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Biomimetic tri-layered osteochondral scaffold : study of early implant stability in a sheep model
Manuela Salerno1, Alessandro Di Martino2, Elisabetta Galassi3
1Applied and Translational Research Center, IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy.
Aims:
The aim of this study was to investigate a biomimetic biodegradable cell-free osteochondral scaffold in a clinically relevant large animal model to quantify the early integration and regeneration phases after implantation.
Methods:
Bilateral critical-sized osteochondral defects were created in 14 sheep. One defect was filled with the scaffold, whereas the contralateral was left empty. The graft integration and regeneration tissue quality were evaluated at 14 and 30 days of follow-up. In particular, samples were evaluated for inflammation grade according to the ISO 10993-6 international standard biological evaluation of medical devices, macroscopic appearance graded according to a modified Fortier et al scoring system, histological quality according to a modified International Cartilage Repair Society (ICRS) II score, and the new trabecular bone formation with a micro-CT analysis.
Results:
At 14 days, a higher defect filling was found in the scaffold group compared to the control in the gross analysis (p < 0.001). Low inflammation was observed in both groups, with a slight increase in the scaffold group at 30 days. The scaffold group had better histological scores, with a significantly higher mean global ICRS II score at 30 days compared to controls (p = 0.031). Finally, the mean percentage of new trabecular bone (BV/TV) was significantly higher in the scaffold group versus the control group, both at 14 days (11.5% (SD 4.5) and 5.2% (SD 2.3), respectively; p = 0.005) and at 30 days (28.0% (SD 8.1) and 8.8% (SD 5.0), respectively; p = 0.002).
Conclusion:
The tri-layered biomaterial showed good integration with surrounding tissues and new tissue growth promotion after 14 and 30 days post-surgery, with no safety concerns. In light of the development of appropriate postoperative rehabilitation programmes to prevent the risk of early implant failure while avoiding delays and providing a proper recovery path, this study provides support for the new cartilage field trend for this osteochondral scaffold, suggesting the possibility of safely shortening the postoperative rehabilitation phase after surgery.
