Aim: This study wants to investigate whether the administration of stromal stem cells (SSC) in a platelet-rich plasma (PRP) scaffold could promote angiogenesis which resulted in a better allograft integration.

Methods: surgery: A monolateral resection of 3cm segment of the metatarsus, was perfomed in 10 adult cross-breed sheep (3–4 years old), weighting 60–70 kg.

Isolation and ex-vivo expansion of SSC: nucleated cells were isolated with density gradient and expanded ex-vivo with alpha-MEM containing 20% FCS.

Radiographic and histomorphometric analysis: Radiographs were made after surgery and after 1, 2 and 4 months. Histomorphometric studies were carried out to study the defect and the new bone formation at the implant site

Results: Union had occurred in all the 5 animals of the SSC group after 4 months as observed radiographically and morphologically, while in the control group the osteotomy line was still visible. Histomorphometric analysis demonstrated a higher % of new-bone formation in both the host (%section quadrant) and the grafted bone in SSC animals.

Conclusions: Results presented suggest that SSC in PRP-based scaffold have improved allograft integration. In conclusion the application of this surgical approach may result in an increased and accelerated bone graft integration, reducing the time required for bone healing and increasing the chances of a successful bone implant.