Table 4 Spearman’s correlation coefficients (rho) between the expression of TGFB1, BMP2, SMAD3, and MMP13 in OA-affected and healthy cartilage, respectively

TGFB1 and SMAD3

rho = 0.07, p = 0.7

rho = 0.50, p = 0.003

TGFB1 and MMP13

rho = 0.28, p = 0.2

rho = 0.46, p = 0.007

SMAD3 and MMP13

rho = 0.05, p = 0.83

rho = 0.15, p = 0.39

BMP2 and TGFB1

rho = −0.50, p = 0.02

rho = 0.24, p = 0.21

BMP2 and MMP13

rho = −0.48, p = 0.03

rho = 0.17, p = 0.35