Synthetic Grafts for Osteochondral Injuries of the Knee
摘要
Repairing articular cartilage has always been a challenging task for orthopedic surgeons. Although several therapeutic strategies have been proposed, both conservative and nonconservative, the results are still mixed, especially when considering the most effective procedures described are very expensive, both socially, economically, and clinically. As such, an advanced therapeutic option for cartilage injuries is still lacking. Due to breakthroughs in bioengineering, 3D printing, and translational studies, biomimetic scaffolds emerged as valuable prospects to become the solution orthopedic surgeons have been waiting for. Bioscaffolds are designed to be implanted in the context of the cartilage lesion, promoting the healing process through the induction of mesenchymal stem cell (MSC) migration and proliferation. Scaffolds foster the growth and reproduction of stem cells and their differentiation into chondrocytes providing a favorable environment. The optimal scaffold should be capable of allowing full weight bearing at the time of patient discharge and, at the same time, protect the proliferating cells from harmful physical stimuli. Concurrently, certain physical stimuli are required on the scaffold cells to provide the proper environment for differentiation and growth. Two of the most advanced scaffolds on the market include the Agili-C and Maio-Regen. Agili-C is a cell-free osteochondral scaffold based on aragonite, designed in two layers to replicate the anatomical subchondral bone layer: a bone phase (calcium carbonate in the crystalline form of aragonite) and a superficial cartilage phase (modified aragonite). Maio-Regen is a nanostructured biomimetic osteochondral scaffold with a three-dimensional (3D) porous composite structure that emulates the complete osteochondral anatomy. Of the three layers that make up the Maio-Regen, the cartilaginous one consists of type I collagen, the intermediate layer of a combination of type I collagen (60%) and hydroxyapatite (HA) (40%), and the lower layer of a mineralized blend of type I collagen (30%) and HA (70%). In this issue, clinical results of the application of both scaffolds in the treatment of human cartilage lesions are presented.