An arthroscopic approach for the treatment of osteochondral focal defects with cell-free and cell-loaded PLGA scaffolds in sheep.

Osteochondral injuries are common in humans and are relatively difficult to manage with current treatment options. The combination of novel biomaterials and expanded progenitor or stem cells provides a source of therapeutic and immunologically compatible medicines that can be used in regenerative medicine. However, such new medicinal products need to be tested in translational animal models using the intended route of administration in humans and the intended delivery device. In this study, we evaluated the feasibility of an arthroscopic approach for the implantation of biocompatible copolymeric poly-D,L-lactide-co-glycolide (PLGA) scaffolds in an ovine preclinical model of knee osteochondral defects. Moreover this procedure was further tested using ex vivo expanded autologous chondrocytes derived from cartilaginous tissue, which were loaded in PLGA scaffolds and their potential to generate hyaline cartilage was evaluated. All scaffolds were successfully implanted arthroscopically and the clinical evolution of the animals was followed by non invasive MRI techniques, similar to the standard in human clinical practice. No clinical complications occurred after the transplantation procedures in any of the animals. Interestingly, the macroscopic evaluation demonstrated significant improvement after treatment with scaffolds loaded with cells compared to untreated controls.