Articular cartilage repair is the repair or improvement of defects of the joint cartilage, either by surgery or biological intervention, or both.

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

cartilage defect on femur

Articular cartilage injury on a weight-bearing part of the femoral condyle.



Articular cartilage injury in the knee

The knee is particularly vulnerable to articular cartilage damage, because of falls and direct blows during sporting activities.

Damage may range from a softening of the cartilage (chondromalacia), to a full thickness lesion (chondral defect), and a chunk of material may even be knocked off into the joint cavity (loose body).


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How do you regenerate articular cartilage?

Articular cartilage is very different from most of the body's tissues, inasmuch as the cells are far apart from each other, suspended in a matrix without a proper blood supply.

Injury means that the cartilage does not heal well, and even where there is some healing the area tends to produce 'fibrocartilage' rather than true articular cartilage.

This has given rise to a number of special techniques involving bringing in blood components from the deeper sub-chondral layer, and also transferring healthy cells grown in a laboratory or tissue pieces transferred from other healthy areas where they are not so important.


Key regenerative techniques include -

  • encouraging stem cells into the damaged area (microfracture, nanofracture, NAMIC, stem cell injections, microfragmented fat injections)
  • growing cartilage cells in a laboratory and injecting them back into the damaged area behind a membrane 'curtain', or growing them directly onto a membrane in the laboratory and gluing that into place (ACI, MACI)
  • transferring plugs of healthy articular cartilage into the damaged area (mosaicplasty)

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Microfracture to allow stem cells and nourishment


Microfracture for articular cartilage repair is a marrow stimulation technique, where holes are picked through the cartilage base plate, to allow blood and cells to track through into the defect.

The procedure may be performed in isolation, or in addition to another cartilage repair procedure.

Nanofracture is a variant of this original procedure, using smaller picks.

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Cell multiplication in a laboratory


ACI techniques rely on cartilage cells being multiplied in the laboratory and being transferred to the damaged area, in this illustration being injected behind a membrane that has been sewn over the defect.

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Transfer of healthy tissue from less important areas

Procedures like mosaicplasty involve plugs of healthy cartilage being transferred from one area to another

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Cartilage repair
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