Thanks very much. No disclosures relevant to this talk. So where do we start with ACL tears in the skeletally immature patients? So interestingly, really before 2000, these were quite rare in terms of getting surgery. So the model traditionally had been brace these kids, do PT activity modification, and wait until they achieve skeletal maturity to get an adult type or conventional ACL. But what unfolded was the 90s and 2000s had a series of papers that all kind of had the same message, which is during these delays, enduring this ACL deficiency, these younger patients were having high rates of meniscus tears and chondro injuries, often irreparable and doing permanent joint damage. So Lyle Michele is our director emeritus at Boston Children's, and really, he performed the first IT band ACL in a three-year-old with congenital absence of the ACL and took a page out of McIntosh's book with this extra articular IT band reconstruction, getting modified to include an intra-articular component. So almost like the reverse of the Sante group and stability groups, they went from extra-articular, in his case, he went from extra-articular to the addition of intra-articular, which at that time was novel. So he was seeing more and more kids come into his clinic with instability with ACL tears and having problems with symptoms, and so began to use this more routinely. And it was really devised as a temporizing procedure until they could get old enough to undergo a standard ACL, but was finding that these patients were maintaining their stability into adulthood and beyond. And so in 99, published his first report in CORE, and sort of the rest is history with PEDS ACL. His rehab for this was a little bit more protective because this IT band was brought, a long graph was brought around the lateral femoral condyle in transcapsular fashion through the middle of the notch, and then placed onto the anterior metaphysis, and then sewn to the periosteum, which is much thicker in this age group. So both there and at the posterolateral aspect of the capsule, these were the fixation points. So the rehab had to be a little bit more protective. So the real difference is just a touchdown weight bearing with crutches for the first six weeks, similar to what many will do with a bad meniscus tear or repair. So not that onerous. And the other difference in rehab is some will move the flexion more slowly, but we found that zero to 90 works just fine. We're not seeing these stretch out or tear. And then we tend to get people back a little bit sooner than the nine months, which is the conventional now for sort of adolescent and adult sports medicine. Six months, most of these kids pass our return to sport test. And we haven't moved from the six to nine months with this younger age group the way we did with older adolescents about five to 10 years ago, like most people in the field. So we've continued to clear them at six months, and they do quite well. So where we are now is essentially using an algorithmic approach to kids with skeletal immaturity, whereby the prepubescent, or males 13 and under, females 12 and under, will get a FICIL-sparing ACL reconstruction. And then those with one or two years of growth remaining, these are the pubescent adolescents that still have growth to go, open growth plates. So it tends to be males 14 to 15, females 15 to 16, or let's see. And so those patients will get a FICIL-respecting ACL reconstruction. So we do trans-FICIL ACL, but metaphyseal fixation, so not across the fixation, and no BTBs. So the older adolescents, those with closing or closed FICIs, can get any adult ACL reconstructions, standard techniques. So if we look at this age group, here's somebody with closing growth plates. You can still see them, but growth is done. You're not going to cause a growth disturbance with any of your ACL reconstructions. Standard tunnels, standard graft options, quad patella and hamstring, as Dr. Bradley went into great detail on. So this middle group, however, will want to measure their bone age precisely. So here's a study from when I was a resident at HSS. We used a left-hand X-ray. So however, instead of the grula compile atlas, which most people don't have, this is a simplified version of the bone age using just one criteria instead of multiple. So we don't rely on our radiologists for this, have this as an app on our phone or have the paper standing by in clinics. So these patients have their growth plates open, their tibial apophysis is usually open. So they've got growth to go, but they're not prepubescent. So you can tell that they're developing and have hit puberty. So these patients will get a transficial ACL. Historically, it's been hamstring, and those tunnels were vertical so as to minimize the fissile damage with the reaming. However, we've evolved a little bit, and now with the sort of anatomic tunnel placement on the femur, we will be more oblique these days. And we have, as long as we stuff those tunnels with soft tissues, just the way we will do when reaming out with a fissile bar resection, so i.e. your graft needs to fill that tunnel nicely, we don't worry about bar formation or fissile integrity disruption and growth disturbances. So you can see this more oblique tunnel, and we haven't had issues with this. So this is a quad technique, which is what I favor, though. If one uses hamstrings and uses an interference screw on the tibia, you'll want to be more distal with a shorter screw so as to not cross the implant across the fissus. You can see this view of the tunnel with the fissus running more transversely than compared to the old vertical circular appearance of the fissus. And the red bone is, of course, the metaphyseal bone, and the yellowish bone, the epiphyseal bone. So there's a view of the lateral. And then for our prepubescent, we'll use, we tend to favor children's, at Boston Children's, the IT band. But of course, the late great Alan Anderson pioneered the all-epiphyseal technique, as you see on the right here. And that's evolved in other surgeons' hands. Ted Ganley, Frank Cordasco, and Dan Green have altered the technique slightly with either interference screws in the epiphysis or blind socket technique with endobutton-type technology. And then there is partial transphyseal. Some will favor that technique where they're all epiphyseal on the femur but transphyseal on the tibia, but it's less common and less well-studied. So the reason that this is becoming a bigger and bigger issue in terms of our PEDS ACLs is we know that the biggest spike is in the adolescents, 15 to 19. So all of the epidemiologic curves really show that, you know, ACLs, of course, affect our adult population, our collegiate and pro athletes. But this is the age that's most affected, and this is, they have the greatest rates of graft failure. So recurrence and the initial injury, this is our most affected population. So for those that are taking care of pediatric and adolescent athletes, this is part of our everyday life. And that didn't used to be true 10 or 20 years ago. So all of the curves and studies have suggested that pediatric ACL tears are increasing annually, and the surgeries are increasing. This is translating to more overall pediatric health care costs and more long-term disability OA and DJD for what we know about natural history studies of the ACL. One epidemiologic point is that while adolescence is much more common amongst females to have an ACL tear, in the prepubescent years, all of our studies suggest this is really much more of a male phenomenon, 80-20, whereas it's two-thirds, one-thirds for females to males in adolescent age groups. So what about the safety and effectiveness of our technique? So MinnKoker published a study in 2005 looking at the first 44 of these and found a 4.5 revision rate with over five-year follow-ups. So they were really surprised by just how rare it was to have these re-tears with really good functional outcome measures and no growth disturbances. So this was sort of deemed to be safe and effective. And when I joined them in my fellowship each year and then in practice pushed to kind of do the longer study on this, the larger study in the population. So in 2018, we published on 237 patients, 240 knees. The mean age was 11. Really a high rate of concomitant injuries, over 50% meniscus tears. About 80% of them repaired, but about 20% were unrepairable, and this is because the mean time from injury to surgery was six months. So many of these kids had undergone that delayed treatment, somebody in the community or even in other regions, waiting for them to get old enough to be ready for their adult ACL and had had recurrent instability and some debilitating meniscal and chondral pathology. So our re-rupture rate was 3.8 overall, but of those that we could reach to ensure over six years that we had all their data, 6.6% of our PRO cohort. So our PROs had similar findings with really quite good PDIKDCs, lysomes, very active. These were all above the normative values for these ages and returned to sports 97%. So I pushed to ask about the donor site morbidity. Dr. Coker and Michele felt like it wasn't much of an issue, but we found very low rates of pain or effect on sports performance. When asked, less than 50%, but 48% noted this asymmetry or fullness. So we'll show you that. So the advantage of this technique is really it was an ALL or LAT before it was common, as well as the ACL in one with one graft. So it's pretty technically simple and straightforward. Our tourniquet times tend to be under an hour for this. So it's a gentle learning curve. Our fellows pick it up pretty quickly compared to some of the other things. And it's really all biologic. So there's no implants. We're suturing the graft to this trough in the metaphysis, and we establish a little trough in the epiphysis with a special rat tail rasp, and that becomes the footprint for the ACLs. It's passing over the anterior aspect of the footprint. Because there's no reaming of femoral condyles and no sort of established injury to the physis, revision techniques when we have to address this are really quite straightforward. It's more like a primary. And then when we've tested it, our hip abduction strength is recovered by six months. If it's even affected, we haven't really tested it before that. So it's really what we find the fastest return, symmetric strength balance, functional hop preservation of other graft options, and preservation of the flexor and extensor groups of the knee. The potential disadvantages, it's been criticized by some as a quote-unquote non-anatomic technique based on the sort of over-the-top placement of the IT band on the femoral side, and then slightly anterior position on the tibial side, though we've, I think, all moved a little more anterior with our tibial tunnels compared to 10 or 15 years ago. And then this lateral thigh fullness, based on this data, you can see one picture. Here's an example of this girl's right thigh has a little asymmetry compared to the left. The young males seem to love it, but occasionally we'll get some complaints from one of our patients. So I really wanted to investigate the long-term implications of this criticism of the non-anatomic nature of the graft. So we brought 40 patients back in different intervals following the ACL to test them at a higher level. So 10 in each from one to two years post-op, two to five years post-op, five to 10 years post-op, and more than 10 years post-op to see if there were differences over time. And so in addition to our standard ACL testing and collecting their PROs, which were pretty much normal, we did 3D kinematic performance to see if their knee moments or ground reaction forces or vertical jump heights were asymmetric. And we found no difference from their injured or their previously operated and uninjured and unoperated knee. We also are undergoing MRI analysis, just seeing how the graft changes over time in terms of its graft size, graft obliquity, the footprint size and location, and whether there's any chondral degeneration. So excited to bring those results soon, but really preliminarily, we're not seeing much of a difference despite a little bit more transverse or oblique positioning at the time of the reconstruction. As they grow, it gets more and more vertical, approaches the appearance of the native ACL. So we MRI-ed all of the contralateral knees of these 40 patients, and we'll sometimes ask the fellows, which side is the reconstruction and which side is the native knee? So the circle marks the ACL side, but a pretty normal looking ACL obliquity and positioning. So working with our radiology team for those measurements. So of course, there's other options, the all epiphyseal is maybe a more familiar technique to many doing adult ACLs. People think of it as anatomic. We sort of don't, just because as we place that anatomic tunnel on the transphysial patient before you saw, the position of the footprint of the ACL really is at the level of the physis. So to be able to go all epiphyseal, one needs to go distal and more anterior. So we feel like the ephemeral position of the all epiphyseal is almost more non-anatomic than our IT band position, but that criticism continues. So the large graph diameter one can use with the all epiphyseal, either with graphing techniques or the quad tendon now, and it does have excellent outcomes return to sports and relatively low growth disturbances. So multiple studies emerging suggesting a very good technique. So we do feel the disadvantages. It doesn't inherently have the extra articular stabilization component. There have been variable graph rupture rates. The largest study, 18.2% in four year follow up from CHOP. And then the more reported growth disturbances, some are overgrowth, some are valgus. The effects of that reamer right along the transverse route of the physis. It may not take out the physis, but it may have a thermal effect or it may stimulate a hyperemia effect that may affect the physis over time. And then it tends to be a limited age group of applicability. Of all the PEDS ACLs, the 10 to 12 year olds are much more common than the four to six or the six to eight. But our technique is what our colleagues who do all epiphyseal will shift to if they have a younger patient, just because the size or the height of the tibial epiphysis starts to run out of room to actually have a tunnel there in that younger age population. So our comparative studies, the Pluto study group led by Minh Coker, my partner, of which I'm a part. We have over 20 surgeons and I'm just finishing up our clinical results. But a systematic review of all the world literature on PEDS ACL, we looked at the pediatric or physio sparing techniques compared to the early adolescent or trans-physio techniques and then compared the different pediatric physio sparing techniques. And so far we've found no significant differences when pooling the studies. Though IT band was 7% compared to 10% all epiphyseal and 8% partial trans-physio. This was not statistically significant. We did find a difference in the complication rate with IT band at 3% compared to 11% all epiphyseal and 15% in the partial trans-physio. And then when we looked at the adolescent or trans-physio graph types, hamstring versus quad, we found no difference. So quad may be slightly lower retail rates as we get larger pooled studies. So the older adolescents, you know, it's really the closing and closed physes. This is the most affected group in all the population, much more than young adults, much more than the collegiate and pro athletes. This is really what we're trying to answer. So we have a new study group, the Saturn group, funded recently by PASNA to try to compare our different graft options or technique options in this young group. And one of them may be a randomized control trial comparing BTB, which we consider the gold standard in this high-risk group, to a modification of that all epiphyseal technique for skeletally mature adolescents, which similar to the Santi group has a tunnel in the femur running from the ACL footprint to the ALL footprint. So a single graph that has an ALL component and then an ACL component as well. So look forward to reporting on that in the future. So thanks very much.

ACL tears

skeletally immature patients

treatment options

ACL reconstruction

surgical techniques