Transplantation of De Novo Scaffold-Free Cartilage Implants Into Sheep Knee Chondral Defects

BackgroundNew cell-based treatments for articular cartilage repair are needed. As the optimal scaffold for cartilage repair has yet to be developed, scaffold-free cartilage implants may remove the complications caused by suboptimal scaffolds.HypothesisThe implantation of a scaffold-free, autologous de novo cartilage implant into standardized full-thickness cartilage defects of femoral condyles in sheep leads to a qualitatively better regenerative tissue than does periosteal flap alone or no treatment.Study DesignControlled laboratory study.MethodsChondral defects 4 mm in diameter (1 per sheep) were created in the center of 1 medial femoral condyle of 48 sheep. Twelve defects were allowed to heal spontaneously, 16 defects were covered with periosteal flaps alone, and 20 defects were filled with autologous de novo cartilage graft and overlaid with a periosteal flap. Differences were assessed macroscopically using the International Cartilage Repair Society score and microscopically using the International Ca...