Repair of osteonecrosis of the femoral head: 3D printed Cervi cornus Colla deproteinized bone scaffolds

BACKGROUND: Osteonecrosis of the femoral head (ONFH) is a common joint disease and a major cause of morbidity. OBJECTIVE: In this study Cervi cornus Colla (CCC) deproteinized bone scaffolds were designed and three dimensional (3D)-printed for the repair of ONFH in rats. MATERIAL AND METHODS: The CCC-deproteinized bone scaffolds were 3D-printed using polycaprolactone mixed with the CCC-deproteinized bone powder. The scaffolds were viewed under a scanning electron microscope and subjected to compression analysis. Osteoblasts were isolated from rats and coated onto the scaffolds. Cell proliferation assays were performed with the MTT (3‑[4,5-dimethylthiazole‑2]-2,5-diphenyltetrazolium bromide) kit from Promega. An ONFH was induced in rats and a CCC-deproteinized bone scaffold was implanted into the necrotic femoral head. General observations, X‑ray imaging, and pathological examination of the femoral head were performed to evaluate the treatment of ONFH in the rats. RESULTS: The scaffolds were porous with a mean pore diameter of 315.70 ± 41.52 nm and a porosity of 72.86 ± 5.45% and exhibited favorable mechanical properties and degradation. In vitro assays showed that osteoblasts accumulated in the pores and adhered to the scaffolds. The CCC-deproteinized bone scaffolds enhanced the proliferation of osteoblasts. The in vivo experiments revealed that the general observation score of rats in the CCC-scaffold implanted group was significantly higher than that in the control group. The X‑ray images showed significant alleviation of ONFH in the CCC-deproteinized bone scaffold implanted rats. The femoral heads of rats in the treatment group showed less destruction or ossification of cartilage cells, few bone cement lines, very little necrosis or irregularities on the cartilage surface and only a small amount of inflammatory cell infiltration in the medullary cavity. CONCLUSION: These results suggest that CCC-deproteinized bone scaffold implants facilitated the repair of ONFH in rats. This research provides a new therapeutic approach for the repair of early and mid-term ONFH.