Three-dimensional bioprinting for bone and cartilage restoration in orthopaedic surgery

Notable shortcomings exist in the currently available surgical options for reconstruction of bone and articular cartilage defects. Three-dimensional (3D) printing incorporating viable cells and extracellular matrix, or 3D bioprinting, is an additive manufacturing tissue engineering technique that can be used for layer-by-layer fabrication of highly complex tissues such as bone and cartilage. Because of the scalability of 3D bioprinting, this technology has the ability to fabricate tissues in clinically relevant volumes and addresses the defects of varying sizes and geometries. To date, most of our in vitro and in vivo success with cartilage and bone tissue bioprinting has been with extrusion-based bioprinting using alginate carriers and scaffold free bioinks. Fabrication of composite tissues has been achieved, including bone which includes vascularity, a necessary requisite to tissue viability. As this technology evolves, and we are able to integrate high-quality radiographic imaging, computer-assisted design, computer-assisted manufacturing, with real-time 3D bioprinting and ultimately in situ surgical printing, this additive manufacturing technique can be used to reconstruct both bone and articular cartilage and has the potential to succeed where our currently available clinical technologies and tissue manufacturing strategies fail.