Mesenchymal stem cells: A new strategy for the treatment of femoral head necrosis.

Avascular necrosis of the femoral head (AVFH) is an orthopaedic disease triggered by ischaemic injury that is characterized by structural destruction of the femoral head and loss of function and severely affects the quality of life of patients. Currently, core decompression, bone grafting with vascularized tips, and artificial hip replacement are the main surgical treatment options used in clinical practice; however, these methods generally have limitations, such as trauma, high cost, and long postoperative recovery periods, which impose significant physiological and economic burdens on patients. In recent years, mesenchymal stem cells (MSCs) have shown great potential in the field of bone tissue engineering because of their unique biological properties. MSCs can self-renew and undergo multidirectional differentiation into osteoblasts, chondrocytes, and endothelial cells, and can also regulate the local microenvironment and promote the vascularization of the hip through the secretion of biologically active substances. MSCs can regulate the local microenvironment and promote new blood vessel and bone tissue regeneration through the secretion of growth factors, cytokines, and exosomes. The advantages of MSCs, such as easy access to materials, strong proliferation ability in vitro and stable osteogenic differentiation potential, make them ideal seed cells for femoral head necrosis treatment. However, ANFH treatment with MSCs faces many challenges: (1) the number of MSCs homing to lesion areas after intravenous infusion is limited; (2) the survival time and biological behaviour of locally injected MSCs are still unclear; (3) the mechanism of the interaction between MSCs and host cells has yet to be elucidated; and (4) efficiently modulating the microenvironment of necrotic areas for tissue regeneration needs to be investigated in depth. There are various innovative strategies to address these issues: enhancing the homing ability and in vivo stability of MSCs through genetic engineering; combining MSCs with biomaterials, such as hydrogels, to achieve precise targeting and slow release; and developing drug delivery systems for MSCs to improve therapeutic efficacy. In this paper, we systematically reviewed the pathological microenvironmental characteristics of femoral head necrosis and discuss the potential application, mechanism, existing problems, and solutions of MSCs in ANFH treatment in detail, providing a new theoretical basis and research direction for advancing the clinical treatment of femoral head necrosis.