Well, again, we missed not being together in person in the cadaver lab, but I hope this virtual course has been helpful for everybody. One of my topics is to talk about hip cartilage repair, including microfracture, biocartilage, de novo, and prochondrics. I hope this will complement Tom's talk very well about the future of cartilage repair in the hip. My primary relevant disclosure is that for a striker, which I am a consultant and have royalties. So, chondral injury is core to femoral acetabular impingement pathology, and it's both mechanical and biochemical. Classically, CAM impingement causes a sheer force to the acetabular articular cartilage and causing more focal stresses and focal lesions. As you see in the middle picture here, the pincer mechanism, though, in contact pressure studies actually shows much broader areas of damage to the cartilage and abnormal shear forces, primarily from that contracoup injury. However, the majority of cartilage injury that we will treat arthroscopically will be due to the classic CAM mechanism. And of course, again, there is typically a longstanding biochemical stress to the cartilage as seen in examples like this where there's a substantial set of items. Again, treatment of chondral defects, we're primarily treating acetabular defects. We use the Beck classification primarily, and treatment options generally include a debridement versus then stabilization with the anchors, as you can see in the picture here, microfracture, and various cartilage restoration techniques. One point I want to make before we get too far into the talk is that we cannot necessarily assume the treatments that work in the knee will work in the hip. Obviously, the vast majority of cartilage restoration work has been done in the knee, and it would be much easier to apply that to the hip. However, research from Virginia Krause here at Duke has shown that the environment in the hip is different than in the knee. And in particular, there appears to be a lesser repair response going on in hip arthritis versus arthritic knee chondrocytes. In the knee, the chondrocytes appear to be anabolic in a high rate of turnover, where in the hip, they're quiescent. I think this is particularly relevant when we think about things like BRP or stem cells, which appear to primarily have a signaling effect. And that could work either way. That may be that it actually helps the hip more because the cells in the hip are not active enough. It could also be that it's not able to help at all because they need to be working. So that's something to think about as you think through the treatments, but also something that we'll need to answer over time. So the classification is there's six grades. You have grade zero, which is normal, one, malacia, two, pitting, three, that's the debonding or classic wave sign, where there's a loss of fixation to subchondral bone, but the cartilage is macroscopically sound as that carbon phenomenon. Grade four, I think we see the most of, and it has a wide variation. Technically, there are some grade fours that are just past grade three, and then there are some that are pretty close to grade fives. And technically, it's defined as a loss of fixation of the subchondral bone with frayed edges, thinning of the cartilage, and a flap. And then grade five are the larger defects, the full thickness defects, and those are primarily the cases where we would consider cartilage restoration therapy. I'll just show you some examples. Here's an example of an isolated grade one back injury in about the two to three o'clock position of this young female hip. And here, there's one that actually we did today, where there's an example of pitting here, and this is part actually of a grade three lesion. These lesions are typically just debrided or cobalt. Grade three, that's the debonding. My preferred option here is to stabilize the chondrolabral junction. You can see there's a very classic example here, where the chondrolabral junction is largely stable, but the flap is loose underneath. And you can certainly mechanically stabilize this with sutures at time zero. I think the question is, what happens then? Paul below is showing that that chondroflap is viable. And in some revision cases, I've found that it remains fairly stable and actually increases the stability. It probably has more to do with eliminating impingement than it does stabilizing the cartilage, but that remains my preferred technique for these grade three lesions. Other described options include fiber and glue, microfracture behind it, and drilling to stimulate healing. Again, as I mentioned, when you're in the grade threes and fours, there's quite a bit of variability. This is what I would call high grade three. You can see there's debonding without loss of the thickness of the cartilage, but it's clearly very loose, and it's certainly losing the same contour as the rest of the cartilage. A grade four is, again, that classic cam impingement lesion, where there's a cleavage at the chondrolateral junction. Most of these are partial thickness. Here's an example of one, and then following stabilization, and then treatment with a debridement and coblation. And there, you want to stabilize the fragments so that there's no loose tissue, and then stabilize the chondrolateral junction. Here's an example of a low grade, grade four. You can see there's technically cleavage, but there's very little thinning of the cartilage, if any, and a strong stability with very little need for any debridement. Conversely, here's a high grade, but you could almost maybe classify this as a grade five. But technically, you can see here, after we've stabilized it and done the labor repair, that you can see here that there is still cartilage. It's not fully exposed, but it ends up over a small area. Many of these types of lesions here will be smaller in size when you have performed the pincer section, as a lot of what appears to be their grade four or five is actually reactive pincer change and more ossification inside of the labrum. So we'll spend the rest of the talk talking about how we treat grade five full thickness defects. For me, the size and the age dictates the treatment. The age of the patient dictates the treatment. So smaller lesions are going to favor microfracture, and also in younger patients. The younger patients have a greater regenerative capacity, and therefore, the microfracture is potentially more likely to be a viable good tissue. In older patients, we'll often even grade five debris and stabilize that, especially if there are degenerative changes, because there's a limited ability to regenerate with microfracture valuable tissue. And probably more likely, what happens is for that microfracture to create amnesty of fight that then damages the femoral head. Right here, this is an ideal example of microfracture with using a curved drill bit with various stimulation that we showed there filling the defect. I consider cartilage restoration rarely in the primary setting, only for really large lesions. I actually now would consider it for this lesion in the video here, as this patient did not do very well with that microfracture. And then, of course, in secondary cases where that appears to be the exclusive cause of the problem, or they failed in other treatments such as microfracture. And probably the three primary options are biocartilage or an allograft, and that's cartilage. Osteochondral allograft are a couple available versus this prochondrics and cardiformer tube, the two examples. And then they may see an often misperformed surgical hip dislocation, but it does not have to be. And we perform it arthroscopically. We'll start with microfracture results. It appears to result in outcomes equal to intact cartilage in the short term. And then macroscopic fill appears to be adequate a second look. Let's compare with return to play and performance. However, we know that microfracture outcomes deteriorate. There are several authors who have shown this, Bendon and Fontana, and here's an example of that against Macy at five-year outcomes, so about approximately 70 patients in each group. And you can see that at about two years and beyond, the microfracture group deteriorates while the Macy group is maintained. This is not an uncommon pattern. We see it with various interventions of the hip. Bendon has also shown that at two years, the capsule repair group relative to non-routine capsule closure, that they were equal, but at five years, the capsule repair group was superior. When you're seeing these patients back early, a non-cartilage restoration technique, that result may not be durable and it's important to follow those patients for a longer period of time. So for a grade five defects, again, these are our options. We have biocartilage osteochondralograft, and then the Macy, this is a prochondrics graft here, and I'll show that technique right now. So my preferred technique is to utilize an osteochondralograft. I use a prochondrics device in particular, and here's an example of a grade five defect after we've stabilized the edges. It typically have this kind of a longer oval shape. I hear we are, this is post-labor repair, we have whip stitched the edges of the osteochondralograft with four of a bico suture. We have not tied any knots at this point, but it's still able because of the several stitches to hold the graft. This particular graft grows up to four millimeters out from the graft, and so the fit does not have to be exact, that's relatively close. We then place percutaneously two spinal needles to insert the fiber glue, and that's where we're positioning here. We'll now turn off the water, dry the hip joint, and place the fiber glue. We typically do use a probe or similar device to hold the graft into place while we insert the glue. And here it is just prior to that fiber glue administration. So, following administration of the glue, we bring traction back down. We will cut these micro-sugars, again, they have no knots against them, so they're air smooth against the cartilage, and of course, absorbable. And certainly, the femoral head compression against the graft is helpful to keep it in place, as is the general conformity of the hip joint. I'll show you a few case examples of prokondroids here. This is a 22-year-old with pain after hip arthroscopy. You'll see that he has several problems, including this severely torn labrum following repair here. But as we look closer, what is the biggest problem in his hip is this proud anchor into the hip joint. There's actually two of them that were into the proud of the hip joint, causing, accentuating this cartilage lesion. We then remove those anchors, and we're left with a relatively large S-tethered defect. The video on the right here shows the prokondroids allograft. This is one where we did have, things don't always go perfect, and this is one we had that broke into two pieces, but you can see that still worked well. We actually used an anchor here to secure this one, and then went ahead and cut that knot on the permanent suture. We left the viper in place. Here is a one-year follow-up. He's actually doing quite well. He's got a painless range of motion. We got an MRI to evaluate it, so he goes, he wanted to return back to impact sports. He's got, again, good strength as well. You can see here that the fill is quite reasonable, given the size of the defect in the boning defect behind it. This demonstrates that, at least for small to modest-sized bony osteochondral defects when there's missing bone, that the prokondroids osteochondroallograft type has the capability to fill that. Here's a case of a 19-year-old college basketball player with classic FAI. You can see here on this coronal view, there is some cartilage abnormality on the MRI. This is what his intraoperative pictures look like, so a low-grade five or high-grade four lesion, where there's certainly some delamination, but there was minimal exposed bone. We actually ended up suturing that cartilage into the labral stitches, and he did very well initially, back to play, but then at six months, returned with a re-injury. He failed conservative management, but we got this MRI, and then you'll see that that cartilage defect appears to be more prevalent and larger. This is at revision surgery, and you can see that despite the stitch still being in place with the cartilage, something happened with either an injury or a strain from tethering it that caused some imagination injury to the bone behind it. This is after we had used a curette to clear the residual cartilage, and there's the defect, and there's the prochondric allograft filling that. We got an MRI at six months before he was injured because he wanted to return back to basketball. You can see here there's a beautiful fill with just a small, small area with conjugal junction, but otherwise, very good fill and very good incorporation to the bone underneath. Some other options include biocartilage. I have not done any of these myself, but Al Subbs has extensive experience with these slides and the data is all from his work. Biocartilage is a micronized allograft and is inserted arthroscopically using fiber and glue. The literature supports its use in other endotropic areas, most notably the foot and ankle, and being superior to microfracture. Al has shown at a presentation at ISHA a couple of years ago that there's significant improvements in patient-reported outcomes with biocartilage. MACIs and other options of matrix-induced chondrogenesis, this does require biopsy initially and then placement arthroscopically at the second stage, but again, the results are good and durable relative to microfracture. So in summary, chondral defects are common. Virtually every hip you operate on will have them. It's important to remember that when we're choosing a treatment for that, that the hip may not be analogous necessarily to the knee. So what we use in the knee, what we learn in the knee, cannot necessarily apply to the hip. Most notably, that it is less metabolically active and maybe has a, therefore has a, potentially has a lower ability to heal. Most cartilaginous injuries, fortunately, are partial thickness. Very few of them are full thickness, but well under 10%. They include primarily grade III debonding, but also low and high grade IVs. We know that the flap is viable. We can stabilize it. It appears to heal on some of the second looks that I've done, but we don't know for sure and we don't know what the long-term outcomes, although generally they appear to be good. And that appears to have a limited effect on the overall outcome. Full thickness defects, when a microfracture has a role for smaller ones, or even just a breedment as a microfracture may lead to development of osteophyte in that spot. We do know that they do lack durability, so having some deterioration in outcome after about two years. Unfortunately, there are several options that we didn't used to have that can be placed arthroscopically and ones that are off the shelf available. So a lot of times we, because the other authors have shown this, that the compression and conformity of the femoral head to the acetabulum flattens that, it smooths, compresses that cartilage flap and then it does not appear to be a full thickness defect, it's harder to see. And so oftentimes you're not aware that it's there until you're in the hip, and fortunately now we have some off-the-shelf options to treat that for larger defects. Thank you.

hip cartilage repair techniques

microfracture

biocartilage

de novo

prochondrics