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 are discussing suture augmentation in tendon and ligament surgery. I'm proud to have a return guest on the podcast, my friend and colleague, Dr. Jorge Chahla, from Midwest Orthopedics at Rush University in Chicago. Dr. Chahla was the senior author on the recent article titled “Suture Augmentation in Orthopedic Surgery Offers Improved Time Zero Biomechanics and Promising Short-Term Clinical Outcomes,” published in the May 2023 issue of the Arthroscopy Journal. Jorge, congrats on your work and welcome back to our podcast.

Dr. Jorge Chahla:

Thank you, Chris, it's always a pleasure to be with you guys discussing relevant topics that I think we all care about and we're interested as we move forward in our field.

Dr. Chris Tucker:

Absolutely. I appreciate you taking time out of your busy schedule to join us again on yet another topic that you seem to be quite an expert on. I don't think there's anything you don't know anything about. Recently, there has been substantial attention paid to this topic of suture augmentation, and with it, a renewed interest in ligament repair surgery. So Jorge, just what is suture augmentation and why the excitement around its use in orthopedic surgery now?

Dr. Jorge Chahla:

So I think there's a lot of things that we have not addressed in a very proficient way in recent years, and I think this comes to solve potentially a gap in what we have in our arsenal to treat people. And it's basically a high strength suture that is nonabsorbable that we use to augment repairs, at times here or maybe during early phases of healing.

And this is something that people have used in the past. When talking to Lars Engebretsen, and he tells you that the pendulum swings and these are things that people, in some way, shape or form have utilized in the past to augment repairs. And I think with new technology, we are revisiting some of the things that in the past have failed, for example. And now we feel that potentially by adding more sutures, and different configurations and potentially better anchors, we can be more effective and treat patients in a better way. And I think that's where all this suture augmentation and renewed interest on repairs of ligaments has become a very hot topic in sports medicine.

That being said, there's a lot of things that we still don't know. And for questions that I don't have a good answer for, I just try to do a systematic review or something to try to understand exactly what the literature says, and make ourselves aware of what's out there at least so that we can inform our patients correctly.

Dr. Chris Tucker:

Well, I look forward to hearing your thoughts on this topic in more detail. Your article covered a lot of ground with respect to the indications, and then the various potential applications of suture augmentation. You did a very nice comprehensive review of the current literature on the biomechanical outcomes, the clinical outcomes and complications. I'm hoping we can unpack as much of that as we can in our episode. So to start, what are the five most common applications we're seeing the use of suture augmentation in orthopedics today?

Dr. Jorge Chahla:

To be honest with you, Chris, the two that I was most interested in because I do mostly knees and hips was ACL repair and MCL repairs. But the ones that have been described in the literature are also UCLs, deltoid repair in the ankle, Achilles repairs and thumb collateral ligaments of the hand. So those are the ones that have some published literature on them.

Dr. Chris Tucker:

All right, let's try to work through each of those. I'm hoping we can just briefly summarize for us how suture augmentation's being used for each of those conditions. I recognize that we're both sports medicine surgeons, and so the elbow, the ankle, the thumb applications may be a little bit out of our lane. But you're quite a talented guy, and you did a very nice review article on these topics. So I'm sure if you could just review for us the biomechanics and some of the clinical data, just to bring us full circle on all of those things, that would be, I think, really advantageous to our listeners. So I just ran through your article in chronological order, starting off with the ulnar collateral ligament repair in the elbow. Could you break that one down for us?

Dr. Jorge Chahla:

Yeah. And I think Chris, most of the data is consistent throughout all the indications. When you look at the biomechanical data, when you have a suture augmentation, the pull to failure actually increases two times to three times for the normal native ligament. So you can have a much stronger construct. But the problem with that is you have a lot more stiffness.

One of the things that we see when we do biomechanical studies is, we want to try to replicate what the native ligament looks like. And certainly what we see here is, there's a lot of more stiffness. As you know, ligaments and tendons have some give, and that's what makes them so difficult to replicate. One of the main issues that we've seen in this review is that all of the applications in biomechanical testing will show that they have more stiffness, but they do have a pull to failure that is two or three times more than the one of the repair alone. So that's advantageous in and of itself. But again, there may be some drawbacks for long-term outcomes when you have that much stiffness.

Certainly one of the things that we have to be very careful with is over constraining of the joints. Because once you do, as you know, this is inextensible and it can cause significant range of motion loss. So that's one of the things that we want to be careful as we use this technology. In the elbow specifically. One of the things that they've noted that was different from the other studies was that there could be some irritation of the nerve. And in several of the studies, they've noted that there was some nerve irritation or nerve symptoms that could have not been associated with internal brace.

Dr. Chris Tucker:

That's interesting. I appreciate your overarching summary of the generalizations for the biomechanical results that we saw across all applications. I don't think we need to probably get into the details of each individual application because you summarized it so nicely. So maybe if we just focus on the unique aspects of each of these indications, that would probably be more useful for us to talk about the differences rather than the similarities.

The one thing I noticed in your article specific to the UCL in the elbow was that there were some clinical investigations comparing UCL repairs with the suture augmentation as to the gold standard of UCL reconstruction, specifically with return to sport rates, which is obviously paramount to anybody who cares for athletes that are throwing athletes and end up having that kind of a surgery. Did you have any other comments on that topic in particular, or do you want to just move on to the thumb?

Dr. Jorge Chahla:

Yeah, Chris. So I think exactly to your point, one of my main surprises from this paper was the range of return to sports. When you look at the repair group, the range is between 2 to 12 months. So that's a huge, huge difference. It's hard to understand why some people will let somebody go back at two months versus 12 months. Clearly there's some soft tissue healing that needs to happen, so at two months, you're pretty much relying on the brace or on the augmentation and not too much on the repair.

So that is something that as we've seen recently with some professional athletes that have gotten this suture augmentation and potentially can go back to sports sooner, I don't think we have enough evidence to suggest that that is or should be the case for most of our athletes, and potentially could help us in the future as we understand more and more of what this means for us in regards to the safety when they come back to play.

But as of now, the data is too sparse. And as you've seen, the range is between... The studies that let people go back at two months or 12 months is really, really big without a specific explanation for that. So I don't think we have the science behind it to support one or the other.

Dr. Chris Tucker:

Yeah, I think your comment earlier about identifying the knowledge gaps is spot on here. I think there just isn't enough data to really have a strong recommendation for or against either of those options. Early return, late return, and just what this augmentation of repairs, how that affects that. I think as we see these studies come out, especially for professional athlete outcomes, there's multiple confounding variables that we have to be aware of. Secondary gain with contracts and return to sport rates in pros, versus recreational athletes.

So I think keeping all of that in mind, you did a nice job in your paper of summarizing and concluding that it's too early to tell for some of these things; more investigation will certainly help us develop our practice in this area. But you do a very nice job of laying out what we know now. And so moving on to the thumb, you also discussed the ulnar collateral ligament repair in the thumb, specifically because it is one of the most common sport related injuries in the hand. Was there anything that jumped out on you in your findings specific to that procedure, for that injury that you wanted to focus on?

Dr. Jorge Chahla:

I think for the thumb, one of the important things is that the working length of the ligament is very, very short. So this could be one of the best indications I think for something that is so rigid. When you talk about, for example, the MCL, the MCL is a very long ligament. This has about 10 to 12 centimeters. So spanning an internal brace from top to bottom may be detrimental in some cases. Whereas in the thumb, it's such a small distance that this may be the indication where I would feel a little bit less concern about one, over constraining, and second of all, having too much stiffness in the construct. So I think from that perspective, the thumb may be one of the best indications as of now that we have.

Dr. Chris Tucker:

Interesting, and very well said for a sports surgeon. So let's move on to something a little more near and dear to both of our hearts, anterior cruciate ligament surgery. Obviously one of the most commonly torn ligaments in our athletic populations. Can you cover for us the current concepts and the available literature on ACL repairs with suture augment?

Dr. Jorge Chahla:

Yeah, so this is a topic that I've always loved. I had the privilege and the honor to talk to John Fegan a really long time, and he would tell you of his early experience at West Point and operating on people at 24, 48 hours after ACL tears and the repairs. And the ones that actually did well initially are the ones that did well for 30 years. So clearly, there's a subset of people that can benefit from repair. Marshall at HSS in 1978, I believe published better outcomes on people that were not as active as cadets from West Point. Although there's a higher retear rate, there may be a subset of people that may benefit from this.

One of the things that the brace or the augmentation may do is protect a ligament that may not have us in great quality when you have a proximal avulsion. But more than anything is preventing that gap that will aid into the failure of the repair. A gap of more than three or four millimeters will aid in failure of the repair. So if you can protect that while it's healing, it may be one of the things that will benefit us.

That being said, in the ACL, I have seen in reconstructions and sometimes in repairs, augmentations that have been fixed in some flexion. So if you fix this at 20 or 30 degrees of flexion, those patients will remain stiff. As we were saying before, this is not something that we stretch out. So I have gone back to the ward and taken some augmentations from other surgeons that have put in inflection and they regain their extension right away. So that's something that we need to reemphasize. If somebody is going to use this technology, make sure that you fix in full extension or even hyperextension if those people have hyperextension.

That being said, there's I think a fair amount of studies now, a lot of studies that came out of HSS, Greg DiFelice and a double bundle repair. Basically each bundle is individually repaired, and I think he adds the internal brace onto the anteromedial bundle. And the outcomes that he has shown, even in the midterm and some in the long-term are pretty promising, and mostly for people that have a less demanding sport and/or are older.

In talking to him, he says that younger individuals that play high level sports of course would be at high risk of re-tearing. And this is what you can see consistently in the literature. We're just finishing out another study now, Chris, looking at repairs with augmentation as well as other technologies, and the failure rates are of course higher when you look at all comers. But I believe that if we can trim down our indications and really select a subset of people that will benefit from this, I think those retear rates may be equal. Just like we've seen with our moon data, where allografts can be equally as good in people over the age of 40. I think if we can select our patients better, I think studies may show at least a non-inferiority.

Dr. Chris Tucker:

Yeah, this is obviously an area of great debate. I wanted to hear your thoughts on one part of your study, or on your paper where I perhaps had a little bit of an unanswered question remaining after reading this a couple times. Specific to the biomechanics of the ACL repair, and you summarized nicely, there's multiple studies out there showing that the ACL repair with suture augment has obviously been shown to possess these higher loads to failure and stiffness as it has in all the other applications we've already discussed.

But then later on, you discuss a few papers that Dr. Hoogeslag, I'm not sure if I pronounced that correctly, has reported with his co-authors about some concerns regarding the suture augment and ACL repairs, and specifically that they observed that even when you have isometrically positioned tunnels for an ACL repair in a cadaver knee, the suture augment was still subject to length changes when it was cyclically loaded leading to slack in the suture augment, which then can either leave your repair unprotected or just not as optimally protected, which is the underlying purpose of the suture augment in the first place. What are your thoughts on those results from those biomechanical papers? I don't quite have a full grasp on what those results mean.

Dr. Jorge Chahla:

It's a good question, Chris, I don't think I have a great explanation either. One of the things that we know is that there's no such thing as a isometry throughout the ligament. There's, as we know, potentially 200, 250 fibers of the ACL that rotate on its axis. So therefore putting a small suture, it's never going to be perfectly isometric.

One of the things that we know is the worst thing you can do is can over constrain the knee. So if that thing is too tight, then they won't be able to regain extension. For example, that's a catastrophic outcome. So I would agree that if in doubt, you should put it a little bit looser. Now certainly if it's too loose, then it's not going to serve any function.

So I think there's a medium point there where you have to look for... The fibers seem to be more isometric. And if you do a double bundle technique, or if you fix each individual bundle to the wall, you see which is the one that will get you a more isometric behavior and just put your suture in there. But I agree with you, those are some of the things that have been reported. And although I agree with the principles, if you're going to leave a suture that is not functioning in any way, shape or form, then there's no reason to leave it in there with the extra potential promise that it can cost.

Dr. Chris Tucker:

Yeah, I think this is one of those areas where we will continue to learn more about the details of just how to use this technology. So along those lines, what kind of information do we have right now in our hands to guide us with respect to clinical studies and outcomes in ACL repair with suture augmentation?

Dr. Jorge Chahla:

I think we have some data in the short term term, and biomechanical data that can support the use of suture augmentation in very specific patients, in very specific indications as long as we're extremely careful in understanding the principles of how the sutures work. I don't think you should put it tighter than what the tendon or the ligament is, because you'll have some stress shielding and potentially avoid the normal ligamentization of the ligaments.

It could be a dangerous maneuver, although it seems to be something quite simple to do. It could end up causing more problems than actually helping you. But if we believe that in the future we will be surgeons that preserve more than just reconstruct at all, then maybe a rule for this technology to help us, at least at the beginning while the ligament heals so that we can avoid that gap in between the ligament and the bone, or in between the two steps of the tendon such as Achilles tendon. There might be a rule for letting these people return to sports sooner, but I just think we don't know enough about this, and it would require certainly large randomized clinical trials for us to have those answers.

So as of now, I think we have very limited data. I'm not a user, to be honest with you, Chris, of suture augmentation. For the most part, I try to augment everything with soft tissue. For example, if I do an MCL repair, I would just throw an augmentation of hamstrings. But I'm not a user, I just wanted to study this to see what was out there. I don't think it's unreasonable to use it based on the data that is out there, but I would caution people to understand how it works, and to understand what the potential complications are so they can try to avoid them at times zero.

Dr. Chris Tucker:

Yeah. I think if I'm to try and summarize your findings for the ACL repair, I looked... You reported on four studies showing that the failure rates for these procedures still have a very wide range of success. Anywhere between seven and almost 50% failure rates, which I think as with all surgery probably has more to do with patient selection, which I think is even more paramount in ACL repair than a lot of things we do. And tell me if I'm wrong, but I feel like it's safe to say that if appropriately selected, patients who might be a good candidate for ACL repair would probably benefit from suture augment with the repair as opposed to ACL repair without suture augment.

Dr. Jorge Chahla:

I would say that the data suggests that, Chris. I don't think there's any studies that compare that side to side, so it's hard to assure the readers that that would be the case. I do think that it seems to be intuitive. It seems from mechanical data that E would work better. But as you said before, I think we're just at the beginning of this new era of preparing more and preserving more, and I think we just need more people like yourself and others that will push the field forward with more studies that will give us the answers that we need.

As of now, it seems like an intuitive thing to do to try to diminish the retear rates, but we don't have the data to suggest that it should be done for sure, because the retear rates may be lower because there's no side-to-side studies that have been done to my knowledge.

Dr. Chris Tucker:

Great. Yeah, I appreciate your thoughts on that. So to stick with the knee, you mentioned earlier your affinity for the MCL as well. I wanted to talk about other knee ligament surgery like the PCL or the collaterals, and specifically the MCL. What's the role for suture augment in those non-ACL knee ligaments?

Dr. Jorge Chahla:

So we've done a study at Cedars on ACL reconstructions with and without internal bracing. We found very similar outcomes where suture augmentation caused less displacement of course, but a more stiff construct. So very similar and in line with all the findings that we've already discussed.

On the lateral side, I usually just do a reconstruction, and I haven't had many issues on the lateral side. On the medial side, it's a little bit more tricky. Because sometimes even when you repair, the tissue may be stretched out, so it may not be as competent as we would want it to be. So sometimes you repair something, and it feels really good in the OR. And then six weeks later when you test it, you do see that one plus valgus.

So that's the one indication that may be a little bit more amenable for suture augmentation. As I said before, every repair that I do on the medial side, I still would augment it with hamstringing autograft. So I'm not a big user of suture augmentation. But if anything, I think that would be the one that I would augment. More even so if you have a repair where you're not sure of the tissue quality. That may be the one that you choose to augment with the suture augmentation.

Dr. Chris Tucker:

Yeah, I noted that in your paper, you reported there's basically no clinical studies out there published evaluating either outcomes or complications of MCL repair using suture augment. So clearly an area that requires more investigation. But as you've said, all of the same biomechanical theoretical principles apply. So I think a lot more to follow in the future on that area.

All right, so moving on to the injury that Aaron Rogers helped bring front and center on every NFL fan's internet feed earlier this season, the Achilles tendon rupture. So what do we know about suture augment for Achilles tendon repairs?

Dr. Jorge Chahla:

So there's not a plethora of data either, Chris, unfortunately. The Achilles tendon, it's a different tendon from others in the body because it has a tendon sheath. It has pretty significant width, and it tolerates way more load than any other tendon in the body. For all those reasons, the Achilles Tendon is a very complex and unique tendon in the body.

When we think about repairs of Achilles, I think there's a lot of confounding factors as well, Chris. As you were saying before, there's people that just would do inner sutures. There's people that would do inner and outer sutures. Core sutures that we believe are important. But I believe that more than anything else in this case, if you had a stronger and stiffer construct, then you can potentially avoid the gapping at the side of the tear.

That being said, the data that we have available that is not biomechanical data, it's not significant. So it's hard to say. We've all seen videos of Aaron Roger's practicing pretty early on after the surgery. And I've trained also with Neil, so I know that his skills are over the top. So I'm very, very hopeful that he's going to do really well, and maybe this is a wake-up call for us to say maybe these are people that we can bring back sooner rather than later, and in a safe manner. But I just think that we need more information.

As you said before, there's many confounding factors as well from a player's perspective, and where in the season, how they get paid, contracts and so forth that can cloud some of the decision making. But certainly, something that we need to follow closely to understand, if this is something that we can start doing and potentially return our athletes way sooner than we have been doing based on the technology that will enable us to do so.

Dr. Chris Tucker:

All right. Lastly, could you just briefly cover for us the uses for suture augments around the ankle, specifically the deltoid ligament repair? I'll admit, I do not do this procedure. I'm not sure if you do either. But I'd like to cover it just for completeness' sake.

Dr. Jorge Chahla:

I don't do either, Chris. But the data was, as I said before, from a hand, short ligaments may be more amenable than longer, elastic ligaments. Because the work length, which is how much this is going to stretch out or not. At the MCL, it can be up to five or six millimeters, so it's quite a lot. Whereas in the thumb or in the ankle, the stretch may be one or two millimeters. So for those reasons, the suture augmentations for these indications may be more amenable than others in the knee.

Of course, having a good native repair is important. Of course, not tightening the suture augmentation more than what the ligament is, is important for the healing of the ligament. And we know that cyclic loading of the suture with an unhealed ligament will not work. So with time, that suture will end up breaking. This is something that we've seen in history, and we had talked to Lars Engebretsen and he will tell you the same thing.

This is the pendulum swinging back, and having a ligament replaced by a non-ligament structure will end up tearing if the native ligament doesn't heal. So I think we need to continue to follow the principles for ligament healing, and use this, as the word says, as an augmentation, and not as a primary sole reason for stability.

Dr. Chris Tucker:

Yeah, I think that's a great summary. Thanks, Jorge. In listening to you and reading your article, from my perspective, it seems like suture augmentation is an emerging technology that's showing us some promising biomechanical and early clinical outcomes for certain of these applications in ligament repair surgery. But as with any procedure, as we know, there is also some risk for potential complications that we have to keep in mind. I think we can all agree that further studies are necessary to better evaluate this. Do you have any other closing remarks, or thoughts on the topic before we wrap up?

Dr. Jorge Chahla:

No, Chris, I think you've asked all the questions that I asked myself before doing this study, so thank you for that. And congratulate you and Matt for the great work that you guys are doing with the podcast.

Dr. Chris Tucker:

Well, thanks, Jorge. I certainly want to thank you for taking your time to share your thoughts with us, and congratulate you on your inquisitiveness to pursue learning more about this topic and then sharing that information with all of us to help us further develop our practices. You're a true clinician scientist, and I'm lucky to know you and work with you and learn from you. So thanks again for sharing your thoughts with all of us today.

Dr. Jorge Chahla:

Appreciate it, thank you.

Dr. Chris Tucker:

Dr. Chahla's article titled “Suture Augmentation In Orthopedic Surgery Offers Improved Time Zero Biomechanics and Promising Short-Term Clinical Outcomes” is available in the May 2023 issue of the Arthroscopy Journal, which is available online at www.arthroscopyjournal.org.

This concludes this edition of the Arthroscopy Journal Podcast. The views expressed in this podcast do not necessarily represent the views of the Arthroscopy Association or the Arthroscopy Journal. Thank you for listening, please join us again next time.

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