Histological evaluation of medial femoral condyle in OA, 4% RSA and ASC-treated groups. (A) Safranin-O/Fast Green staining of representative specimens. Black arrows, fibrillation and delamination processes. Red arrows, Erosion processes. Scale bars = 1,000 μm. (B) Laverty's score. Data are reported in terms of 95% confidence intervals. Statistical values of at least P < 0.01 were observed in all the comparisons.