Synthesis and Characterization of an Injectable and Hydrophilous Expandable Bone Cement Based on Poly(methyl...

Area of Science:

• Biomaterials Science
• Orthopedic Surgery
• Polymer Chemistry

Background:

• Poly(methyl methacrylate) (PMMA) bone cement is widely used in vertebroplasty but can cause refracture due to shrinkage cracks and high stiffness.
• Improving bone-cement interface integrity and mechanical properties is crucial for post-surgical outcomes.

Purpose of the Study:

• To synthesize and evaluate novel hydrophilous expandable bone cements for orthopedic applications.
• To address the limitations of conventional PMMA bone cements in preventing vertebral refracture.

Main Methods:

• Synthesized PMMA-based cements incorporating acrylic acid (AA) and styrene (St), creating PMMA-PAA and PMMA-PAA-PSt variants.
• Assessed volumetric swelling, in vitro cytotoxicity, osteoblast proliferation, and apoptosis.
• Evaluated mechanical properties (elastic modulus, compressive strength) and in vivo bone-cement contact in rabbit models.

Main Results:

• Synthesized cements exhibited significant volumetric swelling and cohesive bone-cement contact in vivo.
• New cements demonstrated lower elastic modulus and compressive strength than PMMA.
• In vitro studies showed reduced cytotoxicity, enhanced osteoblast proliferation, and increased osteogenesis-specific gene expression.
• In vivo analysis revealed direct bone-cement contact and new bone formation within the cement.

Conclusions:

• Hydrophilous expandable bone cements based on PMMA and poly(acrylic acid) (PAA) show promise for vertebroplasty.
• These novel cements offer improved bone integration and reduced risk of refracture compared to conventional PMMA.
• The enhanced osteogenic capacity in vivo suggests potential for bone regeneration.