Three-dimensional-printed titanium alloy porous scaffold combined with trans-cinnamaldehyde for repairing osteonecrosis of the femoral head in a dog model.

Osteonecrosis of the femoral head (ONFH) is a common disorder that may be idiopathic, caused by trauma, or associated with alcohol or glucocorticoid use. The goals of early treatment include delaying or avoiding hip replacement, but there are no effective treatments for early-stage disease. The aim of the present study was to evaluate the effects of treatment with 3D-printed porous titanium alloy scaffold combined with daily intraperitoneal trans-cinnamaldehyde (TCA) in a dog model of ONFH. Four weeks after creation of the ONFH model, MRI examination of the femoral head showed the characteristic "double line sign" of ONFH, verifying the validity of our model. After another 12 weeks, femoral head specimens were harvested and examined by gross inspection; micro-computed tomography; histologic staining (hematoxylin and eosin; Masson); immunohistochemical analysis and quantitative real-time polymerase chain reaction analysis. Gross inspection of the femoral head in untreated ONFH animals at 16 weeks after model creation showed pale, exfoliating articular cartilage and disordered trabecular bone. Treatment with 3D-printed titanium alloy porous scaffold combined with TCA ameliorated the pathologic ONFH changes and significantly reduced inmature bone tissue as well as imature collagen in the femoral head, as shown by Masson staining. This treatment also increased VEGF, BMP2, β-catenin, b-FGF, and RUNX2 expression and decreased PPARγ expression, compared with untreated ONFH. In conclusion, 3D-printed titanium alloy porous scaffold combined with TCA can effectively improve ONFH, which may be related to local repair. This provides the theoretical basis for a new treatment strategy for ONFH.