Confined Compression of Bone Substitute Granules

Abstract

This study investigated the strength of several bone graft substitute (BGS) granular products under compression in a confined fixture characteristic of packing into a contained surgical bone defect. The compressive strength values for columns of granules made of tricalcium phosphate (TCP, dense), calcium carbonate / hydroxyapatite (CC/HA, porous) and ultraporous TCP (TCPu, ultra porous) were 2063.8 ±177.6N, 115.3 ±7.4N, and 40.5 ±8.3, respectively. As a result of their higher strength, the TCP granules did not appreciably reduce in volume after packing. The CC/HA and TCPu granules appreciably reduced in volume after packing, with the final packed volumes being 68% and 41%, respectively, of their original volumes. Based on these results the TCP synthetic bone substitute granules are better able to resist crushing and retain their original volume and osteoconductive capacity during packing in a bone defect than the other BGS granules tested in this study. These properties give the dense granules with a six-arm, interlocking shape superior robustness during handling and implantation compared to other BGS scaffolds produced by porous granules, morsels or blocks, while producing a comparable osteoconductive, resorbable scaffold with interconnected porosity.