Matrix-induced autologous chondrocyte implantation

Matrix-induced autologous chondrocyte implantation (MACI®) is a tissue engineering technique, used for the treatment of deep cartilage defects of the ankle, which requires seeding of autologous chondrocytes on a type I/III collagen membrane, implanted in the lesion using exclusively fibrin glue. Six patients, aged between 18 and 44 years, were treated. Osteotomy of the medial malleolus was performed in all the surgical procedures. In five cases the site of the lesion was the talar dome, while the sixth patient presented a kissing lesion. The mean size of the lesion was 3.3 cm2 (range 2.5 to 4). Follow up averaged 27.5 months (range, 18 to 38). AOFAS scale was used for clinical-functional evaluation. MRIs were taken preoperatively as well as 6, 12 and 24 months postoperatively. All the patients underwent a second arthroscopic look at the time of malleolar screw removal. Membrane structure and its cells were investigated by light microscopy, SEM, immunohistochemistry and electrophoresis before implantation. There was evidence of chondroblasts producing type II collagen. With the exception of the patients with the kissing lesion, an improvement in the clinical-functional status and the presence of hyaline-like cartilage signal at the site of implantation were observed. At the second arthroscopic look, five implants appeared well integrated and stable, while there was no evidence of repairing tissue in the ankle with the kissing lesion. The MACI appears a reliable method for the treatment of chondral defects of the ankle. A careful selection of patients is fundamental for the successful outcome of treatment.