Eight weeks later, the expression of ERRγ in the cartilage of OA mice was significantly increased compared with that in wild-type mice (Zhao et al. 2019), while the expression of matrix metalloproteinase-3 (MMP-3) and MMP-13 increased, and DMM mice showed significant OA manifestations, including cartilage erosion, subchondral osteosclerosis and osteophyte formation (Fang et al. 2018; Tetlow et al. 2001). Here, MMP13 is linked to osteosclerosis.