Steroid-associated osteonecrosis: Epidemiology, pathophysiology, animal model, prevention, and potential treatments (an overview)

Xie, Xin-Hui; Wang, Xin-Luan; Yang, Hui-Lin; Zhao, De-Wei; Qin, Ling

Growth factors such as BMPs and VEGF are osteogenic or angiogenic to promote the bone or vessel formation. BMPs are osteoinductive growth factors that induce osteogenic cell differentiation in vitro and osteogenesis in bone healing in vivo. The growth factors can be used for ON treatment directly or combined with bone graft after core decompression [83] . The growth factor genes could also be transfected into BMSCs and were capable of treating the ON in its early stage(s), e.g., demonstrated at the femoral head in rabbit or goat models and the promoted osteogenesis and angiogenesis were observed [84] . Tissue-engineered approach Although core decompression with supplementation of BMSCs could be used to treat ON, it might not be effective for large ON lesions or post collapse cases. Due to the apoptosis of osteocytes and degeneration of trabecular bone matrix in the femora, the bone harvested showed decreased viability in SAON. Kawate used tissue-engineered approach for treating SAON in the femoral head, where cultured BMSCs/b-TCP composite granules were implanted into the cavity that remained after curettage of necrotic bone, together with a subsequent free vascularised tibia grafting [85] . BMSCs/biphasic calcium phosphate ceramic scaffolds and porous b-TCP loaded with BMP-2-gene-transduced BMSCs performed in animal models also provided effective treatment results [84, 86] .