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Shoulder Instability for Orthopaedic Exams
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Shoulder Instability for Orthopaedic Exams
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Segment:0 .
Good evening, everyone. And welcome to our teaching session, which is this evening is on shoulder instability. And it's a combined session with our truck. My name is Nicky Evans and I'll be co-hosting with Ruth treadgold, who's the head of education at Aiyuk.
This evening, we are privileged to welcome Professor Duncan Tennant, who is a consultant, orthopedic surgeon at St George's hospital, and he's been there since 2003. In addition, he's Professor of orthopedic education at St George's University of London and director of education at South West London elective orthopedic center. In addition, he's an immediate past treasurer of best and simulation league for the boa, as well as being a beer on the BOA council and an examiner for the Fox trauma and orthopedic exam.
We also have Hannah with us this evening who is with our UK, and I'd like to welcome the other mentors Mr. David Hughes, Mr. Harney and Mr. Mohammed Imran. So this evening, we're going to start with the presentation and after the presentation, we'll have time for some questions and an mq poll for you to complete. I'd ask you to write any questions in the chat box and we will monitor this and ask Professor tenant at the end of his lecture.
If you missed any part of this lecture, please don't panic. It is recorded and it will be available on the Fox mentor YouTube channel and the UK website in due course. After the questions, we'll stop recording the session and we'll proceed to the vyver practice again. If you'd like to participate. We request that you raise your hand or identify yourself to us in the chat box, along with when you're sitting the part two exam.
We understand that putting yourself forward for these IVUS can be intimidating, but it's really the best way for you to practice, and we can rest assured that we have all been in a similar position. So without further ado, I will pass you over to Mr. Tennant for the lecture. Thank you for. Thank you.
I'll just get. Share my screen. Right well, if we go, so thank you for the introduction. My name is Duncan Tennant. As you've heard, I'm a orthopedic surgeon and special interest in shoulder and elbow and a Professor of orthopedic education at St Georges. So I've been asked to talk to you about shoulder and stability for the exam.
And I am aware that. A lot of people won't necessarily have done a shoulder firm or a specialist shoulder firm. And some of the stuff in the textbooks is not great, so what I'm going to do is go back to the basics because if you got the basics right, then everything else sort of follows on. So for those of you who do know a bit about shoulders, I'm sorry, some of this is going to be a little bit obvious, but then we'll build it up from there.
So you've got to get understanding. Rest of it should be pretty simple. So I've got to thank Anthony Herndon, who was one of my registrars many, many years ago. All the nice graphics you'll see are the shoulder of his and my colleague Jimmy pierce, who's I've bounced these ideas off over many, many years. So we're going to look at a little bit about classification.
Look about the anatomy and how you examine a little bit of investigations and then we'll get onto that the meat of it, which is how you manage them. Partly the management in the fracture clinic. What do you do with the patient in the fracture clinic, day to day stuff and then a little bit more about the surgical management, which is more what comes up in the exam? So off we go.
As you know, all the textbooks the glenohumeral joint is inherently unstable, and you have to know about the static stabilizers, so the bone cartilage labrum. The fact that there's a negative pressure, there are ligaments and as you'll see in a little bit, the dynamic stabilizes so the muscles in the brain. Now I'm not going to label this, you're going to go look that up in the book.
There's nothing very special there, but you need all of that stuff to make the shoulder stable. So if we look at classification, you can classify them in all sorts of different ways, and this is where people get really muddled. So just break it down, put it on the time front, you can have acute dislocation. They're the ones in any recurrent instability and chronic dislocations.
Now we're not going to pay any attention to the chronic ones. We're going to look at really, we're going to focus on recurrent instability. You can look at the mechanism, this is how you the Andrew Tubbs type one, type two, type III thing. And the direction you tore my anterior posterior, inferior or multidirectional. Now just clear that one up. This gets really muddled in the literature, particularly if you read the American stuff, because in the UK we recognize.
If I show you an X-ray and you'll see one later on of a dislocated shoulder, we call that an anterior dislocation. Now a lot of the Americans got very confused because they said an anterior came straight out, inferior went inferior. And so the sort of things that we see that come out at about 5 o'clock must be an intra inferior and therefore that's multidirectional.
And they got themselves in such a mess. Basically, multidirectional means it will come out the front and it will come out at the back. We're now really going to dwell too much on that. So let's look a little bit at the normal shoulder and the way the normal shoulder works and stay stable. So it has the bony anatomy labrum capsule and some muscles, and as you move, the stretch receptors send a signal to the brain saying shoulders moving, the labrum stressed the brain sends a message back.
The muscles contract and everything comes back into the normal state. And the stretch receptors in the capsule that there are both basically both ends of the capsule and they're really important to the stability. So if we now look at the unstable shoulder. And it gets very confused here. Will you've all heard of almondbury and tubbs? Yeah, now I'm going to tell you, talk is a spectrum, and anne-marie stands for a traumatic multidirectional bilateral.
The treatment is rehabilitation, and if that doesn't work, you can do a thing called an inferior capsule, a shift. And then there's according to a literature of this spectrum to tub's, which is traumatic, unidirectional with a Bankart lesion and the solution is surgery. And that's what everybody gets taught. That's in all the textbooks. The problem is that definition doesn't give you a spectrum. It gives you two fixed points, so your patients either become one or the other.
And what it tells you is, if in doubt, you can't see a Bankart lesion, you get to operate anyway. And this is caused all sorts of problems over the years. So we back in the distant past of 2004. In Bailey. Published his life's work, this is years and years in the making. The Stambaugh triangle, which is now most of you hopefully will have heard of.
And as a triangle, it's got three points. It's got the type I to the rugby players that we think about. It's got the type to which are the gymnast, the swimmers, the very bendy people. And it's got the tight threes, which were the voluntary dislocations, the habitual dislocated, and that's been changed slightly. So we've got type 1 traumatic structural and we'll talk about that type two, which are the eight traumatic, structural and type three, very importantly, are muscle patterning, and they are non-structural, which means there's nothing structurally wrong in their.
So let's have a look at it. Let's concentrate on the tiny ones. So here we go. Shoulder starts to move, labrum fails you dislocate and get a hill sacks, so off it goes flavor and fails. You keep going and you dislocate. And you're all very familiar with this, and this is what I was talking about the anterior or the answer, inferior dislocation.
So hopefully nothing new there. Now you've got a hill Sachs, you've got a bankrupt lesion, so off you go. You start to move. There's no stretch receptors now telling the brain to do anything. So you don't, then have the reflexes to bring the shoulder back, it keeps going. It's lost its.
Static constraints, it's now lost its dynamic constraints, and you can't. So that is a fairly typical type one, very common 95% instability. We look at the titans, so these are a traumatic structural. What we mean there is that these people are loose, they collagen is loose and they can be all the way from the ehlers-danlos, just people who are a bit bendy and therefore the shoulder slides around all over the place.
And he has a feeling of instability, and it may go far enough to dislocate. And then we looked at the type III. Now these you need to get your head around a bit and you need to understand them, they're not as common, they make up about 5% But if you miss them, you're in real trouble. So what do we mean?
So when we talk about the shoulder, this is sort of what everyone envisages. You've got the scapula and it's nice and firm. And it's solid. In reality, it's not that it's that the jelly. So here we go. It's a bit of anatomy. There's the shoulder. Some ribs.
Put some muscles on rhomboids threats as the clavicle. And major, and there's a few others in there as well that you could probably name. So what happens when the shoulder moves is everything's got to go in concerts as the wrong boys and everything contracts at the back. Pet has to relax to go with it and vice versa when the shoulder gets pulled forward.
Everything at the back has to relax. Everything has to work in concert. In the muscle patterning types, what happens? Is that the pet? Stop doesn't relax or it contracts excessively, and it will pull the shoulder out of the joint. There are other patterns which are subscapularis or all that side dominant, and they'll do other things, but major is the main one.
Some peck contracts, it pulls the shoulder out of the joint. And what is peculiar about these people is that they can fully dislocate. They can do it many, many times, and they will not have any damage. There is. It is nonstructural now. They may want to do it. And it typically starts in adolescence, so they may start as the party trick as a teenager because they go, look at me, I can dislocate my shoulder and all the girls go, ooh, that's gross, do it again.
Perfect reinforcement for 14-year-old boy. After a while, they get a bit fed up with this. It's no longer cool, it's just annoying, and they want to stop, but they can't stop. And then there's another population who never wanted to start it in the first place. But it happens. So these are the muscle patterns, and if you scope them, there's nothing to see.
OK, so here we go, we've now got the three polls and you'll notice I've taken the picture of Marty Feldman away and I put in a picture of the muscles. And we know is that you're not fixed in any one corner. You can actually move around between them, so you may well be hyper mobile, but if you fall off your bicycle, you can get a label tag. And vice versa, and in all of these, you can become muscle patterning after a while, you start to learn funny tricks to keep the shoulder in so you can have a bit of a blend of all of these.
So it's important in the history to try and work out what came first. Was it the fall off the bicycle or do they actually have a problem preceding it all? OK why is this important? Well what we know, surgeons can only operate on abnormal anatomy. All right. That means you've got to take away all of those ones in the corner, the type 3s, because they haven't got abnormal anatomy.
And if you want to destroy a shoulder, operate on a type III. You'll tighten it up and your record. So if you're a tight one, we can fix the labrum. We know how to do that. If you're tied to your baggy. And we can do a shift now we know that if you've got really rubbish college and that's going to fail eventually, but we might give you the proprioception and we can talk about that later if you want.
So what do you do with the time threes? It's really simple physiotherapy, but you need to give them the right physio. It's not rubber band and cuff strengthening exercises. It's brain training, so you've got to recognize it so that you can say to the physio, this is what you need to do. OK so let's talk a little bit about clinical assessment there, we get bogged down in this and there are a number of things you can do.
Obviously, you're going to look at the cervical spine because you always do that. You look at the range of motion. Normal versus the mobile shoulder. And sometimes you'll find these people that they don't want to get all the way up to the end range because it feels unstable. Look at the scapulothoracic rhythm. And it's not something you can just read out of a book, you need the experience on it, but you can look at the scapula.
Does it look like the other side or is it doing some weird ass shape thing? Um, and then you get on to the hands on thing. And it's important to know what the difference between laxity and instability are. So laxity is things like the sulcus sign and the app drawer. OK they are evidence that the joint is a little bit loose. However, that can be normal. Instability is a subjective feeling that the shoulder is going to come out of the joint that may or may not be associated with laxity.
So you can be wonderfully lax. No issues. All right. Remember that app drawer and the self-test sign are not signs of instability. So for those of you who don't know, this is the sort of sign you pull out, you pull down on the arm and you see the dip under the acronym. The app drawer, you glide anterior and posterior.
And it may well be positive. It may well be negative, sorry in a lot of people with instability because their muscles will tighten up. They don't like the feeling. And if they're big guys, I can't do it. I cannot make the shoulder move. Now, in terms of tests, there's really only two you need to know. And that's pretty one in the whole of the shoulder.
The apprehension test where you put your thumb in the back of the humeral head. You cut the arm up into abduction, external rotation, and you pull back on the wrist to basically try to dislocate the shoulder by cranking it up, push forward with the thumb. The patient will tell you to stop. All you'll see them contract or twitch, and they will go, stop doing that, please, I don't like it.
And if you say, does that reproduce your symptoms, if they say yes, you've got your diagnosis of all the tests in the shoulder, it's the only one that's actually anywhere near accurate. It's about 90% sensitive and specific. Sometimes it's not very convincing. So you do this marvelous thing, the relocation test. So what you do is allow the patient supine and you crank the arm back in the same way.
But you push on the humeral head at the same time, so you're stopping it from dislocating and then you take your hand off. And usually the facial expression changes very rapidly and they pull the arm in. That's Jones relocation test. Don't do it very often, but it's actually if you're not sure about your apprehensions, let's do this one and that'll make the diagnosis for you.
You then move on to investigations. Does the usual suspects and we'll just go through. So X-rays. There are lots and lots of different X-ray views. You can take the AP pretty standard. The axilo view is certainly very useful, albeit all the lateral view to see to things in joint. And then there are all sorts of funny things. The Burbio view, which you have to get them to put the hand on the head and then point the elbow at the ceiling.
Now, if you've got an unstable shoulder, doesn't work very well. And if you want to look for a hill Sachs, you can do this West Point or strike and not views. To be honest, we find in most departments they don't know how to do these things. You're lucky to get an AP and as you can see on that X-ray there, yeah, there's a flake of bone. Now, I can't tell you whether that's a significant chunk or insignificant.
So I've given up trying to do fancy x-rays because you can get other things. Let me act so CTs. Whether you do them 2D or 3D reconstructions, they're really good for bone loss. The problem with doing things like the picture on the is you need an interested radiologist because they have to digitally remove the humeral head, which is a bit of an effort.
And there are lots of different ways you can measure it. We'll talk about that in a little bit, but they're very good for measuring bone loss. Katharine Graham, very popular in France. Again, it will pick up labor pathology. But it's less good for bone loss, because then when you're trying to subtract the humeral head and do things, the contrast gets in the way. So my colleague quite likes them.
I, I find them a bit of a pain. And they're invasive. MRI, it's great for soft tissue. Um, my indication for an MRI is if I'm not sure about the history, I think something else might be going on or they come to me and I've never got any proof. They say I had 20 dislocations. Never been to any. Never had an X-ray.
I've got no evidence they've ever dislocated, so I'll get an MRI in those situations, but it's good for latent pathology. But unless you've got a super duper high powered MRI, they're not very good for bone loss. I wouldn't count on measuring my bone loss using them. And then the mirror, it's good again for those very subtle lesions, the people who've never had a dislocation, but they feel unstable.
I'm not going to talk about slap lesions today, but if you think you've got a slap lesion. The better for that. And if you've got previous surgery, because to be honest, if somebody had a failed stabilization. You look at the labor and on a normal MRI, you can't no idea what's going on, so they're quite useful in that situation.
So that's a gallop through the investigations. What investigation you pick? Partly depends on local protocols. To my mind, as I said, if I haven't got evidence, I'll get an MRI. Um, otherwise I'll get a CT scan because I really want to know what the bone loss is. So that's the background.
If we look now at the very basics, what do I do with the patient who sits in my fracture clinic and that's not an unreasonable question and get asked now. For the exam, there are the best guidelines, and I'll run you through them very briefly, so we're looking at the first time dislocated up here and we run them down. You've got them in three groups. And you've got the under 25s, the under 40s and the over 40s in all of them getting going.
There's no evidence that immobilizing people really makes a lot of difference. So if you look at the under 25s. If they've got bone loss, if you're worried about them in any way, send them on for a second opinion. In this middle group, if they are symptomatic at three to six months. Send them on.
Now in reality, that's not going to be. You're going to send them to the physiotherapists and save the physiotherapists. If they're still symptomatic, i.e. they re dislocate, then they need a specialist opinion. Over 40, you start to worry about the rotator cuff because you have a higher incidence of cuff tear and therefore you don't want to miss these. You don't want to send them off, and six months later, they can't lift their arm.
So these ones you want to be thinking about, do I bring them back? Do I reassess them? And again, there would be local protocols too. They all come back to a specialist clinic to be go to the physios, but be aware that older age group are at risk. And let me move on to the operative management, because this is something you get asked in your Viber and you're not expected to know masses.
Broadly speaking, operative management, you can divide into soft tissue repair and bony reconstructions, soft tissue repair, you break up into either an open bank, heart repair or arthroscopic labral repair. To be honest, there are very few dedicated shoulder surgeons doing open bank arts these days. Um, pretty much everybody who would call themselves a shoulder surgeon is doing arthroscopic surgery.
On the bones side, don't get too bogged down. There are dozens of operations described. Um, broadly speaking, it falls into do do a Latter day in which you shift the coracoid and the conjoint tendon. So you're getting bone and a slingback. Or do you just put bone in which is iliacus crest, allograft or even distal tibia? The evidence is that whether you do loutish or the others, actually the outcomes are the same.
There's a very good paper from a few years ago that demonstrates that, so you pays your money takes a chance. The most common is the latter j. Um, but we'll see why there's some issues there. So how do you choose which one are you going to do? Because you may get us in the Viva. How are you going to manage this patient? You know, you've got a choice arthroscopic or slap lesion. So there is this thing called the ISIS score.
It's French thing, and it's got these points, so it looks at age, sports, the type of sport, hyper laxity. Um, and then some bone loss things. And if you look at it, six of those points actually come from age and bone loss. This full thing and the high kill accident, a little bit soft in the middle, so really, if you focus on age and bone loss, that will help you with the majority of your base level decision making.
So what are we interested in? So this again, is from that, from a different paper. You'll see the reference and it's got an age and risk of dislocation. And if you look here when you were 15. Have an 86% chance of having a second dislocation by the time you're 30. That goes down to a 40% chance. And then it drops quite rapidly after 30.
So lower age, higher regasification rate. The flip side of that is as you get older, your risk of auxiliary nerve and rotator cuff injury goes up, but it's not quite so dramatic. So you would be more inclined to offer surgery to a younger patient because that they have a higher chance of re dislocating or at least have that conversation, and when you're on, you know, 35 year old, you can say, well, your chances are a lot smaller.
A bone loss. Interestingly, we don't know what the limit for bone loss is. Nobody has done the study where they said at 10% bone loss, you are going to become unstable. But what we do know is that if you operate, you need to take bone loss into account. There are also different ways of measuring bone loss, and again, you don't need to get too bogged down.
But most of them, most are the ones that most people use are done on this circle of best fit. Do you draw a circle that pretty well represents your inferior glenoid and you measure the bit that's missing? And this is a pico technique, which most people know the name of, or seguire doesn't matter as long as you say the circle of best fit on a CT scan. And that's why I get the CT scan. So how much bone loss is important?
And this is a paper again, if you want to quote papers Burkhardt and bear in 2000 in 2000. Said, well, actually, we're really good at doing arthroscopic stabilization. But some of them fail. And they realized that if you had 25% bone loss or an engaging Sachs lesion or come to that, you sort of 67% chance of failing your stabilization surgery.
But because they were good, if you didn't have a bone loss, four percent, there's a massive difference. And this woke everybody up. So they are they should cut off. It's 25% is the magic was the magic number. Um, again, if you get into this, the numbers coming down to about 16% And when you do the maths on that, 16% of the 32 glenoid is only a couple of mil.
It's not a lot. The other thing you need to be aware of is this concept of engaging lesions and what's called on track off track. Unless you are really into this, do not go and look it up. Because that picture there from the original Giacomo paper, what you have to do is you have to work out what your normal glenoid would be and work out what 83% of it is.
That's your normal track. You then take your defect, you take the defense in the humeral head, you do some funny maths on it and it gives you a calculation. Don't even go there. What are you going to know is that if you've got a big hill sex? You may not need such a big glenoid lesion to enable the thing to dislocate.
And you just got to be aware of it, so much of tracking on track off track and assume that the examiner will less than you do about that. So for those of you who don't know, this is basically the steps in an arthroscopic stabilization, there's lots of ways of doing it, but effectively you pass a stitch. You anchor the stitch into the bone and you repeat. Two, three, four times, depending on what you want to do.
The latter may very simply, you take the coracoid. And again, there are the congruence aren't congruent, doesn't really matter. You apply the coracoid to the front of the glenoid bang in a couple of screws. You can either reattach the labrum. And the he captured is decent picture, see that or you don't. Doesn't seem to matter.
And that works very nicely. However, it has some complications. You can get osteoporosis and you can see the picture of the CT scan. There is one of mine. It was a beautiful operation, came back a year later going, yes, not quite right. Bone disappeared. And then when the bone disappears, you get the picture like the microscopic one down at the bottom.
The other thing you can do is you can put your graft in the wrong place, as you can see on the drawing. And you can put it too high. So abuts on the humeral head and the bracelet, you can put it too low. So there's lots of technical things. And this is the list of complications of the latter. Now in that list, they basically said 30% of the passengers get a complication.
Now I think that hematoma is a little unfair. The neurological injuries, the majority are in your apraxia. However, there is a steady trickle that end up up at Stanmore with the peripheral nerve injury unit, where they have permanent musculocutaneous nerve injuries. So these are young guys, mostly athletic. My biceps.
And you get chronically you get subscapularis failures and subscapularis and scapular sorry dyskinesia. So you can end up with some long term problems in this operation. It's not benign. And so to wrap that little bit up, I really have galloped through the broad brush strokes. Think about it classification.
Is it a one, two or three? Now your money is going to be on one, but you've got to be very wary that you don't miss the 3's. Your investigations? You going to see what your local preferences are? But really, you want to know what your bone loss is, is the bone loss is going to dictate. How you manage this ultimately? And then your operative treatment and whether you could offer surgery, obviously it's based on each individual patient, but your conversation is going to be tilted by age.
Now if you do an arthroscopic stabilization with no bone loss or less than I put 20% there, for me, it's 16% You're looking at a 90% success rate, phenomenally low complication rate. Well, that's a shame. Great, 97.5% would have been 98 and 1/2. A success rate, however, 30% complication rate. So you've got to weigh up the pros and the cons. You can reduce some of those if you do an iliac crest, which is what my preference is.
However, you're knocking chunks out of somebody's Zillion crest, and that apparently hurts a little bit. So again, and also you've got the osteoarthritis and all the rest of it. So that's sort of the gallop through a instability. Now I thought I'd talk just a little bit about posterior instability because again, it's not taught very well. And this is just a few slides. So there are lots of mechanisms.
We all know about the fits and shocks. Remember that although fits and shocks are far more common cause of posterior instability, the majority of those will still be anterior and stability. But remember, the fallen, the outstretched hand, the direct impacts, and these are also part of the multidirectional thing. And there are, broadly speaking, two forms. There are the acute dislocated ones that I imagine the majority of you've come across.
They're the ones you get called to A&E because they said as posterior dislocation, hopefully before they're trying to reduce it. So they're not trying to sell you a posterior fracture dislocation. And then there are more chronic label things, which we'll talk about which get missed. So the acute dislocations, they had this loss of external rotation because he's locked, they can't move, right?
I'm not going to tell you how to diagnose them. The light bulb sign and all of that CTs are very useful. Be very wary about trying to reduce these in any because your chance of fracturing something is pretty high. If you do reduce them, remember that you need to brace them in external or neutral, if you put them straight in a sling. They end up dislocated again.
So for these the ones they're back to front, they need to be externally rotated. If you do it open. And so you may get the scenario where they say, OK, you tried to reduce it now and it doesn't work, you're going to go to fair to what are you going to do? You're going to try this reduction in theater, muscle relaxant, all that sort of stuff. And the question that catches everybody.
How are you going to approach this? And the number of times when I ask this question, somebody says I'm going through the back. And, you know, full well, they have no idea what they're talking about. This is an A Dell spectral approach and just Jen, that up, if you're not familiar with it, you go in through the front. You find the rotator interval open, the rotator interval and you're looking into a cavity, which is the only glenohumeral joint and you'll see the glenoid, you then get a bone spike in very gently leaving this thing out of the joint muscle relaxant and all of that on board.
To stabilize it. The traditional is the thing called McLaughlin procedure, where you take the lesser tuberosity and you plumb it into the defect with screws or suture anchors. The other alternative, which a lot of us favor now leave the lesser tuberosity in place. You wrote in the rotator interval, you put one of these anchors down in the defect and you pass it through subscapularis, which is right in front of you and then you tie down so you run side the subscapularis into the defect, and that's quick and easy to do.
But you need to be aware, so the words you need to know does petrol approach? Maclachlan procedure. OK, now the poster is the poster label things. These are different, these will get missed and you will all have missed them. They're rarely unstable and these are often the rugby players or people who've fallen heavily on and on foot the handout or the shoulder charge or something like that.
They get burners, stingers, dead arms and then the sort of people who will happen at the beginning of the season. Another week off settles down, they go back, play a game, they're OK. Then he'll do it again and they keep going around in circles and the physios go, oh, we had to burn or a stinger or, you know, it'll be fine. It's not. If you load the posterior labrum, there's this Jones posterior load test or a posterior glide.
Quite often there's a click and some pain in the back of the shoulder. And if you get it at all more and more all through Graham, you will see either this appearance or the posterior labrum is off. Or this little thing, which you just need to know the name of which is called a skin lesion, where the labrum is intact on the top. It's got a hole underneath.
Symptoms of the same. Now what you do with them is up to you. They're not like the anteriores that they're going to dislocate, they're just uncomfortable. So you can't leave him alone. But actually, this is what you see, so the MRI picture. Is the same patient as that one? So it doesn't look too bad on the MRI, but that's the appearance is completely shredded when you get in there.
So if they don't settle, one of your options is to stabilize them lots of different ways of stabilizing them. This is the way I prefer because this is the way we described. Basically, you do a post area labral repair. It's honest. It's easier than an A There's much more room, and it is pretty straightforward stuff. So just think about post-arrival tests in clinical practice, they're more common, their impact injuries, we give you this dead arm and you get these posterior.
Uh, label repairs, pretty simple stuff. So that's a little gallop through that and. That's all I want to say about instability at this stage. Quick plug for these books, which I can thoroughly recommend are actually very good if you haven't already got them. And a quick plug for Luke, who do a huge amount of work. So in all that spare cash that you haven't been spending on your booze over lockdown, you can Chuck it Ruth's way.
So thank you very much, and hopefully we will have some questions. I'll stop my share. And thank you, prof. That was a very comprehensive lecture, I hopefully all the candidates will feel a lot more confident going into their exams, having gone through all of that. I do believe we have some questions.
Well, the chat box. Honey, do you have the questions? What is Islam, Muhammad is asking about what is off track and how to calculate in reality? In reality, it becomes very difficult to why glossed over it? So first of all, you have to measure the glenoid defect.
Um, then you have to measure the size of the Sachs lesion from the edge of the rotator cuff to the edge of the lesion. And that gives you that distance. You then measure that length. You calculate what 83% of a normal glenoid would be. And you need this 83% and you work out the track, and if your two numbers overlap, the 83% you're considered off track, to be honest, unless you're really getting into Shoulder instability as a consultant.
Don't waste time on it. That it's a combination of Sachs lesion and the anterior glenoid lesion, and that's all you need to know. I personally, I don't use it. I measure my glenoid eyeball the hell sacks. And that's enough. OK don't waste any sleep on it. OK, we have another question from Omar Ahmed. Do you advise for EMG testing when you die out of polar three?
And no, is the short answer. It's a clinical diagnosis, if you are experienced, you put your hands on, you watch the patterns there are pretty simple patterns and you can pick them up in about two minutes. The problem with the EMG is you have to do fine wires and trying to get fine wire. Emg and subscapularis have had it done to me. It's a long way in.
So no, we don't tend to do EMG its clinical diagnosis unless it's really weird. And then you'll do it. OK, and it is very sad, Sophie. She asked, how do you diagnose the three deaths. As you do not have any abnormalities on the scan? Well, they have similar exam finding. And again, no, they. They will give you a lot of it's the history.
So if there's no history of trauma at all. Then there's something going on. And when you examine them, you will see that the pattern is different, so you will see major contracting, it'll flick or as they come up the classic one as the posterior instabilities and they lift the arm up. And as they get to about 140 degrees, there's a clunk. And actually, what that is is, is the shoulder has come out of the joint and it comes back in again.
And if you watch the hand and once you've seen one, it's blindingly obvious they often turn the hand into internal rotation to subscapularis is pulling them into internal rotation. And if you accidentally rotate them on the way up, you cure them. So it's a very different thing, because you see the pattern, whereas most tight ones have a normal rhythm. Against difficult when you've got both, if you've got an abnormal rhythm and a label pathology, then you've got to unpick it and that becomes quite subtle.
The most of the time, it's a history and a straightforward exam. OK so another question, can you explain on track of track concept? Very briefly, and I might ask the question again. What we realized with burckhardt back in 2000 was that bone loss was important. And we started measuring bone loss.
We then with Giacomo in Italy, said, well, hang on a minute. It's not when you as you dislocated shoulder, it's that combination of the hill sacs and the glenoid. So if you've got a massive Sachs lesion, you may not need a very big. Uh, glenoid lesion. And so to Jack and I did all sorts of clever maths on it. He came up with this number of 83% So it's a combination of the size of the hill sacs and the size of the glenoid.
And when you hit, this critical number is deemed off track in practical terms. About 95% of shoulder surgeons don't formally measure it. Because it's not very accurate. And really, you need a CT scan to measure the glenoid and you need an MRI to say where the cuff is to measure the other. So you doing two investigations to measure something, what I will do.
I'll look at the hill sacks and go, whoa, that's a Biggie. I've got a measuring or a weight. Yeah, and if you've got 20% bone loss on the glenoid, it doesn't matter what the Sachs is doing because you're going to do a boning operation anyway. And if you haven't got any bone loss, you're going to be hard pressed to do anything to the tax. So it's a phrase nobody is going to ask you to explain it. Absolutely guarantee that one.
OK, the last question is always said in many of the locked posts location. We do reverse shoulder is the best option. If you want to get by your patient, if you're 25 with a locked posterior dislocation. I think if one did a reverse on that, that's negligent, ok? If you're 85 with a locked posterior dislocation, you will have shredded the rotator cuff.
and then, yeah, it might be a reasonable thing to do, but for the vast majority of patents, I don't think I've ever had to do a reverse for a lot posterior dislocation because they're only locked until he gives them a general anesthetic and unlock it. Now when you unlock it. You look at the human, well, had enough, you're talking about the chronic ones, then these have been out for six months or something.
There's usually something majorly wrong with the patient. OK, but the acute locked first area investigation there may be a few days old unless the patient is biologically awful. Don't do it. The other thing you got to think of is if you've got a lot, if you're going to taste your dislocation, we gave you that list, which is fits shocks and you've got to include the alcoholics, whether they're fit.
Do you really want to put a large piece of metal and some screws into somebody who's going to have another fit because you can see where that's going to end up? So short answer is rarely and certainly not as a standard procedure. OK, thank you. Thank you very much. That was the last question, so we go to KneeKG now.
Yeah, thanks, honey. Thanks, Rob. So what we're going to do now is we're going to move on to the mic questions. So I think booth gives us about two minutes or so to answer them if you could answer them for us so we can see test your understanding of the lecture. Thanks, Ruth. Prof Tennant, if you'd like to read through them, text for the answers.
If that was OK, please do you see those? So, yeah, so we've got the first one. As a six-year-old plays rugby, dislocated shoulder comes to you and the chopped off for the last word, but I think everybody works it out. What do you think the chances of having a further dislocation? So the majority have gone with 80 percent, which is correct. Yeah so remember from the lecture that table and at the top of the table, we had the 15, 16-year-olds and they have, you know, an over 80% chance of recurrent instability.
And if you drop down, he gets lower. So a couple of you may have just got that confused all the way round, but so young people bad outcome, probably related to whether collagen is made. So the next one is 23-year-old woman, recurrent instability. You get a CT scan and it shows 25% bone loss. And she says, I don't want any scars. I want arthroscopic surgery.
And so you have to advise. And the question is, what would be the chances of failure that you're going to tell her when you do an arthroscopic operation and. Well, almost half of you were awake. Is that better come to be a paper said 67% failure with 25% bonus. OK so a few of you being a little pessimistic going up at 77 percent, either that you don't trust your skills.
Some of you there being a little bit optimistic. Yeah so if you do an arthroscopic stabilization and you don't address the bone loss, it has a high chance of failure. And that magic number 25% bone loss. 67% chance of failure. And then. Everyone was asleep well, most everyone was awake nearly. If you're going to do a lot posterior dislocation in theater.
It's dull spectral approach. I know some of you seem to want to do reverses on them, but to be honest, that's few and far between. So the vast majority are going to do adult petrol approach and reach around the back. Yeah, you ever put the direct posterior approach clearly heard the first part of the thing and then fell asleep for the rest of the talk. The rest of the slide.
So it's a Del's petrol approach. Don't go around the back. If you think about it, practically ain't going to happen. OK so most of you got that, so. Those you're not sure, have another look at the lecture. The answers are all in there. OK that's great, Thanks.
Prof yeah, and I'd taken that advice. I think it's worth going back to go over the lecture again before your exams. So what are we're going to do now is we're going to stop the recording.