From intricate to integrated: Biofabrication of articulating joints

Abstract

Articulating joints owe their function to the specialized architecture and the complex interplay between multiple tissues including cartilage, bone and synovium. Especially the cartilage component has limited self‐healing capacity and damage often leads to the onset of osteoarthritis, eventually resulting in failure of the joint as an organ. Although in its infancy, biofabrication has emerged as a promising technology to reproduce the intricate organization of the joint, thus enabling the introduction of novel surgical treatments, regenerative therapies, and new sets of tools to enhance our understanding of joint physiology and pathology. Herein, we address the current challenges to recapitulate the complexity of articulating joints and how biofabrication could overcome them. The combination of multiple materials, biological cues and cells in a layer‐by‐layer fashion, can assist in reproducing both the zonal organization of cartilage and the gradual transition from resilient cartilage toward the subchondral bone in biofabricated osteochondral grafts. In this way, optimal integration of engineered constructs with the natural surrounding tissues can be obtained. Mechanical characteristics, including the smoothness and low friction that are hallmarks of the articular surface, can be tuned with multi‐head or hybrid printers by controlling the spatial patterning of printed structures. Moreover, biofabrication can use digital medical images as blueprints for printing patient‐specific implants. Finally, the current rapid advances in biofabrication hold significant potential for developing joint‐on‐a‐chip models for personalized medicine and drug testing or even for the creation of implants that may be used to treat larger parts of the articulating joint. © 2017 The Authors. Journal of Orthopaedic Research Published by Wiley Periodicals, Inc. on behalf of the Orthopaedic Research Society. J Orthop Res 35:2089–2097, 2017.

Application of quality by design for 3D printed bone prostheses and scaffolds

“…Personalised bone implants with a patient-specific shape can ensure a precise reconstruction of defects from trauma and better mechanical stability. Nevertheless, there are more aspects to bone regeneration than just geometry [ 109 ]. Customised 3D printed bone implants and scaffolds should also be biologically active to restore the functional characteristics of patient’s bone such as vascularization for an appropriate diffusion of oxygen, nutrients and waste products [ 110 ].…”

“…For example, a change in bony geometry at the proximal femur will impact muscle tendon pathways and muscle moment arms at the hip and may also alter the ideal force-length operating range of the muscles during such activities. Moreover, the implant’s material should resemble the mechanical characteristics of native surrounding tissues [ 109 ], e.g. resemble the patient’s bone modulus of elasticity to avoid stress shielding and to promote early bone regeneration [ 94 ].…”

Fixation of Hydrogel Constructs for Cartilage Repair in the Equine Model: A Challenging Issue

“…zonal composition) and cellular aspects (e.g. use of differentiated versus undifferentiated cells) (35,36), but surprisingly little attention has been given to the fixation of the implants.…”

Trends in Decellularized Extracellular Matrix Bioinks for 3D Printing: Inspiring a new Kind of Medicine

“…Millions of people are affected by cartilage problems or disorders at some point in their lifetime, resulting in careers being cut short or lives dramatically changed as movement is affected [201][202][203]. Cartilage defects are caused by trauma, diseases and degenerations over time [204,205]. Currently, cartilage damage or defect is treated through many strategies including drilling into the bone to release stem cells that can help heal the damage.…”