In the mACI procedure, the surgeon performs an arthroscopy to check the status of the joint cartilage and the defect, and to harvest bits of healthy cartilage from part of the lower femur where the cartilage is not really bearing weight.
Living healthy cartilage cells (chondrocytes) are then extracted and cultivated in the laboratory, and treated for a few weeks so that they multiply on a membrane that acts as culture medium.
Then the patient is booked for a second surgical procedure, where the original defect is cleaned up and the new cell-filled membrane is secured into the hole, where it should grow and fill the space and build up its own matrix between the chondrocytes.
"....Several critical factors may determine clinical outcomes and quality of repair tissue after MACI procedure in patients, including 1) successful chondrocyte culture and expansion, 2) technical proficiency of the surgeons...., 3) patient cooperation and compliance in all aspects of the preoperative and postoperative programs...., and 4) timely progression of weight-bearing and adjunct exercises and postoperative rehabilitation...."