WEBVTT 00:00:00.000 --> 00:00:03.000 Welcome to the deep dive, where we really plunge 00:00:03.000 --> 00:00:05.200 into the sources, the articles, the research, 00:00:05.299 --> 00:00:07.940 and pull out those key nuggets of knowledge just 00:00:07.940 --> 00:00:10.660 for you. Today we're diving into something that 00:00:10.660 --> 00:00:13.419 sounds maybe a bit niche, but it's actually incredibly 00:00:13.419 --> 00:00:15.880 vital in modern medicine. We're talking about 00:00:15.880 --> 00:00:19.300 precision, absolute precision in shoulder surgeries. 00:00:19.640 --> 00:00:23.990 Imagine for a second you're maybe facing total 00:00:23.990 --> 00:00:26.769 shoulder arthroplasty, TSA, they call it. It's 00:00:26.769 --> 00:00:28.489 this major procedure, right, designed to get 00:00:28.489 --> 00:00:30.269 rid of awful pain, give you back your movement. 00:00:30.809 --> 00:00:34.109 But the success of that surgery, it really hinges 00:00:34.109 --> 00:00:36.950 on an almost unbelievable level of accuracy. 00:00:37.130 --> 00:00:39.070 We're talking replacing parts of your shoulder 00:00:39.070 --> 00:00:41.429 joint, the socket, the glenoid, getting that 00:00:41.429 --> 00:00:43.250 angle spot on. You might think, well, how much 00:00:43.250 --> 00:00:45.189 difference can a few degrees make? But, you know, 00:00:45.210 --> 00:00:47.030 in the body, especially a joint like the shoulder. 00:00:47.280 --> 00:00:50.539 Tiny angles, huge consequences. Yeah, think about 00:00:50.539 --> 00:00:52.880 this. Using some of the older methods, a surgeon 00:00:52.880 --> 00:00:55.179 might, without even knowing it, place an implant 00:00:55.179 --> 00:00:57.520 based on a measurement that's off by what the 00:00:57.520 --> 00:00:59.340 paper suggests, over 14 degrees in some cases. 00:00:59.439 --> 00:01:02.780 14 degrees. That's massive in this context. Exactly. 00:01:02.960 --> 00:01:05.739 And that tiny sounding error, it could mean years 00:01:05.739 --> 00:01:08.799 of pain -free life versus going back under the 00:01:08.799 --> 00:01:11.519 knife for another really tough, expensive revision 00:01:11.519 --> 00:01:13.780 surgery. Which nobody wants. Nobody. And this 00:01:13.780 --> 00:01:16.180 isn't just for surgeons, is it? It's really for 00:01:16.180 --> 00:01:19.280 anyone curious about how medicine moves forward, 00:01:19.439 --> 00:01:21.780 how brilliant people are pushing for that accuracy 00:01:21.780 --> 00:01:24.680 that genuinely changes lives. Absolutely. And 00:01:24.680 --> 00:01:26.739 what's really remarkable here, I think, is how 00:01:26.739 --> 00:01:29.260 a seemingly small refinement, just tweaking how 00:01:29.260 --> 00:01:31.519 you measure something, can have these huge ripple 00:01:31.519 --> 00:01:34.430 effects. Our mission today is to unpack one of 00:01:34.430 --> 00:01:38.109 those innovations, a potentially groundbreaking 00:01:38.109 --> 00:01:40.310 way to measure that shoulder socket angle, the 00:01:40.310 --> 00:01:43.390 glenoid version. It's called the ellipse modification 00:01:43.390 --> 00:01:45.569 of the Friedman method. Ellipse modification, 00:01:45.629 --> 00:01:47.230 okay. And this isn't just theory, it's backed 00:01:47.230 --> 00:01:49.750 by solid research, a key paper published in the 00:01:49.750 --> 00:01:52.049 Bone and Joint Journal back in February 2020. 00:01:52.250 --> 00:01:55.310 And a really crucial contributor to this work, 00:01:55.469 --> 00:01:57.209 someone instrumental in actually writing the 00:01:57.209 --> 00:01:59.530 manuscript. So really shaping how the findings 00:01:59.530 --> 00:02:01.650 were presented, ensuring that scientific rigor 00:02:01.650 --> 00:02:05.170 is Professor Mo Imam. Professor Imam? Yes, he's 00:02:05.170 --> 00:02:07.609 based at Ashford in St. Peter's Hospital's NHS 00:02:07.609 --> 00:02:11.129 Trust. And he's, well, he's a highly prolific 00:02:11.129 --> 00:02:14.150 researcher. exceptionally cited. We're talking 00:02:14.150 --> 00:02:18.349 146 publications, over 1 ,100 citations. His 00:02:18.349 --> 00:02:20.750 input here really speaks volumes about the thought 00:02:20.750 --> 00:02:23.169 behind this method. That's some serious expertise. 00:02:23.389 --> 00:02:25.990 It is. And the core idea, the whole point, is 00:02:25.990 --> 00:02:28.069 that getting that precision before surgery in 00:02:28.069 --> 00:02:30.610 the planning stage is just vital for success. 00:02:31.129 --> 00:02:33.389 It directly impacts how well you function afterwards, 00:02:33.569 --> 00:02:35.530 your quality of life. So what does this all mean 00:02:35.530 --> 00:02:37.509 for you listening in? Maybe you're not a surgeon, 00:02:37.569 --> 00:02:39.569 maybe you're not having shoulder surgery, but 00:02:39.639 --> 00:02:42.060 Understanding this, this relentless drive for 00:02:42.060 --> 00:02:44.400 getting things exactly right, it gives you real 00:02:44.400 --> 00:02:46.580 insight into how medicine improves, doesn't it? 00:02:46.819 --> 00:02:49.080 It really does. We're going to get into why these 00:02:49.080 --> 00:02:52.020 tiny angles matter so much and how research like 00:02:52.020 --> 00:02:54.659 this, spearheaded by people like Professor Imam, 00:02:55.060 --> 00:02:58.340 makes a real difference. It's science refining 00:02:58.340 --> 00:03:01.180 how we heal. OK, so let's set the stage properly. 00:03:01.439 --> 00:03:04.939 Let's talk about the stakes in total shoulder 00:03:04.939 --> 00:03:07.479 arthroplasty because they are incredibly high. 00:03:07.719 --> 00:03:10.379 TSA, it's a big deal. You're replacing damaged 00:03:10.379 --> 00:03:13.800 parts. the ball of your upper arm bone, the humerus, 00:03:14.180 --> 00:03:16.979 and that shallow cup, the glenoid, your shoulder 00:03:16.979 --> 00:03:19.539 socket, replacing them with artificial parts. 00:03:19.580 --> 00:03:21.520 Prostetic components, yeah. Think of it like, 00:03:21.520 --> 00:03:23.280 I don't know, building a house inside your shoulder, 00:03:23.400 --> 00:03:25.680 high stakes construction. And just like with 00:03:25.680 --> 00:03:27.680 the house, the foundation, it has to be perfectly 00:03:27.680 --> 00:03:30.080 level if it's off even a bit. Everything else 00:03:30.080 --> 00:03:33.500 is compromised. Walls, roof. Exactly. In TSA, 00:03:33.620 --> 00:03:36.080 that foundation is the glenoid component, this 00:03:36.080 --> 00:03:38.939 artificial socket they put in. And the main goal, 00:03:38.960 --> 00:03:41.280 the absolute driver for the... is getting that 00:03:41.280 --> 00:03:44.500 alignment just right, anatomically correct. That's 00:03:44.500 --> 00:03:46.719 the key to making the implant last, making sure 00:03:46.719 --> 00:03:49.620 your shoulder works properly, hopefully for decades. 00:03:50.199 --> 00:03:51.599 Yeah. Pain -free movement. That's the dream. 00:03:51.599 --> 00:03:54.400 The dream. And connecting this to the bigger 00:03:54.400 --> 00:03:57.860 picture. The reason that foundation, that alignment, 00:03:58.159 --> 00:04:00.939 is so incredibly critical is because glenoid 00:04:00.939 --> 00:04:03.879 loosening. Well, it's the most common reason 00:04:03.879 --> 00:04:06.039 why these anatomical shoulder replacements fail. 00:04:06.909 --> 00:04:08.969 loosening, so the implant comes away from the 00:04:08.969 --> 00:04:11.370 bone. Essentially, yes. And that's the number 00:04:11.370 --> 00:04:13.449 one reason patients end up needing revision surgery, 00:04:13.789 --> 00:04:17.490 a second operation, which is complex, costly, 00:04:18.170 --> 00:04:20.949 painful, just something everyone wants to avoid. 00:04:21.050 --> 00:04:22.689 Definitely. And this is where glenoid version 00:04:22.689 --> 00:04:24.790 comes right into the spotlight. It's basically 00:04:24.790 --> 00:04:27.529 the angle of that socket. Is it tilted too far 00:04:27.529 --> 00:04:29.550 forward? That's anti -version? Yeah. Or too far 00:04:29.550 --> 00:04:32.089 backward? That's retroversion. OK, the tilt. 00:04:32.189 --> 00:04:34.910 Yeah, the tilt. If that angle isn't right, Even 00:04:34.910 --> 00:04:37.850 by just a few degrees, it puts abnormal stress 00:04:37.850 --> 00:04:40.610 on the new implant. Constant, uneven pressure. 00:04:41.250 --> 00:04:43.750 And over time, that stress can cause the component 00:04:43.750 --> 00:04:47.050 to slowly work its way loose. Ah, okay. So that 00:04:47.050 --> 00:04:49.089 slight tilt leads directly to the loosening problem. 00:04:49.170 --> 00:04:50.990 It's a major contributing factor, absolutely. 00:04:51.069 --> 00:04:52.910 And these aren't just, you know, theoretical 00:04:52.910 --> 00:04:54.850 worries from research papers, are they? This 00:04:54.850 --> 00:04:58.069 stuff is real. It hits patients hard. Devastatingly 00:04:58.069 --> 00:05:01.329 real. Yeah. and meticulously documented. There 00:05:01.329 --> 00:05:04.089 are studies, right, like Farron and his team 00:05:04.089 --> 00:05:06.810 back in 2006. They found if the glenoid was put 00:05:06.810 --> 00:05:09.649 in more than five degrees too far back, too retroverted. 00:05:09.730 --> 00:05:11.810 Yeah, more than five degrees retroversion. It 00:05:11.810 --> 00:05:14.410 led to a seven -fold increase in micromotion. 00:05:14.810 --> 00:05:18.660 Seven times. Micro ocean. That sounds small, 00:05:18.779 --> 00:05:21.139 but it's bad, right? It's terrible. Imagine tiny 00:05:21.139 --> 00:05:22.899 little destructive wobbles where the implant 00:05:22.899 --> 00:05:25.519 meets the bone. It destabilizes everything. And 00:05:25.519 --> 00:05:29.300 they also sound a 3 .26 fold increase in stress 00:05:29.300 --> 00:05:32.600 right at that bone cement interface. It's basically 00:05:32.600 --> 00:05:35.480 asking for the implant to fail early. Wow. Okay. 00:05:35.860 --> 00:05:38.639 And then there was Shapiro, 2007. They showed 00:05:38.639 --> 00:05:40.839 that if you don't correct that backward tilt, 00:05:41.019 --> 00:05:43.319 that retroversion, you get eccentric loading. 00:05:43.540 --> 00:05:45.360 Eccentric loading, yeah. Think of it like the 00:05:45.360 --> 00:05:47.199 forest isn't spread evenly across the implant. 00:05:47.379 --> 00:05:49.220 It's constantly pushing it off -center. Like 00:05:49.220 --> 00:05:51.240 leaning on one side of a chair leg constantly. 00:05:51.399 --> 00:05:53.680 Kind of, yeah. And that leads directly to more 00:05:53.680 --> 00:05:55.459 wear on the implant material itself. And again, 00:05:55.540 --> 00:05:57.899 it loosens faster. And even small amounts matter. 00:05:58.000 --> 00:06:00.899 I think Neifler's group showed that. Yes. Neifler 00:06:00.899 --> 00:06:04.660 at all. In 2006, they used cadaver models. Very 00:06:04.660 --> 00:06:07.620 precise. Showed that even tiny steps of retroversion 00:06:07.850 --> 00:06:10.410 just four degrees at a time, caused the humeral 00:06:10.410 --> 00:06:12.689 head, the ball part, to shift backward off center. 00:06:13.009 --> 00:06:15.029 And that led to early loosening in their models. 00:06:15.310 --> 00:06:17.829 So even small errors add up. They absolutely 00:06:17.829 --> 00:06:20.850 do. And maybe most importantly for how a patient 00:06:20.850 --> 00:06:23.709 actually feels and functions, Ye -Yin and colleagues 00:06:23.709 --> 00:06:27.149 in 2005 found a direct link. More retroversion 00:06:27.149 --> 00:06:29.509 in the implant. Significantly lower constant 00:06:29.509 --> 00:06:32.089 scores. The constant score, that measures shoulder 00:06:32.089 --> 00:06:34.569 function, right? Pain, movement. Exactly. It's 00:06:34.569 --> 00:06:37.180 a standard measure. Lower scores mean more pain, 00:06:37.439 --> 00:06:39.720 less movement, basically a shoulder that doesn't 00:06:39.720 --> 00:06:42.160 work well for everyday things, reaching up, getting 00:06:42.160 --> 00:06:44.220 dressed. So we're not just talking about implants 00:06:44.220 --> 00:06:46.759 revival here. We're talking about real day -to 00:06:46.759 --> 00:06:49.420 -day pain and limitation for the patient and 00:06:49.420 --> 00:06:51.779 potentially needing another operation. Precisely. 00:06:52.279 --> 00:06:54.899 And while, sure, other things play a role, patient 00:06:54.899 --> 00:06:58.350 factors like age, sex. the implant design itself, 00:06:58.490 --> 00:07:00.550 getting that glenoid position right, that's a 00:07:00.550 --> 00:07:03.269 huge factor. And crucially, it's something the 00:07:03.269 --> 00:07:05.269 surgeon can control. It's controllable. That's 00:07:05.269 --> 00:07:07.810 the key. It is. It's a critical moment in the 00:07:07.810 --> 00:07:11.189 OR where accurate measurement can literally change 00:07:11.189 --> 00:07:14.449 the patient's future. OK, so the stakes are sky 00:07:14.449 --> 00:07:18.129 high. Getting that angle right is non -negotiable, 00:07:18.250 --> 00:07:21.230 which brings us to the obvious question. How 00:07:21.230 --> 00:07:24.759 do surgeons measure it accurately? You mentioned 00:07:24.759 --> 00:07:28.500 CT scans. Regular x -rays aren't enough. No. 00:07:28.779 --> 00:07:30.399 Conventional x -rays just don't give you the 00:07:30.399 --> 00:07:33.000 detail you need for version. You absolutely need 00:07:33.000 --> 00:07:35.399 a CT scan, computed tomography. It gives you 00:07:35.399 --> 00:07:37.899 those cross -sectional slices. Right. But even 00:07:37.899 --> 00:07:41.000 with CT scans, you said there's no single best 00:07:41.000 --> 00:07:43.399 way everyone agrees on. That's the surprising 00:07:43.399 --> 00:07:45.759 thing. There isn't universal consensus. Different 00:07:45.759 --> 00:07:48.139 techniques exist. But one thing everyone does 00:07:48.139 --> 00:07:51.019 agree on is that the CT scans must be properly 00:07:51.019 --> 00:07:53.199 reformatted. Reformatted? What does that mean? 00:07:53.399 --> 00:07:55.480 It means digitally realigning the images so you're 00:07:55.480 --> 00:07:57.699 looking squarely at the shoulder blade, the scapula, 00:07:57.860 --> 00:08:00.519 and its natural plane. You remove any tilt or 00:08:00.519 --> 00:08:02.720 rotation from how the scan was taken. It's called 00:08:02.720 --> 00:08:05.139 the scapula plane reformat. OK, so you have to 00:08:05.139 --> 00:08:07.600 get the image lined up perfectly first. Absolutely. 00:08:07.699 --> 00:08:10.500 If you don't do that basic step right, any measurement 00:08:10.500 --> 00:08:12.600 you take afterwards is basically garbage. It 00:08:12.600 --> 00:08:15.680 won't be accurate or reproducible. Got it. Foundational 00:08:15.680 --> 00:08:19.339 step. So assuming you've got your properly reformatted 00:08:19.339 --> 00:08:22.839 CT, what's been the main method people use? Historically, 00:08:23.199 --> 00:08:25.459 and still very common because it's relatively 00:08:25.459 --> 00:08:28.079 straightforward, the go -to has been the Friedman 00:08:28.079 --> 00:08:31.540 method, described way back in 1992 by Friedman 00:08:31.540 --> 00:08:34.139 and his colleagues. Friedman method. OK. How 00:08:34.139 --> 00:08:37.039 does that work? It uses a bony landmark called 00:08:37.039 --> 00:08:40.399 the coracoid process. It's this hook -like bone 00:08:40.399 --> 00:08:41.879 sticking off the front of your shoulder blade. 00:08:42.279 --> 00:08:44.899 You find that, and then you measure the glenoid 00:08:44.899 --> 00:08:47.399 version on an axial slice, a cross section that's 00:08:47.399 --> 00:08:49.720 10 millimeters below it. 10 millimeters below 00:08:49.720 --> 00:08:52.220 the coracoid? Seems specific. It is specific. 00:08:52.220 --> 00:08:55.139 Yeah. But, and here's the crucial but, if it's 00:08:55.139 --> 00:08:57.389 so widely used, what's the problem? Why bother 00:08:57.389 --> 00:08:59.250 developing something new like Professor Imam 00:08:59.250 --> 00:09:01.169 and his co -authors did? Yeah, good question. 00:09:01.210 --> 00:09:03.789 What's the catch? The catch is the coracoid itself. 00:09:04.289 --> 00:09:07.769 Ah, the reference point. Exactly. And this is 00:09:07.769 --> 00:09:09.330 where the paper we're looking at gets really 00:09:09.330 --> 00:09:10.990 interesting and where the ellipse method comes 00:09:10.990 --> 00:09:14.509 in. The paper points out quite directly that 00:09:14.509 --> 00:09:18.470 the coracoid process is highly variable. Variable 00:09:18.470 --> 00:09:23.370 how? Like shape? Position? Both. Its shape can 00:09:23.370 --> 00:09:25.889 differ quite a bit between people. and critically, 00:09:26.350 --> 00:09:29.070 its exact position relative to the actual glenoid 00:09:29.070 --> 00:09:31.470 socket isn't consistent. So if your landmark 00:09:31.470 --> 00:09:33.250 moves around... Your measurement starting point 00:09:33.250 --> 00:09:35.970 moves around. It makes it really hard to consistently 00:09:35.970 --> 00:09:39.769 find what everyone agrees is the true mid -glenoid 00:09:39.769 --> 00:09:42.350 level. Mid -glenoid level. Why is heading that 00:09:42.350 --> 00:09:44.590 exact middle point so important? Because the 00:09:44.590 --> 00:09:46.870 glenoid version... that angle we care so much 00:09:46.870 --> 00:09:48.730 about. It actually changes along the face of 00:09:48.730 --> 00:09:50.690 the socket. It's not the same angle top to bottom. 00:09:50.909 --> 00:09:53.669 Really? It varies. Oh, yeah. Typically, the upper 00:09:53.669 --> 00:09:56.009 part of the glenoid is more retroverted, tilted 00:09:56.009 --> 00:09:58.570 back, more than the middle part of the true equator. 00:09:58.950 --> 00:10:02.370 Ah, OK. So if you measure too high or too low 00:10:02.370 --> 00:10:04.470 because your coracoid landmark put you in the 00:10:04.470 --> 00:10:06.789 wrong spot. You get a skewed measurement. You 00:10:06.789 --> 00:10:09.710 might think the version is, say, 10 degrees retroverted, 00:10:09.809 --> 00:10:11.730 but the true version at the middle might only 00:10:11.730 --> 00:10:14.929 be five degrees. or vice versa. You're measuring 00:10:14.929 --> 00:10:18.090 the wrong slice, essentially. And that inconsistency, 00:10:18.309 --> 00:10:20.990 that reliance on a variable landmark, that's 00:10:20.990 --> 00:10:23.970 the Achilles heel of the Friedman method. That's 00:10:23.970 --> 00:10:25.909 exactly what the authors argue. It introduces 00:10:25.909 --> 00:10:28.090 this inherent variability that surgeons have 00:10:28.090 --> 00:10:30.750 just had to kind of deal with. Now there are 00:10:30.750 --> 00:10:33.149 other methods, sure, Randelli's method, Poonin 00:10:33.149 --> 00:10:35.740 -Ting's vault method for... tricky cases. But 00:10:35.740 --> 00:10:37.980 Friedman's has been the most popular. Generally, 00:10:38.200 --> 00:10:40.320 yes, because it seems relatively easy to apply, 00:10:40.799 --> 00:10:43.740 which makes this variability problem even more 00:10:43.740 --> 00:10:46.259 significant. You know, it highlights why a more 00:10:46.259 --> 00:10:48.559 reliable way to find that mid -glenoid level 00:10:48.559 --> 00:10:50.659 was really needed. And what's really cool about 00:10:50.659 --> 00:10:53.179 the ellipse method is where it came from. It 00:10:53.179 --> 00:10:55.200 wasn't just dreamt up in a lab somewhere. It 00:10:55.200 --> 00:10:57.240 came directly out of the clinical trenches, you 00:10:57.240 --> 00:11:00.340 could say. The authors, including Professor Mo 00:11:00.340 --> 00:11:02.799 Imam, who, remember, was key in actually writing 00:11:02.799 --> 00:11:04.730 this paper, articulated the findings they were 00:11:04.730 --> 00:11:06.710 facing, these exact limitations of the Friedman 00:11:06.710 --> 00:11:09.070 method, day in, day out in their own surgical 00:11:09.070 --> 00:11:11.409 practice. They were living the problem. Exactly. 00:11:11.750 --> 00:11:14.289 And especially with newer digital imaging, where 00:11:14.289 --> 00:11:17.429 you can see the axial and sagittal views cross 00:11:17.429 --> 00:11:20.029 -section and side view side by side simultaneously. 00:11:20.309 --> 00:11:23.169 Ah, that must make the inconsistencies more obvious. 00:11:23.370 --> 00:11:25.769 It really does. You start seeing how relying 00:11:25.769 --> 00:11:29.070 on just the coracoid isn't always hitting the 00:11:29.070 --> 00:11:32.340 same spot relative to the glenoid itself. So 00:11:32.340 --> 00:11:36.019 their goal became really clear. Find a way to 00:11:36.019 --> 00:11:38.679 consistently, reliably nail down that mid -glenoid 00:11:38.679 --> 00:11:41.779 level every single time. Not just guess, or hope 00:11:41.779 --> 00:11:43.860 you're in the right place. Precisely. It wasn't 00:11:43.860 --> 00:11:46.240 about totally changing how you measure the angle 00:11:46.240 --> 00:11:48.399 between the lines, but about making sure where 00:11:48.399 --> 00:11:50.559 you draw those lines is standardized and accurate. 00:11:50.750 --> 00:11:52.850 picking the guesswork out. OK, so let's unpack 00:11:52.850 --> 00:11:54.769 it. How does this ellipse method actually work? 00:11:54.889 --> 00:11:56.610 Walk us through the steps. It sounds like a visual 00:11:56.610 --> 00:11:58.710 journey. It is, and it's actually quite elegant 00:11:58.710 --> 00:12:00.850 once you break it down. It's basically five steps 00:12:00.850 --> 00:12:04.029 using those modern CT views. Step one, you start 00:12:04.029 --> 00:12:05.909 with the sagittal view, the side view of the 00:12:05.909 --> 00:12:09.309 shoulder. And on that view, you draw what they 00:12:09.309 --> 00:12:11.620 call a best fit ellipse. Right around the entire 00:12:11.620 --> 00:12:14.200 glenoid fossa, top to bottom. Like putting an 00:12:14.200 --> 00:12:17.059 oval picture frame around the socket from the 00:12:17.059 --> 00:12:19.419 side. That's a perfect analogy. You capture the 00:12:19.419 --> 00:12:22.299 whole vertical extent. That ellipse becomes your 00:12:22.299 --> 00:12:25.519 geometric guide. Step two. Step two. Measure 00:12:25.519 --> 00:12:27.600 the vertical diameter of that ellipse you just 00:12:27.600 --> 00:12:30.639 drew. The total height. Simple measurement. Got 00:12:30.639 --> 00:12:34.700 it. Full height. Step three. Step three. Calculate 00:12:34.700 --> 00:12:37.340 the exact midpoint of that vertical diameter. 00:12:37.549 --> 00:12:39.870 Just divide the height by two. That gives you 00:12:39.870 --> 00:12:42.149 the precise vertical center of the glenoid in 00:12:42.149 --> 00:12:44.769 that side view. The geometric middle, not based 00:12:44.769 --> 00:12:46.929 on a wobbly bone landmark. Exactly. That's the 00:12:46.929 --> 00:12:49.669 key innovation. Use this geometry, not variable 00:12:49.669 --> 00:12:52.570 anatomy, to find the center. Clever. Okay, step 00:12:52.570 --> 00:12:55.389 four. Step four. Now, you use the power of the 00:12:55.389 --> 00:12:58.110 linked views. You find the axial slice, the cross 00:12:58.110 --> 00:13:00.309 -sectional view, that corresponds exactly to 00:13:00.309 --> 00:13:02.470 that calculated midpoint you found on the sagittal 00:13:02.470 --> 00:13:05.070 view. You scroll through the axial slices until 00:13:05.070 --> 00:13:06.789 you hit the one that lines up perfectly with 00:13:06.789 --> 00:13:09.570 your midpoint marker. Ah, so the sagittal view 00:13:09.570 --> 00:13:12.490 guides you to the correct axial slice. Precisely. 00:13:12.750 --> 00:13:15.610 That specific slice is your defined, consistent, 00:13:15.909 --> 00:13:18.889 reproducible mid -glenoid level. Found it. No 00:13:18.889 --> 00:13:23.490 more ambiguity. And step five. Step five. Now 00:13:23.490 --> 00:13:25.629 that you're confidently on the right axial slice, 00:13:26.029 --> 00:13:29.210 you measure the glenoid version, and you use 00:13:29.210 --> 00:13:31.789 the exact same landmarks as the original Friedman 00:13:31.789 --> 00:13:34.590 method. You draw the glenoid line across the 00:13:34.590 --> 00:13:37.389 socket face. You draw the scapular axis line. 00:13:37.529 --> 00:13:39.389 And measure the angle between them. Correct. 00:13:39.570 --> 00:13:41.429 So the angle measurement itself is familiar, 00:13:41.850 --> 00:13:43.850 but the plane you're measuring it on is now defined 00:13:43.850 --> 00:13:47.029 with much, much greater consistency thanks to 00:13:47.029 --> 00:13:48.990 that ellipse. Okay, let me make sure I've got 00:13:48.990 --> 00:13:51.750 this. It's not a totally new angle measurement, 00:13:51.789 --> 00:13:54.350 but a much, much better way of making sure you're 00:13:54.350 --> 00:13:57.129 measuring that angle at the right spot, the true 00:13:57.129 --> 00:13:59.230 middle of the glenoid every single time. You've 00:13:59.230 --> 00:14:01.889 got it. It refines Friedman by fixing its biggest 00:14:01.889 --> 00:14:04.909 weakness. Finding the correct level reliably, 00:14:04.909 --> 00:14:07.649 it gives it a stable geometric foundation. That 00:14:07.649 --> 00:14:09.450 makes a lot of sense. And this leads to a really 00:14:09.450 --> 00:14:12.490 important question. What does this mean, practically, 00:14:12.990 --> 00:14:14.909 for the surgeon in the operating room? Yeah, 00:14:14.929 --> 00:14:17.289 beyond just a better number on a planning sheet. 00:14:17.399 --> 00:14:20.919 Well, finding that true mid -glenoid level accurately, 00:14:21.779 --> 00:14:24.279 it doesn't just help plan. It gives the surgeon 00:14:24.279 --> 00:14:28.200 a much clearer picture of the ideal entry point 00:14:28.200 --> 00:14:30.159 for the central guide wire when they're actually 00:14:30.159 --> 00:14:32.539 putting the glenoid component in. The first pin 00:14:32.539 --> 00:14:35.120 they place to guide the implant. Exactly. The 00:14:35.120 --> 00:14:37.740 paper calls it intraoperative corroboration. 00:14:38.460 --> 00:14:40.820 It means the surgeon has a better map during 00:14:40.820 --> 00:14:43.039 the surgery itself. They could be more confident 00:14:43.039 --> 00:14:45.159 they're aiming for the right spot, the center 00:14:45.159 --> 00:14:47.519 they identified in planning. So it connects the 00:14:47.519 --> 00:14:50.340 plan to the action much more reliably. That's 00:14:50.340 --> 00:14:53.460 the idea. Potentially fewer errors in placement, 00:14:54.059 --> 00:14:56.100 better positioning of the actual implant, it 00:14:56.100 --> 00:14:58.460 builds that bridge between planning and doing. 00:14:58.740 --> 00:15:01.019 Okay, so the message sounds elegant, logical. 00:15:01.470 --> 00:15:03.350 Very clever, actually. But how did they prove 00:15:03.350 --> 00:15:05.409 it works? How did they test it rigorously? Right. 00:15:05.529 --> 00:15:07.710 The study design. This was a retrospective study, 00:15:07.809 --> 00:15:09.350 meaning they went back and looked at data that 00:15:09.350 --> 00:15:11.070 already existed. Sedation scans already done. 00:15:11.250 --> 00:15:14.190 Exactly. They pulled up 100 CT scans from 100 00:15:14.190 --> 00:15:16.230 different patients who were all getting their 00:15:16.230 --> 00:15:18.830 first primary shoulder replacement. So a good 00:15:18.830 --> 00:15:21.470 size group. An irrelevant group, the actual patients 00:15:21.470 --> 00:15:23.950 who need this. Definitely. It was a mix, 58 women, 00:15:24.309 --> 00:15:28.370 42 men, average age around 65, 66, but ranging 00:15:28.370 --> 00:15:31.690 all the way from 19 to 93. So it captured that 00:15:31.690 --> 00:15:33.990 typical TSA demographic pretty well. And the 00:15:33.990 --> 00:15:35.990 stands themselves, they made sure they were suitable? 00:15:36.169 --> 00:15:38.350 Oh, absolutely crucial. They used a standard 00:15:38.350 --> 00:15:40.889 protocol, thin, one millimeter slices through 00:15:40.889 --> 00:15:44.100 the glenoid. And importantly, they ensured all 00:15:44.100 --> 00:15:47.100 scans were properly reformatted into that scapula 00:15:47.100 --> 00:15:48.879 plane we talked about. Giving the alignment right 00:15:48.879 --> 00:15:51.759 from the start. Essential. They also had clear 00:15:51.759 --> 00:15:53.899 rules for who was in and who was out inclusion 00:15:53.899 --> 00:15:57.200 -exclusion criteria. Had to be adults, first 00:15:57.200 --> 00:16:00.580 -time TSA, needed a good quality CT scan available 00:16:00.580 --> 00:16:03.399 digitally. And who did they exclude? People who'd 00:16:03.399 --> 00:16:05.379 already had shoulder replacements or surgery 00:16:05.379 --> 00:16:07.360 on their scapula, anyone whose bones weren't 00:16:07.360 --> 00:16:10.899 fully mature, or if the CT scan was just technically 00:16:10.899 --> 00:16:13.960 inadequate, not properly reformatted, didn't 00:16:13.960 --> 00:16:15.480 show the whole shoulder blade, that sort of thing. 00:16:15.639 --> 00:16:17.899 So they were careful to compare like with like, 00:16:18.320 --> 00:16:20.399 making sure the data was clean. Very careful. 00:16:20.779 --> 00:16:22.820 That's vital for results you can trust. Okay, 00:16:22.820 --> 00:16:25.039 so they had the scans. Who did the measuring 00:16:25.039 --> 00:16:28.000 and how? Two senior observers did the measurements. 00:16:28.659 --> 00:16:32.320 The paper calls them SJ and SH. Experienced clinicians 00:16:32.320 --> 00:16:35.450 who know how to read these scans. And they both 00:16:35.450 --> 00:16:37.690 measured glenoid version using the classic Friedman 00:16:37.690 --> 00:16:40.370 method and the new ellipse method on all 100 00:16:40.370 --> 00:16:43.110 scans. So a direct comparison on the same patients. 00:16:43.309 --> 00:16:45.309 Both methods, both observers, okay. But they 00:16:45.309 --> 00:16:48.409 added another layer of rigor, observer 1, SJ. 00:16:49.570 --> 00:16:52.429 They measured Friedman once, but they measured 00:16:52.429 --> 00:16:55.750 using the ellipse method twice. Twice. Why? With 00:16:55.750 --> 00:16:57.549 a one -month gap between the two measurements. 00:16:57.730 --> 00:17:00.509 This was to test intra -rater reliability. How 00:17:00.509 --> 00:17:02.990 consistent is the same person using the ellipse 00:17:02.990 --> 00:17:05.170 method over time? Do they get the same result 00:17:05.170 --> 00:17:07.769 if they measure again later? Yeah, checking for 00:17:07.769 --> 00:17:10.049 drift or inconsistency in one person's measurements. 00:17:10.309 --> 00:17:13.210 Smart. Very smart. And observer two, SH, measured 00:17:13.210 --> 00:17:15.470 the ellipse method once. So this whole setup 00:17:15.470 --> 00:17:16.789 allowed them to look at everything. Likewise. 00:17:16.970 --> 00:17:19.589 Well, comparing ellipse versus Friedman directly. 00:17:19.980 --> 00:17:23.460 Comparing observer 1 versus observer 2 using 00:17:23.460 --> 00:17:25.839 the ellipse method that's iterator reliability. 00:17:26.400 --> 00:17:29.180 Consistency between different people. And comparing 00:17:29.180 --> 00:17:31.500 observer one's first ellipse measurement to their 00:17:31.500 --> 00:17:33.940 second Heller, that's the inter -rater reliability 00:17:33.940 --> 00:17:36.599 we just talked about. Wow, okay. That's thorough. 00:17:36.859 --> 00:17:39.539 Covering all the bases for reliability. Extremely 00:17:39.539 --> 00:17:41.359 thorough. It's how you really build confidence 00:17:41.359 --> 00:17:43.700 in a new measurement technique. So they had all 00:17:43.700 --> 00:17:45.660 these measurements. How did they analyze the 00:17:45.660 --> 00:17:47.740 numbers? What stats did they use? They used a 00:17:47.740 --> 00:17:50.200 solid statistical toolkit to really dig into 00:17:50.200 --> 00:17:53.440 what the numbers meant. First, a paired t -test. 00:17:53.640 --> 00:17:56.119 This basically checks if the average difference 00:17:56.119 --> 00:17:58.000 between two sets of measurements like Ellipse 00:17:58.000 --> 00:18:00.559 versus Friedman or Observer 1 versus Observer 00:18:00.559 --> 00:18:02.799 2 is statistically significant. Is the difference 00:18:02.799 --> 00:18:05.640 likely real or just random chance? Okay, average 00:18:05.640 --> 00:18:07.920 difference. Then, critically, they use bland 00:18:07.920 --> 00:18:10.369 Altman plots. These are brilliant for looking 00:18:10.369 --> 00:18:12.950 at agreement between methods. Instead of just 00:18:12.950 --> 00:18:15.170 averages, it plots the difference between two 00:18:15.170 --> 00:18:17.329 measurements for each patient against the average 00:18:17.329 --> 00:18:19.410 of those two measurements. So you see the spread. 00:18:19.490 --> 00:18:21.509 How much individual measurements might disagree? 00:18:21.849 --> 00:18:24.289 Exactly. It visually shows you the range of disagreement. 00:18:25.089 --> 00:18:27.349 Are the methods generally close across the board, 00:18:27.430 --> 00:18:30.509 or do they sometimes differ wildly? You look 00:18:30.509 --> 00:18:33.630 for the limits of agreement on the plot. Narrow 00:18:33.630 --> 00:18:36.789 limits mean good agreement. Wide limits? Not 00:18:36.789 --> 00:18:39.190 so much. Okay, Bland -Altman for agreement. What 00:18:39.190 --> 00:18:41.450 else? The Interclass Correlation Coefficient, 00:18:41.869 --> 00:18:44.730 or ICC. This gives you a single number between 00:18:44.730 --> 00:18:47.769 0 and 1 that quantifies reliability or consistency. 00:18:48.130 --> 00:18:50.190 Higher is better. In this study, they defined 00:18:50.190 --> 00:18:54.730 0 .90 or above as excellent. ICC for reliability. 00:18:54.849 --> 00:18:57.190 Got it. And finally, the repeatability coefficient. 00:18:57.809 --> 00:18:59.589 This gives you a practical number. It tells you 00:18:59.589 --> 00:19:01.390 how much difference you'd expect to see between 00:19:01.390 --> 00:19:03.210 two measurements made by the same person using 00:19:03.210 --> 00:19:06.599 the same method. 95 % of the time. A smaller 00:19:06.599 --> 00:19:08.880 number means better repeatability, higher precision. 00:19:09.480 --> 00:19:11.880 So t -test for significance, bland Altman for 00:19:11.880 --> 00:19:14.839 agreement spread, ICC for overall reliability, 00:19:15.480 --> 00:19:17.480 and repeatability for single user precision. 00:19:17.579 --> 00:19:19.859 That's comprehensive. It really is. And one more 00:19:19.859 --> 00:19:23.140 crucial thing. They defined beforehand what they 00:19:23.140 --> 00:19:25.990 considered clinically significant. Ah, not just 00:19:25.990 --> 00:19:28.109 statistically significant, but actually mattering 00:19:28.109 --> 00:19:30.970 in practice. Exactly. For this study, they set 00:19:30.970 --> 00:19:33.190 that threshold at a difference greater than plus 00:19:33.190 --> 00:19:35.930 or minus five degrees between methods. Five degrees. 00:19:36.009 --> 00:19:38.690 Why five? That's generally considered a threshold 00:19:38.690 --> 00:19:41.029 in orthopedics, where the difference is large 00:19:41.029 --> 00:19:43.369 enough that it might actually change the surgeon's 00:19:43.369 --> 00:19:46.660 plan, affect implant choice, positioning strategy 00:19:46.660 --> 00:19:48.799 and potentially impact the patient's outcome. 00:19:48.940 --> 00:19:51.119 Okay. So they had a clear line in the sand for 00:19:51.119 --> 00:19:54.319 what really matters clinically. Yes. It allows 00:19:54.319 --> 00:19:56.880 them to interpret the statistical results in 00:19:56.880 --> 00:19:59.440 a really practical, meaningful way for surgeons 00:19:59.440 --> 00:20:01.319 and patients. All right. The moment of truth. 00:20:01.680 --> 00:20:04.220 They did all this careful work. What did the 00:20:04.220 --> 00:20:06.519 numbers actually show? Let's start with the average 00:20:06.519 --> 00:20:09.720 differences. Friedman versus ellipse. OK, so 00:20:09.720 --> 00:20:12.339 the average glenoid version measured by the traditional 00:20:12.339 --> 00:20:15.880 Friedman method was maggots of 3 .11 degrees. 00:20:16.299 --> 00:20:18.400 That negative means retroversion tilted slightly 00:20:18.400 --> 00:20:22.759 back. OK, average Friedman minus 3 .11. The average 00:20:22.759 --> 00:20:24.819 measured by the ellipse method using observer 00:20:24.819 --> 00:20:28.420 1's data was minus the 1 .95 degrees retroversion. 00:20:28.779 --> 00:20:31.779 Minus 1 .95, so slightly less retroverted on 00:20:31.779 --> 00:20:34.299 average with the ellipse method. On average, 00:20:34.559 --> 00:20:37.349 yes. The mean difference between Ellipse and 00:20:37.349 --> 00:20:40.289 Friedman was 1 .16 degrees. And statistically, 00:20:40.869 --> 00:20:42.869 this difference was significant. The p -value 00:20:42.869 --> 00:20:47.190 was 0 .002. OK, 1 .16 degrees difference on average, 00:20:47.450 --> 00:20:50.549 and statistically significant. But you hinted 00:20:50.549 --> 00:20:52.609 earlier that the average isn't the full story, 00:20:52.789 --> 00:20:55.130 right? Not even close. This is exactly where 00:20:55.130 --> 00:20:57.710 it gets really interesting and why those bland 00:20:57.710 --> 00:21:01.289 Altman plots are so vital. That 1 .16 degree 00:21:01.289 --> 00:21:03.410 average difference. Honestly, it might sound 00:21:03.410 --> 00:21:05.450 pretty small. Maybe not clinically huge on its 00:21:05.450 --> 00:21:07.470 own. Yeah, you might think, okay, about a degree, 00:21:07.549 --> 00:21:10.269 maybe not a disaster. Right. But that average 00:21:10.269 --> 00:21:12.349 hides the spread. It tells you nothing about 00:21:12.349 --> 00:21:14.809 how much the methods might disagree for an individual 00:21:14.809 --> 00:21:16.869 patient. And that's where the blind Altman plot 00:21:16.869 --> 00:21:18.849 comes in, comparing Ellipse versus Friedman. 00:21:19.009 --> 00:21:21.319 Exactly. And the results there were... Well, 00:21:21.359 --> 00:21:23.859 quite startling, actually. The 95 % limits of 00:21:23.859 --> 00:21:26.619 agreement were huge. They ranged from minus 6 00:21:26.619 --> 00:21:30.539 .15 degrees all the way up to plus 8 .46 degrees. 00:21:30.900 --> 00:21:33.319 Oh, minus 6 to plus 8 .5. What does that mean, 00:21:33.440 --> 00:21:36.779 practically? It means. OK, let's say the ellipse 00:21:36.779 --> 00:21:39.599 method measures a patient's glenoid at exactly 00:21:39.599 --> 00:21:42.730 0 degrees version. The Bland -Altman plot tells 00:21:42.730 --> 00:21:45.410 us that for that same patient, the Friedman method 00:21:45.410 --> 00:21:48.549 could, 95 % of the time, report value anywhere 00:21:48.549 --> 00:21:52.849 between meganis 6 .15 degrees and plus 8 .46 00:21:52.849 --> 00:21:55.369 degrees. That's a potential range of almost 15 00:21:55.369 --> 00:21:57.549 degrees for the same shoulder, depending only 00:21:57.549 --> 00:22:00.589 on which method you used. Precisely. That represents, 00:22:01.049 --> 00:22:03.410 in the author's words, and by any clinical standard, 00:22:04.069 --> 00:22:07.140 poor... agreement. The two methods might be close 00:22:07.140 --> 00:22:09.319 on average, but for any given patient, they could 00:22:09.319 --> 00:22:11.559 give you wildly different numbers. And that could 00:22:11.559 --> 00:22:13.380 lead to totally different surgical decisions 00:22:13.380 --> 00:22:15.480 for the same person. Absolutely. And remember 00:22:15.480 --> 00:22:17.700 that five degree threshold for clinical significance. 00:22:17.859 --> 00:22:20.440 Yeah. The study found that in 16 % of the patients, 00:22:20.819 --> 00:22:23.500 16 out of 100, the difference between the ellipse 00:22:23.500 --> 00:22:25.059 measurement and the Friedman measurement was 00:22:25.059 --> 00:22:28.779 more than five degrees. 16%. Nearly one in five 00:22:28.779 --> 00:22:30.960 patients had a clinically significant difference 00:22:30.960 --> 00:22:33.740 depending on the method used. Yes. For almost 00:22:33.740 --> 00:22:36.160 a fifth of these patients, the choice of measurement 00:22:36.160 --> 00:22:38.099 method could have directly led to a different 00:22:38.099 --> 00:22:40.720 surgical plan, potentially impacting their outcome. 00:22:41.240 --> 00:22:43.500 It really drives home how much finding a consistent 00:22:43.500 --> 00:22:46.339 method matters. Wow. Okay, so poor agreement 00:22:46.339 --> 00:22:48.759 between the methods, but how did the ellipse 00:22:48.759 --> 00:22:50.519 method perform on its own? You mentioned they 00:22:50.519 --> 00:22:53.819 tested its internal consistency. Ah, now that's 00:22:53.819 --> 00:22:56.779 where the story flips. In stark contrast to the 00:22:56.779 --> 00:22:58.720 poor agreement with Friedman, the ellipse method 00:22:58.720 --> 00:23:01.380 showed excellent reliability and reproducibility, 00:23:01.799 --> 00:23:04.319 both between observers and within the same observer. 00:23:04.440 --> 00:23:06.119 Okay, let's break that down. First, between the 00:23:06.119 --> 00:23:08.519 two observers, interrater reliability. Right. 00:23:08.920 --> 00:23:11.400 Comparing observer 1 and observer 2, using the 00:23:11.400 --> 00:23:13.420 ellipse method, the mean difference between them 00:23:13.420 --> 00:23:18.140 was tiny. It's just... 0 .063 degrees, not statistically 00:23:18.140 --> 00:23:20.160 significant at all. Basically, they got the same 00:23:20.160 --> 00:23:22.880 average result. Good start. And the bland Altman 00:23:22.880 --> 00:23:25.299 limits for ellipse between observers? Were they 00:23:25.299 --> 00:23:28.980 wide, like before? Remarkably narrow. The 95 00:23:28.980 --> 00:23:32.400 % limits of agreement were only 1 .98 to plus 00:23:32.400 --> 00:23:36.640 2 .0 degrees. Minus 2 to plus 2. So 95 % of the 00:23:36.640 --> 00:23:40.059 time, two different surgeons using the ellipse 00:23:40.059 --> 00:23:42.890 method would get a result within about two degrees 00:23:42.890 --> 00:23:44.589 of each other for the same patient. Exactly. 00:23:44.710 --> 00:23:46.849 That's excellent agreement. Much, much better 00:23:46.849 --> 00:23:49.690 than the nearly 15 degree range we saw when comparing 00:23:49.690 --> 00:23:52.210 with Friedman. Okay. And the ICC value for that? 00:23:52.529 --> 00:23:54.829 The interclass correlation coefficient for iterator 00:23:54.829 --> 00:23:59.410 agreement was 0 .993. 0 .993. That's way above 00:23:59.410 --> 00:24:02.069 the 0 .90 threshold for excellent. Absolutely. 00:24:02.470 --> 00:24:04.529 It indicates excellent reproducibility between 00:24:04.529 --> 00:24:06.690 different users. Fantastic. Okay, now what about 00:24:06.690 --> 00:24:09.569 iterator? The same observer measuring twice a 00:24:09.569 --> 00:24:11.839 month apart. Even better, actually. Observer 00:24:11.839 --> 00:24:14.380 1, measuring the same scans twice with the ellipse 00:24:14.380 --> 00:24:16.759 method. The mean difference was minuscule. 9 00:24:16.759 --> 00:24:19.799 is 0 .8 or 41 degrees. Again, not statistically 00:24:19.799 --> 00:24:21.839 significant. Almost zero difference on average. 00:24:22.000 --> 00:24:24.480 Pretty much. And then 95 % limits of agreement. 00:24:24.640 --> 00:24:27.720 Even tighter. From 9 is .98 degrees to plus .90 00:24:27.720 --> 00:24:31.180 degrees. Less than one degree variation 95 % 00:24:31.180 --> 00:24:33.359 of the time if the same person measures again. 00:24:33.599 --> 00:24:35.500 Incredible, isn't it? That's superb precision. 00:24:36.000 --> 00:24:38.160 And the repeatability coefficient confirmed this. 00:24:38.319 --> 00:24:42.559 It was 0 .94 degrees, meaning 95 % of repeated 00:24:42.559 --> 00:24:45.019 measurements by the same person will differ by 00:24:45.019 --> 00:24:48.400 less than one degree. Wow. And the ICC for IntraRater? 00:24:48.779 --> 00:24:51.559 Almost perfect. 0 .999. OK, so to summarize, 00:24:52.000 --> 00:24:55.170 ellipse versus Friedman. Poor agreement, potentially 00:24:55.170 --> 00:24:57.549 large clinically significant differences, but 00:24:57.549 --> 00:24:59.529 ellipse versus ellipse, whether between users 00:24:59.529 --> 00:25:02.910 or by the same user over time. Excellent agreement, 00:25:03.109 --> 00:25:05.690 highly reproducible, very precise. That's the 00:25:05.690 --> 00:25:08.069 core finding in a nutshell. The ellipse method 00:25:08.069 --> 00:25:10.230 demonstrated a level of reliability that the 00:25:10.230 --> 00:25:12.269 traditional Friedman method simply couldn't match 00:25:12.269 --> 00:25:14.490 in this study. So this really raises the question, 00:25:14.529 --> 00:25:17.809 doesn't it? What could this level of proven precision 00:25:17.809 --> 00:25:20.869 mean for actual shoulder surgery moving forward? 00:25:21.049 --> 00:25:23.970 It suggests we now have a tool, a method, that 00:25:23.970 --> 00:25:26.289 can provide a much more trustworthy and consistent 00:25:26.289 --> 00:25:28.789 number for that critical glenoid version angle. 00:25:29.210 --> 00:25:31.430 You can standardize planning, reduce variability 00:25:31.430 --> 00:25:34.049 between surgeons, and give everyone more confidence 00:25:34.049 --> 00:25:36.670 in that initial assessment. And that confidence 00:25:36.670 --> 00:25:39.869 should, hopefully, translate into better surgical 00:25:39.869 --> 00:25:42.569 execution and, ultimately, better patient outcomes. 00:25:43.039 --> 00:25:45.619 Okay, let's zoom out a bit. Let's talk broader 00:25:45.619 --> 00:25:48.599 context and really hammer home the so what of 00:25:48.599 --> 00:25:51.339 all this The main message from the paper then 00:25:51.339 --> 00:25:54.400 isn't just here's a new method It's that the 00:25:54.400 --> 00:25:57.180 real breakthrough is having a reliable way to 00:25:57.180 --> 00:25:59.839 find that mid glenoid level, right? That's what 00:25:59.839 --> 00:26:02.460 the authors including professor Imam in his writing 00:26:02.460 --> 00:26:05.640 really emphasize They call consistently defining 00:26:05.640 --> 00:26:08.279 that mid glenoid level the most important step 00:26:08.279 --> 00:26:10.819 for getting accurate 2d CT measurements of version 00:26:10.819 --> 00:26:13.579 and it's so important because Other ways of trying 00:26:13.579 --> 00:26:15.359 to find it, like just counting slices down from 00:26:15.359 --> 00:26:16.920 the top or something. Yeah. They just weren't 00:26:16.920 --> 00:26:19.220 reliable enough. Exactly. The paper cites another 00:26:19.220 --> 00:26:22.319 study, Vandebunt et al., from 2015, that tried 00:26:22.319 --> 00:26:25.440 a slice counting method. Their ICC for reliability, 00:26:25.779 --> 00:26:31.059 only .70. .70 versus the ellipse method's .993 00:26:31.059 --> 00:26:34.380 between observers. That's a night and day difference 00:26:34.380 --> 00:26:37.720 in reliability. It really is. It shows the ellipse 00:26:37.720 --> 00:26:40.779 method isn't just a small tweak. It's a significant 00:26:40.779 --> 00:26:44.269 leap in consistency. It takes the ambiguity out 00:26:44.269 --> 00:26:46.589 of where you measure, ensuring everyone's looking 00:26:46.589 --> 00:26:49.130 at the same anatomically relevant spot. Right. 00:26:49.269 --> 00:26:51.190 Getting everyone on the same page measurement 00:26:51.190 --> 00:26:53.769 -wise. And this touches on something else. The 00:26:53.769 --> 00:26:55.650 paper highlights the importance of using the 00:26:55.650 --> 00:26:58.349 right statistical tools and using them together. 00:26:58.509 --> 00:27:01.910 The Bland -Altman plots and the ICCs. Yes. Professor 00:27:01.910 --> 00:27:03.990 Imam and his co -authors stress this point in 00:27:03.990 --> 00:27:06.289 the manuscript. The Bland -Altman shows you the 00:27:06.289 --> 00:27:08.509 side of the differences, the practical agreement. 00:27:08.890 --> 00:27:11.509 The ICC gives you that overall reliability number. 00:27:11.660 --> 00:27:14.380 Using both gives you a much better picture of 00:27:14.380 --> 00:27:17.000 the true reliability. So you see not just if 00:27:17.000 --> 00:27:19.099 they're correlated, but how well they actually 00:27:19.099 --> 00:27:21.859 agree within limits that matter clinically. Precisely. 00:27:22.220 --> 00:27:24.680 It's about robust science. Not just finding a 00:27:24.680 --> 00:27:26.980 difference, but understanding its magnitude and 00:27:26.980 --> 00:27:29.720 consistency. That kind of methodological rigor 00:27:29.720 --> 00:27:32.380 is just as important as the clinical idea itself. 00:27:33.000 --> 00:27:35.380 Absolutely. And you mentioned this study's reliability 00:27:35.380 --> 00:27:37.599 for the ellipse method was better than what other 00:27:37.599 --> 00:27:39.599 studies found when comparing Friedman to other 00:27:39.599 --> 00:27:42.759 methods like Randellis or the vault method. That's 00:27:42.759 --> 00:27:45.680 right. Comparing the ICCs reported here for the 00:27:45.680 --> 00:27:49.039 ellipse method, those high 0 .99 values, with 00:27:49.039 --> 00:27:52.420 ICCs reported in studies by Rouleau et al. comparing 00:27:52.420 --> 00:27:54.980 Friedman and Randalli, or Mezzimora at all, comparing 00:27:54.980 --> 00:27:57.519 Friedman and Valt, the ellipse method demonstrated 00:27:57.519 --> 00:28:00.339 superior consistency in this particular investigation. 00:28:00.880 --> 00:28:03.900 It really seems to set a new benchmark for 2D 00:28:03.900 --> 00:28:06.640 measurement liability. OK. But what about 3D? 00:28:06.880 --> 00:28:09.500 We hear a lot about 3D planning and surgery now. 00:28:10.299 --> 00:28:13.000 Does this 2D ellipse method still matter in the 00:28:13.000 --> 00:28:15.289 age of 3D? That's a really important question. 00:28:15.650 --> 00:28:17.609 And the paper acknowledges 3D reconstruction. 00:28:17.809 --> 00:28:19.950 For really complex cases, severe deformities, 00:28:20.170 --> 00:28:21.990 3D planning is often seen as the benchmark. It 00:28:21.990 --> 00:28:24.809 gives you that full volumetric picture. But it 00:28:24.809 --> 00:28:27.789 has limitations for routine, everyday use right 00:28:27.789 --> 00:28:29.970 now. It's generally expensive, needs special 00:28:29.970 --> 00:28:32.869 software, powerful computers. It requires significant 00:28:32.869 --> 00:28:35.630 training and expertise to use properly. OK. Cost 00:28:35.630 --> 00:28:38.710 and training hurdles. And even with 3D, there's 00:28:38.710 --> 00:28:41.660 still user variability. The surgeon still has 00:28:41.660 --> 00:28:44.140 to define reference points and axes on the 3D 00:28:44.140 --> 00:28:47.279 model, which can introduce inconsistencies. Ah, 00:28:47.500 --> 00:28:49.960 so 3D isn't automatically perfect either. Not 00:28:49.960 --> 00:28:52.799 necessarily. And maybe the biggest point is the 00:28:52.799 --> 00:28:55.859 direct link between using 3D planning and actually 00:28:55.859 --> 00:28:58.119 achieving better long -term clinical outcomes 00:28:58.119 --> 00:29:00.880 for patients, like lower revision rates, better 00:29:00.880 --> 00:29:03.940 function scores, years later that link. still 00:29:03.940 --> 00:29:06.619 needs more robust, independent proof across the 00:29:06.619 --> 00:29:08.859 board. So the jury's still out on whether 3D 00:29:08.859 --> 00:29:11.119 consistently leads to better results yet? The 00:29:11.119 --> 00:29:13.240 evidence is still building. And until we have 00:29:13.240 --> 00:29:15.779 that definitive proof, and maybe until 3D becomes 00:29:15.779 --> 00:29:18.400 more accessible and standardized, having a really 00:29:18.400 --> 00:29:21.119 accurate, reliable 2D measurement, a precise 00:29:21.119 --> 00:29:23.220 numerical angle remains incredibly important. 00:29:23.420 --> 00:29:26.220 Why? Why keep focusing on the 2D number? For 00:29:26.220 --> 00:29:28.839 clear communication between surgeons. For comparing 00:29:28.839 --> 00:29:31.359 results in research studies effectively. for 00:29:31.359 --> 00:29:34.140 tracking outcomes over time. You need that consistent, 00:29:34.480 --> 00:29:36.859 quantifiable angle. And that's exactly what the 00:29:36.859 --> 00:29:39.519 highly reliable ellipse method provides. It fills 00:29:39.519 --> 00:29:42.420 a crucial need, even as 3D evolves. Okay, that 00:29:42.420 --> 00:29:45.339 makes sense. So, let's boil it down. What's the 00:29:45.339 --> 00:29:48.519 absolute core take -home message from Professor 00:29:48.519 --> 00:29:51.460 Imam and the other authors of this paper? They 00:29:51.460 --> 00:29:55.309 really drive home three key points. One... Getting 00:29:55.309 --> 00:29:57.289 that preoperative glenoid version measurement 00:29:57.289 --> 00:30:00.230 right is absolutely crucial for planning and 00:30:00.230 --> 00:30:03.250 executing a successful TSA. It's foundational. 00:30:03.650 --> 00:30:06.529 Non -negotiable first step. Two, if you have 00:30:06.529 --> 00:30:08.829 a good quality CT scan that includes the whole 00:30:08.829 --> 00:30:12.190 scapula and is properly reformatted in the scapular 00:30:12.190 --> 00:30:15.210 plane, the ellipse method is a highly reproducible 00:30:15.210 --> 00:30:18.029 and reliable way to find the true mid -glenoid 00:30:18.029 --> 00:30:20.970 level. That's its unique strength. Reliable identification 00:30:20.970 --> 00:30:23.630 of the mid -glenoid. And three, Measuring version 00:30:23.630 --> 00:30:26.450 at that specific mid -glenoid level refines the 00:30:26.450 --> 00:30:28.609 old Friedman method. It gives you an accurate 00:30:28.609 --> 00:30:30.890 2D angle measurement, plus it crucially shows 00:30:30.890 --> 00:30:33.369 the surgeon the ideal spot for that central guide 00:30:33.369 --> 00:30:35.410 wire during surgery. It offers that valuable 00:30:35.410 --> 00:30:37.990 intraoperative corroboration. So better planning 00:30:37.990 --> 00:30:40.190 and more confidence during the actual operation. 00:30:40.390 --> 00:30:42.250 That's the promise. Precision translating into 00:30:42.250 --> 00:30:44.849 practice. Now good science always acknowledges 00:30:44.849 --> 00:30:47.410 its limits, and this study is no exception. The 00:30:47.410 --> 00:30:49.589 authors are upfront about the limitations. OK, 00:30:49.750 --> 00:30:51.450 what are the main ones we should keep in mind? 00:30:51.789 --> 00:30:54.930 Well, first and foremost, this all hinges on 00:30:54.930 --> 00:30:58.589 having that CT scan correctly oriented and reformatted 00:30:58.589 --> 00:31:00.750 in the scapular plane to begin with. Right, the 00:31:00.750 --> 00:31:03.289 foundational step we talked about. Exactly. If 00:31:03.289 --> 00:31:06.349 that basic requirement isn't met, if the initial 00:31:06.349 --> 00:31:09.630 imaging isn't done right, then even the ellipse 00:31:09.630 --> 00:31:11.730 method will give you an erroneous measurement. 00:31:12.410 --> 00:31:15.210 It's not magic. It relies on good data in. So 00:31:15.210 --> 00:31:17.710 the quality of the initial scan is paramount. 00:31:17.819 --> 00:31:20.480 That could be a practical hurdle for widespread 00:31:20.480 --> 00:31:23.039 use if imaging protocols aren't standardized 00:31:23.039 --> 00:31:26.000 everywhere. It certainly could be. It highlights 00:31:26.000 --> 00:31:28.640 the need for consistent, high -quality imaging 00:31:28.640 --> 00:31:30.539 standards if we want to leverage methods like 00:31:30.539 --> 00:31:33.359 this effectively across different hospitals and 00:31:33.359 --> 00:31:35.920 clinics. Okay. What else? The study was retrospective. 00:31:35.960 --> 00:31:38.039 They looked back at past data. Right. So they 00:31:38.039 --> 00:31:40.359 couldn't directly compare patient outcomes. Correct. 00:31:40.509 --> 00:31:42.210 Because they were looking at scans that had already 00:31:42.210 --> 00:31:44.430 been done, they couldn't say, OK, group A was 00:31:44.430 --> 00:31:46.569 planned with ellipse, group B with Friedman, 00:31:46.589 --> 00:31:48.789 and group A had fewer revisions five years later. 00:31:49.250 --> 00:31:51.609 They could only assess the reliability of the 00:31:51.609 --> 00:31:53.890 measurements themselves. But they do argue that 00:31:53.890 --> 00:31:56.390 better planning generally leads to better outcomes, 00:31:56.390 --> 00:31:59.710 right? Yes. There's a strong consensus in orthopedics 00:31:59.710 --> 00:32:02.910 that accurate planning improves results. But 00:32:02.910 --> 00:32:05.349 to directly prove that the ellipse method causes 00:32:05.349 --> 00:32:08.430 better long -term outcomes would require a future 00:32:08.430 --> 00:32:10.980 prospective study. Following patients forward 00:32:10.980 --> 00:32:13.900 in time. Exactly. Comparing groups planned with 00:32:13.900 --> 00:32:15.559 different methods and tracking their function, 00:32:16.140 --> 00:32:18.740 pain scores, implant survival rates over several 00:32:18.740 --> 00:32:21.380 years. That's the next logical step in research. 00:32:21.680 --> 00:32:24.660 Got it. Any other limitations or maybe strengths 00:32:24.660 --> 00:32:27.319 to balance those? A key strength was that they 00:32:27.319 --> 00:32:30.019 used consecutive CT scans. They didn't cherry 00:32:30.019 --> 00:32:32.700 pick easy or hard cases. They took the scans 00:32:32.700 --> 00:32:35.539 as they came. representing the real mix of patients' 00:32:35.779 --> 00:32:38.539 assurgencies. That makes the findings on measurement 00:32:38.539 --> 00:32:41.539 reliability much more generalizable. So it reflects 00:32:41.539 --> 00:32:44.420 real -world practice better. Yes. And they also 00:32:44.420 --> 00:32:46.660 noted that the ellipse method seemed usable even 00:32:46.660 --> 00:32:48.819 when the glenoid was significantly deformed, 00:32:49.140 --> 00:32:51.619 which adds to its potential versatility. Okay. 00:32:52.000 --> 00:32:55.109 So, thinking about all this... What does it mean 00:32:55.109 --> 00:32:57.970 for you, the listener, looking ahead? We've seen 00:32:57.970 --> 00:33:00.990 how this, well, quite elegant refinement in measurement, 00:33:01.430 --> 00:33:03.849 driven by clinical need and rigorous research 00:33:03.849 --> 00:33:06.690 involving experts like Professor Imam, can boost 00:33:06.690 --> 00:33:09.650 precision. Where does that lead? Well, you start 00:33:09.650 --> 00:33:11.329 to think about the knock -on effects, don't you? 00:33:11.430 --> 00:33:14.190 Like how it might change training. Could this 00:33:14.190 --> 00:33:16.430 become the standard way orthopedic residents 00:33:16.430 --> 00:33:19.430 are taught to assess glenoid version, making 00:33:19.430 --> 00:33:22.049 this level of precision just standard practice 00:33:22.049 --> 00:33:24.069 from day one? It certainly could influence curriculum 00:33:24.069 --> 00:33:26.710 development, yeah. Standardizing the approach. 00:33:26.930 --> 00:33:29.450 Then what about technology? Could this method 00:33:29.450 --> 00:33:32.309 be built into surgical planning software? Maybe 00:33:32.309 --> 00:33:34.730 even automated with AI to measure a version super 00:33:34.730 --> 00:33:37.150 consistently, taking human variability out even 00:33:37.150 --> 00:33:39.730 further? That's a definite possibility. Integrating 00:33:39.730 --> 00:33:42.130 validated, reliable methods into software is 00:33:42.130 --> 00:33:45.529 a clear pathway for innovation, reducing potential 00:33:45.529 --> 00:33:48.730 for error. And the big picture. If this leads 00:33:48.730 --> 00:33:51.410 to more accurate surgery, fewer implants failing 00:33:51.410 --> 00:33:53.650 early, what about the savings for health care 00:33:53.650 --> 00:33:55.869 systems, fewer expensive revision surgeries? 00:33:56.210 --> 00:33:58.430 That's a potential long -term benefit. Absolutely. 00:33:58.829 --> 00:34:01.450 Better outcomes often mean lower overall costs 00:34:01.450 --> 00:34:03.990 down the line. So it leaves you wondering, doesn't 00:34:03.990 --> 00:34:06.029 it? What's the next piece of research you'd want 00:34:06.029 --> 00:34:09.800 to see? Is it that direct link to patient outcomes? 00:34:10.099 --> 00:34:13.079 Studies quantifying fewer revisions, faster recovery, 00:34:13.639 --> 00:34:15.780 better long -term comfort, specifically because 00:34:15.780 --> 00:34:18.079 the ellipse method was used. Those outcome studies 00:34:18.079 --> 00:34:20.739 are definitely key. Connecting the improved measurement 00:34:20.739 --> 00:34:23.719 directly to improve patient lives is the ultimate 00:34:23.719 --> 00:34:26.340 goal. It really shows how this constant push 00:34:26.340 --> 00:34:28.639 for precision, even in something as specific 00:34:28.639 --> 00:34:31.099 as measuring an angle, is what drives medicine 00:34:31.099 --> 00:34:34.260 forward, aiming for that perfect outcome one 00:34:34.260 --> 00:34:36.539 step at a time. Well, that was a truly deep dive, 00:34:36.559 --> 00:34:38.860 wasn't it, into orthopedic precision, medical 00:34:38.860 --> 00:34:42.039 innovation, how research like the paper co -authored 00:34:42.039 --> 00:34:44.699 and articulated by Professor Mo Imam can take 00:34:44.699 --> 00:34:46.679 an existing method and just refine it, make it 00:34:46.679 --> 00:34:49.099 so much more reliable, potentially leading to 00:34:49.099 --> 00:34:50.719 really significant improvements for patients. 00:34:50.960 --> 00:34:52.980 Yeah, we went from understanding why glenoid 00:34:52.980 --> 00:34:55.159 loosening is such a critical issue in shoulder 00:34:55.159 --> 00:34:57.619 replacements through the problems with older 00:34:57.619 --> 00:35:00.579 measurement methods, right, to this elegant ellipse 00:35:00.579 --> 00:35:02.619 solution and what it could mean for accuracy. 00:35:02.800 --> 00:35:06.000 It's a fantastic example of how focusing on precision, 00:35:06.219 --> 00:35:08.960 even on what seems like a small detail, can have 00:35:08.960 --> 00:35:12.539 these huge downstream effects in medicine. Absolutely. 00:35:12.840 --> 00:35:15.019 That relentless pursuit of getting it right, 00:35:15.079 --> 00:35:16.960 of building a better foundation through accurate 00:35:16.960 --> 00:35:19.780 measurement, that's how patient care truly advances. 00:35:20.280 --> 00:35:22.400 one reliable step at a time. We hope you found 00:35:22.400 --> 00:35:24.639 that insightful. Join us next time for another 00:35:24.639 --> 00:35:26.800 deep dive, where we'll unpack more sources and 00:35:26.800 --> 00:35:29.059 extract those crucial insights for you. Until 00:35:29.059 --> 00:35:31.219 then, stay curious, stay informed.