In two individual case reports of cartilage degeneration of knee, Centeno et al. (Centeno et al., 2008a; Centeno et al., 2008b) demonstrated statistically significant changes  in visual analogue-scale pain scores and cartilage volumes on MRI. Davatchi et al. reported the result of three knee osteoarthritis patients who were injected with 8-9 X 10(6) mesenchymal stem cells. Clinical parameters improved in transplanted knees at 6 months. Then, they started gradually to deteriorate, but at 5 years remained improved compared to baseline values (Davatchi et al., 2015)