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 (r2 = 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.