An in vivo evaluation of a novel malleable composite scaffold (polypropylene carbonate/ poly(D-lactic acid) /tricalcium phosphate elastic composites) for bone defect repair

An osteoconductive scaffold can facilitate bone defect repair. In this study, a novel elastic porous composite comprising poly(propylene carbonate) (PPC), poly(D-lactic acid) (PDLA), and β-tricalcium phosphate (β-TCP) was prepared as an osteoconductive scaffold. A salt-leaching method is a non-solvent and easily operated method used to mold up the porous scaffolds. The cylinder scaffold was implanted into a 5. mm in diameter and 10. mm in height rabbit femur condyle defect in 6 rabbits. 4 other rabbits with the same defect that did not have the scaffold implanted served as a control group. Rabbits bone tissue specimens were retrieved at 4 and 12 weeks after surgery. 3 reconstructed and 2 unreconstructed rabbits were examined at each time point. The assessments included a computed tomography (CT) scan and a histological examination. The results demonstrate that a PDT porous scaffold made at a PPC/PDLA/TCP weight ratio of 90/8/2 is (1) biocompatible, yielding a positive cell culture study and minimal inflammatory response in vivo; (2) malleable, such that the scaffold can be molded into the bone defect easily without fracturing; and (3) biodegradable and osteoconductive, promoting the progressive formation of new bone into the bone defect. These results indicated that combination of this scaffold with osteoinductive agents such as bone morphogenetic protein, demineralized bone matrix, or mesenchymal cells may generate new biomaterial for bone defect repair.