Monomer release from methacrylate bone cements during simulated in vivo polymerization

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Orthopedic Surgery

Background:

• Methylmethacrylate (MMA) bone cements are widely used in orthopedic procedures.
• Understanding monomer release is critical for assessing potential adverse effects and ensuring patient safety.
• In vivo polymerization conditions can influence the extent of residual monomer leaching.

Purpose of the Study:

• To quantify monomer release from MMA bone cements under simulated in vivo conditions.
• To investigate the impact of various clinical variables on monomer leaching.
• To establish optimal cement formulations and handling techniques to minimize monomer release.

Main Methods:

• Disk-shaped MMA bone cement specimens were immersed in an aqueous environment.
• Monomer release was quantified using gas chromatography.
• Simulated polymerization was performed under varied conditions mimicking clinical scenarios.

Main Results:

• The majority of monomer release occurred within the first 15 minutes of immersion.
• Under recommended conditions, monomer release was consistently below 3% of the total monomer weight.
• Thin specimens released less monomer per unit area compared to thick specimens.
• A monomer/powder ratio of approximately 0.4 ml/g minimized monomer release.

Conclusions:

• Monomer release from MMA bone cements is generally low and rapid under simulated physiological conditions.
• Clinical variables such as delayed insertion time and specimen geometry have a limited impact on monomer release.
• Optimizing the monomer/powder ratio and specimen thickness can further reduce monomer leaching, enhancing cement safety.