Extracellular vesicles derived from mesenchymal stem cells mediate extracellular matrix remodeling in osteoarthritis through the transport of microRNA-29a

Table 1 The Pelletier gross scoring criteria

Articular surface conditions	Rating
The articular surfaces are intact and of normal color	0
The articular surface is slightly rough, with small fissures visible and loss of luster	1
Mild damage to the articular surface, with cartilage damage reaching the superficial or middle cartilage layer	2
The articular surface is heavily damaged, with the defect reaching deep into the cartilage but not yet exposing the subchondral bone	3
The cartilage defect is severe, and the subchondral bone is exposed or even damaged	4