Application of Biological Composite Materials in the Regeneration of Subchondral Defects and Articular Cartilage in a Synovial Joint: An Experimental Model

Objective: Since the benefits of Nano-material usage have been well documented in orthopedic surgery, this study was conducted to explore the effect of polyvinyl alcohol/nano-hydroxyapatite/polyamide 66 (PVA/n-HA/P66) on repairing of traumatic cartilage defects in rabbit knee joint. Methods: New Zealand white rabbits were used to make a rabbit knee traumatic cartilage defect animal model. All rabbits were randomly located in three groups. Group-A (PVA/n-HA+PA66 implanted in cartilage defects); Group-B (HA nanospheres implanted in cartilage defects)/Gelatin sponge composite scaffold); Group-C (only cartilage defect without implant). The repairment of articular cartilage defects and the general observation were studied by using pathological staining and gene expression of collagen using RT-PCR after 12 weeks. Results: After 12 weeks, we observed a small amount of fibrous tissue growth in group C without soft cell filling. The repaired tissue in group B was stained with immunohistochemical and toluidine blue staining for collagen and type II collagen is positive, but chondrocyte structure is more visible. The relative mRNA expression of type II collagen was higher in group B in comparison to other groups. The results of the Wakitani score were 5.50 +/- 2.59 for group A, 8.83 +/- 2.79 for group B, 11.50 +/- 1.05 for group C. Results showed no significant difference between group B and C; however, significant differences were found in the scoring results between groups A and B, and between-group A and C. Conclusion: This study showed the high effectiveness of PVA/n-HA+PA66 in the treatment of cartilage defects through increasing the expression of type II collagen.