Results of the experimental repair of osteochondral lesions in a pig model using tissue engineering

OBJECTIVE: To repair experimental osteochondral knee lesions in pigs using tissue engineering. MATERIAL AND METHODS: Eight 40-kg pigs underwent surgery. Cartilage and periosteal biopsies of their control knee were taken. Cartilage and periosteal cells were independently isolated, cultured and seeded in biodegradable PGA and PLA polymers that were fixed on the bottom of an osteochondral defect in the pig's experimental knee, with bioabsorbable Mitek implants. Four months later the pigs were sacrificed and the knees were analyzed with nuclear magnetic resonance imaging (NMRI), macroscopic assessment, histology, electron microscopy (EM), scanning electron microscopy (SEM) and SEM element analysis. RESULTS: All the defects were filled with cartilage-like tissue according to the NMRI evaluation and the visual examination. Hyaline-like cartilage was obtained in 3 defects and fibrocartilage in 5. The EM showed chondrocytes in the repair tissue. The SEM showed appropriate integration to the bone and the surrounding tissue. SEM element analysis showed sulphurized matrix attached to the bone with calcium and phosphates as predominant elements. DISCUSSION: Tissue engineering enabled the production of tissues similar to normal ones. The polymer fixation system was effective.