Thanks, Dr. Kelly, for the kind intro, and it should be an intimate group, so hopefully we can make it as interactive as possible. I'm going to just kind of get us started, since it's 7 a.m., with an intro to things, and then from there, I think it's going to become a lot more interactive, and hopefully this just stimulates the way we think about glenoid bone loss. Dr. Kelly charged me with the task of really critically evaluating how we looked at bone loss, or glenoid bone loss specifically, but as I really dove into the literature, realized that I couldn't really be looking only at glenoid bone loss, if we were really going to be looking at shoulder instability, and how this has played out over time. Disclosures are in the app, and so the outline of the talk is as follows, and really, what I came away and went into, looking at the takeaways that I was hoping for, is how do we use imaging, and how are we evaluating glenoid bone loss, but practically speaking, how are we actually making this a part of our practice, and making it change the way we make decisions, and offer different surgical procedures to our patients. From that, I came away with two takeaways. There's two factors. I tried to simplify it as much as possible, but specifically, patient factors and anatomic factors that play into our decision-making and our counseling of the patients. So with that, I found it really interesting, and I've taken a page out of my mentor's book when it comes to Dr. Tokish, really looking at the history, and really doing a deep dive, and so I really kind of went through the last couple decades of a timeline of where and how we really come to where we are with glenoid bone loss. This really started out with the two pioneers, between Dr. DeVere and Burkhardt, where they looked at, in this landmark paper in 2000, where you would think, and you can almost imagine Dr. Burkhardt saying this out loud as he reflected in his introduction, we're bone doctors, and we've been primarily treating this up until this time with soft tissue procedures. Thermal capsuloraphy was popular at that time, but he was really able to recognize that glenoid bone loss led to significantly increased rates of recurrence and failure, and coined the term of engaging health sacs, as well as this inverted pair, and how that was significant glenoid bone loss. This was validated through a biomechanical study by Dr. Itoi, who found that 21% bone loss led to an inability to restore stability of the shoulder with a labral repair alone. So as we start heading through, well, we know glenoid bone loss is significant in terms of risk of recurrence, but how are we measuring it? So we looked at the glenoid bare spot, and we needed to validate it in some way, shape, or form, and we did it surgically. When you found that there's an inverted pair, when he measured this repeatedly, he found that this equated to approximately 20 to 25% of bone loss. So this became significant and altered his surgical decision making, where we started adding bone to the front of the glenoid. If we need to look at it preoperatively, how are we doing this? We started looking at different views and found that if 50% of a sagittal cut on the CT, that became significant for 21% bone loss. Similarly, with the West Point view, that same quantification with recognition of bone loss equated to approximately 18% bone loss. Well, how often was this occurring? Sagai showed that this occurred in 90% of patients, that there was either an actual bony fragment, or there was a compression fracture or attritional bone loss for the additional 40% of the time. So starting to head through the 2000s, we need to biomechanically validate this. We don't actually know where it is. It most often occurred perpendicular to the long axis of the glenoid. So from that, we came up with an algorithm. But geez, this is way too confusing for me to handle, and this is 2005 as we started going through multiple iterations and practically applying this in my practice, that it was beyond what I could do when you're seeing many patients in a day. I think 2006, 2007, there was a big change in how we started evaluating this and looking at that outcomes change, whether it was attritional versus whether it was traumatic in a bony bank cart, their outcomes did better than if it was attritional bone loss. And so when they're not the same, even though there's the same amount of bone loss, we can't necessarily predict or offer the same procedure with expecting the same outcomes. So 2007 rolls around, and I think this was a significant year, is that Dr. Boileau similarly started really evaluating clinical factors and patient factors on how this could lead to recurrence. Although the ISIS score can be critically evaluated, and it's been done time and time again to where if you add up any score now in Europe, you're getting a ladder J, I think it took into a lot of factors that were important into putting patients at risk for recurrence. So in comes the concept of the glenoid tract in a biomechanical study that looked at what the glenoid tract occupied and found that it's 84% of the width from the medial footprint of the rotator cuff that occupied this. This predicted on-track and off-track. It still needed some iterations for validation whether or not this was clinically relevant, but it started to occur. Clinically significant bone loss, can we measure this just with our physical examination? Mid-hour reduction was validated in being sensitive and specific. It was a simple maneuver that I think we can practically apply in our practice to say whether or not we need advanced imaging, or whether or not it could lead and predict recurrence just based off of significant bone loss alone. So we've been measuring it through linear models to this point, and Dr. Preventer, who's another mentor of mine, starts to do his normal thing and think way outside the box of how are we actually even accurately measuring this. And through a super complex trigonometric measurement, they did this with the secant method and showed that it was more accurate than the linear methods that we were performing to date. They also compared this to surface area methods, demonstrating that the surface area methods were more accurate than linear models, yet we continue to perform studies and measure bone loss just based off of linear methods alone. So 2011 rolls around. We start seeing that there's other certain factors based off of total dislocations, recurrence, and whether or not there's prior surgeries that have been performed that dictate whether or not patients are at higher risk of recurrence. Still to date, no imaging modality had been validated or termed as the gold standard up until this 3D study done, 3DCT study was performed, where it did validate. And it showed that the 3DCT was the most accurate, and I think what people have been leaning on since then. Dr. Berventer did a clinical validation of the glenoid tract concept looking through MRIs. And as you'll start seeing and noticing here, this was done through a linear model, even though he had already stated in his study prior that this was not the most accurate way to be measuring glenoid bone loss. But it was the most facile and, I think, the most simplified way of doing so. They did find that they were able to most accurately, in a sensitive and specific way, predict those that were going to be on-track and off-track. Did on-track and off-track start changing our operative paradigm? And I think when you have three authors like this that start putting forward both opinion and clinical papers to show that it is predictive, I think it has led a lot of us down a route of looking at the tract and then making operative decisions and offering operative procedures for these patients off of that. So 2015, we really have started to look at, well now we're looking at the linear model. And as it gets bigger, we find that it's less accurate. And can this change and does it alter our decision-making? The bigger the defect, the more inaccurate it is when we're using a simple diameter and linear-based model. So this is still probably one of the best pictures when you get up on Google Images of Dr. Tokish. I think this is probably the same smile that he had when this paper was published because up until this point, critical bone loss was between 20 and 25 percent. So all of us have been basing operative procedures and discussing and counseling our patients based off of this. And he dropped that down a couple of millimeters and found that 13.5 percent led to worse outcomes. And it changes how patients do in a high-demand population. So I think at the end of the day, he started laughing at us all because he knew he was a step ahead of us throughout this whole process in thinking. 2016, we validated that it's biomechanically that subcritical bone loss is probably significant and that it can't be restored from labor repair alone and that clinical outcomes are affected. And so I think that it altered the paradigm. It was a paradigm-shifting paper. Surface-to-area measurements were once again compared to linear methods, showing that linear methods once again grossly overestimated what we do. Bipolar bone loss became a much more significant way in how we evaluated our patients and understanding that there is an interplay in where the hillside lesion is oriented, how far medially it goes, and that measuring glenoid bone loss alone was not predictive of whether or not they were going to recur. I like to study out of rush that looks at significant glenoid bone loss simply by drawing a straight line. I think this is a simplified version for current Air Force physicians to be able to evaluate whether or not there's significant bone loss. And so just measuring a line that's perpendicular to the anterior edge of the glenoid is significant for 12.8% bone loss. I think this is a practical way that we can look in our practice to be able to determine is there recognizable bone loss. So the on-track, off-track was just in 2019, so not too long ago, validated arthroscopically to determine a predictive nature of engagement in off-track lesion. So we've been looking at bone loss, but what about concavity? So concavity starts to come into play, and it just starts to make everybody's head spin, realizing that within the first 10% of bone loss, that alters the stability ratio of the shoulder significantly, up to 90%. So we're in the final stretch here, and now we're on off-track, off-track. Well, what about near-track or peripheral-track lesions? Found significantly worse outcomes as well as risk of recurrence if the lesion is occupying zone 3 and zone 4. So it starts to get close to the track, but it's still not in the track. So it's still considered on-track. And the Utah group, Dr. Tajjan and Chalmers, I was able to meet them this past year. They found that CT scan with linear-based models can alter operative plans up to 34% of the time. So it made me think, are we routinely just looking at linear-based models and basing our surgical decisions and offering surgical procedures off of that? So we rely on the efforts of the experts and the opinions of the experts to help guide us what we do. And going through the literature, this is what they found to be the most significant in terms of what they can agree upon. 3DCT remains supreme. That multiple dislocations or failed surgery is predictive of recurrence in Hill-Sax lesions still, to this day, are poorly quantified and understood. Stability ratios can be restored through bony procedures, which is significant, and my two mentors will be talking about those. And a keynote out of this study is we're still looking, over the last 20 years, about how do we measure bone loss, but if you notice, the one thing that I found interesting is that we're still utilizing linear-based models as our primary source of measurement, and so we have to be critical of the literature as we do this. Over the past couple of years, Dr. Lenny's presented at this conference his concept of distance to dislocation, so essentially this near-track lesion. If you're getting close, or as if you're within 8 millimeters, they found that you were 8 millimeters of the Hill-Sax interval, that you're likely to recur. And then, lastly, Dr. Dickens and his group found that if you just had a prior arthroscopic procedure, this is something that I think we constantly evaluate and look at and see, do we need to add bone, even if there's no bone loss in the setting of recurrence? They found a 44 percent failure, unable to return to duty at that time. The distance to dislocation and near-track concept was validated by Dr. Barrow, who's another surgeon that came out of the Pitt group, that helped validate that it does increase risk of recurrence. So just within this last year, the group had a veil that shows that CT changes 25 percent of operative plans, but the other 75 percent were using patient factors alone to help evaluate this, and Dr. Sheen, one of my colleagues, showed that even after 23 years, we still have no standardized way. So when we looked at those takeaways, looking at imaging, looking at things in how do we impact it and how do we change our decision-making based off of how we've evaluated glenoid bone loss, I had three takeaways that I came away with after making this talk. First off, does on-track, off-track matter? And I think that there's a great military paper that we do a significant amount of instability, and we found that the track concept, at least in 2023, is not altering surgical decision-making in the military. They found that still, glenoid bone loss alone, when evaluating that, does predict whether a surgeon's going to be doing a glenoid bone augmentation procedure, and that in the setting of a Hill-Sachs lesion, where glenoid bone loss is 17 percent, remplisage is reigning supreme. Step two, I polled a lot of my mentors, asking them what makes their clinical-in-chief decision and what procedure to do. Listening to the patient remains supreme. Patient factors alone can predict what type of procedure that we offer them and what will convince and honestly predict how their outcome will be. So knowing the number of dislocations they've had, whether or not they've had a prior stabilization procedure, and are they at high risk, high-risk sport, high-risk athlete. So I think that that takes me back to the 2007 paper, although not perfect, and it's been modified. It sure sounds very similar to the ISIS paper that was performed in 2007. Last but not least, my personal algorithm, Dr. Kelly charged me, well, what did you learn from this? And I, like I said, I've had to make this as simple as possible, just because as we're all busy and we're rolling through clinic, we've got to figure out quickly how to counsel our patients. And essentially what I came out with is, is there any recognizable bone loss? If there is, and they're high-risk, special forces, high-risk overhead athlete, contact athlete, multiple dislocate of prior surgery, they're getting bone, plus or minus remplisage. If they're a low or medium-risk individual, then yes, I'm going to the glenoid side to look at how much glenoid bone loss they have. And if they do have significant bone loss, I'm replacing it with bone. If they don't, I'm taking Dr. Kelly's approach, and I'm doing a Bancart with a remplisage. And so it's amazing to be up here with my two mentors and look forward to learning more. Travis, that was fantastic, and I want you, the audience, to know that Travis reviewed about 1,400 abstracts for this, so that is a lot of work. And you've got to teach me those video tricks here, Travis.

glenoid bone loss

shoulder instability

evaluation

treatment

patient factors