Hollow‐Tube‐Whisker‐Modified Biphasic Calcium Phosphate Ceramics Loaded with SDF‐1α and EPCs for Steroid‐Induced Osteonecrosis of Femoral Head

Abstract Steroid‐induced osteonecrosis of the femoral head (SONFH) remains a significant challenge in orthopedic clinical treatment. In this study, a novel 3D hollow‐tube‐whisker‐modified biphasic calcium phosphate ceramic (H‐BCP) is successfully fabricated using an in‐situ growth technique. Compared to conventional BCP ceramics, H‐BCP exhibited increased specific surface area, enhanced mechanical strength, and improved biocompatibility. Utilizing the hollow‐tube whisker structure, H‐BCP is functionalized with stromal cell‐derived factor‐1α (SDF‐1α) to construct the H‐BCP@SDF‐1α sustained‐release system. In vitro studies demonstrated that H‐BCP@SDF‐1α effectively recruited bone marrow stromal cells (BMSCs), promoted their osteogenic differentiation, and supported the angiogenic differentiation of endothelial progenitor cells (EPCs). Furthermore, EPC‐loaded H‐BCP@SDF‐1α (H‐BCP@SDF‐1α/EPC) is used to construct vascularized tissue‐engineered bone and implanted into a SONFH rabbit model following core decompression surgery. At 12 weeks post‐surgery, animals implanted with H‐BCP@SDF‐1α/EPC exhibited significant new bone formation, bone integration, and in situ revascularization. Additionally, it is found that H‐BCP@SDF‐1α/EPC activated the PI3K/AKT signaling pathway in BMSCs, upregulating osteogenic gene expression. This study explores a novel material system integrating mechanical support, bioactivity, and drug delivery, offering a promising approach for SONFH treatment.