Stimulation of Bone Healing in Sheep with a Reinforced Bone Substitute and Colloss®E

INTRODUCTION: The demand for bone graft materials has been increasing dramatically during the past years. Synthetic calcium phosphate bone substitutes, such as hydroxyappatite (HA) and β-Tricalciumphosphate (β-TCP), have received increasing attention due to their similarity in chemical composition with bone and their ability to resorb whilst regenerating new bone. Colloss®E is a lyophilized complex of the proteins from the extracellular matrix of equine bones, and it has been shown to have both osteoinductive and osteoconductive potentials. The aims of this study were two folds: to test the mechanical properties of HA/β-TCP reinforced with biocompatible polymer Poly-Lactic-Acid (PDLLA), and to evaluate the effects of this novel PDLLA-reinforced bone substitutes and Colloss®E on bone healing using a critical size defect model in sheep. We hypothesized that the mechanical properties of PDLLA reinforced HA/β-TCP were comparable to those of human cancellous bone; and that the Colloss®E combined with the PDLLA-reinforced HA/β-TCP might be better than Colloss®E or the PDLLA-reinforced HA/β-TCP alone in stimulation of bone healing.