Larger Chondral Lesions Treated with Collagen Membrane - Matrix-Induced Autologous Chondrogenesis - Show Larger Increase in Clinical Scores

Treatment of Chondral Lesions in the Knee

Articular cartilage injuries are common and lead to early joint deterioration and osteoarthritis. Articular cartilage repair techniques aim at forming a cartilaginous neo-tissue to support the articular load and prevent progressive degeneration. Several techniques are available for this purpose, such as microfracture and chondrocyte transplantation. However, the procedural outcome is often fibrocartilage, which does not have the same mechanical resistance as cartilaginous tissue. Procedures with autologous osteochondral graft have a morbidity risk, and tissue availability limits their use. As such, larger lesions undergo osteochondral transplantation using fresh or frozen grafts. New techniques using minced or particulate cartilage fragments or mesenchymal stem cells are promising. This paper aims to update the procedures for treating chondral lesions of the knee.

Autologous matrix-induced chondrogenesis is effective for focal chondral defects of the knee

Focal chondral defects of the knee are common and their management is challenging. This study investigated the efficacy and safety of Autologous Matrix-Induced Chondrogenesis (AMIC) for focal chondral defects of the knee. A systematic review and meta-analysis was conducted (according to the 2020 PRISMA statement) to investigate the efficacy of AMIC in improving symptoms and to compare AMIC versus microfracture (MFx). In January 2022, the following databases were accessed: Pubmed, Web of Science, Google Scholar, Embase. No time constrain was used for the search. All the clinical trials investigating AMIC and/or those comparing AMIC versus MFx for focal chondral defects of the knee were accessed. Only studies published in peer reviewed journals were considered. Studies which investigated other locations of the defects rather than knee were not eligible, nor those reporting data form mixed locations. Studies which reported data on revision settings, as well as those investigating efficacy on kissing lesions or multiple locations, were not suitable. The mean difference (MD) and odd ratio (OR) effect measure were used for continuous and binary data, respectively. Data from 18 studies (548 patients) were retrieved with a mean follow-up of 39.9 ± 26.5 months. The mean defect size was 3.2 ± 1.0 cm². The visual analogue scale (VAS) decreased of − 3.9/10 (95% confidence interval (CI) − 4.0874 to -3.7126), the Tegner Activity Scale increased of + 0.8/10 (95% CI 0.6595 to 0.9405). The Lysholm Knee Scoring System increased of + 28.9/100 (95% CI 26.8716 to 29.1284), as did the International Knee Documentation Committee (IKDC) + 33.6/100 (95% CI 32.5800 to 34.6200). At last follow-up no patient showed signs of hypertrophy. 4.3% (9 of 210) of patients underwent revision procedures. The rate of failure was 3.8% (9 of 236). Compared to MFx, AMIC demonstrated lower VAS score (MD: − 1.01; 95% CI − 1.97 to 0.05), greater IKDC (MD: 11.80; 95% CI 6.65 to 16.94), and lower rate of revision (OR: 0.16; 95% CI 0.06 to 0.44). AMIC is effective for focal chondral defects of the knee. Furthermore, AMIC evidenced greater IKDC, along with a lower value of VAS and rate of revision compared to MFx.

Recent strategies of collagen-based biomaterials for cartilage repair: from structure cognition to function endowment

Collagen, characteristic in biomimetic composition and hierarchical structure, boasts a huge potential in repairing cartilage defect due to its extraordinary bioactivities and regulated physicochemical properties, such as low immunogenicity, biocompatibility and controllable degradation, which promotes the cell adhesion, migration and proliferation. Therefore, collagen-based biomaterial has been explored as porous scaffolds or functional coatings in cell-free scaffold and tissue engineering strategy for cartilage repairing. Among those forming technologies, freeze-dry is frequently used with special modifications while 3D-printing and electrospinning serve as the structure-controller in a more precise way. Besides, appropriate cross-linking treatment and incorporation with bioactive substance generally help the collagen-based biomaterials to meet the physicochemical requirement in the defect site and strengthen the repairing performance. Furthermore, comprehensive evaluations on the repair effects of biomaterials are sorted out in terms of in vitro, in vivo and clinical assessments, focusing on the morphology observation, characteristic production and critical gene expression. Finally, the challenge of biomaterial-based therapy for cartilage defect repairing was summarized, which is, the adaption to the highly complex structure and functional difference of cartilage.

Graphical abstract