FIGURE 2.

Model of scaffold degradation in osteochondral defect. (A) and (C) Elastic modulus and volume fraction, respectively, of the scaffold material prior to degradation; (B) and (D) Elastic modulus and volume fraction, respectively, of the “artificial” scaffold with matched degradation speed at day 25 (complete scaffold degradation set to day 50). The left, middle, and right columns show the scaffold degrading by surface erosion, bulk degradation, and bulk degradation with autocatalysis, respectively. At the time point shown in the plots, the surface and bulk elements of the scaffold degrading by surface erosion and bulk degradation with autocatalysis, respectively, were completely degraded. The dash-dot and solid red lines mark the axis of symmetry and the articular interface, respectively. The legends to interpret the plots are on the right side of the corresponding rows. The volume fraction is expressed as percentage of the total volume in one element.