Healing of long-bone defects in sheep metatarsals using bioceramics and mesenchymal stem cells

Background Autologous bone is the most effective bone graft procedure but is limited in quantity and requires a second surgery site. These drawbacks have encouraged scientists and surgeons to find alternative approaches. The aim of this study was to investigate the ability of biphasic calcium phosphate ceramic granules to promote bone regeneration in a preclinical model. Methods In this work, a 2.5-cm critical-sized bone defect was created using Masquelet's technique in sheep metatarsals. The defect was filled with a poly-methylmethacrylate spacer, which was replaced 6 weeks later with biphasic calcium phosphate granules, with or without autologous mesenchymal stem cells (n = 7 per group). Results After 12 weeks, nondecalcified histology demonstrated good and homogeneous bone formation for biphasic calcium phosphate ceramic granules, with or without autologous mesenchymal stem cells. No significant difference was observed between the two groups; however, all the implants were able to support bone formation and for certain cases exhibited bone unions. Conclusions These results highlighted the potential of biphasic calcium phosphate ceramic granules to be used as scaffolds for mesenchymal stem cells in the reconstruction of critical-sized bone defects instead of autologous bone grafts.