Safety, osseointegration, and bone ingrowth analysis of PMMA‐based porous cement on animal metaphyseal bone defect model

Abstract

Bone defects created after curettage of benign bone tumors are customarily filled with solid poly(methyl methacrylate) (PMMA) or other bone substitutes. In this study, we depicted a porous PMMA-based cement (produced by mixing sodium bicarbonate and citric acid) and evaluated the prospect of its clinic application. Cement samples were characterized by high-performance liquid chromatography (HPLC) coupled to mass spectrometry and its cytotoxicity evaluated in fibroblast cultures. Implantation in rabbits allowed the histologic analysis of bone, kidneys, and liver for toxicity and coagulation tests, and MRI images for hemostasis evaluation. Osseointegration was analyzed through radiography, microtomography (micro-CT), SEM, and histology of sheep specimens. Rabbit specimens were analyzed 1, 4, and 7 days after implantation of porous or solid bone cement in 6.0 mm femoral defects. Sheep specimens were analyzed 3 and 6 months after implantation or not of porous or solid cement in 15.0 mm subchondral tibial defects. The production process did not release any detectable toxic substance but slightly reduced fibroblast proliferation in vitro. Until 7 days after surgery, no local or systemic alterations could be detected in histology, or hematoma formation in histology or MRI. Sheep implants showed 6 mm linear ingrowth from the bone-cement interface and 20% bone ingrowth considering the whole defect area. Radiography, micro-CT, SEM, and histology confirmed these findings. We conclude that our porous PMMA-based cement is an attractive alternative treatment for bone defect filling that combines osseointegration and early weight bearing. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 649-658, 2018.

Surface degradation–enabled osseointegrative, angiogenic and antiinfective properties of magnesium-modified acrylic bone cement

“…H&E staining and Masson trichrome staining results (Fig. 7E) indicate this interfacial layer was a fibrous capsule that formed by connective tissue between the PMMA and ossification layer, agreeing with the results reported by others [13]. On contrary, direct bony contact was established between 0.2-Mg implant and bone, supported by the SEM and H&E and Masson trichrome staining results that a new compact bony layer was formed at the bone/implant interface.

Figure 7 In vivo bone response evaluations.

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“…The inadequate interface strength was attributed to the lacks of osseointegrative and biodegrading ability of PMMA [8], [9], [10]. Modification of PMMA by incorporating bioactive or biodegradable additives has shown great potential to tackle these two problems simultaneously [9], [10], [11], [12], [13].…”

The “Magnesium Sacrifice” Strategy Enables PMMA Bone Cement Partial Biodegradability and Osseointegration Potential

“…The change from hydrophobic surface to hydrophilic surface by adding Mg microspheres to PMMA bone cement may also be helpful for cell adhesion and growth ( Figure 3 ). A previous study also showed that PMMA-based porous cement could promote osseointegration [ 37 , 38 ]. New bone could grow into the pores of degraded Mg microspheres within the PMMA–Mg bone cement, which would increase the interface bonding strength and result in the long-term stability of the cement.…”

Applications of Carbon Nanotubes in Bone Tissue Regeneration and Engineering: Superiority, Concerns, Current Advancements, and Prospects

“…[1,2,3]. Although, unlike many soft tissues, bone has the ability to self-repair and regenerate when damaged, its self-regeneration ability is limited [3,4,5]. High-impact trauma or critical-sized bone defects may result in insufficient self-repair and require additional clinical treatment [6,7,8].…”