What is this procedure?

Picture showing microfracture stages – an area of bare bone is present. Tiny puncture holes are made on the surface of the bare bone. This encourages healing with scar cartilage.

Microfracture is done in order to encourage cartilage re-growth on areas of bone which have lost their covering of articular cartilage. The articular cartilage normally covers the ends of the bone within the joint, and allows the two surfaces to glide smoothly against each other. Sometimes there can be a damage to this cartilage which results in a split (fissure) or a small area of bone without any cartilage covering. It is not possible for the cartilage to repair itself but if only a small area of cartilage is affected then it may be possible for the body to grow some fibrous cartilage (scar cartilage) instead. Like a scar in the skin, the fibrous cartilage that grows in the defect is not as smooth or tough as the articular cartilage which would normally cover the bone but it is better than having no cartilage.

Arthroscopy images pre micro-fracture.

Microfracture is done as an arthroscopic (keyhole) procedure. Where bare bone is present, tiny puncture holes are made in the bone ends. This causes a small amount of bleeding, releasing bone marrow cells onto the bone end, and stimulates the formation of scar tissue (fibrous cartilage).


Who should consider this operation?

If a focal area of cartilage loss is discovered on knee arthroscopy then microfracture should be considered.

What are the benefits?

Around 8 out of 10 people who have a focal area of cartilage loss will report an improvement in symptoms after microfracture.

Arthroscopy images during micro-fracture.

Results tend to be better in younger individuals and if there is widespread cartilage loss, as seen in osteoarthritis, microfracture is not effective. Like other arthroscopic surgery, microfracture is minimally invasive.


What are the risks?

The new ‘scar’ cartilage that the body makes usually lasts for 5-10 years but can become worn out. Other potential complications are as for knee arthroscopy.

What happens in the post-operative period?

Arthroscopy images following successful micro-fracture.

The post-operative period is similar to that for any knee arthroscopy, but it may be necessary to avoid putting the full body weight through the knee whilst the new cartilage is forming. Therefore crutches may be required for the first six weeks.


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