EVALUATING THE COMPRESSIVE STRENGTH OF CALCIUM SULFATE-CALCIUM PHOSPHATE BONE GRAFT COMPOSITE WITH POLYGLYCOLIC ACID FIBERS: A BIODEGRADABLE SPACER ALTERNATIVE

Abstract

Background:   Injectable tricalcium phosphate/calcium sulfate (TCP-CS) granules are used as a synthetic bone graft replacement. They are designed to be inserted into a bony space during surgery, where they cure to form a strong ceramic in vivo. TCP-CS bone grafts have been reported to achieve an immediate intra-operative strength of 40 megapascals within the first 2 hours.

Purpose: This study evaluates the compressive strength of TCP-CS when used as a spacer. The research then assesses the impact of adding polyglycolic acid fibers has on the strength of the composite, followed by a comparison of both mixtures.

Materials and Methods: The study compared two groups: an experimental group with TCP-CS bone graft mixed with 100 absorbable polyglycolic acid fibers, and a control group with TCP-CS only. Using ASTM protocols, the materials were mixed and injected into cylindrical molds (12.7 mm diameter, 8 mm height), and incubated in saline baths at 32°C (stage one) and 37°C (stage two) for up to 24 hours. Compressive strength was then tested at 60 minutes, 135 minutes, and 24 hours.

Results and Discussion: The compressive strength of TCP-CS with fibers was greater than TCP-CS alone after 24 hours. The TCP-CS alone samples softened and cracked after 24 hours at 37°C, while fiber-reinforced samples remained stronger. Differences in initial compressive strength compared to previous studies may be due to variations in sample size and preparation. The addition of fibers enhanced strength, but ideal physical properties for maintaining disc height and promoting fusion remain uncertain.

Conclusion: In conclusion, injectable, eco-friendly cement with better physical properties is still missing. A reproducible, sensible string structure might strengthen the cement composite to provide the needed physical strength and stiffness and create macro channel structures suitable for bone ingrowth in vivo. Further development is needed to achieve the desired physical properties and support bone ingrowth effectively.