Figure 2

Longitudinal evaluations of cartilage defects in immature and mature cartilage. (A) Sagittal SPGR 3D FS knee MRI and macroscopic evaluation of cartilage defects in immature and mature joints at different time points after MASI. (a,b) MRI of two representative immature knee joints at 12 weeks after MASI demonstrates persistent cartilage defect which extends into the subchondral bone. (c,d) MRI of immature knee joints at 24 weeks after MASI demonstrates further increased cartilage and subchondral bone defects. (e,f) By comparison, a cartilage defect in a mature joint has been almost completely repaired at 24 weeks after MASI. There is no subchondral edema or defect. (g,h) Macroscopic specimen of the immature knee joints demonstrated incomplete cartilage defect repair at 12 weeks and increasing defects in the cartilage and (i,j) subchondral bone at 24 weeks. (k,l) By comparison, macroscopic specimens of the mature knee joints demonstrated complete cartilage defect repair at 24 weeks. (B) Corresponding Pineda cartilage score of cartilage repair in immature (after 12 and 24 weeks) and mature joints (after 24 weeks). Data are displayed as means and standard deviation of four cartilage defects per group. The Pineda score of cartilage defects of immature joints at 24 weeks was significantly higher compared to the Pineda score of mature joints. (C) Corresponding cartilage repair score of immature and mature pigs according to Wakitani cartilage repair scoring system (*p < 0.05, **p < 0.01, ***p < 0.001).