So these are my disclosures, they're all in the website. So what about history? In 1879, Paul Sagan described avulsion fractures at the anterolateral tibia called the Sagan fracture. We've all seen these. In 2012, Vincent named this pearly, resistant, fibrous band the anterolateral ligament. And then in 2013, there was a publication of the anatomic description of the anterolateral ligament. So still all relatively new. So why is there this renewed interest and why should we care, why should we think about implementing this? Well, ACL graft rupture rates in our young, high-risk population can be up to 18 to 28%. Return to pre-injury level of sport, we know, is after an isolated ACL reconstruction, only around 50 to 65%, if we look carefully at the literature. The rate of a residual pivot shift after a primary ACL reconstruction is up to 20 to 30% for an anatomic single bundle technique. And even higher, I would say, for your chronic revision ACLs and those with a higher grade preoperative pivot shift and knee hyperextension. So what about the anatomy? So if we look at the MRI studies have shown that around 76 to 100% of the time, the ALL is present on an MRI. Two systematic reviews concluded the ALL is a distinct ligamentous structure. The femoral origin has a variable description based on the lateral epicondyle. It's been shown to be proximal and posterior in some studies, anterior and distal in fewer studies, and even directly on the lateral epicondyle. And the tibial insertion has been more consistent between studies. The IT band with associated capillaries fibers, as well as the lateral meniscus, are also important to consider. So when we think about the anterolateral complex, not just the ALL, we want to talk about the ALL origin, which is roughly about three millimeters posterior and proximal to the FCL. The tibial insertion has been described to be midway between the center of GERDES tubercle and the anterior fibular head, one centimeter below the joint line. The IT band and capillaries fibers are important to consider. This controls tibial internal rotation, anterolateral rotatory instability, closer to full extension. Here the proximal and distal capillaries fibers. And as we know, the lateral meniscus also controls anterolateral rotatory instability. I think this is a nice study that was done at a Rob LaPrade's group in Vail, where they looked at the radiographic ALL anatomy. And I'll use my intraoperative dissection, looking at anatomic landmarks, but I'll also use intraoperative fluoro to assist with being more accurate. The femoral origin is shown here on your AP and lateral imaging. And then here you can see the tibial insertion on the AP and lateral imaging. If we look at the function of the ALL complex, it's a secondary restraint to anterior tibial translation. Tibial internal rotation, which is greatest at greater than 30 degrees flexion, maximal at 60 to 75 degrees. Again, the IT band and capillaries fibers also control tibial internal rotation, but closer to extension. It contributes to the control of anterolateral rotatory instability, or your pivot shift. And it may also affect varus and medial laxity of the knee, which I'll talk about later. There's increased length of the anterolateral complex with increased flexion. So again, the ALL is tight in flexion. So there's really still debate with regards to the knee flexion angle when you're fixing the ALL. The posterior and proximal origin point is a little more isometric. And if you pass your graft deep to the FCL, this is slightly more forgiving as well. Some cadaveric studies have shown better internal rotation and tibial translation control with an ACL plus in ALL reconstructions, but others have not. There's conflicting data regarding the function and optimal technique with regards to ALL reconstruction versus a lateral extra-articular tenodesis. And biomechanical evidence for lateral compartment over-constraint has been shown for both ALL and LAT, although a recent study of an LAT with and without partial lateral meniscectomy showed no increased lateral contact pressure. So this may not be clinically relevant. If we look at the injury patterns, this is a series of cases of ACL surgery where they did a lateral exploration in every case, and they found that 22% of the time there's a complete tear of the ALL near the insertion, and an additional 10% had an osseous tibial avulsion or a sagon fracture. And this is an MRI study after ACL injuries, and what they found is that 39% of these had a high-grade ALL injury, and it was frequently associated with an FCL injury, MCL injuries, and also your lateral osseous contusion injuries. So when we look at techniques for ALL reconstruction, typically this is a hamstring tendon allograft or an autograft. Again, the femoral side is pretty consistent between studies, although a couple of studies have shown that they place this anterior and distal on the femur. The tibia is very consistent with one study showing more of a docking technique distally. I think the LAT is pretty straightforward across the board. This is basically taking a 1 by 8 centimeter posteriorly-based IT band slip. You then route that deep to the fibular collateral ligament, and you can fix that proximally with a staple. You can pull it through a tunnel and fix it with a screw, or you can fix it with suture anchors. So I've reviewed basically all of the systematic reviews, expert consensus papers out there to try to come up with what are our primary and secondary-based indications, and a lot of this is still Level 4 evidence. So primary indications were typically a high-grade pivot shift, hyperlaxity, a revision ACL, Sagan fracture, and returning to a pivoting sport. Secondary indications could include your young athletes, medial meniscal repair, meniscal insufficiency, posterior tibial slope of more than 12 degrees, a lateral femoral notch sign, and those patients presenting with a chronic ACL insufficiency. My indications that I use in my practice, and again, I think it's more of an art than a science right now trying to figure out who is best indicated for this, but I would say a high-grade pivot shift, in particular if you're not performing an MCL or a postural lateral corner reconstruction, or not performing a lateral meniscus root repair. In a revision setting, the same, if you're not performing a concomitant multiligament knee surgery and if they have a high-grade meniscal lesion. For me, hypermobile patients, and we found in a study that we did that heel height greater than 5 centimeters was predictive of higher risk for failure of your ACL graft, and a Sagan fracture you may consider a primary repair. I think about it if they have a chronic ACL with secondary restraints being stretched out, posterior tibial slope of greater than 12 degrees, deep lateral femoral notch sign, meniscal deficiency. Again, getting back to pivoting sports, which the majority of these patients are. Recent studies showed the coronal FCL sign, which is where you look at a coronal image on the MRI and you can see the FCL from the top to the bottom, which would really indicate a level of anterolateral rotatory instability, and I think when your FCL is more parallel on the coronal image, you also have the potential for some increased laxity, even in the setting of a normal FCL and posterolateral corner. What about clinical outcomes for ACL plus an LAT? So for chronic ACL with or without an LAT, they found better stability, higher sports activity and lower failure rates with an LAT. Two systematic reviews showed better stability for Lachman in a pivot shift in the LAT group. This is probably our best study by Al Getgood. This is a randomized controlled trial. All these patients had hamstring tendon autographs. The criteria is they had to meet two of the three, having either a grade two or greater pivot shift, return to high risk sports and hyper laxity, and these are all young patients. Clinical failure, which was defined as graft failure plus an asymmetric pivot shift and or an asymmetric pivot shift, they had a failure rate of 40% in the isolated ACL group versus 25% with the addition of an LAT. Overall graft failure rates were 11% versus 4%. So in the end, an LAT plus an ACL resulted in a decreased relative risk of graft rupture by 66%. And again, remember, this is in our highest risk population. And there was a return to sports delay of about a month with an LAT. What about ACL plus an anterolateral ligament reconstruction? So this is a review of five studies, the Santee Study Group. Graft failure rate was two and a half to three times lower with the addition of an ALL reconstruction and medial meniscus repair failure rate was two times lower with the addition of an ALL reconstruction. In this study, looking at revision ACL with or without an ALL reconstruction, they had a significant decrease in the post-op pivot shift, greater return to prior level of sports with an ALL and an additional or with an ACL with an additional ALL reconstruction. And then in this chronic ACL study at two-year follow-up, they had better results with the ALL reconstruction for graft failure, pivot shift and patient-related outcome measures. I think this was an interesting study that came out. This is consecutive groups, but looking at hypermobile patients with an ACL reconstruction and then a second group of patients that were hypermobile that had the addition of an ALL reconstruction. And I think this is pretty interesting. The most significant finding here is the reduction in ACL failure rate. It was 21.7% in the hypermobile group without an ALL and 3.3% with the addition of an ALL reconstruction. If we look at systematic reviews directly comparing an ALL reconstruction to a lateral extra-articular tenodesis, there's not a lot out there, but, you know, the bottom line is there were no differences between the two procedures in this study with the exception of an ALL reconstruction resulting in a higher return to play. In this other study, looking at 12 studies, a systematic review, they found that a residual pivot shift and patient-related outcome measures were not different, but the percent with a grade two to three Lachman was higher in the LET group. So what about my experience with this? So this is a study that I published, I was pretty humbled by, six-year follow-up after ACL reconstruction. And what I did is I looked at patients who had generalized hypermobility versus those that didn't. And I had about a 24% failure rate in the group that had generalized hypermobility. And what we found is that if your heel height was greater than five centimeters, that was predictive of failures. So today I performed about 150 ALL or LET reconstructions. Again, all of these are high-risk primary or revision patients, predominantly based on their grade of pivot shift or hypermobility. I probably performed about 150 ACLs a year, so about 15% of my cases I'll add an ALL reconstruction or an LET. I use a free tendon reconstruction with semitendinosus allograft for an ALL. And then lateral extraticular tenodesis is with an IT band. And again, I identify my points of fixation, both direct dissection as well as with intraoperative floral. If we look at our patient-related outcome measures, again, these are all high-risk ACL patients. For primary ACL reconstruction, 17.5-month follow-up, patient-related outcome measures, I think, are good when we look at our IKDC, Cincinnati, and Leisholm scoring. I think even more impressive for me was the revision group showing our postoperative numbers in the low to high 80s, which is very comparable with pooled numbers in the revision papers. Again, these are the highest-risk patients. And then with reoperation and failures, this is where I probably had the most, I was most impressed with. One graft failure in the primary group, 1.4%, and one graft failure in the revision group. And I would say in the revision group, our patient-related outcome measures, graft failure rate, all were equal or better than the pooled high and low-risk ACL revision studies that we've seen with the MARS group and Anand et al. So in summary, I'd say anterolateral ligament complex consists of the ALL, your IT band, capillaries, fibers, and lateral meniscus. These are frequently associated with ACL tears. Current indications seem to be clearest for a high-grade pivot shift, hypermobility, or revision ACL. And at this point, maybe even more so with your soft tissue graft reconstructions in your younger athletes versus the BTB, which we're not sure about yet. There are some concerns over potential for lateral compartment overload, but this may not be clinically borne out. And my final thoughts would be that they're not required for all patients. The early results, in my hands at least and in the literature, are promising, but there are conflicting data at this point in time. I am a believer at this point, based on what I've seen, what I've read, I'll continue to perform these, follow these principles, but we have to carefully follow the literature and follow our own patients. And there may be an expanding role, but again, further research is critical at this point. So thank you very much.

Anterolateral Ligament

ACL reconstruction

Indications

Techniques

Clinical outcomes