Intro: UAB MedCast, a continuing education podcast for medical professionals, providing knowledge that is moving medicine forward. Here's Melanie Cole.

Melanie Cole, MS (Host): Welcome to UAB MedCast. I'm Melanie Cole. And today, we're focusing on current concepts in ACL surgery. Joining me is Dr. Amit Momaya. He's the chief of Sports Medicine at UAB Medicine. Dr. Momaya, it's such a pleasure to have you join us today. I'd like to start with ACL tears. How prevalent are ACL injuries in sports and non-sports? Kind of tell us the main cause of them. We know that this is something that happens in youth sports and specifically girls, but tell us about the general population.

Amit Momaya, MD: Sure. You know, ACL tears are quite prevalent, like you mentioned. The number of ACL reconstructions done annually in the United States is over 250,000, and that number seems to be increasing with increased concentration on youth sports, increased kind of organizational sports, and training regimens and practices, and increased participation from female athletes also has led to an increase in that number.

Obviously, we know about the ACL tears that can happen in actual athletes. But of course, your weekend warriors and other individuals can experience an ACL tear if they're doing some kind of fitness routine or have a traumatic accident, or even just going for that once-a-year skiing trip.

Melanie Cole, MS: Do we have a theory on why girls of a certain age are more prone to these injuries?

Amit Momaya, MD: Yeah, there's a lot of factors that go into why the female is that approximately two to eight times higher risk of an ACL tear compared to their male counterparts. Some of the leading theories behind why girls are increased risk include neuromuscular control. Girls land at different ways on the ground compared to boys.

Also anatomy, the notch size for girls inside the knee is smaller than guys'. There's hormonal differences. There's differences between the quad and hamstring ratio. Girls tend to be more quad dominant, which means they're quads are much stronger relative to their hamstrings compared to boys. So, a lot of those differences kind of play into these factors. So, it's quite multifactorial.

Melanie Cole, MS: It certainly is, and you've brought up some great points. So, tell us about diagnoses. When this happens, is it something, it's an emergent situation at the time? Is it something that kind of grows as the time goes and what's involved in diagnoses?

Amit Momaya, MD: Yeah. In terms of diagnosis, you know, it's based on the history and physical exam. Typically, a patient who tears his or her ACL will experience a giving out moment of their knee. Usually, it's non-contact, over 70% are non-contact mechanisms. They'll oftentimes feel a pop in the knee followed by swelling in the subsequent few hours. And that can kind of clue you in that there may be an ACL injury in that knee.

Prompt diagnosis is crucial to limit the meniscal and cartilage damage that can happen by continuing to play or be active on an ACL that is not sufficient or torn. In terms of diagnosis, we certainly get x-rays to check and make sure there's no fractures. There can be some signs on an x-ray, such as a Segond fracture, which is a little fleck off the anterolateral tibia region that can demonstrate possible ACL. But really, the exam is key. When we test the knee in a Lachman, which is where the knee is bent approximately 20 to 30 degrees and we pull the shin bone forward and relative to the femur to see if there's movement, also an anterior drawer, which is done at 90 degrees of knee flexion. We pull the tibia forward. and see how much motion there is compared to the contralateral side. Those are two key exam techniques for acute diagnosis of an ACL tear.

Melanie Cole, MS: Then what, Dr. Momaya? What happens next? Are these something that always have to be repaired? Do they tend to heal a bit on their own, albeit with tons of scar tissue, or is repair necessary?

Amit Momaya, MD: Right. So, we have a discussion with a patient depending on their activity level, their age, their demands, most ACL tears benefit from surgery. Now, there's a lot of subtleties within that you can undergo ACL repair or you can undergo ACL reconstruction. So, ACL repair used to be tried many years ago, but the failure rate was incredibly high. And more recently though, there's been an uptick on ACL repair, especially when selecting the appropriate patient population and appropriate type of tear is where we keep the actual ACL stump intact, and we stitch it up with some type of suture and reattach it to the wall of the femur where it tore off from. That's actually something that you can keep your own ACL and repair it as opposed to the gold standard, which is ACL reconstruction where we debride the ACL remnant that you had, and use a graft to reconstruct it.

Now, non-operative care can be appropriate for certain people. But like you mentioned, it's generally a little bit of scarring that happens. The ACL stump scars the surrounding tissue. It's not quite as functional as it was once. Those patients can exhibit continued pivoting, looseness in the knee and that can lead to further damage to the meniscus and cartilage, even some life-altering injuries, the meniscus called a bucket handle meniscus tear when the ACL is treated non-operatively.

Melanie Cole, MS: So, what's important for patients to know prior to surgery? Are they doing prehab? Are they doing physical therapy? I'd like for you, Dr. Momaya, to emphasize for us the importance of this communication lines between pre-op, what's going to happen beforehand, post-op, the rehab and prehab components of the repair and recovery process.

Amit Momaya, MD: Sure. It's paramount to have good prehab. There's been some good studies out there that demonstrate that patients who underwent prehab had better outcomes at two years compared to patients who did not. What does that mean? When someone tears their ACL, like we talked about, their knee is swollen, the knee is tight. It's hard to gain full extension, hard to gain full flexion, and the muscle has atrophied right away. The quadriceps is not activating.

And so, prehab involves a process in which the patient goes to physical therapy prior to surgery to decrease swelling, normalize their gait, activate their quadriceps, get their terminal extension back prior to surgery. Because if that motion is regained and the swelling goes down prior to surgery, then it's going to be easier after surgery to get that motion back and have a good outcome postoperatively.

The discussion between the surgeon and the physical therapist is also important. I often communicate with our physical therapist of whether a patient looks ready for ACL surgery. You know, some patients can get ready within a few days to a week. Some patients may take a few weeks to get ready, and that communication's important between the surgeon and the physical therapist about how their prehab is going, make sure they're ready.

And after surgery, like you mentioned, postoperative rehab is important. I send my patients to physical therapy day one after surgery to start moving immediately. One of the most important things to gain after surgery is your terminal extension. That is one of the hardest things to gain after ACL surgery. And you want to gain your extension back quickly because otherwise there's a small window and, if you don't get it back in the first few weeks to months, it's really hard to gain after that.

Melanie Cole, MS: Dr. Momaya, what determines return to activity?

Amit Momaya, MD: There's multiple factors for return to activity. Traditionally, people used to talk about ACLs can get back six months after surgery. But, you know, most of us knew that no one really looks good or ready to go back six months after ACL surgery. The ligament is still going through a process of maturation. The athlete usually does not have their muscular strength near symmetric to the contralateral side. Some studies have shown that if you go back prior to nine months, your risk of retear increases.

So, we certainly want to do a few things. One is timeline. I tell my patients to wait at least nine months to return to sport and activity that's cutting, pivoting, you know, high demand to decrease their retear risk. Number two, we also go through a battery of tests on the physical therapy side, such as isokinetic testing to test their strength. We try to get limb symmetry close to 85% of their contralateral side. We also do single hop testing, other functional testing, T shuttle runs to determine what kind of function they exhibit and how they're moving kind of more actively.

In addition, sometimes we're incorporating psychological readiness. You know, we have some studies that show that if you feel that you're psychologically not ready to go back to sport and have a greater fear of re-injury, you actually may have an increased risk of re-injury. So, I think that's playing out in the literature more and more is the psychology of return to sport. And is someone mentally ready?

Melanie Cole, MS: Well, that's a whole podcast in itself, Dr. Momaya, isn't it? The psychology of returning to sport, the psychology of fear, and getting over that fear to be able to compete at certain levels. I mean, that really is such an important aspect you brought up.

I'd like you to summarize for us and give your best advice to coaches, primary care, parents, internal medicine, anyone listening that wants to know if there's ways to decrease ACL tears, prevent them, whether we're talking about lateral training or plyometrics or whatever. We're talking about ways to try and decrease this. And really give your best advice.

Amit Momaya, MD: On the preventative side, there's a lot of programs out there to help decrease ACL injury to begin with, and that's probably one of your best management strategies. One of the programs out there is called actually FIFA 11. It's a series of warmups that can be done a few times a week, involving like a warmup jog, followed by jumping mechanics and landing, followed by core activation. It's well studied that that can decrease ACL tear risk throughout multiple sports. There's variations of that FIFA 11 program, and how to train with that. But that has clearly shown to reduce tearing for primary ACLs.

Also, we work with our athletes on make sure their quad-to-hamstring ratio is somewhat normalized. They have good limb symmetry. And they land not with a thud with straight knees, but bent knees with a soft landing. Those are some of the things that we check. Make sure they don't go into too much valgus, which means their knees kind of going inward when they land. So, those are some of the things on the preventative side to make sure that we prevent an ACL tear to begin with.

Also, you want to be careful about training schedules. Some of these athletes are training and fatiguing quickly, because of their training schedules. You want to make sure these athletes are not too fatigued going into play, make sure they have appropriate nutrition, vitamin D intake, definitely encourage my athletes to make sure their vitamin D levels normalized. Taking vitamin D calcium supplements probably important for most athletes. We try to get our athletes above 40 if possible.

And then, on the side of retear, so once someone does tear their ACL, what are some methods we're using to decrease their retear risk? At UAB, we've actually studied a lot of this and kind of on the forefront of this, one of the methods we've been doing is called the lateral extra-articular iliotibial band tenodesis, fancy word, but it's a ligament surgery on the outside where we provide another rope to prevent the ACL from being unstable and retearing, take the forces off the ACL and share them a little bit. That's been studied well in randomized controlled trials to decrease the retear risk.

And then, we've also been using biologics. We have used a biocomposite scaffold on the ACL to increase its biology, maturation, and thickness in the knee. And so, we've been using that .And we have ongoing studies with regards to that to help decrease retear risk and improve the biology of the ACL. So, those are some of the things that kind of I counsel coaches, parents, other doctors on.

Melanie Cole, MS: Thank you so much, doctor, for joining us today. And that was really an interesting discussion and thank you for sharing your expertise. For more information, please visit our website at uabmedicine.org/physician. That concludes this episode of UAB MedCast. I'm Melanie Cole.