone Cements

Inadequate strength at the bone/cement interface is one of the main drawbacks of poly(methylmethacrylate) (PMMA) bone cement in the current orthopedic surgeries. In the present work, a partially degradable PMMA/Mg composite bone cement (PMC) was developed for enhancing the bone/cement interfacial strength, which is proposed to be accomplished by increasing the osteo-conductivity of PMMA and enhancing the mechanical interlocking between bone tissue and the porous PMMA surface formed by the degradation of Mg on the surface of the cement. PMCs were prepared with various concentrations of Mg particles with different sizes and alloy compositions. The effects of Mg particle size, composition and content on the injectability, mechanical and degradation properties, and biocompatibility of PMCs were evaluated. The results show that these parameters affected the properties of the PMCs simultaneously. The good injectability and compressive strengths of PMMA were preserved, while the compatibility to osteoblasts was enhanced when adding Mg particles in a proper manner. The PMCs degraded at the surface with time and formed porous surface structures in the physiological environment, while maintaining the original compressive strengths. This preliminary study shows that the PMC is promising for minimally invasive orthopedic surgery; however, it still requires to be optimized and evaluated in the future.