An Overview of Scaffold Design and Fabrication Technology for Engineered Knee Meniscus

Abstract

Current surgical treatments for meniscal tears suffer from subsequent degeneration of knee joints, limited donor organs and inconsistent post-treatment results. Three clinical scaffolds (Menaflex CMI, Actifit^® scaffold and NUsurface^® Meniscus Implant) are available on the market, but additional data are needed to properly evaluate their safety and effectiveness. Thus, many scaffold-based research activities have been done to develop new materials, structures and fabrication technologies to mimic native meniscus for cell attachment and subsequent tissue development, and restore functionalities of injured meniscus for long-term effects. This study begins with a synopsis of relevant structural features of meniscus and goes on to describe the critical considerations. Promising advances made in the field of meniscal scaffolding technology, in terms of biocompatible materials, fabrication methods, structure design and their impact on mechanical and biological properties are discussed in detail. Among all the scaffolding technologies, additive manufacturing (AM) is very promising because of its ability to precisely control fiber diameter, orientation, and pore network micro-architecture to mimic the native meniscus microenvironment.

Keywords: additive manufacturing; meniscal scaffold; scaffold design and fabrication.

Figure 1

(a) Anatomical photograph of meniscus; (b) internal microstructure at cross-section. Figure 1 illustration of Human Knee Meniscus (adapted from [1,2]).

Figure 2

Scaffold-based approach for meniscus regeneration.

Figure 3

(a) Fabrication pathway; (b) 3D wedge-shaped meniscal scaffold (adapted from [68]).

Figure 4

Fabricated meniscal scaffold (adapted from [68]).