Fig. 7

Morphological and mechanical evaluation of regenerative cartilage. A Representations of osteochondral defects with different treatments. B Macroscopic observation show that osteochondral repair was improved with time from 4 to 12 weeks post implantation. Particularly, the smooth neocartilage with similar appearance to adjacent native tissue was found in EMF group. C Strain–stress curve of regenerative tissue with representative points at intervals of 0.5% strain. D The compression modulus was calculated at strain of 5% and the highest modulus in EMF group suggested excellent mechanical properties. Data are shown as mean ± standard deviation (n = 5). # indicates no significant difference, *p < 0.05, **p < 0.01, ***p < 0.001 compared to the group as indicated