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 cm(2). 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.