The Science of Actifuse

Silicate substituted calcium phosphate

This chemistry is unique to Actifuse and it increases the material’s bioactivity. Circulating proteins essential for bone cell adhesion and activation are attracted to the material surface in increased numbers. This process distinguishes Actifuse from traditional bone graft substitutes. As a result, bone formation is enhanced leading to more bone being produced in less time 1,2,3,4,5,6 TOP

Optimized scaffold

Actifuse has a unique structure that provides an optimized, interconnected porous graft to support rapid bone formation. The macro and micro pores, combined with high strut (wall) porosity ensures the free passage of cells, fluid, nutrients and signaling molecules throughout the graft material. The surface architecture of Actifuse is highly appropriate for cell attachment. Actifuse has >95% interconnectivity which enables bone regeneration throughout the graft.

Mineralization and collagen formation results in Actifuse being truly integrated with host bone; this is not the same for other graft materials, where a fibrous interlayer can develop between the implant and newly formed bone.TOP

Pure chemistry

Strict safeguards in the ApaTech production process ensure the chemical and crystalline purity of silicate substituted calcium phosphate in Actifuse. High purity prevents adverse macrophage reactions which can lead to the formation of fibrous tissue in place of bone. Whilst purity is not unique to Actifuse, it is important to note that many other synthetic products do not meet the same high purity standards, containing multiple impurities.TOP

Porosity

The porosity of a product will determine its ability to bear weight and influences the rate at which new bone can form in the graft material. Actifuse has a porosity of 80% which is appropriate for use in non load-bearing procedures and delivers rapid bone growth. There is a large variability in porosity among other synthetic products. For a given material chemistry, lower porosity can lead to a lack of interconnectivity and affects the time it takes for a scaffold to be resorbed. This can result in a poor quality repair. Excessively high porosity can result in the material crumbling during inter-operative handling and the potential for rapid scaffold dissolution.TOP

Resorption profile

In a sheep model Actifuse demonstrates predictable resorption, remodeling via cellular action at a rate appropriate to the individual patient rather than dissolving at a fixed rate

Resorption profile for Actifuse

resporption profile of actifuse

Bone graft should ideally resorb at the rate required to meet the needs of individual patients – Actifuse achieves this and evidence shows Actifuse resorption is cell mediated so it remodels at the rate that the body requires, avoiding the biologic race between graft dissolution and bone formation as often seen with competitor bone graft products.6TOP

  1. 1 Guth K et al. Protein adsorption and early osteoblastic behavior on phase pure hydroxyapatite (HA) and silicon substituted hydroxyapatite (SiHA). European
  2. 2 Wheeler DA et al. Efficacy of silicate substituted calcium phosphate graft in posterolateral lumbar fusion in sheep. Spine J 2007; 7 (3): 308-317.
  3. 3 Hing KA et al. Key Engineering Materials 2001; 192-5: 373-376 Influence of phase purity on the in vivo response to hydroxyapatite
  4. 4 Guth K et al. Silicon dissolution from microporous silicon substituted hydroxyapatite and its effect on osteoblast behaviour. Key Eng Mat 2006; 309-311: 117-120.
  5. 5 Rashid N et al. Effect of silicate substitution on the surface charge of hydroxyapatite. 7th World Biomaterials Congress, Sydney, 2004.
  6. 6 Hing KA et al. Comparative performance of three ceramic bone graft substitutes. Spine J 2007; 7(4): 475-490.