Vonda Wright, M.D., M.S., an orthopedic surgeon at UPMC in Pittsburgh, Pennsylvania, talks about a new therapy that could help young adults and even teens who are struggling with damaged knees.
Interview conducted by Ivanhoe Broadcast News in December 2016.
I wanted to ask you about this new procedure, could you tell me a little about it?
Dr. Wright: The name of the procedure that April had is called a bio uni, which for many years we have been capable of replacing only a part of the knee with metal and when you do a partial knee replacement, it is called a uni; one condyl; unicondyl. But as you can imagine putting metal in a young person such, as April would be completely and totally suboptimal. Yet for kids like her have a very large cartilage problem, there were not a lot of options until now.
What causes a cartilage problem in someone who is so young? In middle-aged people when you think of it; it is just as the normal wear and tear. When you have someone so young, what is going on?
Dr. Wright: There are a lot of reasons people wear and tear their cartilage or sometimes it is almost like a dye punch, punch a hole in it. It can be trauma, it can be simply using a joint excessively, and over-loading it with weight but in young athletes cases, especially in what April had the lesion is called an Ostial Chondral Defect. Something has made a portion of her bone and the attached cartilage die and not be attached to the rest of the bone, so when that happens the knee begins to swell; there begins to be pain and they usually arise in typical places in a child and that’s why we believe it typically has to do with the blood supply. The first thing we do when a child’s presents with literally a pothole in their cartilage is if their growth plates are still open we try to put them on crutches and let nature take over and let them heal; and many times they do. If they don’t heal there are several procedures we try first, including taking tiny screws that we can bury and just compressing the natural piece back to its base. Sometimes, surgeons then try to add blood supply by drilling from behind the legion hoping that the little pathways that are formed will enrich the blood supply, because everything needs blood to heal. In April’s case all of those procedures were tried by other surgeons and she came to me with her knee locked because the pieces of her cartilage that had failed to heal back, they had come completely loose and had floated around in her joint and got stuck like a rock in her knee; so she could not move her knee at all when I saw her. That is a relative emergency, so the next day we took her to the operating room and I simply removed those pieces, which were essentially dead and not useful, but that gave me an opportunity to accurately sized the pothole in her cartilage and it was literally large. It was the size of the end of my thumb and in that we had very limited options, the standard cartilage options such as using her own tissue to take tiny grafts and fill in the space; it was simply too big. It would have taken five or six of those little grafts, the traditionally OCD plugs that we have always used. The disadvantage of those is that you have a cobble stoning affect; it’s literally like a brick street instead of an asphalt street. That’s not optimal but it would have been her tissue if the hole was small enough. None of the modern cartilage procedures, such as using part grafts, part stem cells were appropriate for her because not only was her cartilage layer the smooth asphalt layer, if you will, over the knee gone but the bone was damaged. The bedrock, if you think of a road was gone too, so she really needed a graft. That was cartilage and bone together and that is what we were capable of giving her at this point.
Can you describe how this is done?
Dr. Wright: Yes, absolutely. You saw the pictures of April, she has a scar on the front of her knee, and it is about three inches. We opened her knee joint through the skin, through the three layers that cover the knee so that we were looking at the inside of her cartilage and by bending her knee up, we were able to see the hole in the front of her knee. At that point, we prepared her Ostial Condrayl Defect and made the sides smooth, made them using a jig; it is a little, it is very mechanical and when we do it, it is a lot like carpentry using those same skills but with surgically instruments. We made the defect in her knee perfect; so that it would be receptive to a perfectly matched piece of bone and cartilage from a donor person.
Tell me about how that was done. Was this a live donor, a deceased donor?
Dr. Wright: Right, right not a live donor.
How does this work?
Dr. Wright: When we have a child or any person actually with a very large Ostial Condrayl Defect and we want to use this new technology, which frankly has only been out for less than a year. The bio uni, we send all the scans to the company that is responsible for this technology; and we find someone that is nearly perfectly matched. We want the contour of the bone to be ideally matched with the person. You can imagine taking a big, big grown man type cadaver bone and putting it in a little person; the contour would be wrong. We want the anatomy to match, as well as it can. Then we want a perfect piece of cartilage, we don’t want anybody donating bone that is already scraped up and sub optimally, especially, in a person like April who is only 15 years old. We want to give her perfect cartilage back, so once we find a graft we have a very limited amount of time to do the surgery because this is a live piece of bone and cartilage is the only thing that’s done on it; making sure that it is perfectly infection free. Two sets of test and cultures are done and once we determine that we get a call and we have seven days to do the surgery; so the person, it’s like being on a transplant list except we have a week instead of one day. When we brought April in and we prepared her knee the way I described to you and because we knew the perfect size that her knee required we took that using the same special jigs, the mechanical tools from the cadaver bone. We had a perfect match; it was simply tapped in with a method called press fitting, because bone is elastic so we gently tap it in and her bone expands briefly and then accepts it and locks it in.
Was there anything that had to be done to ensure that the two were a perfect match I guess it’s not blood type because it is bone?
Dr. Wright: No when you are talking about muscular skeletal tissue it is very different then if you are talking about a kidney, or a intestine, or a liver because the same kind of immune rejection that can happen soft organs tends not to happen with muscular skeletal tissue. Although the donor bone had been washed and processed she does not have to be on any kind of rejection drugs at all; the bone of the grafts will heal into the bone of her body or actually, vice versa, her body will replace the grafts, eventually, and our hope is that in a few years we would not be able to tell the difference.
Since this is a still live cell, are they growing, how does that work inside of April’s body?
Dr. Wright: The cartilage cells within the matrix of the cartilage they are live, they are receiving nutrition from the environment. In behaving like any natural cartilage cell would, the bone portion of the graft will literally heal like a fracture heals to her body; so that all her body knows is that it is healing bone to bone.
Is this a bridge until she gets older or is this a fix, for someone?
Dr. Wright: We are hoping this is a permanent fix for her and that her knee will wear in the same in the way it would as if she was never damaged. Now the caveat to that is, that is what we hope will happen, this is a new technology; we know from other Ostial Congrayl grafts that they perform very well but we tend to advise athletes do not pound on these new joints. My goal for April is a pain-free productive adult life where she can be active but I would not want her to be and ultra marathoner or even a triathlete. Now, April’s very active, she’s a competitive swimmer, she marches in the band, all of which have been fine for her knee; even this early but I think, whether it is me just hoping that it last forever, I don’t want to push the envelope and say go out and do ultra marathons or a run a hundred miles because if this fails our only alternative might be metal and she’s far too young for that.
What are the implications for having something like this available to surgeons?
Dr. Wright: Oh, what it means to sports surgeons, or any surgeons trying to preserve a joint, is that we have another tool in our toolbox to prolong and preserve a joint that would otherwise be unsalvageable. Her defect was so large that prior to this there was really no good answer. This provides us with an entire toolbox that we never had and this works not only in the Condrayls of the femur and the sides of the femur, this can work directly in the center or even under the patella. You know I have no doubt that this type of technology can work in the shoulder but it came out first for the knee so that’s why we done it first in the knee.
Dr. Wright: The bio uni as a technology that came out first for the knee. Now, I have done many allografts in the shoulder but that tissue has been previously frozen, but this is the first live tissue graft.
Is there anything that I didn’t ask you that you would want people to know?
Dr. Wright: It’s optimally used these allografts and any procedure where you are requiring the host body to interact to be regenerative, we are most regenerative in our youth and April is certainly in our youth. We think that regenerative capacity slows down with age, so you know by that, we usually draw the line in the sand at forty or so, however, after April I did one of these for a man in his high thirties and we are pushing that envelope. Also, because as you have a discreet, meaning a shaped cartilage lesion and not just sand paper off; you know this is a good option. If in a person in my age for instance, it doesn’t work and it doesn’t heal then I have the option of metal. It is not a terrible tragedy for me to get a true metal knee, but this opens up an entire new avenue to treat younger patients with really no other good options.
END OF INTERVIEW
This information is intended for additional research purposes only. It is not to be used as a prescription or advice from Ivanhoe Broadcast News, Inc. or any medical professional interviewed. Ivanhoe Broadcast News, Inc. assumes no responsibility for the depth or accuracy of physician statements. Procedures or medicines apply to different people and medical factors; always consult your physician on medical matters.
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UPMC Lemieux Sports Complex
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