Cartilage Repair – What is the state of play

Can cartilage be regrown?
The answer is not really or kind of.
So what is the best method to repair an articular cartilage lesion of the medial femoral condyle in a 25 year old footballer?
The answer to this is very simple. I don’t know.

So what kind of information can help in the management process. Let’s say that there is a defect on the medial femoral condyle on the MRI. It appears to be full thickness and may be 2cm in diameter. Given the limitations of MRI especially with 1.5 tesla scanners as opposed to 3 tesla machines it is difficult to advise a patient pre operatively on what is best.

Microfracture is one option where the diseased cartilage is removed with mechanical shavers and curettes and then the base is microfractured or peppered with small holes to release bone marrow stem cells which will go on to cover the defect with fibrocartilage rather than the normal hyaline cartilage. This is a reasonable treatment option even though the results may deteriorate after 2 years. Defects that are larger than 2cm2 are considered beyond the range for microfracture but these lesions are quite small and I think this technique can work with lesions of 2cm in diameter.

Lots of surgeons have moved on from this and have tried to get hyaline cartilage to grow rather than fibrocartilage. ACI autologous chondrocyte implantation is where cartilage is taken from the patient at the first operation. Then this tissue is sent to a lab where cartilage cells are grown from it. Then at a second operation these cells are implanted under a covering of periosteum which has been sutured over the defect.

The technique has been further improved so that now the cartilage cells that are grown in the lab are seeded on a membrane and then implanted in the patient. This is the MACI matrix autologous chondrocyte implantation technique.

So why don’t all patients with cartilage defects get a MACI done?

Well the technique has not been completely shown to grow normal hyaline cartilage.
It is very expensive to grow these cartilage cells in the lab.
It takes 2 operations. 1 to harvest the cartilage and another to implant them after they are grown.
The patient needs to be non weight bearing for 3 months and is off sport from 9 to 12 months.

This is not an exhaustive list of options. What about bovine scaffolds which fill the defect and then your own cartilage grows in to the scaffold and you have new hyaline cartilage grown back. Sounds great. We await the research proof on this one.

So what might be a reasonable, middle of the road, not very expensive, not too much hassle operation that has OK results.

You could do worse than try a microfracture, resect the diseased cartilage back to healthy tissue sharply with a curette, remove some of the hard surface bone, put holes in the defect through to the bone marrow but not too deep, put the patient on a continuous passive motion machine for 2 hours a day, stay 20% partially weight bearing for 6 weeks on crutches, do all the rehab, return to sport after 3 to 6 months and hope for the best.

And you could also inject the patient every week for 3 weeks with platelet rich plasma after the microfracture operation. This might be the killer app that pushes microfracture to the front of the peloton again. The platelet growth factors have been shown to enhance the growth of cartilage in the defect. The regenerated cartilage is somewhere between fibro and hyaline cartilage which is an improvement.

Now all you have to do is work out which PRP system is the best for this procedure.
Get back to me when you have that figured out.