Autologous chondrocyte implantation (ACI, ATC code M09AX02 (WHO)) is a biomedical treatment that repairs damages in articular cartilage.

[1] The occurrence of subsequent surgical procedures (SSPs), primarily arthroscopy, following ACI is common.

For example, in the Study of the Treatment of Articular Repair (STAR), 49% of Carticel ACI patients underwent an SSP on the treated knee, during the 4-year follow up.

[2] A recent study from Germany, published in the November 2008 issue of the American Journal of Sports Medicine, analyzed 349 ACI procedures of the knee joint.

[3] Techniques such as the EELS-TALC[4] to enhance ACI and its next generation advancement called Matrix Assisted Chondrocyte Implantation (MACI)[5] with enabling chondrocytes to be tissue engineered with long term native knee cartilage phenotype maintenance in vitro and in vivo,[6][7] with the engineered tissue construct containing stem cell progenitors[8] along with those expressing pluripotency markers[9] and with added advantage of enriched hyaluronic acid (HA) expression[10] by the cells have been reported which will contribute to improved regenerative therapies for cartilage damage.