Dr. Chris Tucker:
Welcome to the Arthroscopy Journal podcast. I'm Dr. Chris Tucker from the Walter Reed National Military Medical Center and the podcast founding editor. Today we're discussing anterior cruciate ligament reconstruction with the addition of the lateral extra articular tenodesis. I'm honored to be joined today by Dr. Alan Getgood from the Fowler Kennedy Sport Medicine Clinic in London, Canada, and the lead investigator of the Stability Study Group.
Dr. Getgood was the senior author on the article titled Anterior Cruciate Ligament Reconstruction Plus Lateral Extra Articular Tenodesis Has A Similar Return To Sport Rate To Anterior Cruciate Ligament reconstruction Alone But A Lower Failure Rate, published in the February, 2024 issue of the Arthroscopy Journal. Al, congrats on your work and welcome to the podcast.
Dr. Alan Getgood:
Thanks very much, Chris. Pleasure to be on.
Dr. Chris Tucker:
Al, it's pretty well known that the ACL is the most studied topic in all of sports medicine, potentially in all of orthopedics. Yet it seems like the paradox is the more we learn, the more we seem to realize how much more we have yet to understand. That being said, your work with the Stability Study Group is nothing short of monumental and it's had a profound impact on many of our practices and certainly on our thought process about the pathology and treatment of ACL tears. Before we get into the specifics of this article, could you just give us some background on the history of the Stability Study Group to give us some perspective on the overall project and some context for this particular subgroup analysis and where it fits into the overall aims of your group?
Dr. Alan Getgood:
Yeah, thanks Chris. I think the first thing just to point out is that it is a huge group. It's a large group of people and I'm very, very fortunate to effectively quarterback that group. But without all of the people that are involved in the multiple studies that we've performed over the years, then it wouldn't be possible. But everything really started probably in 2012, if you cast your mind back to then, there was that original paper regarding the anterior lateral ligament by Steven Claes and that really kick-started the whole discussion around the anterior lateral complex and whether or not you needed ant ligament reconstruction. There were a number of centers in Europe at the time doing lateral extraarticular tenodesis and of course, that had been around for years and that really struck my interest.
And so, when I started in practice, I started at Fowler Kennedy in 2012, so it was really serendipitous that the start of my career, this area of interest came up and I was very intrigued by it. And we started with doing some pretty simple TOMAC studies with a master's student, Scott Caterin, at the time, and then another master's student, Chris Hewison, who's actually interesting. He just come back to doing a fellowship with us next year as part of his orthopedic program.
But that was a systematic review that Chris did, and this was all in and around trying to understand what was happening with the anterior lateral complex. And round about that similar time, ISAKOS sent an application ... request for proposals for applications for multi-center, multi-continent, clinical trials grant. And so with everything that came about, we then came up with the idea of doing a randomized clinical trial looking at ACL reconstruction with or without tenodesis. And that was the genesis of the Stability Study Group.
And really, where it came from, was I had ... very, very lucky to have great mentorship from my senior partner, Bob Litchfield, and then multiple colleagues in Canada likes of Pete McDonald, Nick Batadi, Bob McCormick, Mark Herd, Dave Bardani, people who were involved in research and had research infrastructure in place. And with getting these guys together and also Tim Spalding and Peter Verdonk in Europe, we brought the group together and they got behind this idea that we could do this trial for a relatively limited budget. I mean, this was small numbers that we're talking about and really they did a huge amount of this work nearly from a charitable point of view.
I'm sure you appreciate just how much money it often costs to run a large randomized clinical trial, but I got the backing of these very influential people. And yeah, we started the trial. We were told that we'd never manage to recruit 600 patients into a randomized clinical trial. And without the dedication of all the team members, not just the consultants, not just the surgeons but research assistants and many of the research directors within the different clinics, we were able to pull that off and subsequently end up publishing in 2020 our primary outcome paper.
So, it was a long process. And then subsequent to that we've then ... with having collected large amount of data, we've been able to then publish multiple papers from this large dataset, which has really helped us try and understand a little bit more about really trying to control rotatory laxity and reduced graft failure in this at-risk population.
Dr. Chris Tucker:
That's an interesting background and appreciate you bringing us up to speed on how it all came about. I think you and all your coworkers are to be commended for, like you said, just the amount of diligence and resilience that it requires to get a study of this size started, funded and completed. So that all being said, before we discuss the findings of this study, could you just get us all on the same page and run through the technique for the lateral extraarticular tenodesis that you do, just as it was performed for this cohort?
Dr. Alan Getgood:
Yeah, I mean we called it a modified Lemaire technique. The original Lemaire technique was the strip of the IT bound. That was then rooted underneath the fibular collateral ligament and then attached is posterior proximal to the lateral epicondyle through a small bone tunnel.
Now, our attachment point's a little bit more proximal to that, so more on the metaphyseal flare, extending the posterior cortex to the lateral thermal condyle. Hence why we called it a modification of the Lemaire technique. You could also call it a modification of the MacIntosh technique. I mean, they're all one on the same thing. But yeah, so for all the patients that were involved in the Stability trial, it was a strip of the IT band underneath the FCL, reattached to the metaphyseal flare and then fixed with a titanium staple.
Dr. Chris Tucker:
Yeah. So for clarification, for your study, everybody in the Stability trial got fixed with the staple, correct?
Dr. Alan Getgood:
Correct, yeah.
Dr. Chris Tucker:
Because I know there have been modifications to the modification and I know fixation techniques have evolved and I know there's a number of folks using suture anchors, suture staples, pull through technique with a tenodesis screw. But in your cohort it was just primarily the staple, correct?
Dr. Alan Getgood:
Yeah. And the likelihood is it probably doesn't matter that much. We felt it was important that we did something that was relatively inexpensive, that if it did work and we wanted to expand that to centers all around the world. So, you're really trying to improve the knowledge translation of the work that you're doing and we felt it was more transferable into multiple healthcare systems.
Dr. Chris Tucker:
So, this study's stated purpose was to determine whether the addition of the LET to ACL reconstruction would improve the return to sport rates in young active patients who play these high-risk sports. So for those familiar with your award-winning paper reporting the initial findings of Stability Study Group published in January, 2020, like you said, you and your group are to be commended for the extremely strict inclusion criteria, which I think contributed to the validity of your findings.
So, with that in mind, before we get to the key findings for this publication, could you just outlined for us just how this subgroup analysis defines both the young active patient and also the high risk sport? Because I think those contribute significantly to your findings.
Dr. Alan Getgood:
And I think it's one of ... maybe one of the most proud things I'm of what we've been able to achieve with Stability is really changing the way we look at our patient population. I think up until Stability, and maybe MOON also to a degree, because MOON really did a lot of subgroup analyses on their younger patient populations and very clearly showed as a predictor of re-injury, that the young patient was at a higher risk. But up until that time, the majority of studies that you look at, the mean age is maybe 27, 29. Most of the systematic reviews were up in the upper limits upper border of the 20s.
We wanted to focus on patients who were clearly at risk of re-injury and that by doing so, we could then effectively increase our event rate and therefore, was make it a more feasible trial to be able to get an adequately powered study. So when we're looking at young patients, well, I mean we know the highest risk group is going to the under 20 age group.
Feasibility-wise, just doing a study under the age of 20 is very tough, particularly the numbers that we're talking about. So, we felt that up to 25 was appropriate, that would be consistently doing sport. So, 25 was the upper age limit.
And then when we talk about high risk sports, well it's really just looking at cutting and pivoting sports that we just described as high risk. And what we're doing with this subsequent analysis is really a deeper dive into that return to sport, what things may be more predictive of a successful return to sport, whether or not knee stability, or rehabilitation, or different aspects of rehabilitation has an impact in getting your patients back to return to sport.
Dr. Chris Tucker:
So, with that in mind, could you just now go through for us the methodology for this study, this subgroup analysis and how you went about investigating the addition of the LET to ACL? And outline for us your key findings from this paper?
Dr. Alan Getgood:
Yeah, so I mean, it's the same patient population as the original Stability study trial. So, of the 618 patients that were randomized, we then wanted to look at those that had returned to high risk, or going from basically from a high risk to a ... high risk sport preoperatively to high risk. And then depending on the level of sport postoperatively. There's only a small number of patients that never actually were doing sport preoperatively and qualified for the study based on some of the other criteria which were high Beighton score, high degree of rotatory laxity, young age. So, we just excluded those. And then there were a number of patients that didn't have any return to sport data at the six, 12 and 24 month mark for one reason or another, so we excluded those. Only took out about 50 something patients. So, we still were left with a large number of patients that had gone back to some form of high risk sport at a specific type of level.
So at 24 months we had 285 patients that had just the ACL alone and 268 patients at an ACL plus LET. And then we looked at a number of different outcomes associated with that. So if we look at our return to sport data, really it mirrors that what we showed in the original paper, we had about 87% return to sport across the whole group. If we just look at those, that's going back to a high risk sport data, it was about 76%. Not that surprising. If you compare that to some of the systematic reviews that have been published, they've looked at maybe 63% has been shown in terms of a general return to sport rate following ACL reconstruction.
Our population is a little bit more different in that. One of the criteria for being part of the study in the first place was young age as well as being involved in sport, so it probably skews the information somewhat.
And then if we look at then the re-rupture rates. Now the re-rupture rates again also mirror that was found in the original paper. The denominator is slightly different just because some of the patients were excluded to those ones that were at a low risk or were not involved in high risk to start with, but effectively we got a 70% relative risk reduction in failure rates and those that are going back to sport with the addition of a lateral tenodesis. So, really seeing very similar results than what we saw with the primary outcome paper.
And then we try to do a bit of a deeper dive in terms of some of the predictors of patient of return to sport, looking at strength, looking at some functional measures such as limb symmetry index, of hop tests. So we didn't find hop tests to be very helpful at all. Most patients, majority of patients were up over 90% limb symmetry index at the six-month mark before they re-embarked a sport. So, we don't find that hop testing is very helpful.
If you look at strength, we found that the stronger you were, there seemed to be a slight improvement, a general trend of being able to return to sport, but it wasn't really in any way isolated to any particular group. And then we looked at knee stability and if you look at knee stability, we seem to be a dose response. So effectively, the more stable your knee was, the more likely you were to get back to a high risk, high level of sport. Then you run into problems, right?
If you start to try and break that down even further to understand if that's being driven by the LET, or not the LET, and really then you get into sort of subgroup analysis which then become underpowered and it becomes very messy. So, I think there are a number of different things and hypotheses that we stated in the discussion in the paper, that may be going on. I think patients that maybe haven't had an LET, they might be able to get back to a better level support because they've improved strength, whereas the LET may help provide better stability and could also have an impact on strength gains postoperatively, but we just can't prove any of that within this particular study population.
Dr. Chris Tucker:
Yeah, I think one of the things that I value in your papers is the discussion section certainly fairly eloquently describe the thought process about what you hypothesize might be happening in some of these patients and admit what you are powered to state and what you're not necessarily powered to state, but where your findings are trending. I noted that comment you made about the stable knee stable having a nearly two time greater odd of returning to high risk sport. I think your odds ratio was 1.92, but chicken or the egg, what's coming first and what's more important? Is it the ACL and the LET or is it the strength that's returning?
I know you also mentioned the patient's returning to higher risk sports had better hamstring symmetry and of note, all these ACLs were done with autograft hamstring tendons. So, eliminating that with a different graft selection, I'm not sure what the impact would that have. Not to get too far ahead of ourselves, but I think you're going to be addressing that in a follow-on study with different grafts being used instead of the hamstring.
But I think one of the important notes I wanted to ask you about too was there was a comment in your results section where you had mentioned that in those patients who did return to high risk, high level sports, there was a 70% relative risk reduction in graft failure if they had the addition of the LET. So I know it's a subgroup of a subgroup, but like you said, those who went back to a high risk sport, those cutting, pivoting sports and they went back to the high level, so not just dropping down a level or two, but actually getting back to that competitive level at the highest of risk sports, they did have a fairly significant risk reduction in failing their ACL if they had the LET, far as risk patients for that.
Dr. Alan Getgood:
Yeah, I mean it's very similar to what we ... if you just look at the whole study as a whole, it was a 66% relative risk reduction in graft failure with the addition of the LET. So we effectively know that your biggest risk of returning your graft is if you go back to high risk sport and the more you do of that sport, then the greater exposure time, the greater risk that you're putting yourself in front of to be able to have a higher chance of failing. And if you're playing at a high level, the likelihood is that you're playing at that level more often than if you're playing at a low level.
So, it really comes down to exposure time. That's one of the massive challenges that we have when we try and really delve into return to sport rates. There's one thing looking at a measure of just did patient A go back to sport, but what level did they go back to? I mean, have they gone back at a level which is good? Are they going back at playing 45 minutes of a 90-minute game of soccer? Are they playing full games and what's their level of performance?
There's so many other metrics around returning to sport that we very rarely capture in our ACL research and I think it behooves to try and improve on that and really try and understand it a little bit better. But effectively the LET is protective of graft failure and if you can protect someone, if you protect an athlete from having a re-rupture, they'll play sport longer. I think that's probably one of ... the main take home.
Dr. Chris Tucker:
I think it's important at this point. If we could acknowledge the editorial commentary that accompanied your article. It was authored by Dr. Jason Grassbaugh and he discussed the importance of critically examining these subgroup analyses just in general. He gave you and your entire group significant praise. Like I said, the dedication required to perform these randomized control trials of surgical procedures in large number of patients, but he also highlighted the caution that we need to have when interpreting these subgroup analysis when the secondary outcomes are reported. I just wanted to hear your thoughts on his comments on your subgroup size, the overlap with the original study, as well as your evaluation of the secondary measures, which differed from the primary outcome of your original study.
Dr. Alan Getgood:
Yeah, I mean, I think Jason brings up a very valid point and we have to be very careful in terms of the interpretation of looking at secondary outcomes, but secondary outcomes are important. There are things that we can learn an awful lot, particularly when you go into the trouble and expense of trying to run such a large trial. You want to try and garner as much information as you possibly can so you can try and move the needle forward, but we have to be very, very careful in terms of how we interpret that. So yes, the original study outcome was clinical failure.
Why did we choose clinical failure? Well, it was a composite outcome and really the composite outcome as actually Jason picked up on, was really just to try and increase the event rate and with a higher event rate then you can power your study a little bit better. And we guessed that based on this type of population, we would potentially have a 40% risk of having asymmetric pivot shift as well as graft rupture. And that actually was a very lucky guess because it was absolutely spot on.
We saw a both statistically significant and clinically significant reduction in that clinical failure event, that primary outcome event. Now, if you then ... part of that composite outcome is graft rupture. Graft rupture as surgeons is much, much easier to understand. But then you can make the argument, well, you weren't powered to look at graft rupture and so then we can come down and well then you can look at your confidence intervals and you can look as a measure of precision and then we have to understand that and really interpret that to determine whether or not change in graft rupture is clinically meaningful.
And we actually tried to do this in a paper a little while back when the ACL study group was published in Knee Surgery, Sports Traumatology, Arthroscopy, really trying to determine what as clinicians we feel is an important change and an important change in failure rates. And if you look at our confidence intervals I think the risk difference goes from 3% to 12%, the upper limit being 12%, lower limit being 3%. And is that enough to change practice?
And so again, we felt that this was both clinically and statistically significant change in our graft rupture rates. And our findings are effectively mirroring what we saw within this new sub-analysis looking at our patients that are going back to sport. And so, we're not really trying to say anything different. It's really just a matter of really trying to tease out of the patients that went back to sport, were there any factors that would maybe push them back to sport versus not? And as you said within our discussion, there are lots of factors that have been brought out, particularly in regards to patients that have kinesiophobia, or just don't have confidence in going back to sport. It's one of the major reasons patients didn't go back to sport.
Dr. Chris Tucker:
I think following that same train of thought, there's many reasons athletes may not get back to their sport, with knee stability only playing a part. You talked about this in your paper and I think you and your co-authors are to be commended for trying to dive into that psychology of returning to play through your surveys. And in your cohort, the most cited reason for not returning to sports was a lack of confidence and/or fear of re-injury, like you had mentioned, that kinesiophobia.
So, this seems to me to be a fairly under-studied area of ACL surgery, but it's gaining some traction lately. What are your thoughts on that psychological component of returning to activity in general, sports after ACL surgery as in your study, and what do you think we need to be doing to improve that aspect of care for our athlete patients?
Dr. Alan Getgood:
Yeah, I think it's a huge area that's really ... there's a number of groups working on it. Kate Webster, Julian Feller should be commended, develop the ACL-RSI score, of course in multiple groups across the world that are really trying to understand this a little bit better. So myself, colleague Dianne Bryant, who's co-PI on Stability as well as Stability 2, have been very fortunate to be co-supervising physical therapy PhD student Hannah Mamura.
Hannah has been very prolific over the last number of years in doing a lot of this type of work. She's been performing a qualitative study looking at patients and interviewing patients, many of whom are part of Stability, some are part of Stability 2, and really trying to understand some of the psychological aspects about how they deal with their post-injury experience, but also pre-reconstruction and then post-reconstruction, so at baseline and at a year post-op. And there are certainly, there are characteristic personality traits that go along with their coping strategies and there'll certainly be a number of athletes who from the get-go are very much focused on sport and for them it's probably not going to be as big an issue.
There will be other athletes where sport is maybe not as big a focus and it's not as big a part of their life and they have other things going on that they can get an awful lot of attention from, whether it's their schoolwork, their occupation, their family, and that then helps them create some coping mechanism around about their injury pattern. I think as clinicians, we probably will need to get to the stage where we need to be a little bit more clued up as to the individual sitting in front of us, which maybe goes back to what I said at the very, very start. When we're breaking down these patients into it's becoming much more individualized. ACL surgery is not just about one size fits all. It's becoming individualized surgery, but also individualized rehabilitation and gearing up their rehab and understanding their needs going forward. And I think it's going to take a much greater multidisciplinary approach than what maybe you and I can do just as surgeons on putting a graft from point A to point B.
Dr. Chris Tucker:
We touched on this earlier, but I just wanted to hear your thoughts because you do have the benefit of observing such a large cohort of people with such detailed clinical analysis, but all these patients had their ACL reconstructed with autograft hamstring. I just wanted to hear your thoughts on any implications that may have in light of the other graft options being used for ACL surgery in young athletes and then if you observed or think of any gender effect as well.
Dr. Alan Getgood:
Yeah, we didn't really see any sort of sex difference within Stability, but there's no question that's something that we need to be investigating further. The graft question is always going to be something that needs to be addressed and there are not just our study, but there are multiple other studies. Nick Batadi's study was important and some of the work by the SANTI study group as well, showing that isolated hamstring grafts, the addition or the failure rates with an isolated hamstring graft in a young age population going back to high risk sport, the failure rates are higher generally than maybe an extensor mechanism graft.
I think what Stability adds to the mix is that if you are treating patients that are under the age of 25 going back to contact pivoting sports, then you probably shouldn't be doing an isolated hamstring graft in that patient population. And that's also being shown in New Zealand registry. There's multiple sources of information that's really highlighting that.
Now, that doesn't mean to say that hamstring graft's a bad graft, it's just not the best option in that specific patient population. Now, the big question of then, well, can you mitigate risk by using maybe an extensor mechanism graft either a BTB or a quad graft? Well, that's the focus of our study in Stability 2. So we're about 840 patients randomized into Stability 2 now. So, that's now a 30-center randomized clinical trials, NIH supported, CIHR supported.
We've been going now nearly for five years in recruitment. We hope to finish recruitment by the end of this year. It'll be 1,236 patients, so that's quad tendon versus patella tendon, with or without the addition of tenodesis, with the ultimate goal of amalgamating all the data from Stability 1 and Stability 2. So we'll have three grafts all with or without tenodesis under the age of 25.
And I think that should allow us to tease out these differences in grafts and whether or not graft truly does make a difference or not. So, at this stage, I have no idea, complete equipoise, so we'll have to wait and see what that data shows. But I think where I don't have equipoise anymore would be to randomize a patient to a hamstring graft on its own because I think that data is really pretty much overwhelming from that point of view that we shouldn't be doing that in the young age population.
Dr. Chris Tucker:
Yeah, I know there's many of us anxiously awaiting Stability 2 results, yourself included, I'm sure. As we've said, the ACL is the most studied topic in all of orthopedics and there's a lot of continued advancement in the field as with papers such as yours. That being said, what do you think is currently the most exciting area of research needing to be done? What do you see as the most important unanswered question in the area of ACL research right now?
Dr. Alan Getgood:
Yeah, that's a great question. I think, I mean, the first thing I would think about is prevention, and it's not really much a question that needs to be answered. I think the question has been answered regard to prevention, but that's more implementation science.
We know that prevention works and really we should be doing an awful lot more implementing prevention programs across high schools and universities, and various other organizations. So, I think that's something that's very, very important and will have a dramatic impact on the number of patients that we're seeing. Other than that, I'm very hopeful, fingers crossed that Stability 2 will help us answer the question regarding graft choice in lateral tenodesis. It'd be nice if we could park that question once and for all, but I'm sure we won't be able to. Someone will come up with another ramification of that question.
But I think really going forward, it's going to be post-traumatic OA that still is the critical piece here. Yes, it'd be great if we can reduce graft rupture rates, if we can get patients back to sport, but there's still an injurious event. There's still a very unphysiologic intervention that we as surgeons perform and we can't get away from the fact that unfortunately, many of our patients do develop post-traumatic OA at a younger age, and we really need to be putting a lot more focus on that to see if we can try and reduce that risk.
Dr. Chris Tucker:
Yeah, I think those are fantastic questions to be at least investigated and looked at the potential for biologics, the potential for postoperative rehab protocols to potentially alter some of that PTOA. Hard to know, but agreed, that's the inevitable, that none of us can undo the initial injury. Despite the best surgical technique, we can't undo that original injury.
So Al, you provided us a really nice summary of the inclusion of the lateral extraarticular tenodesis in conjunction with the ACL reconstruction and its implications for returning to sport and re-rupture rates in these young active patients. Did you have any other closing remarks before we wrap up our episode?
Dr. Alan Getgood:
No, I mean, I think just, I guess lastly, just to thank you, thank Arthroscopy journal for publishing our work, and it's important that this sort of information gets out there and it's a great opportunity for us to be able to discuss it further and really highlight a lot of the work that Stability group and my co-authors have really contributed to this space. So, thank you very much.
Dr. Chris Tucker:
You're welcome. Thanks for being here. Al, I want to congratulate you again on your work, and thank you for sharing your time and your thoughts with us.
Dr. Getgood's article titled Anterior Cruciate Ligament Reconstruction Plus Lateral Extra Articular Tenodesis Has A Similar Return To Sport Rate To Anterior Cruciate Ligament Reconstruction Alone But A Lower Failure Rate, is published in the February, 2024 issue of the Arthroscopy journal, which is available online at www.arthroscopyjournal.org.
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