The ability of damaged articular cartilage to recover with normal hyaline cartilage is limited. Our aim was to study the mechanism of in vivo cartilage repair in case of severe osteochondral lesions using a three-dimensional matrix implanted without any preseeded cells in the osteochondral defect in a rabbit model. According to the ICRS scores from macroscopic observations of the femoral condyles, the average scores in the scaffold groups were higher than those in the control groups at every time (P[0.001). Histological examination of the ostheochondral defects, revealed regeneration of new tissue with hyaline-like cartilage features only in matrix groups. At twelve weeks from implantation, complete filling of the defect with hyaline cartilage with a tendency of mineralization and the absence of implant material is observed. The superficial area of the defect is completely covered with hyaline-like cartilage. The scaffold used leaded to the regeneration of articular tissue with an ordered histoarchitecture.

Currently, microfracturing is the most commonly used cartilage repair procedure in cartilage defects. Our aim was to study the mechanism of in vivo cartilage repair in case of full-thickness articular cartilage damage of the knee using a three-dimensional matrix implanted without any preseeded cells in the defect. We also investigated whether platelet-rich plasma application after microfracture procedure of the knee is associated with improved outcome compared with traditional microfracture treatment alone in a rabbit model. Histological examination of the chondral defects, revealed the largest amount of new tissue with hyaline-like cartilage features in Hyalofast group. At 12 weeks from implantation of the Hyalofast scaffold demonstrated complete filling of the defect with hyaline cartilage in admixture with the scaffold and bone metaplasia in the deepest areas. In the PRP group, complete filling of the defect with an admixture of fibrous and hyaline-like cartilage tissue appeared with a discreet tendency of endochondral ossification. We confirmed the superiority of the autologous matrix-induced chondrogenesis compared to microfracture and PRP or microfracture alone in case of full-thickness articular cartilage damage of the knee.