Rocky S. Tuan, PhD, Abstract
Cartilage damaged by trauma has a limited capacity to regenerate. Current methods of managing small chondral defects include palliative treatment with arthroscopic débridement and lavage, reparative treatment with marrow-stimulation techniques (eg, microfracture), and restorative treatment, including osteochondral grafting and autologous chondrocyte implantation. Larger defects are managed with osteochondral allograft or total joint arthroplasty. However, the future of managing cartilage defects lies in providing biologic solutions through cartilage regeneration. Laboratory and clinical studies have examined the management of larger lesions using tissue-engineered cartilage. Regenerated cartilage can be derived from various cell types, including chondrocytes, pluripotent stem cells, and mesenchymal stem cells. Common scaffolding materials include proteins, carbohydrates, synthetic materials, and composite polymers. Scaffolds may be woven, spun into nanofibers, or configured as hydrogels. Chondrogenesis may be enhanced with the application of chondroinductive growth factors. Bioreactors are being developed to enhance nutrient delivery and provide mechanical stimulation to tissue-engineered cartilage ex vivo. The multidisciplinary approaches currently being developed to produce cartilage promise to bring to fruition the desire for cartilage regeneration in clinical use.