Hello and welcome to this webinar on developmental elbow disease. I'm Doctor James Guthrie, and I'll be your host. I am a small animal specialist in surgery and canine sports medicine and rehabilitation.
So today's focus is elbow dysplasia, or what is more frequently being referred to nowadays as developmental elbow disease. And we're going to cover the main triad of conditions that fall under the umbrella elbow dysplasia. This includes medial coronoid disease, and this is what most of our attention will be focusing on because this is the most common form of of elbow dysplasia.
We'll also look at, a united and canal process and osteochondrosis. And then I feel they also do feel, fit into the category of developmental elbow disease. We'll look at humeral intrachondral fissures.
We look at more severe forms of of Radio ul the incongruity, although due to time restrictions, they're only going to cover that very briefly, and they're also going to run through medial compartment disease. This is the sort of sequence of events that happens after medial coronoid disease. Now, I will be honest.
There is going to be a bit of a surgical bias, bias to this lecture. Because I feel that developmental elbow disease is primarily a surgical condition. It's a problem with anatomy.
Surgery allows us to change anatomy in order to, achieve improvements. I'll run through doing the presentation, but there will be some, clinicians who might feel that actually, this condition should just be managed medically, wi with pain relief. But I'll kind of run through whereby.
I feel perhaps they might be misled in terms of their, thought process or perhaps some things to or for them to consider. So, in terms of kind of medical management of elbow pain elbow disease osteoarthritis. OK, we're not going to have time to cover that, today, But we'll focus a little bit more on surgery.
So I guess what is developmental elbow disease? Well, it's several different developmental abnormalities that can lead to a a range of pathology often referred to as as elbow dysplasia. And this is something that the clients would have heard the phrase most likely, but again, because there is lots of variety in, elbow dysplasia.
It means that if they meet somebody in the park with a dog it might be their dog has something quite different to their dog. Or even if their dog has something very similar. We can see quite a spectrum of, pathology and severity of clinical signs, and therefore there can be quite a lot of variation, so it can be quite hard for clients to compare their dog to another dog.
And this is also an issue we have as vets. It's very hard to compare one dog to another because there can be such a huge variation in terms of what is happening within their elbow. So it's primarily an in, a misfit between the radius and the ulnar and the humerus as they all come together.
It leads to pain, lameness and inflammation of the joint to ultimately osteoarthritis. So I'm not sure where this image originally comes from, but it's really, really useful. It's showing an elbow, slightly opened up, distracted, a kind of medial view, and you can see these little red highlighted areas.
These are the areas where problems happen on the elbow, and this is really useful because it means if you're looking at any imaging, a radiograph CT MRI of an elbow. These are the areas to look at because these are gonna be where the problems lie. So we're gonna focus on the elbow as we just touched on.
The elbow is made up of three bones that all come together and with developmental elbow disease. The problem is that those three bones don't fit together perfectly, and therefore that can lead to increased pressure in certain areas. And the way I tend to describe this to clients is it's a bit like having a pair of shoes that don't quite fit you.
Now you've ordered in most situations the right pair of shoes for your feet. You bought the right size, but just that particular brand happens to to rub on your foot. You've not ordered a pair of shoes, three sizes too big or three sizes too small.
They're the right shoe for you, but they are rubbing on your foot. And what happens is we get increased pressure within certain areas within the elbow joint, and the main place that happens is an area known as the medial coronoid process. And this is this little sort of cranial tip on the, part of the ulna, which is the medial coronoid process highlighted within the orange circle on the images on the left.
And you can see that we have the humerus coming down on top of the medial chrono process on the first image. And on the second image, we can see that the radius is also in contact with the metyl chide process and can cause some rubbing there. So what tends to happen is we start to get some pressure building up over that mule chrono process.
The bone becomes harder in order to deal with that extra force, the bone becomes more dense, and as the bone becomes more dense, it can become more brittle. And then you can start to get little micro cracks forming within that brittle bone. And if enough of these cracks start to coalesce and come together a little bit like cracks on a frozen lake of ice.
Suddenly the ice splits, and suddenly the bone splits and cracks and a piece can fissure and fragment. So again there's this friction happening. Increased pressure in the bone.
This can then lead to the bone becoming more sclerotic. We have these micro fractures forming and then the coronoid can fragment and fissure. Additionally, something quite important that we will come on to, as we go through is that there also on top of the bone is the cartilage and just like the rubber on the brake pads of your car.
If you're having increased pressure, you're braking excessively. The rubber brake pads can get worn down. If there's increased pressure within the joint, the cartilage can get worn down as well.
So with medial coronoid disease, there are different patterns, that are described, and either we can see a fissure or we can see the fissure becomes displaced. And therefore we have a fragment and a lot I've said displaced. The fragments tend not to float off around the joint.
Occasionally they do, but most of the time they sort of sit in place, rock back and forth and can cause irritation. And even if they haven't fragmented and come loose, just having a fissure in the bone can be very painful. And it's not too uncommon that if we see dogs with a fragment in one side and a fissure in the other elbow, it's not that uncommon for the Fure side to actually be more painful and more lame.
Now, in terms of the shape of the fissure or the fragment, we typically tend to describe three, sort of fissure fragment patterns, based on a micro CT study, done by Noel Fitzpatrick. And we can see a tip, fissure or fragment, and that's the image on the left. It's just the very tip of the meyl chromo process is affected.
We can have a radial incisor, fissure or fragment. And this is kind of a curved, fissure that runs through the bone. It's it's the middle image on the screen, and the thought process is this is primarily coming more from the radius, rubbing against the ulna, and then the most common type is effectively a combination of the two, so we often refer to that as a radial incisor tip or an RIT.
This is whereby we do have a curve at the caudal aspect of the fragment, but it does not curve all the way back around cranially but extends out the, medial side of the apex of the medial chronic process. And because there's this huge variation, this is whereby. It can be hard to compare one dog to another because they can get different types of of Fisher or fragment form.
Now, in terms of our our diagnosis of this condition, one of the first early signs is, changes on radiographs that can be picked up, which is sub trochlear sclerosis. So just inside the orange circle, we can see this increased white area of bone. You'll almost see it kind of extending into the medulla.
And this is whereby this bone is becoming hardened to deal with the extra force because of the increased pressure, it becomes more dense, more sclerotic. And we can see that as an early indicator on radiographs. The other thing that we can see is osteophyte formation.
So as we have degeneration within the joint, we start to get osteophytes forming. We can sometimes see them on the radial head and on the caudal aspect of the humerus, as highlighted in this example, the early place they tend to start is on the, ancon process. So taking a media lateral radiograph of the elbow with the elbow in a a flex position allows you to see that an canal process more clearly and see the osteophytes on there.
Now, in terms of the fragmented coronoid process itself, it's very hard to see that on radiographs. It's It's very rare for you to actually be confident enough to see it on a radiograph because it is hidden in between all of the other three large bones. So the best way to see it on imaging is with the CT scan and on AC T we can see it in both the frontal, sagittal and transverse planes.
We can see a fragment to the tip of the medial chrono process. So in this example, we have kind of an RIT fragment. Now, another great way for us to see these fragments.
Is with arthroscopy and arthroscopy has two great advantages. One, it allows us to see the cartilage, which we can't see on on radiographs or CT. And because the cartilage in dogs is very thin, it's also quite difficult to see it on an MRI scan, particularly if you want to assess partial cartilage damage on an MRI in a canine.
It's very challenging, if not impossible, because of how thin the cartilage is so arthroscopy allows us to see the cartilage, and I'll come on to it a little bit further on. But seeing the cartilage can allow us to help predict the prognosis, because the more damage of the cartilage, the the worse the prognosis and also may make us want to consider additional procedures. If we can see there's a lot of damage occurring, a lot of friction occurring in the the medial compartment of the joint.
Now the other advantage of arthroscopy is it allows us to provide some treatment. So if we kind of go back to the shoe analogy that I tend to discuss with clients, I say the shoe is rubbing on their foot, and then a little piece of the inside of the shoe breaks loose a little bit like having a stone in your shoe. And if you had a stone in your shoe, you might want to walk less.
You might want to take some pain relief, or you might want to take the stone out of your shoe, and we can do the same thing with the elbow joint so we can take the fragment out of the joint and by removing it we will very frequently, have, quite a significant improvement in lameness as long as the rest of the joint is otherwise looking healthy. So as long as there's not significant damage to the cartilage in the joint, so we can go in and remove the fragment, and that will be one of the treatment options available to us with arthroscopy. Now, if we don't have a fragment, but we have a fissure, what we can do is go in and remove that abnormal disease fissured bone.
And we could do that via a procedure called a subtotal coronoid ostectomy. And effectively, what we do with this is we take away the kind of disease bone and potentially a little small margin of of healthy bone along healthy bone alongside it. So, the the images on the left kind of show a red line at the tip of the Mel chide process trying to represent the fragments of the fissure.
And then the green line is kind of showing you whereby you may take away, part of the, of the Mel Coron process with an SCO. Now, that diagram is is probably a little bit aggressive we maybe don't tend to take away quite so much. Nowadays, I think most surgeons are generally being a little bit more conservative and just trying to take away the more, diseased area of bone.
So how how do we do that? Well, we tend to position dogs on their back, and most dogs are affected bilaterally. So very frequently, we will do both elbows.
Arthroscopic treatment at the same time. So we can see both, limbs are prepped and draped. And then we have an assistant to hold the limb, trying to leave open the elbow by levering the limb over a sandbag that's tucked underneath the drapes.
So what I'll do is I'll just show you how we or how I introduce an arthroscope into the elbow joint. So, first of all, I use a needle and syringe. Enter into the joint, draw back some joint fluid to confirm the needle is inside the joint.
Then I take a syringe full of sterile fluid and inject that into the joint in order to cause the joint capsule to to swell up, create some pressure in the joint, then take a scalpel blade, make a little incision through the skin, and then we can introduce our troche and cannula into the joint. And because the joint is full of fluid, we just pop in like popping into a balloon. And then we enter, insert the scope, and then we're inside the joint.
We kind of position ourselves and then insert a needle to act as an egress. And this will allow fluid to flow in through the arthroscope and out of the needle, continually flowing fluid through the joint to keep the screen clear. So once we then get inside the joint, a little air bubble float past, we can look down to the meal coronary process, and there we can see a fragment, and that fragment is loose.
As we insert a needle, we can give it a little poke, and you can see that rocking about inside the joint. So that's our sort of stone in the shoe sort of scenario. So, in terms of of removing this, what I tend to do is remove the fragment and also then just effectively smooth off this area where it's come away from.
So it's kind of a combined SCO combined fragment removal. So first of all, we insert a needle into the joint that the direction that we would want our SCO to be, I then introduce a scalpel blade and push that through into the joint in order to create an opening through that opening. I can then place an osteotome so we can see the tip of that on the image on the left.
It's kind of like a a chisel. And then what I do is tuck that down into the bone, acting a bit like a I tend to describe it as being like a submarine. So just the top of the osteotome is sticking above the surface and the rest is down below.
So you get a nice deep portion of bone that we remove. And by doing that, we're not only removing the portion of bone that the humerus is rubbing on, but we're also thinking about removing the portion of bone that can rub against the radial head. So, we then tap the osteotome to go through the bone, and then we remove the piece that we've, essentially chiselled away as well as the fragment, so we can see in in this, little video.
There's a little piece that we've chiselled away. The little fragment, and we're going to take those out. And then we ended up with two little incisions, a little bit of skin glue to kind of close those over so very minimally invasive, generally a very simple procedure to perform, and low risk of complications.
Now, what you might find, or what some surgeons may say is they say the results can be variable, so some dogs seem to respond very well. Some respond a little bit, and some this arthroscopic treatment seems to make no difference. Well, I think the reason for that is most likely because they're not comparing all joints the same.
And it depends on the amount of damage to the cartilage it's often referred to. We have a grading scheme called the Modified Outer Bridge score now, in terms of damage to the cartilage. If we go back to our shoe analogy, the way that I describe this to clients is that yes, a piece of the inside of the shoe may have broken loose and acting like a stone in your shoe.
But if that shoe is really rubbing on your foot and has caused you to get a blister or a a wound. Open up on your foot. If you take a stone out, you may feel a bit better, but you're still gonna have a sore foot because you've still got a big wound on your foot.
And that's the same with the elbow joint that if we do have damage to the cartilage, digging these fragments out can cause an improvement. But sometimes that improvement can be small if there is more severe damage to the cartilage. And if you think about it, we're only treating one part of the problem.
Which is taking out the fragment, and the fragments, not the cause of the problem. It's the joint not fitting together, and rubbing is the cause of the problem, and the fragment is a a consequence of that. So we're only treating maybe one of the consequences, and therefore, some studies kind of tried to compare dogs having surgical and non surgical treatment, but sometimes they have not been equally grouped, and we might find that because some dogs have not had arthroscopy done.
It might be that they happen to be dogs with, better looking cartilage, and ones who have had arthroscopy have actually had worse cartilage, and they're not sort of equally compared. So in my experience, I tend to find if dogs have minimal damage to the cartilage and you take out the fragments of fishes that will typically tend to near enough resolve the the lameness for the time being. It might be things progress throughout the dog's life, but we can definitely get an improvement, whereas if the joint is quite severely affected with osteoarthritis and there is substantial cartilage, where then taking the fragment out makes near enough no real difference.
So you can generally predict the degree of cartilage damage from radiographs and CT, depending on the amount of degenerative joint changes. So the amount of osteophytes that are formed occasionally you can get caught out where a joint looks very healthy on CT or X ray, and suddenly you find inside the joint much more damage to the cartilage than you're expecting. But usually there's quite a good correlation now in terms of this modified out of bridge scoring system.
It depends on the amount of damage to the the cartilage. And maybe an easy way to describe it is with snow. So, healthy cartilage should be very, very super smooth, freshly laid snow that would be kind of a grade zero.
A Grade one is where we start to have some softening to the cars, so it often looks fairly normal. But if you were to try to probe it, it would feel softer. It's quite hard to do this in reality, and then Outerbridge score Grade two.
This is where we start to have some superficial wear to the cartilage, sometimes described as a cobblestone appearance. Or it looks like like the image on the left like there's just been a little bit of light rain on the snow, just starting to cause us little dimples in the surface. Now Outerbridge Score three is where there's kind of a deep fissure running through the cartilage, starting to go down towards the underlying bone.
So that's like the middle image and our footprint in the snow and then a modified at score. Grade four is when the subchondral bone is exposed. So that's the image on the right, where the ground underneath is exposed.
The snow is completely, rubbed away. The cartilage is completely rubbed away. And then the grade five is when the bone, actually starts to become almost sort of worn down, smoothed over or kind of eber nated.
And that's in the most severe. And sometimes you can't even start to get ridges of of bone W worn away when the joint really starts to collapse. So we tend to then refer to this as kind of medial compartment disease.
So we no longer just have pathology localised to the medial chide process. But it's actually extending further through the medial compartments so further back along the ulnar and also up on the opposing surface of the medial aspect of the humeral Condy. So medial coronary disease typically progresses to medial compartment disease whereby we have progressive loss of cartilage now with medial compartment disease.
There is, unfortunately I suppose, no cure. We can't completely resolve the condition and the same with medial coronary disease. We we can't make a completely normal elbow back to, a normal elbow.
So whatever we do, we're trying to make it as best we possibly can, both in the kind of short terms, but also potentially trying to have some longer term benefits as well. So any surgery is having the goals of reducing pain, reducing lameness, and also maybe to try and preserve cartilage or slow down the rate of further cartilage where maybe even try and prevent further cartilage where, they typically tend to group these surgical procedures, into three categories. So arthroscopic, unloading surgeries where we try to unload the medial compartment and resurfacing surgeries where we can resurface.
The medial compartment. And there are, I suppose, different sort of strategies. And there has been published an algorithm that that Noel Fitzpatrick published.
That can kind of give you some some guidance. And again different clinicians may have different thought processes, different theories. There's nothing that's really proven to be, you know, the best way.
But kind of a modified version of this is, I tend to use so in terms of procedures that can be done. I mentioned one of them can be arthroscopic. So a procedure can be, a AB a biceps ulnar release procedure.
Now, again, this procedure, I suppose, is not completely proven, and it's a bit more, maybe of a theory, and studies published so far have been looking more at proving that it's can be performed. It can be safely performed, but how much of a difference this makes is still a bit of an unknown. So it's, basically the the biceps and brachialis sort of tendon complex inserts on both the radius and the ulnar at the medial aspect of the elbow joint and contraction of this muscle will lead to compression of the the the radial head into the the radial incisor of the ulnar.
So it's gonna kind of gonna pull the ulnar up against the the radial head. So the thought process is that by releasing the, arm of the the biceps brachialis that attaches onto the ulnar, it will prevent the ulnar getting pulled against the radial head quite so aggressively and therefore reduce some of the friction. So, we can see on the image on the centre.
We can see quite clearly where the, medial chide process meets the radius. And that sort of semi circular curve of the, ulnar is is called the radial incisor. And that's what rubs against the the radial head.
And we can see on the image on the right that as that biceps pulls because it's eccentric, it's off to one side. It's gonna be causing a twisting, torque movement whereby the ulnar can get pulled into the radius. So with the the bur procedure, essentially that attachment is cut.
It can either be done through an open approach or it can be done through an arthroscopic approach. So, on the right hand side, we can just see a push knife coming in. And we can see the biceps, tending that we're going to cut.
And we don't want to damage the medial collateral ligaments. You need to be very careful whilst performing this procedure to avoid damaging that medial collateral ligament. So that's the burp.
Now. The next set of procedures are the sort of unloading or osteotomy procedures, and the goal of these surgeries is to try and reduce pressure and friction within the medial compartment, which can then reduce pain and reduce further cartilage wear. And the probably four most kind of well described procedures are AD UOPUO Paul, an SHO We love an acronym in orthopaedics, so we'll start off with the DUO.
This is a distal ulnar osteotomy or in more situations, more commonly an ostectomy. We actually remove a portion of bone. And the, kind of goal of this procedure is to try to uncouple the radius and the ulna whilst they're still growing.
Because the thought is that if the radius and ulnar are not growing in sync, that can lead to a mismatch at the elbow joint. So if we uncouple the two, then hopefully they will fit together better at the level of the elbow. And now this procedure is predominantly used in young dogs, typically those who are less than sort of, say, six months of age.
If we were to perform this in older dogs, often the interosseous ligament, between the radius and the ulnar becomes much stronger. And there's therefore much less flexibility of the two bones to manoeuvre relative to to one another. Now, the next procedure, is the proximal ulnar osteotomy, and and the aim of this surgery again is to improve the fit of the elbow joints, reduce pressure between the humerus and the der now in terms of the DUR, we said that's typically for dogs, maybe less than six months of age.
What about the PUO? Well, again, Typically, this procedure is done on younger dogs, maybe say under 12 months or 18 months of age. The reason for that is that the bone will tend to heal much more rapidly.
So there is less recovery time, less morbidity, because dogs are often quite lame after this procedure, until the bone fuses and heals. And as we touched on as the dogs get older, the interosseous ligament tends to become stronger, tougher, less flexible and therefore a thought that if we do this surgery in older dogs, we might get less movement because that into osteo ligament will hold the bones together. So it might be, perhaps in an older dog.
You might actually go and disrupt the inter osteo ligament to encourage some more movement. And if we do have concerns about the bone healing or taking a longer time to heal, then some surgeons may consider placing an intra medullary pin to provide some stability to the ulnar. But we still want it to have some freedom because we want it to find its own natural best fit.
Now, the way in which I would kind of recommend you do a PUO is the kind of bilik proximal osteotomy procedure that was described in the paper by, Alex Konen and Noel Fitzpatrick. And although it's referred to as proximal, it's basically just in the proximal half of the ulnar. If you divide the ulnar in half, we're kind of going in the proximal half, so it's not really kind of right at the top.
And it's actually quite hard to see the original cut when this is done. So the image on the left it's quite hard to see the cut, but it's done it quite a steep slope. And then we typically want the ulnar to move the proximal piece of the ulnar to move up and and kick back a little.
Now the amount of kick back in this example is is quite pronounced. It's quite useful to use in a in a slide, cos it makes it easier for the audience to see if they haven't seen this procedure before. How this bone can move, but we don't want it to move too much, and we don't want it to move too much because you could have quite severe complications.
So what I really recommend is do not perform up a kind of a proximal cut. So a very proximal cut and kind of like a transverse, angle relative to the ulna deficit. This kind of image is what you might find in some older textbooks.
And I would really be cautious about this because if you actually look at this type of cut in the literature, you can see a very high complication rate. So I'd recommend the kind of B oblique PUO that's done at a very steep angle and a little further down the the ulnar because it just lowers the risk of complications. Because what can happen is the triceps can pull on the electron on and cause this proximal ulnar to completely flip round the other way, and dogs will be severely lame, and it can be quite hard to repair the the ulnar and have it stable enough to heal.
So that's our PO. Now the next procedure is a sliding humeral osteotomy an SHO. It's kind of based on a high tibial osteotomy procedure that's done in humans if they have unicompartmental knee, wear, and what we're trying to do is shift the weight bearing axis to transfer load to the, kind of unaffected lateral portion of the elbow joint.
So the the image on the left we can see essentially the way that forces would run down through the humerus. This red line typically kind of coming down through the medial side of the joint. If we look at a mechanical axis, so by shifting the distal aspect of the humerus across immediately, then forces will be transferred to the lateral side.
And also, this procedure does cause some abduction, which is a good thing because that will also further unload the medial compartment. And the way that the abduction happens is because the medial surface of the humerus does have a slight curve to it, particularly distally. As you start to get close to the super condal ridges and as you compress the bone against the plate, the curve distally hits the plate and therefore starts to tilt the distal diaphysis of the humerus.
So it's a combination of of translation and a little bit of abduction as well. And that's what allows the medial compartment to be unloaded. And then we have this special stepped plate, That then allows the bone to be translated, realigned and stabilised.
And this is what we may see. So image on the left is immediately post surgery. We can see that translation.
We could see the cut to the osteotomy. Then around about six weeks post surgery, we can see some advanced callous formation. That's the image in the middle.
And then by 12 weeks we have complete union of the bone. So with regards to sliding human osteo toys, there's a few papers now reporting the use of the procedure. And in this it was one of the the first papers, was that was published by Noel, basically saw that lameness improved actually in all limbs by by 26 weeks, and lameness had resolved in 66% of cases.
Now in that paper, they kind of described three variations of techniques and some of the major complication rates was quite high for some of these techniques, at sort of 17% 22%. But then, with the third variation, that was down to 4.8%.
So a big improvement in terms of, reducing some of the the complication rates. The paper published by Wendel Beg and Brian Beal. That showed that 90% of owners thought that lameness had improved.
And in terms of complications, there were six dogs that were considered to have major complications need for surgery. So we can say it is possible to get some significant complications with this surgery, and it's obviously quite scary to have major complications. And I think therefore that has maybe put a lot of surgeons off from taking on this this procedure.
But I think it's all down to having appropriate technique and also having a strong implant. That has lots of of screws to provide stability and to prevent screws from breaking. And in the 2015 paper that that, was published from Fitzpatrick referrals, this had again a further modification of the technique, and there were, zero major complications.
In that case, series lameness had improved for for all limbs by 12 weeks. Post surgery and lameness had appeared to resolve in about 80% of cases. So I suppose my experience of this procedure is that so far touch wood.
I've not had any major complications. I do see that patients are better following surgery. Not all patients will have a resolution of their lameness, and some might need some further management.
And that maybe depends on how severely affected the the joint is now in terms of kind of choosing this procedure, again, when surgeons tend to do procedures, it can vary. So for me, if I was to do a PUO procedure, I'm generally thinking about doing that when we have modified to bridge grade two or three cartilage pathology in a younger dog. If I have a dog that's perhaps beyond one year beyond maybe 18 months and has modernised grade score three or perhaps some vocal four, then I would maybe be thinking about a sliding humeral osteotomy.
Now, in some situations, I might still go ahead with the procedure if there is more significant damage to the cartilage. So perhaps some more diffuse Grade four if they were a very young dog, and that's because I have some concerns with resurfacing a elbow in a young dog, and I'll come on to that shortly. But, I'll just show you this something very cool with SHO.
So these two images image on the left is arthroscopy. Prior to sliding, femoral osteotomy used to evaluate the joint and remove a fragmented portion. Of the medial carno process.
And what you can see there is you can easily see this pink. The pink is the bone. Cartilage is white.
The bone is pink. We can see that. We have full thickness cartilage loss.
We have this exposed bone. Now, the image on the right is the same elbow. But you can see there is cartilage.
And this is actually arthroscopy performed just over a year later with a needle scope. And it all came in for some additional management of its elbow. And we were going to inject some medications into the joint.
So whilst we had the needle into the joint in order to provide the, medical therapy, we also then inserted the needle camera to look inside. And what we saw was that cartilage had regrown and no regenerative medicine was used. This is just purely from unloading the medial compartment.
Now that cartilage is not going to be perfect cartilage. And if you had to look at that histologically, it's probably more of a a fibro cartilage. But it has allowed resurfacing, recovering of the exposed subchondral bone.
So this is effectively to me. This is proving that that medial joint compartment has been unloaded in order to allow tissue to grow and not be rubbed and worn away. So that's, very, very cool thing to see now, another procedure that works kind of in a similar way to SHO by trying to unload the medial compartment and transfer weight to cross.
And also cause some, abduction of of the elbow, is the pole procedure or the proximal abducting, ulna Osteotomy. Now, in this procedure, an osteotomy is done to the ulnar, and a specially developed stepped plate is used to shift the alignment of the ulnar. And again, it's trying to shift weight off the medial side of the joint.
Now, in terms of, literature on Paul, the, top study, they saw that around about 75% of clients would go through the process again. They would kind of repeat the procedure, but it shows that a quarter of clients wouldn't go through the process again. So, again, not all clients were happy with with the results of this surgery, and and 12% of dogs had had major complications.
And then in the paper by Alan Dan Elsy and other authors. They specifically were looking at the complications after the pole procedure and trying to find some prognostic factors, and they saw that one in four dogs had major complications. So I think sometimes there's a maybe a thought, that the ulnar is easier to operate on, less likely to have complications, perhaps, than the humerus.
But actually you can see much higher rates, at least in the published literature of complications with Paul. Compared to SHO, now it might be. In reality, complication rates aren't that high for other surgeons with pool.
And maybe if other surgeons were publishing their results on SHO, maybe they would have higher failure rates. So you can't necessarily compare the two, but it's it's obviously not a benign procedure to perform. It does carry some risks, and and that's the concern with these osteotomy procedures, particularly procedures like the pool.
And the SHO is just wanting to be sure that it's the right thing for the dog. So we don't want to be going ahead. I don't think we want to be going ahead when Carthage disease is is minimal.
So if we have, you know, normal cartilage or maybe some focal outer bridge grade two, then I wouldn't be jumping to performing these kinds of procedures. But likewise, if we have severe damage inside the joint, you know, full loss of cartilage throughout the medial compartment collapse of the medial compartment. Then again, I think those dogs are too far gone to benefit from these procedures.
So I do think that it's a lot of the success of these procedures is down to careful case selection and the way I tend to describe these procedures. Declines is maybe we're trying to adjust the shape and the fit of the shoe to make it fit your foot better. So it might be like loosening the laces.
It might be like putting in a different insole. We're trying to make it a better fit. It's not gonna be the perfect shoe, but we're trying to make it a bit better than it is in terms of the way that fits now.
The next series of procedures are potentially resurfacing. So the kind of commercially available, more sort of established resurfacing procedure for the medial compartment of the elbow is the canine uni compartmental elbow replacement. Now, this is kind of partial resurfacing of the joint with vocally recovering some exposed subchondral bone on the medial aspect of the humerus and on the medial corona, the process.
So for me, if I still see there is cartilage present, I wouldn't be going for a resurfacing procedure. But if we have exposed subchondral bone, then I would be considering, a resurfacing procedure such as the queue they've put in her age to operate. And that's because what has been seen with this procedure is that they can be ongoing where within the medial compartment, and there can be ongoing way to or where to the plastic component and that can wear out.
We have maybe seen that happen to dogs maybe sort of four or five years after the procedure. And if you don't insert the implants correctly, then you can actually see that sooner, perhaps even at three years again, perhaps even younger if you if you're very off with your implant alignment. So that's a bit of a concern for me with performing this procedure in a young dog, because it would mean that if the dog was maybe 23 years of age, then when the dog is perhaps sort of six or seven, you might then be in a very difficult situation.
So I generally wouldn't perform this procedure on dogs who are under maybe sort of five or six years of age. I'll be reserving it for dogs who are a bit older, and hopefully then the implants will last them for their their their lifetime. So I will sometimes consider SHO in dogs, whereby there is perhaps more severe damage to the media compartment if they're very young.
Because although we don't want to put them through multiple surgeries, we do still have the option of AC UE later down the line. So this is what that procedure or the implants look like. There's essentially a a metal piece and a plastic piece.
Each has a trabecular metal base that allows for bone growth. So it's a press fit into the reamed bone, and then the bone grows into the implants to secure them in place. And it means that the plastic and metal should kind of glide over each other.
Rather than having the the bone on bone contact now, in regards to the the literature on on the Q procedure, so the kind of first clinical outcome paper published by by Jimmy Cook and and many other surgeons, reported, sort of complication rates of of kind of, 1% catastrophic, 10% major and sort of 28%. Minor. And they reported outcomes following the queue as having full F function, which again is a bit debatable.
How you define full function but full function in around 48% of cases acceptable function in about 44% and then unacceptable function in in around 8% of cases. And there's been a more slightly recent, study that came out which, reported complications in 21% of dogs, with with 15% being major and, major complications included kind of refractory pain and lameness, in five cases, and then in sort of last follow up in that study, 25% of cases were considered to have full function, 73% acceptable function, and then one case, it was deemed unacceptable function. So I suppose my thoughts on this procedure my kind of interpretation, my experience is with my cases, I tend to find that the majority of patients do improve.
But the amount of improvement that we have can be variable. And in some dogs, it can be quite a reasonable amount again, they never I would say completely, free of lameness back to how they were as a puppy. It's not like that.
But they can perhaps be walking with no lameness, much less lameness or requiring less medical management on top of of the surgery. But it can vary, and it can be quite hard to predict which dogs you'll see quite a good improvement and in which dogs. There's almost very little or minimal improvement following the the procedure.
So whereas procedures like SHO maybe see that nearly all dogs have some degree of improvement, it's maybe slightly less so with the CE. But the problem is, we can't compare the two and then this is the thing because case selection is different. So, as I alluded to, I would tend to use a SHO in procedures that have out of bridge score three, maybe focal four.
Whereas I'd use the CUE when they have diffuse four or perhaps, mo out score grade five. So it's almost impossible to really compare these procedures. We tend to at least I tend to use them for slightly different scenarios.
Now, what happens if the major compartment is eroded, worn down the joint, then starts to collapse and you'll see dogs with their elbows sticking out from the side of their their body. And, when they do that, that means the medial compartment has collapsed. And then when the medial compartment collapses, we then start to get wear and erosion to the lateral compartment.
And if that happens, just resurfacing the medial side of the joint is then not gonna be very beneficial because the lateral compartment is affected. Now, at this point, surgical options aren't great. We have arthrodesis fuse the entire elbow.
Yes, it can remove some pain from the elbow joint. But patients can have more of a challenge to ambulate when they can only move their their shoulder so their their functions. They can often ambulate, perhaps be more and more comfortable, but they again going to struggle to to run jump.
BB, as active to L, a replacement to date, has an extremely high failure rate, so I generally wouldn't be recommending an elbow replacement to anybody at the moment. And if you are having a dog and managing a dog with me, coral disease, media compartment disease or any elbow pathology don't have the mindset. Oh, we can always just fall back to an elbow replacement because they generally do not go particularly well.
So I would do everything you can to avoid having to even consider an elbow replacement. An amputation is usually not an option for many dogs because quite frequently they are affected bilaterally, so amputations frequently not an option. So in that sort of situation, typically, I would tend to go down the route of medical management.
Make sure we've exhausted all medical management before, considering something like an arthrodesis or an elbow replacement. So medical management can be analgesics, and they can be systemic or they can be intra-articular. And that can also include an intra regenerative medicine therapies.
Weight loss is extremely important. And then modifying exercise, modifying lifestyle and rehabilitation. So the next, condition I wanted to cover was an unit and canal process UAP.
So the the anal process is the sort of back of the ulna notch, and it has a separate centre of ossification in in many dogs. And this procedure is kind of a a failure for this hypothesis of the anal process to fuse onto the ulna diaphysis. And the reason why this tends to occur is because of pressure between the caudal humeral condyle and the, anal process preventing, fusion of the angular process.
And in this image, you can see quite clearly, quite a pronounced example whereby the ulna is too short, meaning the radial head is effectively too long. It's putting pressure on the humeral condyle, which is subsequently putting pressure on the ANC canal process, preventing it from fusing, so we can see that a little bit more clearly in this slide. Here we have that UAP in the image on the left and the image on the right shows this incongruity a relatively short der.
And, therefore, you can see how we can have pressure building up on the end canal process. So the kind of, sort of classical treatment would be to place a screw to secure the anal process in order to reduce any any movement, to make it more stable and therefore allow it to heal. And that can either be done with kind of a traditional screw or there are some headless compression screws.
That can also be quite useful for for this particular situation. So, in terms of kind of performing this procedure, tend to have an approach to the quadrilateral aspect of the elbow, dissect through the anal muscle to reveal the anal process, and then a separate, little approach on the caudal aspect of the proximal ulna. Then got a AC, aiming device that's positioned onto the anal process and on to the coral aspect of the DER.
Then drive a guide wire through into the inal process, can then use a cannulated drill to drill over the guide wire, and then insert a screw, and just use some bone holding forceps to hold the anal process in place whilst the screw is inserted. And, in the example that we saw on the CT that was this this basset hound, we can see on the immediate post op x-rays already. It looks like the ulnar has shifted and moved.
And that's because we've done a cut to the ulnar. That's gonna allow things to be freed up. So we've cut the ulnar and that will take pressure off.
Allow the proximal portion of the ulnar to move approximately. Therefore reducing the contact pressure between the ANC canal process and the humerus and then at some follow up radiographs, we can then see that the UAP is healed. And then our ulna has gone and healed into position as well.
So we can see that there now. It might even be that in dogs who are very young. And if the ANC canal process has not been displaced, then perhaps just performing an ulnar osteotomy could allow you to have fusion of the ANC canal process for me.
I think if I'm going in to do surgery, I kind of think if we're going in once, we may as well go in and place a screw in order to ensure the anal process is stable. But in select cases, I think you probably could consider just doing an ulnar osteotomy alone. You'd have to have very careful case selection for that.
And if these are chronic and they are therefore unlikely to fuse, then you can consider removing the, unit an canal process. What I would tend to say is, if dogs have minimal to no lameness, then I would actually consider leaving the UAP piece in place because I haven't seen some dogs where lameness has been minimal. The fragment the UAP has been removed, and dogs have then been more lame afterwards.
And typically I'll tend to use arthroscopy to actually assess how mobile or not that, an canal process is. So with an oscopy in place, you can see how much movement occurs, and that could perhaps influence your decision making as to whether you remove the piece, try to fix it in place or just leave it alone. Now, the next of the three conditions that classically make up, elbow dysplasia is, O CD osteochondritis disc cancers.
And if you remember back to one of the very first slides I showed you where the three, problems of elbow dysplasia occur, or I shouldn't say the problems. Three consequences of elbow dysplasia occur. And the O CD lesions typically always tend to be on the medial aspect of the humeral condom.
An O CD occurs because of a failure of endochondral ossification. Now, sometimes these OC DS can be very Avax like on the images on the left with the ring around them. Or sometimes they can be more widespread, like the image on the right taking up a much larger portion of the, medial condo, and they can vary in size.
Some can be very small, whereas some can be much larger now in terms of treatment of O CD, one of the most commonly performed procedures is sort of micro picking or micro fracture. So typically we tend to take away the sort of loose cartilage flap. If it's perhaps still in place.
Sometimes it has already moved, moved away. And what the kind of micro picking does is it tries to stimulate bleeding from the subchondral bone. So what we can see in this video, you can just see little stringy lines of blood, a little bits of blood starting to come from the subchondral bone where it's been picked up.
And the aim is to try to bring healing substances within the blood from inside the bone to the surface to stimulate a sort of fibro cartilage covering of that exposed bone. Another procedure that can be performed is to resurface with an osteochondral graft. So this is whereby a core of bone and cartilage is taken and then inserted into a, a hole that's made in over the O CD D effect.
Now, with regards to this procedure, you typically need to take bone and cartilage from the same patient and and perhaps going into a healthy joint. Typically, it's it's the stifle joint that's used in the abaxial aspects of the femoral trochlear. So that's quite an off-putting.
Reason for performing an osteochondral graft is that you'd have to go and cause some damage to an otherwise healthy joint and also the areas that we can take graph from the surface topography of the cartilage on the sides of the femoral trea tend to be concave, but the surface of the medial condyle is more convex, so they often don't match perfectly. Now you could use allograft. But it's not that readily available for for from dogs.
Now, in terms of our O CD say one of the common treatments is to actually take the flap away. So this is an example, actually, of a shoulder. This is the humeral head, not the humeral condo.
We can see this large O CD lesion. We can see the flap that's removed. And then this defect and the way that I tend to describe, O CD lesions to clients is they're like having a pothole on the road on the tarmac.
And the loose flap is like a loose bit of tarmac sat in the hole. Every time we drive over it, it rattles back and forth. And if you take that piece away less rattling, it'll make it a slightly smoother ride.
Now, if you have a very small, hole in the road, often the tyre kind of glides over. It doesn't cause too much of a problem. And if you have a small O CD lesion.
Then typically, we'd be thinking about something like micro picking, in order to act as a potential treatment. But if that pothole was very large in the road, then you'd really want the council to come and resurface it. And the same thing with perhaps our O CD.
We have a very large lesion. We may want to resurface that and end up with a smooth surface. So the way that can be done is is with, an implant called a Sinar.
Now this is the the shoulder, but I'll just show you as an example how the procedure is performed. So we first of all place in an aiming device to this cylinder over the defect and then drive a guide wire through, and it's important that we get the guide lined up correctly, so that's gonna set everything for the rest of the procedure. So it is going to take plenty of time to focus, make sure that we have the guide in the correct place and then drive a pin into centre of the O CD D effect.
Next step, then, is to create the core. So we're going to insert a a rema and this goes over the the pin that we just inserted, and this is then going to ream a little hole into the bone. It's like a little apple pourer, and then we can take our implants.
This is the Sinar implant again. It's a a press fit. It's very similar to the CUE in terms of design.
So we have this ultra smooth plastic top surface and then a trabecular bone metal on the underside. and the bone can grow into the trabecular metal. So this honeycomb appearance.
So we we take our our little plug, insert it into a little introducer, pop it into the hole, and then we can begin to tap it in place and then remove the introducer, and then we just need to see the implant in. So we're just gonna tap it in OK just to ensure it's fully seated. And that's our defect resurfaced.
And that's what that looks like on the humeral head again. That's the most common place for dogs to have an O CD lesion, and then the second most common place is the medial aspect of the humeral condyle and that's what an O CD lesion can look like. And that's our Sinar resurfacing.
So we tend to do a kind of quad medial approach to the elbow joint in order to access the, media aspect of the human condom so we can see that implant in place. The plastic doesn't show up on on the CT or the radiograph. We can see the, trabecular metal portion.
No, because a reason why the bone may fail to diffuse is because of pressure in the medial compartment and and actually in the majority of O CD cases in the elbow. Most dogs do also have concurrent medial coronoid disease. So because these dogs are often having increased pressure within the medial compartment and a poor fit to the joint, and they're usually diagnosing these dogs when they're under a year of age, I will very frequently combine them with a B oblique proximal ulnar osteotomy.
Now, another condition that I wanted to kind of quickly run through because we have reached an hour so we'll just try to go through. These last few is, these fissures that form within the humerus, and they used to be called or often referred to as as incomplete ossification of the Humeral condo IOHD. So you can see the image on the left.
We can see this transverse phys and when dogs are slightly younger, they do also have a a vertical phys as well. Running from the transverse phys down through the phesis towards the articular surface, it almost forms a T shape. Now, in this example, the kind of base vertical line of the T has already fused and you can see the horizontal line now in the middle image.
You can see that there is this fissure running through. There's this gap and the thought was that the bone never fused correctly and we had this gap that we can see on CT and we can also see it on the radiograph on the right and again classic is the sort of springer spaniels would have this this condition. But then in various practises, they started to get CT scanners, and we started to find partial fissures running through and also found some dogs who had AC T scan and there was no fissure.
And then later in life, AC T was repeated and a fissure formed and that therefore proved these fishes were not in complete ossification, but they were subsequently forming. And here's an example of an elbow that on the top two images you can see that there is some sclerosis. You can maybe see the very faint start of a Fisher.
And then when CT was repeated, we can see the sclerosis has progressed through the, human conduct and we can see that the fissure is also progressing so we can actually track this on sequential CT imaging. And if we look inside with an arthroscope again, we can see that linear fissure running through the back of the cartilage. So we tend to now no longer use IOHC as the diagnosis as a phrase, but more commonly using the phrase H I or humeral intracondylar fish.
Now the sort of classical treatment for H I has typically been to place a transcona screw in order to stabilise the fissure. Now, frequently, the bone becomes very sclerotic and often the fishes don't heal. But the screw is trying to prevent micro motion, at the fure site, which can lead to pain and lameness and also prevent the Condy from fracturing now the thought process that is been around for probably the last decade or so.
That's becoming a bit more widespread. People are considering it more. Is that perhaps these, this condition a hip occurs because of incongruity to the elbow, and the thought process is that it might be that the anal process is not fit fitting into the, caudal aspect of the humeral isthmus, the humeral condyle very well and therefore causing increased pressure and causing these fishes to form and therefore the thought process that's been discussed a lot and some surgeons are kind of going with, is to actually try to improve the congruity of the elbow or reduce pressure in the elbow by performing an ulnar osteotomy.
So you can see in in this, case of mine, I've actually gone and performed an a B que ulnar osteotomy in order to try and relieve pressure within the the elbow, which potentially may mean there's less force on this screw the screws having to do less work, and therefore less chance of the metal fatiguing and the screw breaking. And, what has also been been published is a case report whereby a hi I was diagnosed. An ulnar osteotomy was performed with no screw being placed.
And then evidence of that Hi healing. I know that and Danielski has has done this in a number of cases, and hopefully we'll be publishing results soon. But the results of that data might then start to make this this concept a bit more widespread of performing an ulnar osteotomy.
Now the downside is it's an additional procedure. Additional morbidity. These do tend to be older patients rather than one or 1.5 years of age.
They tend to be more maybe middle aged and they are springer spaniels, so very lively. So we can frequently, have worries about that ulnar healing and therefore perhaps these cases where, additional fixation with, say, an IM pin might provide some greater support. Now back back to the very beginning.
I discussed about the analogy of shoes, and I said at the time that very frequently with all these elbow conditions, we've touched on so far that the elbow looks like it generally fits together quite well. So I said, you've generally chosen shoes that are the right size for you, but occasionally we have elbows that just do not fit well. And maybe you have got some clown shoes or you have got some, toddler shoes and they're just not gonna fit your feet well at all.
So we can sometimes have some more severe forms of of incongruity to the elbow. And typically, we tend to either see a very short ulnar like in this example, or we may see a very short radius. And with these cases, we are typically wanting to consider trying to make the elbow a better fit.
Now again, the elbow joint is is very complex. It's a three dimensional structure. We often look at these radiographs, see things in two D, and you might think, Well, we just need to move the ulnar portion a little bit more proximal to make things fit together better.
But you almost need to think these is more like a a kind of a ball fitting into a socket. And it's, a very abnormal shaped kind of double Condi ball that has to fit into this socket of two pieces that subsequently twist and move relative to one another. So, we never get the joints to fit together absolutely perfectly, but we're trying to make them a better fit than perhaps this sort of situation.
So if we do have a short ulnar and we want to try to make the ulnar and radius match, either we can lengthen the ulnar or we can shorten the radius. And most surgeons would elect to, lengthen the ulnar, and that could be done with an ulnar osteotomy and allowing AAA gap to open and form again. Typically, we might be placing a pin into place to provide some additional stability.
Whilst that that bone fuses and heals. If we had a very short radius, then either we can lengthen the radius, or we can shorten the ulnar. Now shortening the ulnar in an already short radius would make that limb a little bit shorter than the contralateral.
But we're usually talking a small amount like a few millimetres, which is of generally minimal consequence, particularly in a in a quadruped. So it's typically easier to shorten the ulnar than it is to lengthen the radius. So that would be the procedure most commonly chosen so essentially would make a cut.
Of taking a a wedge out from the ness, taking a portion out. And then you can imagine that as this leg is loaded, that gap would compress down, and shorten the ulnar, causing the joint to fit together more appropriately. Now, if we do have a huge incongruity to the elbow, it's usually because of a mismatch in the length of the growth between the radius and the ulna.
So it's a problem in the antebrachial and as well as concerns of the elbow not fitting together very well. Frequently, we can have a abnormality in the shape of the Antebrachial, so we may have this antebrachial growth of V. This is the kind of classical example of of the sort of short ulna whereby we have increase increased Proco art, external torsion and valgus to the distal anti.
So if you do see a dog with an antebrachial growth deformity, also be thinking about its elbow joint. And could that elbow joint be, a mismatch of shape and dogs like this? We may need to correct the anti braum, so the foot is on at almost 90 degrees to the elbow, and then we want to do surgery to correct, realign and straighten the limb.
So we go from a a bendy leg to a straight leg. So that's it for this webinar. We have gone through elbow dysplasia or you might see a bit more commonly used.
Now is the phrase developmental elbow disease. We spent a lot of time on Media coronoid process, disease, because that is the most common, type of of elbow dysplasia. It's probably the most common cause of persistent thoracic limb lameness.
It's going to be high on our differential diagnostic diagnosis list for any dog with a thoracic limb lameness. We talk about how medial chal disease can progress into medial compartment disease. We also run through UAPO CD HIF.
And then we finished off with, just commenting that we can sometimes get real mismatch in the shape of the elbow. But that is usually uncommon. Usually the shoe is a kind of a close fit, but just not perfect.
It causes some rubbing and causes these problems, and that's the underlying problem. It's It's the elbow developing incorrectly as the dog is growing throughout the early months of life. So thank you very much for for joining me.
I hope you've picked up some, useful tips and pieces that you can take away and use in clinical practise. And if you do have any further questions, then just feel free to to reach out and get in touch, and I'd be happy to help.