Cell-Free Scaffolds as a Monotherapy for Focal Chondral Knee Defects

Abstract

Chondral knee defects have a limited ability to be repaired. Current surgical interventions have been unable to regenerate articular cartilage with the mechanical properties of native hyaline cartilage. The use of a scaffold-based approach is a potential solution. Scaffolds are often implanted with cells to stimulate cartilage regeneration, but cell-based therapies are associated with additional regulatory restrictions, an additional surgical procedure for cell harvest, time for cell expansion, and the associated costs. To overcome these disadvantages, cell-free scaffolds can be used in isolation allowing native cells to attach over time. This review discusses the optimal properties of scaffolds used for chondral defects, and the evidence for the use of hydrogel scaffolds and hydrogel–synthetic polymer hybrid scaffolds. Preclinical and clinical studies have shown that cell-free scaffolds can support articular cartilage regeneration and have the potential to treat chondral defects. However, there are very few studies in this area and, despite the many biomaterials tested in cell-based scaffolds, most cell-free studies focused on a specific type I collagen scaffold. Future studies on cell-free scaffolds should adopt the modifications made to cell-based scaffolds and replicate them in the clinical setting. More studies are also needed to understand the underlying mechanism of cell-free scaffolds.

Evaluation of a Cell-Free Collagen Type I-Based Scaffold for Articular Cartilage Regeneration in an Orthotopic Rat Model

“…Tissue engineering for regenerative approaches emerges as one of the most promising biomedical applications for cartilage tissue regeneration. The latter is based on the use of innovative biomaterials, which act as scaffolds, mimicking a three-dimensional (3D) extracellular matrix (ECM) microenvironment, with or without the use of chondrocytes or mesenchymal stem cells from different sources [7][8][9][10]. Over the past decades, several advances in this field have arisen, based on the innovative techniques used for biomaterial characterization, design and functionalization [11,12].…”

AMIC for traumatic focal osteochondral defect of the talar shoulder: a 5 years follow-up prospective cohort study

“…The current literature evidences a high ratio of preclinical to clinical studies on this topic, suggesting that we are in a transition phase to human application. Many synthetic polymers are currently available or under experimentation as potential scaffolds, such as polyglycolic acid (PGA), polylactic acid (PLA), polylactic-co-glycolic acid (PLGA) and polyethylene glycol-terephthalate/ polybutylene terephthalate (PEOT/PBT) [67,68].…”

“…These limitations affect considerably the reliability of the conclusions; therefore, results of the present study must be interpreted with caution. Further studies should investigate the potential of AMIC in a larger scale, comparing them with other more recently regenerative strategies, such as hydrogels or synthetic polymers [67][68][69][70].…”

The Role of Collagen-Based Biomaterials in Chronic Wound Healing and Sports Medicine Applications

“…In this application, a collagen scaffold that would fill the hole formed by missing cartilage would be placed on top of the bone that has been punctured by the microfracture procedure. Kwan et al recently compared the outcomes of different cartilage repair studies where microfracture treatment was augmented with scaffolds from both animals and humans [ 20 ]. The results from these studies support that collagen scaffolds may aid the regeneration of cartilage after the bone marrow stimulation of microfracture, with one to two years of data indicating good patient outcomes with tissue that resembled native hyaline cartilage.…”