Chih-Chan Lin, Nai-Jen Chang, Ming-Long Yeh, Chien-Feng Li and Yung-Chang Lin
Background: An initial constrained weight-bearing period achieved via immobilization (Imm) is recommended during osteochondral regeneration to avoid tissue re-injury. However, remedying osteochondral defects with a scaffoldbased treatment and Imm intervention has yet to be studied in osteochondral defect models. Therefore, we investigated the combined outcome of short-term Imm on osteochondral defects with and without porous poly (lactic-co-glycolic acid) (PLGA) scaffold implants.
Methods: Twenty-four rabbits were divided into empty defect (ED) and PLGA-implanted (PI) groups. Each rabbit’s unilateral knee, which contained an osteochondral defect, was immobilized at full extension with a splint for 2 weeks after surgery and subsequently remobilized until sacrifice at 4 weeks or 12 weeks post surgery. The health status; gross appearance; histological analysis detailing collagen, glycosaminoglycan, and matrix metalloproteinase (MMP)- 13 expression levels; and micro-CT images of the rabbits were evaluated.
Results: At 4 weeks, the ED and PI groups both exhibited degenerative cartilage features, including an irregular joint surface, fibrous or fibrocartilage formation, decreased glycosaminoglycan (GAG) expression, and increased MMP-13 expression. However, at 12 weeks, the PI group exhibited significantly higher GAG expression, lower MMP- 13 expression, and more bony deposition matrix and trabecular bone than the ED group.
Conclusion: Our findings indicate that the short-term Imm is harmful to articular cartilage; however, PLGA grafts could provide a matrix for tissue regeneration