Acrylic bone cement is significantly weaker and of lower modulus of elasticity than compact bone. It is also weaker in tension than in compression. This limits its use in orthopedics to areas where tensile stresses are minimum. Many authors have shown that addition of small percentages of fiber reinforcement by hand mixing improved the mechanical properties significantly but with variable results. In this investigation we have examined the mechanical properties of machine-mixed, commercially available carbon-fiberreinforced bone cement. Appropriate samples of normal low-viscosity cement and carbon-fiber-reinforced cement were prepared and tested mechanically. Carbon fiber increased the tensile strength and modulus by 30% and 35.8% respectively. The compression strength and modulus, however, increased by only 10.7%. Similarly, bending and shear strengths improved by 29.5% and 18.5%, respectively. Diametral compression strength, which is an indirect measure of tensile strength, however, showed only 6.2% improvement. The maximum temperature rise during polymerization was also reduced significantly by the fiber reinforcement.
M. Warman, and J. Mitchell, unpublished data, 1977) have attempted to improve the mechanical performance of bone cement with small percentages of various types of fiber reinforcement, e.g., carbon or graphite, steel, Aramid@, and glass fibers. In all these attempts, small percentages of fibers (usually 1 to 5% of the weight of the polymer, with lengths varying from 6 to 13 mm and diameters from 6 to 15 pm) were manually mixed with the