Invictus Reviews

How to Never Miss an Elbow Fracture Again: A Radiographic Roadmap

• Mel Herbert

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We explore the essential techniques for accurately interpreting elbow X-rays, focusing on key lines, fat pad signs, and common fracture patterns that help reveal hidden injuries.

• Standard elbow series includes AP, lateral, and oblique views, with the lateral being the most critical "money shot"
• Two essential lines to draw: anterior humeral line (should pass through middle third of capitellum) and radiocapitellar line (should bisect the capitellum)
• Fat pad signs are crucial indicators – posterior fat pads are NEVER normal and always indicate pathology
• Pediatric injuries typically involve supracondylar fractures (60% of all pediatric elbow fractures)
• Adult injuries commonly involve radial head fractures, with 20-40% showing only fat pad signs initially
• Always check and document neurovascular status before and after any intervention
• Displaced or comminuted fractures require urgent orthopedic consultation
• Simple non-displaced fractures can be splinted with outpatient orthopedic follow-up

Check out the complete lecture and more educational content coming soon to the Invictus Board Review site.


Speaker 1:

All right party people. This is a short excerpt from one of our lectures that's going to be on the Invictus show. This is about the elbow, and this is about the lines that you need to draw in order to work out whether there's a fracture there or not, because they're sometimes not obvious. Daniel Campagne, let's do it.

Speaker 2:

So when you order an elbow series at most hospitals this is what you're going to get. You're going to get an AP, a lateral and oblique film. Every hospital is different so you may only just get an AP and a lateral, but this is the traditional. Most elbow series come with these three views. So we're going to kind of go through each view and talk about how best to approach those. So here's the AP elbow. You're going to take a look at this and see. You really want to look at the capitellum that articulates with the radial head. Of course you're going to take a look at all the outer bony cortexes and make sure there's no fracture, no break, no translucency going through that. Really make sure that everything just kind of lines up well. But this is a really good shot of that radial head. So you really want to look at and see, does that radial head line up with the capitellum? And really just draw a line there. The middle of that radial head should touch that capitellum and that way you know there's no radial head dislocation. Now this is the lateral of the elbow. I call this the money shot of the elbow. Right, if you only get one view of an elbow, this is the view you want, right? So it's kind of a great way to really assess the radial head. Really look at that coronoid process and really look at the olecranon. A lot of bones do overlap here, though, so there are some times you can't see something. So we're going to talk about it a little bit Like there's occult fractures that might be hidden in there that you can't see, but there's other tricks or clues that this view will show us that we can go and take a look on. So, really, here you're going to look and see does that trochlea articulate with the olecranon? Like, is everything in place so that there's no dislocation?

Speaker 2:

Let's also take a look at the lateral view, and things I want you to do is draw two lines and look at fat pads. So the two lines the first one is the anterior humeral line and the second one is the radiocapitellar line. So we're going to show you this on a diagram first. So the anterior humeral line is basically the line that goes on the surface of the humerus and it should pass through the middle third of the capitellum. So let's look at this on a film, right? So you're going to see, here's your lateral view of the elbow and here's your anterior humeral line. So you can see you drop from the anterior surface of the humerus. It's going to go straight down and intersect that capitellum and this shows it actually intersects the tip of the capitellum, not the middle. Third, so you can see that there's a subtle supracondylar fracture. So the radiocapitellar line is a line that's drawn through the shaft of the radius. So you take, kind of the middle of that radius, that red line. You're going to draw it all the way through and that should also bisect the capitellum. So these lines should intersect nice and beautifully.

Speaker 2:

So here is an example of this. You can see, on the top is the lateral view and you can see that that line intersects the capitellum perfectly. And then, once again, on the AP view, you're going to see that that radial head does line up with the capitellum. So here's a case for you. Take a look at it, let's draw our lines together. So you're going to say where's my anterior humeral line and where's my radiocapitellar line. So this one has a very abnormal radiocapitellar line. So you can see that when it goes through the radius it does not even touch the capitellum, right the capitellum and it are far away. There's your capitellum there, and so this is a dislocation of the radial head. You can see how it's easy to miss unless you draw your lines. Once you draw your lines it really stands out for you. So let's review the lines of the elbow.

Speaker 2:

So every elbow, if you're taking an x-ray for pain, take an x-ray because they can't move it, take an x-ray because they fell. You're going to draw the lines of the elbow. So you have the anterior humeral line and you have the radiocapital line. Next is you're going to look at fat pads. So fat pads we call them the fat pad sign. Small anterior fat pads can be normal. Big fat pads on the anterior surface are called a sale sign. Those are always abnormal. So in this x-ray you can see there's an anterior fat pad that's large, quite large. It's a sale sign.

Speaker 2:

And there's a posterior fat pad that you can see. It's just kind of that hazy lucency that you see behind the bone. So if you think about it, basically you have the olecranon fossa in the posterior side of your humerus and really when you get an effusion in your joint, so you fall on your elbow, you get blood in there, you get some kind of liquid in there. It pushes out that fat pad and that's what we're seeing. So in the x-ray, that's why it has a nice lucency, so that fat pad gets displaced out of the electron fossa. So it's never, never normal to have a posterior fat pad. So in your mind, just think, if I see a posterior fat pad, something's going wrong in this elbow. I don't know exactly what, but I know that something's wrong in this elbow.

Speaker 1:

So really important point there. Any effusion blood in an elbow joint can produce that sail sign. So the normal fat pad is sort of stuck right near the anterior humerus. If it's sailed out there's an effusion, and if there's trauma we presume that that effusion is blood. But it can occur just from, like septic arthritis or anything else as well. Very important point.

Speaker 2:

Let's go through some cases and talk about these and draw our line and look for our fat pads. First case 12-year-old. He's playing with soccer. He falls on his outstretched hand, he complains of elbow pain, is unable to range his elbow. Here's his x-ray. So you go ahead, draw your lines, look for fat pads. Let's go through it together.

Speaker 2:

So is there a fat pad sign? Yes, there is right. Posterior fat pad sign yes, there is right. Posterior fat pad always abnormal. What about my lines? You know, there's my anterior humeral line. It is displaced a little bit. It's in the front right of that capitellum. It should be in the middle right. It should be in the middle third of that capitellum. So there's abnormal. Now you say do I see a fracture in there? You may peek and see a fracture. Your radiocapitellar line is pretty normal, but there your fracture. So it's a very subtle supracondylar fracture. If you had missed that supracondylar fracture and not seen it, it would be okay, because you knew there was a fat pad, you knew there was an anterior humeral line that was off and you would have sling them or splinted them and sent them to ortho for an outpatient. So one way, doing your lines and looking for your fat pads kind of saves you because you know that that's abnormal. You're going to put them in a sling or a splint and get them to follow up. So if it's a kid, it's almost always an occult supracondylar. If it's an adult, it's an occult radial head fracture. So this is a supracondylar fracture. It's a kid that was playing soccer, so we know that it's a kid.

Speaker 2:

Now supracondylar fractures I want to delve into a little bit. So they're very common 60% of all elbow fractures in pediatrics. So you're going to see these a lot. They're almost always a fall and an outstretched hand. The biggest thing is the neurovascular bundles that kind of go by that elbow. So here's a nice illustration to show you that when you have this fracture it's really close to the median nerve, it's really close to the brachial artery.

Speaker 2:

So it's very important to document on your chart and to do an exam with the patient before you even move this elbow, before you touch it, before you do anything. Do they have a pulse? Do they have intact vasculature? So 20% of these cases are going to have a nerve injury and the nerve injury is usually median and radial nerve. So let's just go over our nerves a little bit.

Speaker 2:

So, remember, in supracondylar fractures, you're going to examine them. Distal to the injury, right? So remember, in supracondylar fractures, you're going to examine them. Distal to the injury, right? So they just injured their elbow, so you're gonna look at their hand. So here's a great diagram of sensation of the hand to reflect the nerves. So a sensation of that medial nerve, right, you're going to. It's the kind of purplish blue color. Here You're going to see the palmar side, the pal, the hand, and so I always like to do it in between your thumb and first finger, make sure they can feel. And then for motor, it's like can they make the okay sign and then can they give you a thumbs up for radius, for the radial nerve, or can they don't have wrist drop. So those are things you want to just make sure are always documented in your chart referrals.

Speaker 2:

And really, if they have those deficits, this becomes a much more urgent call to orthopedics. Right, they have a deficit of a nerve, they've got a deficit of a pulse. This becomes an emergent case. So how do you treat supracondylar fractures? Right, so you're going to splint them. They're going to get outpatient referral to orthopedics. Now I say, splint them if they're stable fractures very small, non-displaced or minimally displaced. So that's the supracondylar fracture we saw in this case. Right, just a tiny ditzel, easy to miss. It's very small. What if it's giant? So let's talk about that. What if it's, this case, a displaced supracondylar fracture?

Speaker 2:

So this is one that your pharmacist or an administrator walking through your hospital will see this x-ray and go, ooh, something's wrong with this elbow, like anybody will know that this is broken and this is very abnormal. So this one you're not going to touch, you're not going to reduce it. You're going to really check that neurovascular status because the chance of them having a deficit is really high. I mean, look at how wide that is, how spread out that poor humerus is and there's all those vascular bundles and the nerves that just ran right by those fracture fragments. So this is an urgent orthopedic consult in the ER.

Speaker 2:

Now, if this is a kid and you're in a small rural place, you might transfer them to a pediatric center, right, that has pediatric orthopedics. So this one you would call your orthopod in the middle of the night. You're going to transfer them, if you don't have orthopedics or you don't have pediatric ortho, because these need an ORIF. Don't reduce them, don't move it. So you're going to feel for a pulse. They have a pulse. You're going to feel sensation, even if they have decreased sensation, but they have a good pulse. You're going to splint them as they lie. What you worry about is they have a good pulse even though it looks like this. If you try to reduce it, you can make it much, much worse. So the door as an ER doctor I would not touch this unless I've talked to orthopedics, because a lot of these are going to go straight to the OR and they're going to reduce them on their fluoro and they're going to operate on them to fix this and you don't want to make something worse. So trying to reduce this can actually cause a pulse deficit and we don't want to do that.

Speaker 2:

Lunch up to a new case 24 year old playing basketball falls on his outstretched hand. He comes in complaining of elbow pain. So once again, we go through our lines, go through our fat pads. Take a look at this before we go through it together. So here's our line anterior humeral line. Here's our radiocapitellar line. So the radiocapitellar line is pretty off right. It doesn't bisect the capitellum at all. What about fat pads Right? So the posterior fat pad there is just a sliver of one, but it is there and it's abnormal. Remember, they're always abnormal. So just a reminder to everybody here's your lines right Anterior humeral line needs to be in the middle third of the capitellum and then that radial capitellar line needs to bisect the capitellum. So we already know in this x-ray that something's off, something's wrong because the lines don't line up. So what's the diagnosis?

Speaker 2:

But first let's look at the AP view. So you kind of see in the AP view what's going on there in the radial head. There's a little crack there so you can see, oh, there's a radial head fracture. And then, if you wanted to also do your lines on your AP view, you would see that the radial head that was still in place is not dislocated. It does articulate with the capitellum but it is an interarticular fracture of the radial head. So you can see on the lateral view you can would still sling this person because you'd say, hey, there's an abnormal fat pad, there's abnormal lines. I know there's an occult radial head fracture here. I'm going to put them in a sling.

Speaker 2:

So this is a review of those lines. We just looked at how that radiocapitellar line is off. The anterior humeral line looks okay, but that fat pad's abnormal. So you're going to treat it as a radial head fracture. Now, what about this one? So you're going to treat it as a radial head fracture?

Speaker 2:

Now what about this one? So you look at this view and you say, danielle, it looks pretty crooked. A lot of us see these in our hospitals, right, the radiology tech uploads it just like this. It's off to the side. So I highly recommend to you rotate it, put it like you're used to seeing put the humerus straight up the radius and ulna going the other direction. Kind of. Give yourself all the tools and tricks. We can go back and you could tilt your head and kind of angle at it and go okay, I think I see my lines. But really do yourself a favor. Most of those software programs allow you to rotate images pretty easily. You have to turn the screen of your computer, but you really want to look at a lateral film, just like this. So your brain kind of gets used to seeing these patterns and recognizing them. So look at them always the same way.

Speaker 2:

So let's go ahead and go through this one, right? So what are my lines? Are there any fat pads? Do I see a sale sign. So there's my lines anterior humeral line, radiocapitellar line. What do you think about those? So the radiocapitellar line is a little bit off. Right, it should be in the middle there and should bisect it, and it's not.

Speaker 2:

And then what about the fat pads? There is a posterior fat pad and there's even a sale sign. So you'd see that very large anterior fat pad. So remember, posterior should never be there. So we know that's abnormal. Number one Sale sign is big. That's abnormal. Two, and then abnormal line.

Speaker 2:

So even if I see no fracture on this, I know that something's wrong with this elbow. So we're going to call it an occult radial head fracture. So how do I treat these right? So here's radial head fracture pearls so about 20% to 40% are associated with just fat pads alone. So that means that on all your x-rays all you're going to see is a fat pad. And that's okay because you're going to sling them. I put that asterisk there because, remember, you're going to sling them for simple, non-displaced fractures, ones that just like the ones we've been reviewing, the very tiny, tiny chips. No one's going to operate on those, those are going to heal on their own. They're going to get orthopedic referrals and outpatient, you know they want to be seen in the next. You know seven to 10 days Now for a radial head that's comminuted, that's displaced, that looks really bad, that needs an orthopedic referral in the ER. So you got to call them and say, hey, this is a displaced radial head, it's comminuted, it's in tons of fracture pieces because those are going to have an operation.

Speaker 2:

Let's jump to a new case. 20-year-old motorcycle crash comes with severe elbow pain, has a deformity on his elbow on the scene. But he says that the deformity actually kind of went away when the paramedics tried to splint it in like those box splints. This is their x-ray. So you take a look at it and you see, oh, there's a lot of crunchy bones in there right. So off the get-go you know something's wrong with it. You can't even get your lines right Because there's not even a true lateral on that lateral x-ray. So you can try but nothing's going to work because you're not even a true lateral film.

Speaker 2:

So we take a look at you say, okay, what pieces do I see are broken. So this is trying to do your radiocapitellar line. You can't do it because things are too broken. Now on the AP view you can see that that radial head is broken there, but it's not dislocated, just the fracture fragment is moved. So let's take a look at this again and just say, okay, what are my injuries? I've got an olecranon fracture. I've got a fracture of the proximal radius, so it's a proximal ulnar fracture and a proximal radial fracture. So you've got two bones very important that make up the elbow, both of them broken.

Speaker 2:

So when we talk about this, what are you going to do with this? You're going to consult the orthopedics in the emergency department. So if you don't have ortho in your department, you got to transfer them somewhere and you got to splint them. These are going to be a posterior long arm split. So the idea is to immobilize the elbow and the wrist. You want no supination, no pronation, no flexion, no extension and then really do a good neurovascular exam before and after your intervention. So you're going to do it before you splint them and then you're going to do it after to make sure that nothing has changed.

Speaker 1:

All right. So now you know those lines go from a lot of times because this is definitely on the exam. This is on the exam all the time. There's a lot more to this lecture and it will be coming soon to the Invictus Board Review site that we're building and collecting all the information and all the people in the lectures and it's going to be awesome Coming soon-ish, robert, out.