Experimental Drillable Magnesium Phosphate Cement Is a Promising Alternative to Conventional Bone Cements

Research progress on the application of magnesium phosphate bone cement in bone defect repair: A review

BACKGROUND

Bone defects arising from diverse causes, such as traffic accidents, contemporary weapon usage, and bone-related disorders, present significant challenges in clinical treatment. Prolonged treatment cycles for bone defects can result in complications, impacting patients' overall quality of life. Efficient and timely repair of bone defects is thus a critical concern in clinical practice.

OBJECTIVE

This study aims to assess the scientific progress and achievements of magnesium phosphate bone cement (MPC) as an artificial bone substitute material. Additionally, the research seeks to explore the future development path and clinical potential of MPC bone cement in addressing challenges associated with bone defects.

METHODS

The study comprehensively reviews MPC's performance, encompassing e.g. mechanical properties, biocompatibility, porosity, adhesion and injectability. Various modifiers are also considered to broaden MPC's applications in bone tissue engineering, emphasizing drug-loading performance and antibacterial capabilities, which meet clinical diversification requirements.

RESULTS

In comparison to alternatives such as autogenous bone transplantation, allograft, polymethyl methacrylate (PMMA), and calcium phosphate cement (CPC), MPC emerges as a promising solution for bone defects. It addresses limitations associated with these alternatives, such as immunological rejection and long-term harm to patients. MPC can control heat release during the curing process, exhibits superior mechanical strength, and has the capacity to stimulate new bone growth.

CONCLUSION

MPC stands out as an artificial bone substitute with appropriate mechanical strength, rapid degradation, non-toxicity, and good biocompatibility, facilitating bone repair and regeneration. Modification agents can enhance its clinical versatility. Future research should delve into its mechanical properties and formulations, expanding clinical applications to create higher-performing and more medically valuable alternatives in bone defect repair.

An Overview of Magnesium-Phosphate-Based Cements as Bone Repair Materials

In the search for effective biomaterials for bone repair, magnesium phosphate cements (MPCs) are nowadays gaining importance as bone void fillers thanks to their many attractive features that overcome some of the limitations of the well-investigated calcium-phosphate-based cements. The goal of this review was to highlight the main properties and applications of MPCs in the orthopedic field, focusing on the different types of formulations that have been described in the literature, their main features, and the in vivo and in vitro response towards them. The presented results will be useful to showcase the potential of MPCs in the orthopedic field and will suggest novel strategies to further boost their clinical application.

Degradation and Bone-Contact Biocompatibility of Two Drillable Magnesium Phosphate Bone Cements in an In Vivo Rabbit Bone Defect Model

The use of bone-cement-enforced osteosynthesis is a growing topic in trauma surgery. In this context, drillability is a desirable feature for cements that can improve fracture stability, which most of the available cement systems lack. Therefore, in this study, we evaluated a resorbable and drillable magnesium-phosphate (MgP)-based cement paste considering degradation behavior and biocompatibility in vivo. Two different magnesium-phosphate-based cement (MPC) pastes with different amounts of phytic acid (IP 6) as setting retarder (MPC 22.5 and MPC 25) were implanted in an orthotopic defect model of the lateral femoral condyle of New Zealand white rabbits for 6 weeks. After explantation, their resorption behavior and material characteristics were evaluated by means of X-ray diffraction (XRD), porosimetry measurement, histological staining, peripheral quantitative computed tomography (pQCT), cone-beam computed tomography (CBCT) and biomechanical load-to-failure tests. Both cement pastes displayed comparable results in mechanical strength and resorption kinetics. Bone-contact biocompatibility was excellent without any signs of inflammation. Initial resorption and bone remodeling could be observed. MPC pastes with IP 6 as setting retardant have the potential to be a valuable alternative in distinct fracture patterns. Drillability, promising resorption potential and high mechanical strength confirm their suitability for use in clinical routine.

Hydration Behavior of Magnesium Potassium Phosphate Cement: Experimental Study and Thermodynamic Modeling

The microstructure and performance of magnesium potassium phosphate cement (MKPC), a kind of magnesium phosphate cement (MPC), are determined by the hydration products. In this paper, the hydration behavior of MKPC is investigated through various material characterization methods and thermodynamic modeling, including X-ray diffraction (XRD), thermogravimetric and differential scanning calorimeter (TG/DSC), scanning electron microscopy (SEM), mercury intrusion porosimetry (MIP) and GEMS software. The results of XRD, TG/DSC and SEM all indicate that K-struvite (MgKPO₄·6H₂O) is the main hydration product of MKPC. When the curing age is 1 day and 28 days, the TG data indicate that the mass loss of MKPC in the range of 60-200 °C is 17.76% and 17.82%, respectively. The MIP results show that the porosity of MKPC is 29.63% and 29.61% at the curing age of 1 day and 28 days, respectively, which indicates that the structure of MKPC becomes denser with the increase in curing age. In addition, the cumulative pore volume of MKPC at the curing age of 28 days is 2.8% lower than that at 1 day, and the pore diameters are shifted toward the small pores. Furthermore, the thermodynamic modeling is well suited to make an analysis of the hydration behavior of MKPC.

[Cement augmentation and bone graft substitutes-Materials and biomechanics]

BACKGROUND

Materials with different characteristics are used for cement augmentation and as bone graft substitutes.

OBJECTIVE

Cement augmentation and bone graft substitutes are the subject of current research. The evaluation of new knowledge allows its specific application.

MATERIAL AND METHODS

Selective literature search and outline of experimental research results on cement augmentation and bone graft substitutes.

RESULTS

Augmentation and bone graft substitutes are essential components of current trauma surgical procedures. Despite intensive research all materials have specific disadvantages. Cement augmentation of implants enhances not only the anchorage but also influences the failure mode.

CONCLUSION

Cement augmentation has large potential especially in osteoporotic bone. In load-bearing regions acrylic-based cements remain the standard of choice. Ceramic cements are preferred in non-load-bearing areas. Their combination with resorbable metals offers still largely unexplored potential. Virtual biomechanics can help improve the targeted application of cement augmentation.

Biodegradable magnesium phosphates in biomedical applications

As an essential element, magnesium is involved in a variety of physiological processes. Magnesium is the second most abundant cation in cells and the fourth most abundant cation in living...