Engineered cartilage, bone, joints, and menisci. Potential for temporomandibular joint reconstruction

Reconstruction of many musculoskeletal structures can be accomplished by bone grafting and implantation of prostheses. Alternate approaches are needed, however, for repair of complex structures such as articular cartilage surfaces and the temporomandibular meniscus and joint. Tissue engineering, either cell-free or cell-based, offers promise because of recent advances in materials research and in our knowledge of the cellular and molecular mechanisms of tissue repair. There are three considerations in designing a construct for engineered tissue: the source of cells, if any; the nature of the carrier or scaffold; and use, if any, of genes, factors, or adjuvants. Autogenous cells, often expanded in vitro, have been useful for cartilage tissue engineering. Precursor/progenitor cells are advantageous for bone tissue. There are many natural and synthetic resorbable materials with good biocompatibility and tissue compatibility that can be modified to have the porosity and mechanical properties needed for specific applications. The scaffolds can also be modified to provide biological signals to augment repair and integration.