When we analysed OA development in Col2a1-Cre;Runx1<sup>fl/fl</sup> and Runx1<sup>fl/fl</sup> mice by surgically inducing joint instability, Cartilage degradation and osteophyte formation of Col2a1-Cre;Runx1<sup>fl/fl</sup> joints was accelerated compared with joints in Runx1<sup>fl/fl</sup> animals 8 weeks after surgery.