Development of a bovine collagen-apatitic calcium phosphate cement for potential fracture treatment through vertebroplasty

The aim of this study was to examine the potential of incorporating bovine fibres as a means of reinforcing a typically brittle apatite calcium phosphate cement for vertebroplasty. Type I collagen derived from bovine Achilles tendon was ground cryogenically to produce an average fibre length of 0.96 +/- 0.55 mm and manually mixed into the powder phase of an apatite-based cement at 1,3 or 5 wt.%. Fibre addition of up to 5 wt.% had a significant effect (P <= 0.001) on the fracture toughness, which was increased by 172%. Adding <= 1 wt.% bovine collagen fibres did not compromise the compressive properties significantly, however, a decrease of 39-53% was demonstrated at >= 3 wt.% fibre loading. Adding bovine collagen to the calcium phosphate cement reduced the initial and final setting times to satisfy the clinical requirements stated for vertebroplasty. The cement viscosity increased in a linear manner (R-2 = 0.975) with increased loading of collagen fibres, such that the injectability was found to be reduced by 83% at 5 wt.% collagen loading. This study suggests for the first time the potential application of a collagen-reinforced calcium phosphate cement as a viable option in the treatment of vertebral fractures, however, issues surrounding efficacious cement delivery need to be addressed. (C) 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.