mACI

mACI is an abbreviation of 'matrix-induced autologous chondrocyte implantation', which means the implantation back into a patient of their own cartilage cells after laboratory processing.

Page updated April 2024 by Dr Sheila Strover (Clinical Editor)

harvesting cartilage cells
A non-weight-bearing part of the articular surface is used for harvest.

 

Technique of mACI

Damaged joint cartilage does not heal well on its own.

Procedures of cartilage repair have been developed to fill in deep defects with more viable cartilage material.

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.

 

  • Quote from peer-reviewed paper:

    "....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...."

    Citation: Zhang Z, Zhong X, Ji H, Tang Z, Bai J, Yao M, Hou J, Zheng M, Wood DJ, Sun J, Zhou SF, Liu A. Matrix-induced autologous chondrocyte implantation for the treatment of chondral defects of the knees in Chinese patients. Drug Des Devel Ther. 2014 Dec 5;8:2439-48. doi: 10.2147/DDDT.S71356. PMID: 25525334; PMCID: PMC4266264.

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Comparing mACI and ACI

ACI is an earlier cartilage repair procedure, and mACI was developed from it and is a more sophisticated procedure.

ACI is a two-stage procedure, and the cultured chondrocytes are injected into the defect behind a 'curtain' of connective tissue harvested from adjacent bone and which has been sutured over the defect to contain the cells.

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Comparing mACI and AMIC

A one-step procedure - AMIC - has also been developed -

  • mACI (matrix-induced autologous chondrocyte implantation) is a two-step cartilage repair technique, where the expanded cells are seeded onto a membrane in the laboratory, and which is then implanted back into the patient.
  • AMIC (autologous matrix-induced chondrogenesis) is a one-step procedure, where the defect is subjected to microfracture to release underlying stem cells, and a membrane is glued over the area using fibrin glue.

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Forum discussions

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Synonyms: 
Matrix-induced autologous chondrocyte implantation
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Dr Sheila Strover (Editor)
BSc (Hons), MB BCh, MBA

See biography...

See also -

Professor Adrian Wilson2011 - MACI discussion - by Prof Adrian Wilson (Knee Surgeon)