Circular RNAs(circRNAs)are a class of closed-loop non-coding RNAs(ncRNAs)formed by head-to-tail covalent bonds.CircRNAs participate in the development of osteoarthritis by regulating extracellular matrix degrada-tion,inflammatory response and homeostasis of chondrocytes;It regulates the osteogenic differentiation of bone mar-row mesenchymal stem cells,the activity of bone microvascular endothelial cells and angiogenesis to affect femoral head necrosis;It regulates the differentiation of bone marrow stem cells,osteoblasts and osteoclasts to cause osteo-porosis and it affects the invasion,metastasis and drug resistance of osteosarcoma through different pathogenesis.CircRNAs are expected to become a new clinical diagnostic marker in the future.