Indications, Techniques, Outcomes for Matrix-Induced Autologous Chondrocyte Implantation (MACI)

Symptomatic cartilage defects of the knee are a common problem facing orthopaedic surgeons. Several operative treatments exist for patients who have failed nonoperative management. These treatments can be broadly broken down into reparative and restorative procedures. While reparative procedures can be used on very small defects with moderate to good results, restorative procedures are more effective for larger lesions, and for longer lasting improvements in outcomes over time. Matrix-induced autologous chondrocyte implantation (MACI) is a third generation autologous chondrocyte implantation product in which the patient's previously harvested chondrocytes are expanded in culture and seeded onto a collagen scaffold. The technique is indicated for symptomatic articular cartilage defects with minimal subchondral bony involvement. The seeded collagen scaffold is used to cover the articular cartilage defect, using fibrin glue to secure it into place, thus simplifying the technique and addressing some of the issues seen with the first and second generation autologous chondrocyte implantation. Clinical results, including patient satisfaction, pain reduction, and ability to return to sport following MACI have been encouraging in short, medium, and long-term studies. MACI is a reliable option for treatment of symptomatic cartilage defects.