Emerging treatments of large articular cartilage defects of the knee: a critical review

INTRODUCTION: Despite the availability of various treatment options, large cartilage defects of the knee remain particularly difficult to manage due to the lack of regenerative capacity of cartilage and the mechanical stresses these defects place on the joint. This study aims to review current treatment strategies for large articular cartilage lesions and systematically evaluate emerging technologies by analyzing recent literature.EVIDENCE ACQUISITION: A general literature review was conducted for the narrative portion of this study. For the systematic review, PubMed, Scopus, and Web of Science databases were searched from 2019 to 2024 to identify studies reporting clinical outcomes of emerging treatments for large focal cartilage defects (at least 2-4 cm2) of the knee. Emerging treatments were defined by novel approaches introduced within the last five years. Studies on autologous chondrocyte implantation, matrix-induced autologous chondrocyte implantation, and osteochondral allograft transplantation were excluded as these were discussed in the narrative review.EVIDENCE SYNTHESIS: Thirty-five studies analyzed ten emerging technologies for large knee cartilage defects, including scaffold designs (BST-Cargel, Cartiheal, Chondro-gide, Hyalofast, MaioRegen, Revocart, Trufit) and stem cell-based therapies (Cartistem, mesenchymal stromal, Lipogems). BST-CarGel showed improvements in KOOS and Lysholm scores (+25.8 and +22.5) at an average follow-up of 42.5 months. Cartiheal, an FDA-approved osteochondral scaffold, showed significantly improved KOOS and IKDC scores in 247 patients, with a 12% graft failure rate. Chondro-gide, combined with microfracture, improved Lysholm and KOOS scores significantly in a 4.56-year follow-up. Hyalofast showed improvements in IKDC and VAS scores with an 11.5% failure rate after 14 years. MaioRegen showed significant improvements in IKDC and Tegner scores at 2 years, with a 12.3% failure rate. Revocart demonstrated improvements in IKDC and KOOS scores with no revision surgeries at 2 years. Trufit improved KOS-ADL and IKDC scores at 5 years but showed no significant difference from microfracture. Cartistem, using umbilical cord-derived mesenchymal stem cells, is in Phase 1/2a trials. Studies on Cartistem, often used with high tibial osteotomy, showed clinical improvement with no significant differences from BMAC, though Cartistem showed better second-look arthroscopy results. MSCs showed promising results in two studies, with improvements in KOOS and VAS scores, and Lipogems demonstrated early improvements in VAS and WOMAC scores after 1 year.CONCLUSIONS: Emerging technologies for large articular cartilage lesions show promise, but a consensus on the optimal treatment has yet to be established. Future research should prioritize cost-effectiveness analyses and extended follow-up studies to enhance the evidence supporting these innovations. Additionally, addressing concomitant injuries and joint malalignment is crucial for optimizing patient outcomes in cartilage repair.