Articular cartilage cells are immersed in semi-solid matrix and isolated from the rest of the body because of lack of nervous fibres, and blood and lymphatic vessels. Trauma and aging processes result in cartilage ultrastructure disorders. Those changes leads to progressive decreasing of durability and rigidity of cartilage. Research on articular cartilage reconstruction focuses on, among other things, reaching by newly formed tissue optimal amount of vital cells. The aim of this part of the study was microscopic evaluation of repair tissue degenerative changes (cellularity and signs of necrosis).
Material and methods: Repair of partial thickness cartilage defect (III tertiary grade) on distal femur joint surface was evaluated (25 adolescent rabbits). Procedures were performed in two groups: I--autologous chondrocyte transplantation under periosteal flap, II--periosteal graft. Chondrocytes were isolated from the cartilage specimens by enzymatic digestion and cultured in vitro. The follow-up periods were established at 4, 8 and 12 weeks. Repair tissue was evaluated microscopically according to modified O'Driscoll scale.
Results: Repair tissue cellularity. In group I (with chondrocytes), 4 weeks after the procedure tissue of high cellularity was formed, corresponding in amount of cells to the structure of early differentiated hyaline-like cartilage. Amount of cells slightly decreased with time, as it occurs in maturing cartilage. In group II (without chondrocytes), 4 weeks after the procedure the repair tissue was characterized by small amount of cells, which was decreasing with time. Signs of necrosis. In group I, 4, 8 and 12 weeks after the procedure moderate intensity of necrotic signs was observed. In group II, significant intensity of necrosis signs in all observation periods was observed.
Conclusion: Obtained results indicate, that autologous chondrocyte transplantation in treatment of partial thickness cartilage defects effects with forming tissue of high cellularity, not degenerating with time, much better as compared to untreated defect.