Dual-Stage Resorption

Bone grafts perform a specific function during healing:

• When a bone graft is implanted, its porous structure serves as a scaffold for new bone formation.
• Once the porosity is filled in with new bone, the function of the graft is relatively complete.
• However, the graft material is still present at the implant site and continues to take up space. As a result, complete healing cannot occur until the graft material is fully resorbed.

Bone graft resorption is directly dependent on the composition and structure of a graft material. Optimally, grafts would have a slower resorption process while bone is forming and then a faster resorption once the scaffold is filled in.

This is possible due to TrelCor’s unique dual-region composition:

• A thin, slow-resorbing hydroxycarbanoapatite (HCA) surface layer which stays around long enough for new bone to form, and
• A fast-resorbing calcium carbonate (CC) core which resorbs only after substantial bone growth has already occurred

This advanced bone graft property is unique to TrelCor and optimally matches graft resorption with the stages of bone graft healing. Slowly-resorbing when bone is forming, and fast-resorbing once more space is needed.

No other bone grafting product on the market offers dual-stage resorption.

This effect was clearly seen in the pre-clinical studies evaluating TrelCor’s in vivo resorption.

• Twelve-week histological imaging of TrelCor implanted in a rabbit bone defect is shown below. The dual composition of TrelCor can be seen in the magnified section, with the calcium carbonate core (green) and the HCA surface layer (white).
• At this 12-week timepoint, prominent bone growth (yellow) is visible on the surface of the TrelCor granules while also penetrating into the calcium carbonate area.
• This timepoint captures both the initial resorption of the HCA layer and penetration of new bone into the calcium carbonate region. This demonstrates that resorption and new bone formation have penetrated the HCA surface and quickly progressing through the calcium carbonate.

TrelCor-based bone grafts resorb by timing bone formation to graft resorption, allowing it to resorb at two different rates ideal for an optimal patient-specific resorption response.