Mg–Sc alloy promotes angiogenesis–osteogenesis coupling and ameliorates steroid‐induced osteonecrosis of the femoral head

Abstract Steroid‐induced osteonecrosis of the femoral head (SONFH) is a severe bone disorder that was clinically treated by core decompression (CD) combined with bone grafting. However, the clinical outcome of this therapy for SONFH is usually unsatisfactory. Magnesium (Mg) is a biodegradable material reported as an ideal orthopedic implant. The Mg 2+ released from its degradation is considered an effective factor for bone tissue formation, but the rapid degradation rate limited its application. Here, we reported a magnesium–scandium (Mg–Sc) alloy for promoting bone regeneration in SONFH. We discovered that Mg–Sc alloy with satisfied corrosion resistance, anti‐apoptosis, angiogenic, and osteogenic properties in vitro, could facilitate osteogenic differentiation by activating the Wnt/β‐catenin signaling pathway. In the clinically relevant SONFH model, CD combined with suitable Mg–Sc alloy implantation promoted angiogenesis–osteogenesis coupling and alleviated osteonecrosis. We observed fewer apoptotic osteocytes and empty bone lacunae, but more blood vessels and new bone formation in the Mg‐Sc alloy implanted CD tunnel region compared with CD‐treated SONFH rabbits. Properly degraded Mg–Sc alloy maintains high structural integrity and provides reliable mechanical support for the osteonecrotic femoral head, which is conducive to further clinical translation.