Additive Manufacturing: The Next Generation of Scapholunate Ligament Reconstruction.

Ligament reconstruction, as a surgical method used to stabilize joints, requires significant strength and tissue anchoring to restore function. Historically, reconstructive materials have been fraught with problems from an inability to withstand normal physiological loads to difficulties in fabricating the complex organization structure of native tissue at the ligament-to-bone interface. In combination, these factors have prevented the successful realization of nonautograft reconstruction.  A review of recent improvements in additive manufacturing techniques and biomaterials highlight possible options for ligament replacement.  In combination, three dimensional-printing and electrospinning have begun to provide for nonautograft options that can meet the physiological load and architectures of native tissues; however, a combination of manufacturing methods is needed to allow for bone-ligament enthesis. Hybrid biofabrication of bone-ligament tissue scaffolds, through the simultaneous deposition of disparate materials, offer significant advantages over fused manufacturing methods which lack efficient integration between bone and ligament materials.  In this review, we discuss the important chemical and biological properties of ligament enthesis and describe recent advancements in additive manufacturing to meet mechanical and biological requirements for a successful bone-ligament-bone interface.  With continued advancement of additive manufacturing technologies and improved biomaterial properties, tissue engineered bone-ligament scaffolds may soon enter the clinical realm.