Back

Making Bone Graft Stronger

When are bits of bone and pieces of sand alike? When scientists test them for strength. The same methods, formulas, and principles used in the science lab for measuring the strength of sand are also used for bone.

Sand that is used in building must be strong enough to withstand many kinds of forces. Bone, when used in bone grafts, must also hold up against similar forces. Studies to improve bone graft strength use mechanical properties of sand as a basis for research.

For example, there are math formulas to measure how far particles of sand will slide against each other. The formulas also hold true for measuring the strength of particles that lock together to form a bond. Scientists in Scotland used these concepts to improve bone graft material.

They found that bone dust particles of varied sizes and shapes are stronger than bone graft that is all one size. Uniform particle size means lower shear strength. Shape is also important. Round particles have lower shear strength compared to spike-shaped particles of bone graft.

The authors of this article show that washing bone graft before using it increases the interlocking of small pieces. Washed graft has greater shear strength. This is probably caused by the removal of fat and marrow from the graft. The graft can fit together more tightly without these other parts.

This research shows that washing bone graft is the best way to improve strength for any graft material. Removing fat and marrow tissue in the process also reduces the risk of the patient's body rejecting donor bone graft. These discoveries will especially benefit people who require bone grafting during revision hip surgery.

References: Douglas G. Dunlop, MD, FRCS, FRCSED (TR and Orth), et al. Techniques to Improve the Shear Strength of Impacted Bone Graft. In Journal of Bone and Joint Surgery. April 2003. Vol. 85-A. No. 4. Pp. 639-646.

Back