A poly(propylene fumarate)--calcium phosphate based angiogenic injectable bone cement for femoral head osteonecrosis

Osteonecrosis of the femoral head commonly occurs when the blood supply to bone was disrupted. The general treatment for early stages of necrosis in the femoral head is core decompression. However, the long-term outcome of this operation is usually compromised due to collapse of the necrotic bone. In this study, poly(propylene fumarate) (PPF) and calcium phosphate cement (CPC) were combined to provide appropriate mechanical strength after core-decompressed femoral heads and offer the properties of osteoconductivity. Effects of different ratios of CPC to PPF on mechanical and cytotoxicity were investigated. Results show that bone cement is less cytotoxic with the C/P ratio raise, and the increment of the CPC proportion also strengthens the mechanical strength, reduces the crosslinking temperature and diminishes excessive swelling of the cement. With addition of ginsenoside Rg1 the bone cement composite can also offer angiogenic effect. The drug release profiles were analyzed and the angiogenecity of released Rg1 was confirmed by the assay of tube formation in human umbilical vein endothelial cells (HUVECs). In summary, the newly developed angiogenic bone cement composite possesses remarkable development potential for application to treating osteonecrosis of the femoral head.