The knee joint is often affected by the degenerative disease process. It is not just knee trauma. What are the surgical aspects of degenerative knee osteoarthritis treatment? Degenerative knee conditions or diseases are part of the aging process, of course. We all are getting older. We all have degeneration of our knees in these cases. People day by day and year after year are getting more active. They are doing more sports, which is, of course very healthy. But the knees or the knee joints suffer from this increase in sports activities. So, the first thing regarding the prevention of knee joint degenerative process is to protect our joints. Try to be reasonable. Running 40 kilometers every two days is not healthy for our knees, our hips, or our ankles. And not only that. But also people who perform, for example, long-distance running, they don’t train [whole body]. They don’t work out, and they forget to strengthen their muscles, their lower limbs muscles. This will protect the knee when you are doing some contact-based sport. And that’s one point. On the other hand, once the degenerative condition is affecting the knee, you got to consider again the age of the patient. You have to understand what the patient wants, the expectation of the patient. So it’s not the same if you have a degenerative knee at the age of 30 as if we have knee degeneration at the age of 75. Of course, you may be 70 or 75, and you have osteoarthritis. A “metal solution,” a total knee replacement or partial replacement, is a very good solution. Knee replacement is a very good treatment. It has decades or even a century of very good results reported in normal people. When these degenerative knee conditions arise in a patient who is not old enough to undergo knee replacement. We have to provide long-lasting treatments for osteoarthritis. So in those cases, we have to try and give the knee a chance. We have to give a patient a try and provide conservative therapy to improve the degenerative knee problem. Of course, we must improve the patient’s current functional status. We must decrease current knee pain. But we also have to delay “metal solutions” [knee replacements]. And that is what I consider to be the focus and specialization of our clinic. And that’s why, for example, I perform a special kind of total knee replacement. It is called biological total knee replacement. Instead of using a metal solution, I use a fresh condyle cartilage allograph to replace the injured area of the knee. Let me also give you some information. Let me explain what is a fresh cartilage allograft. In general, in orthopedics, most of the tissue that we keep in the tissue banks can be kept there in frozen condition at minus 80 degrees Celcius. That’s good for most of the tissues, but not for the cartilage. When the cartilage is frozen, it dies. The only way to have healthy and living cartilage is to obtain it from the donor and keep the cartilage cooled. You cannot keep the cartilage alive for a long time. You have to keep it at four degrees Celcius or 37 degrees Fahrenheit. Usually, at 4 degrees, you can only keep the freshly harvested cartilage for two or three weeks. So in those cases, that’s why we call it fresh cartilage transplantation. Because the cartilage is well preserved at four degrees for only a very short period, and these knee cartilage allografts are obtained from a very young patient. Of course, you cannot obtain fresh knee cartilage from a patient, a donor, who is 50 or 60 years old because they will already have their knee cartilage degeneration. So that’s why it’s not so easy logistically to provide fresh knee cartilage for transplantation. We have limited availability of fresh osteochondral cartilage. I’m here in Barcelona, Spain. I am a referral doctor for 8 million people in the population of Catalonia. Patients are also coming from abroad. Last week I performed a knee cartilage transplantation on a patient from London. I have another patient from Ireland waiting for a knee cartilage transplant. Patients from some European countries are coming here to have their fresh osteochondral knee allographs. Because in Europe, very few places offer this kind of treatment. It is not only for the lack of donors but also because logistically, it is a difficult treatment. It’s very important. There are many law regulations, government regulations regarding cartilage transplantation. Fresh osteochondral allografts are not approved and not allowed in most European countries. I cannot say about Asia and South America too. The donors of cartilage have the same demographics as other organ donors? Do donors die from a trauma death? Yeah, yeah. Fresh cartilage donors are the same donors as for other organs. You can obtain different organs, and only some donors are suitable to provide cartilage allografts. Yes, for fresh osteochondral allografts, there are different exclusion criteria for donors. There is a lot to consider. Cartilage can be transplanted only during the first week after being obtained from a donor. Cartilage allografts are screened for many different diseases. We must rule out any condition that can affect the recipient side, the patient. But yeah, just for an example, around 35 to 40% of the potential donors for this kind of knee cartilage transplantations are finally excluded. It happens because of different problems like trauma, neoplastic diseases, infections, and Coronavirus infection. In the coronavirus times, it is even more of a problem. There is a higher chance that we cannot use the cartilage in these cases. Is the rejection of a problem in the transplantation of cartilage freshly obtained from donors? No, it’s a very good question, Anton. It is not a problem. It’s not an issue, allograft rejection. Mainly because the cartilage doesn’t cause any kind of immune reaction. Tissue rejection is not a problem because of the bone layer that we use. We clean the bone very well from the bone cells. So they do not cause immune rejection. Patients who are transplanted don’t need to take any immune suppression treatment. It is different from when you receive another organ. With cartilage transplantation, this is not the case. In the knee, there hasn’t been reported any rejection, as far as I know. There has been some case report of transplanted cartilage rejection in the ankle, but not in the knee. But again, it didn’t get rejected in the ankle itself. These two reports didn’t cause any specific severe disease. Cartilage transplant just was reabsorbed. That was what happened. But this was not an issue, an immune rejection of transplanted knee cartilage.