Autologous chondrocyte implantation (ACI) is a surgical procedure involving the injection of a person's own cultured joint cartilage cells back into a prepared defect in the cartilage.


cells being cultured in a petri dish


In one operation (eg arthroscopy) a bit of healthy cartilage is removed. The matrix is broken down in the laboratory and the chondrocytes (cartilage cells) are multiplied.


The defect is cleaned up and then the chondrocytes are then injected behind a membrane that is sewn onto the defect


The two-stage procedure of ACI

This is known as a two-stage procedure, because the surgeon needs one procedure to harvest some healthy cartilage from a less important area and send the sample to a laboratory for culture (where they are multiplied and make many cells), and then there is a second procedure to implant the expanded cells into the damaged area to grow into healthy cartilage.

Autologous chondrocyte transplantation

A simple flowchart with links to show the possible interventions in cases of knee arthritis.

This is the editor's 'interpretation' of a 2011 publication in the medical journals that gives an overview of cartilage injury, a brief description of current treatment options and outcomes, and a discussion of principles and techniques of MACI.

Biologic Knee Replacement

A course by knee surgeon, Dr Kevin R Stone M.D. of the Stone Clinic in San Francisco, California, USA.

This is the editor's interpretation of a 2009 medical publication outlining a study that was undertaken by a team from the Cartilage Repair Center at the Brigham and Women's Hospital in Boston, Massachusetts in 2009.

Articular cartilage repair

A short but sound overview of the issue of damage to the joint cartilage, and what can be done about it.

Which articular cartilage repair procedure?

Part 3 of an in-depth review on Articular Cartilage Repair by Karen Hambly PhD BSc MCSP (Sports Scientist/Physiotherapist).



Applications of Chondrocyte-Based Cartilage Engineering: An Overview Phul A-R ,Eo S-H, Abbas Q, Ahmed M and Kim SJ. Biomed Res Int. 2016; 2016: 1879837.

Cell-based tissue engineering strategies used in the clinical repair of articular cartilage. Huang BJ, Hu JC and Athanasiou KA. Biomaterials. 2016 Aug; 98: 1–22.

See also -

eBook about ACi ten years on

eBook - ACi ten years on

Discussing the progression of the ACi procedure (for defects of joint cartilage) over the last decade.

Click for details and download