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Articular cartilage replacement (grafting)
The Chondrotissue Graft is the latest development in articular cartilage repair and or replacement surgery.
Damage to articular cartilage or damage to both the cartilage and the underlying bone does not repair itself spontaneously and results in joint pain and poor function. Thinning and roughening of the articular cartilage can progress to severe wear and eventually patches of bare bone rubbing on bare bone in the knee leading to arthritis.
Such damage, which is common after trauma, can lead to osteoarthritis if left untreated. The knee is the most commonly affected joint. Articular cartilage has no blood supply and therefore doesn’t heal on its own or repair itself. There are a number of surgical techniques available for cartilage repair and or replacement, and each has its own specific indications.
Microfracture is an excellent technique for treating small patches (less than 1cm² defects). It can be performed easily via keyhole (arthroscopic) surgery and does not require complicated equipment. It can give 80% success rates at 5-years follow-up. However, the bigger the area of cartilage damage, the worse the results tend to be, and microfracture does not tend to work well with areas of damage much greater than about 2cm².
For bigger cartilage defects, the best options currently available are either MACI (Matrix-induced Articular Cartilage Implantation/transplantation) or the use of a Chondrotissue Graft.
The Chondrotissue Graft is a high-tech scaffold that is a sterile absorbable matrix sponge-like textile made of non-woven polyglycolic acid treated with hyaluronic acid. It has been shown to induce mesenchymal progenitor cells (stem cells) to differentiate into cartilage cells. The larger patch of cartilage damage is treated by microfracture, but the Chondrotissue Graft is then fixed over the defect. The graft then ‘captures’ the blood, bone marrow cells and stem cells released by the microfracture, giving them a scaffold in which to grow and mature into new cartilage tissue.
Studies have shown that the new cartilage produced with Chondrotissue Grafts is superior in quality to that produced by microfracture alone, and highly encouraging clinical results are beginning to be reported in the scientific literature. It is, however, only with further time that we will have results to show us what the long term outcomes are comparing the Chondrotissue Graft to other techniques such as MACI.
One of the main attractions of the Chondrotissue graft is that more invasive procedures such as MACI require two separate operations – the first to harvest cartilage cells for culture, and the second to implant the cultured cells whereas Chondrotissue can be implanted by a single-stage operation.
The latest advance that we are now using in articular cartilage replacement surgery, in conjunction with Chondrotissue, is a biological glue called Vivostat Platelet Rich Fibrin (PRF).
Biological glue called Vivostat Platelet Rich Fibrin (PRF)
Vivostat PRF has been used extensively for years in cardiac surgery, vascular surgery and plastic surgery. It involves taking a blood sample from the patient, spinning the blood down and extracting the fibrin (part of what forms a natural blood clot), combined with a high concentration of platelets (which also contact growth factors). This forms a biological glue that can be sprayed around the edges and over the top of the Chondrotissue graft, to help fix it firmly in place in the knee.
In the past we used to use Tisseel glue to secure grafts in place. However, Tisseel is a fibrin glue that’s manufactured from pooled blood donations (i.e. from multiple donors, all mixed in together), and it doesn’t contain platelets.
Vivostat, on the other hand, comes from the patient’s own blood (autologous), so there are less concerns about potential disease transmission or infection. Also, Tisseel doesn’t contain platelets, whereas Vivostat PRF does. Therefore, Vivostat PRF is not just a biological bioabsorbable glue, but it is also autologous and ‘bioactive’ – to help try and promote healing of the tissue and in-growth of new cartilage