Bone-bonding ability of bioactive bone cement under mechanical stress

Area of Science:

• Orthopedic biomaterials
• Spinal surgery
• Biocompatibility studies

Background:

• Bioactive bone cement (BABC) forms a calcium-phosphate layer for bone bonding.
• Previous evaluation of BABC occurred in non-load-bearing rat models.
• The mechanical behavior of BABC in spinal fixation requires investigation.

Purpose of the Study:

• To assess BABC performance in a posterolateral spinal fixation model under mechanical stress.
• To compare BABC with polymethylmethacrylate (PMMA) bone cement in terms of bone bonding and fixation stiffness.
• To evaluate the long-term interface stability of BABC in a spinal environment.

Main Methods:

• Posterolateral spinal fixation using L5-L6 segment in Japanese white rabbits.
• Application of BABC and PMMA bone cement to transverse processes.
• Postoperative analysis at 1 day, 4, 8, and 16 weeks using Giemsa staining, SEM, and biomechanical torsion testing.

Main Results:

• BABC demonstrated direct bone bonding without intervening soft tissue at 4, 8, and 16 weeks.
• PMMA bone cement consistently showed soft tissue at the bone-cement interface.
• BABC-spine constructs exhibited greater stiffness than PMMA-spine constructs throughout the study.

Conclusions:

• Bioactive bone cement achieves direct bone integration under mechanical loading in spinal fixation.
• BABC provides superior fixation stiffness compared to PMMA bone cement.
• BABC shows promise as a biomaterial for load-bearing spinal applications.