Matrix-Induced Autologous Chondrocyte Implantation (MACI): clinical results, mri findings and morphological analysis of implants.

Aims: To evaluate the clinical-functional and MRI results achieved in two patients, who underwent arthroscopic autologous chondrocyte implantation for the treatment of chondral defects in the lateral tibial plate. Methods and materials: The matrix-induced autologous chondrocyte implantation (MACIÒ) technique, which requires the use of a chondrocyte-seeded collagen membrane, was performed arthroscopically on two male patients affected by traumatic chondral lesions, sized respectively 2.5 and 2 cm2. The procedures were performed through traditional artrhoscopic portals and the seeded membrane was fixed on the defects with fibrin glue. Clinical-functional evaluation was performed according to ICRS score, modified Cincinnati knee score, IKDC, Lysholm II and Tegner scales. MRIs (FSE Fat-Sat T2, SE T1, GRE T2) were taken 6, 12 and 24 months postoperatively. Results: No complications were observed in the postoperative period. At two-year follow up, all the clinical scores were improved in both patients. MRI showed filling of the defects with hyaline-like tissue with reduction of subchondral bone edema and restoration of a regular articular surface. Conclusions: Even though the MACIÒ technique is mostly performed with an open procedure, the site of these lesions could not be reached without sacrifying tendinous and ligamentous structures of the knee. The arthroscopic approach allowed to achieve an optimal view of the lesion and appeared the best solution for these patients. The use of fibrin glue for fixating the seeded membrane has made possible to perform the procedure arthroscopically in a simple and safe way. No specifically designed instruments were used in these cases. The size of these defects was too large for bone marrow stimulation techniques and/or osteochondral grafts to be successful