Treatment of Full-Thickness Cartilage Defects with Pedunculated and Free Synovial Grafts: A Comparative Study in an Animal Model.

Abstract

The purpose of this study was to compare the potential effects of pedunculated and free synovial grafts in the repair of full-thickness articular cartilage defects on an animal model with histological and immunohistochemical analysis. A comparative study in an animal model was performed with 24 rabbits, divided into two groups. Full-thickness cartilage defects were created bilaterally on the knees of all rabbits. Pedunculated and free synovial grafts were applied to the right knees of Group 1 and Group 2, respectively. Left knees were left as the control group. Six rabbits from each group were randomly selected for euthanasia 4 and 8 weeks postoperatively. All samples were examined histologically with a cartilage scoring system. For immunohistochemical analysis, the degree of collagen 2 staining was determined using a staging system. All data were statistically compared between the study groups with Student's t-test or Mann-Whitney U-test. The correlations between categorical variables were analyzed with Fisher's exact test and Chi-square test. In Group 1, the mean defect size had significantly decreased at 8 weeks postsurgery. It was also significantly smaller than that of Group 2. Both pedunculated and free synovial grafts had significantly better histological and immunohistochemical outcomes compared with the controls. Contrastingly, the results of comparison between the study groups (Group 1 vs. 2) at the 4th and 8th week were not statistically significant with regard to histological scores and immunohistochemical staining. Synovial tissue, whether pedunculated or free, provided much better cartilage recovery compared with the control. It can be used as a mesenchymal stem cell (MSC) source, and synovium-derived MSCs have the chondrogenic potential for the in vivo treatment of full-thickness cartilage defects.