ACI is an abbreviation for 'autologous chondrocyte implantation', a two-stage surgical procedure to repair damaged joint cartilage.

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

cells being cultured

 

Healthy cartilage is removed from a relatively unimportant part of the joint and cultured in a laboratory.

ACI

A membrane is created by harvesting a bit of the connective tissue covering the bone, and sewn over the defect in the bone. The cultured cells are then injected behind it.

 

 

What does autologous chondrocyte implantation (ACI) mean?

Autologous means from a person into the same person - where cells from the patient are manipulated in a laboratory and then transplanted back into the same person. A chondrocyte is a cartilage cell.

In the ACI procedure, a healthy cartilage sample is harvested from a relatively unimportant part of the same joint, and the cells or chondrocytes are separated, expanded in number in a laboratory, and injected back into the knee behind a membrane that has been sewn over the damaged area to contain the new cells.

ACI is a mainstream surgical procedure for localised full-thickness cartilage defects of the knee.

 

  • Quote from peer-reviewed paper:

    ...."ACI is a two-stage procedure, beginning with arthroscopic....biopsy to harvest approximately 200 to 300 mg of cartilage....The cryopreserved cells are thawed and expanded to the cell population needed for the second-stage open ACI technique...."

    Citation: Minas T, Ogura T, Bryant T. Autologous Chondrocyte Implantation. JBJS Essent Surg Tech. 2016 Jun 22;6(2):e24. doi: 10.2106/JBJS.ST.16.00018. PMID: 30237933; PMCID: PMC6145632.

  • Quote from peer-reviewed paper:

    Stages include "....identify all associated abnormalities....harvest cartilage tissue from the non-weight-bearing area....parapatellar arthrotomy [to] expose the lesion....Debride all fissured and unstable articular cartilage....sew....the membrane patch....Gently deliver the cells and fill the defect...."

    Citation: Minas T, Ogura T, Bryant T. Autologous Chondrocyte Implantation. JBJS Essent Surg Tech. 2016 Jun 22;6(2):e24. doi: 10.2106/JBJS.ST.16.00018. PMID: 30237933; PMCID: PMC6145632.

Back to top

 

When is ACI indicated in cartilage repair?

ACI is indicated for focal cartilage defects, where most of the rest of the cartilage covering is normal.

Because joint cartilage usually contains only a small number of cartilage cells relative to the large volume of surrounding matrix material, this procedure allows expansion of the relative number of cells proportional to the matrix when the sample is injected back behind the membrane.

 

Back to top

 

Protection of ACI graft area after surgery

Because the graft area and the cells are very fragile for some weeks, the patient has to be extremely careful to keep weight off the graft area until the cells have consolidated into true joint surface.

 

Back to top

 

Forum discussions

Back to top

 

Synonyms: 
autologous chondrocyte implantation
-

Dr Sheila Strover (Editor)
BSc (Hons), MB BCh, MBA

See biography...


Also relevant -


Specialist opinion -

Dr Kevin Robert Stone2010 - Biologic Knee Replacement - by Dr Kevin Stone (Knee Surgeon)



eBook about ACi ten years on

eBook - ACi ten years on

Professor Paul Lee discusses the progression of the ACi procedure (for defects of joint cartilage) over the last decade.

Free to download