Thank you for the invitation. I'm Bharti Khurana, and I'll be speaking on hip emergencies. Here are my disclosures. So in the next 15 minutes, I will be focusing on what not to miss, how not to miss, and why not to miss when you are interpreting hip studies in the emergency department. So as we all know, the hip joint is a synovial joint with a ball and socket configuration. The femoral head is well seated in the deep fossa of the epitabulum, making it a very stable joint. The neck is also strong. It's like a pyramid with a broad base. But as we get older, we start seeing femoral neck fractures. And the importance of hip fracture is reflected by this statement from a famous hip surgeon of the last century. We come into the world under the brim of the pelvis and go out through the neck of femur. Let's see where we stand in 2020. We have very high annual incidence. And even though we are doing a great job with osteoporosis prevention and treatment, the incidence of fracture is rising due to increasing lifespan. Our elderly folks are a lot more active on more medications, making them prone to fall. A prompt diagnosis of hip fracture is important because the delay of only two days when surgical treatment is needed can double the mortality. Post-traumatic osteonecrosis can double up in one third of patients. And the current recommendation is to treat the displaced fracture within 24 hours. So imaging does play a huge role. So let's start with our first case. 66-year-old woman, status post-fall from standing with acute right hip pain. And you have two radiographs. So we have healing or subacute superior-inferior pubic rami fractures. Now, this finding was missed. And if we do CT, there is an impacted subcapital femoral neck fracture. And this impacted femoral neck fracture was misconstrued as an osteophyte. So here is another example. Same thing, mushroom capping and a subtle zone of sclerosis. That is varus-impacted subcapital femoral neck fracture. Here is an illustration from our radiographics article. The femoral head has slipped medially. And you may or may not see the fracture line laterally. So how does an osteophyte look like? Now, osteophyte continues as a fine line of sclerosis. The sclerosis due to impacted fracture often has ill-defined margins. Now, if you draw a line along the lateral cortex of femoral neck, it often intersects. It should intersect the portion of femoral head. But in varus-impaction, it does not intersect femoral head because the femoral head has displaced medially. So the other fracture which often gets missed is the valgus-impaction. There is a subtle cortical disruption at the femoral head neck junction laterally. And that's the valgus-impaction fracture. So here are two more examples of valgus-impaction. Again, there is subtle contour change or abrupt contour change of the lateral femoral head neck junction. So these are examples of valgus-impaction often get missed. And often, the reason is that we don't have the correct view. So always make sure that you have a nice internal rotation view where you can clearly see the femoral head neck junction. So how do these fractures get treated? So it depends whether the fracture is non-displaced or displaced. So if it's a young patient less than 65 or active, the goal is to preserve femoral head, avoid osteonecrosis, and achieve union. So non-displaced fractures get percutaneous fixation. But if it's a displaced fracture, then you get ORIF. But if it's an old patient or the patient is immobile, the goal is to restore mobility and minimize complications. Still, if it's non-displaced, you do percutaneous fixation. But then if it's displaced, you end up getting arthroplasty. So here is another fracture you should know. This is actually the fracture at the junction of femoral neck and intertrochanteric region. And it's called basi-cervical fracture. So femoral neck fracture comes in three flavors. You have subcapital, transcervical, and basi-cervical. It is important for us to differentiate basi-cervical from subcapital and transcervical. There is no point in differentiating subcapital and transcervical because they are managed exactly the same way because both are treated as intracapsular. However, basi-cervical is treated as extracapsular. So something to remember. There are two examples of basi-cervical. It's just always at the junction of the femoral neck and intertrochanteric region. It's slightly proximal to the intertrochanteric region, but it's treated differently. So sometimes you have radiographs like this where you follow all the rules. You still don't see fracture line. So where is the fracture? When you do MRI, you see a non-displaced fracture, and you call it as occult hip fracture. Here is another radiograph where you don't see fracture line, but there is an intertrochanteric fracture on MRI. And we all know the difference between occult and missed fracture. It is an occult fracture if you have read the radiograph, and it's a missed fracture if your partner has read the film. So what is an occult hip fracture? It's an incomplete fracture or a complete fracture without displacement. It is more common in elderly with osteoporosis and minor trauma. Just to give you an idea, in our ED, when we went through all our MRI studies, one-third of studies were positive for fracture. And out of those, one-third of fractures were in femur. And there's a new meta-analysis actually just published in Radiology where they showed actually high frequency of radiographically occult hip fracture or radiographically occult surgical hip fracture in elderly patients. So you are not wrong in recommending advanced imaging in elderly and osteoporotic patients. Now, how does it look like on CT? So CT, if there is a lucency, you can clearly see on CT. MRIs are used to seeing this fracture lucency well. You don't miss on CT. However, if it's an impacted fracture where you really have to see the alignment of trabecula, just like in radiograph, you can miss. So this kind of fracture with diffraction, you will see that on radiograph anyway. But, you know, the impacted fractures can get missed on CT. So here's another example where it's very nicely seen on coronal because, you know, you know where to look for and, you know, you have to see like different reformations. But these impacted fractures, you can imagine if you just look at the axial, you are going to miss them. So dual energy CT is actually quite promising in this area. It does give confidence to our trainees when they are able to see marrow edema, just like MRI. And we have very few cases where we got both CT and MRI and definitely, you know, all our CTs are done with dual energy. So here are some examples where we did dual energy CT on pan-scan trauma, and they could see fracture involving greater trochanter, and here is the dual energy CT showing marrow edema extending to the intertrochanteric area. And it actually correlates well with MRI images. So here is another patient, sorry, here's another patient. We have the greater trochanteric fracture and then marrow edema going and correlating pretty nicely on MRI. So the advantage with MRI is that you really don't worry, you don't have to worry about trabecular displacement or cortical displacement. You are calling based on edema. And that's the great point with MRI. It is much easier to see on MRI because of associated marrow edema. And at our institution, we've been using abbreviated or focused hip MRI, which includes steric coronal, T1 coronal, and T2 facet axial. And we've been doing it for almost 80 years, and we have great experience. And it's actually great because it takes only 15 minutes, and we get definite answer. So make sure that you have steric coronal, so don't compromise. So you can see this example. It's actually hard to see marrow edema, sometimes it looks like erythropoietic marrow, but on ster, you can be confident with the marrow edema. So ster is essential, don't compromise there. And just be careful. You know, you might miss a small cortical edelgen fracture on MRI. So MRI is not just one-stop shopping. Here is an example. We have gluteus medius tendon edema, or tear, this is how it was called. And there was bursitis. We did x-ray afterwards and one could see fracture. And then CT, definitely fracture. And retrospectively, there was a tiny fracture of the greater trochanter. So again, just like spine, we can miss these small edelgen or cortical edelgen fractures. So let's go to our second scenario. 43-year-old woman preparing for marathon with worsening right hip pain. So we see this irregular line on MRIs. This is stress fracture. So we are more used to seeing this kind of stress fracture, where you have marrow edema, a lot of marrow edema, and subtle fracture lines. So that is more of, that is called fatigue fracture. Now, femoral neck stress fracture comes in three flavors. So you have compressive fracture, the classic one which you tend to see with fatigue. Tensile is more often involving the lateral component, the supralateral component, and it can become displaced and it's often considered unstable. And then you have the displaced variety. So here is the example of tensile fracture. So tensile stress fracture needs to be treated surgically because they tend to get displaced, like in this patient. So patient got her MRI at an imaging center and then got x-ray. By the time she got to ED, her fracture was fully displaced. So remember insufficiency fracture. Insufficiency fracture is where the bones are weak. So you look for those classic locations. So sacral fracture, supracetabular, superior and inferior pubic MRI fractures, parasympathia, and ischial. So always look for those. And remember, they are often multiple, so just don't stop at one. If you're reading focused MRI and ED, always look for multiple fractures. So you have supracetabular femoral neck, intertrochanteric, contralateral femoral neck, contralateral supracetabular, and bilateral sacral. So often they are multiple. So here is our third example. An 83-year-old woman, status post-fall from standing, presenting with acute left hip pain. And here is a fracture. So is this a subtrochanteric fracture? So remember, the typical subtrochanteric fractures are often oblique or spiral. They're often culminated and present with significant shortening. And their prognosis is poor because of high rates of failure. So this is a typical subtrochanteric fracture. So the fracture I showed you is an atypical subtrochanteric fracture because it's a short, oblique, or transverse fracture. There is no combination. There is medial spiking. And there is thickened lateral cortex. Now, again, use the correct terminology, which we covered in our radiographics article. So we saw stress fractures earlier, which are due to microcracks in otherwise normal bone. Now, the etiology of bisphosphonate-induced insufficiency fractures is thought to be secondary to abnormal bone remodeling from prolonged osteoclast suppression in the subtrochanteric femoral shaft. Now, this is different from pathologic fracture, which are due to deposition of focal lesions disrupting the ability of bone to repair. So make sure you use the correct terminology. Now, if you see an atypical femoral fracture, it's always a good idea to do the contralateral side because there is a high likelihood that you would see a little bump, which is representing an incomplete insufficiency fracture. And if you wait, it can progress to a full subtrochanteric fracture. So you want to avoid this. So that's why you want to catch when you're seeing little bump. So that is an incomplete fracture. Now, this is pathologic subtrochanteric fracture because you have a lytic lesion. And through that lytic lesion, the bone has fractured. So that is pathologic subtrochanteric. And here is another case with diffuse breast cancer metastasis and a pathological fracture. So here is our fourth scenario, 46-year-old man, status post-MBA. And here is a pelvic radiograph. So what's wrong with left hip? So there appears to be an acetabular fracture, which was called, but this dislocation was missed initially. Now, remember your Shenton's line. So if you draw along the inferior aspect of the superior pubic ramus, it should nicely go along the femoral neck, along the medial femoral neck. So this is dislocated hip. And remember why we do pelvic radiographs before doing whole body CT in cases of trauma. The reason is actually hip dislocation. Everything else we can see on CT. If there is hip dislocation, the surgeons would like to reduce before going to CT. So we want to reduce as soon as possible. So make sure that you are always looking at bilateral hips because that is extremely important before we do CT. So obviously we never want to see dislocated hip on CT. So here we have femoral head going posterior to the acetabulum. So it's dislocated hip with fracture and lipohemothorosis. So get used to the appearance of hip dislocation on pelvic radiographs. So remember it's usually supralateral if there is posterior dislocation and the femoral head usually appears smaller compared to the contralateral side if it's dislocated posteriorly, unlike anterior dislocation where it will move infromedially. And also the femoral head would appear larger compared to the other side because it has moved in anterior direction. So there will be magnification. So we have covered more details of dislocation in our article, but in the interest of time, I'm just going to stop here. Hello, everyone. I'd like to welcome you to RC408B. And I'm going to talk to you about knee imaging today. I'm Jonathan Flew from the Mayo Clinic in Arizona. I'd like to thank the RSNA for finding a way to make this meeting work this year despite all the immense challenges out there. And I'd like to thank the course directors for inviting me to speak to you all. I have no financial resources. We're going to talk about how to recognize subtle injuries of the knee and other less recognized injuries around the knee, talk about some of the pathophysiology of these knee injuries, learn to use cross-sectional imaging when clinically relevant, and talk about some of the things that are clinically pertinent that will help reports that trigger treatment. Here's an outline of some of the etiologies and areas we're going to talk about. And this is just a review of some of the clinical decision rules used in the ED for when to decide which patients need knee x-rays. So I want to start by talking about simple joint effusion. So this is a very important finding for knee trauma in the ED. X-ray can be sensitive to detect up to 4 to 5 mLs of joint fluid. And what we want to look for is increased density in the super patellar recess. But particularly we want to see this density coursing between the anterior super patellar and pre-femoral fat pads outlined by the white and black arrows respectively. We have two corresponding MR images showing those fat pads and showing the way the super patellar recess courses between them. In ligamentous injuries, you can have a hemarthrosis acutely, which changes to a reactive effusion 12 to 24 hours. And here's an example where on the left we have a large joint effusion and you can see the soft tissue attenuation between the two fat pads we previously discussed. In the middle, we have a lipohemarthrosis in a patient who had a cross-table lateral view. So we have layering between the fat and fluid, which if we were to rotate, the x-ray would be parallel to the floor. And in the case on the right was actually a patient with lipohemarthrosis from an osseous contusion that wasn't suspected. So he was actually imaged upright and you can see that we now have the layering fat fluid components again parallel to the floor, but upright as we would expect given the image. So I want to start with a very common yet challenging diagnosis in the ED, which are tibial plateau fractures. And if we look here, the AP and oblique views, if you look in the blue box, you can see the little defect in the tibial plateau corresponding to the non-displaced fracture. The black arrow is just showing some deeper extension of the fracture, which came into play later on in this patient. When we take the lateral view of the knee and rotate it the way the patient was imaged, we can see the layering lipohemarthrosis, which indicates an intra-articular fracture. So these tend to be high energy injuries. It's more common to have a lateral tibial plateau fracture because of the stronger cancellous trabecula medially. And the Schatzker classification is used to classify these fractures. Now, I don't think it's important to know all six of these by heart, but I think it is important to recognize what are the clinically pertinent features of these fractures that you may want to describe in your review. And just to show you on this patient, here are the initial x-rays on the left. You can see the fracture was non-displaced. This patient actually went on to non-union. And after six months, you can see the depression of that lateral tibial plateau, and now the sclerosis extending to the medial tibial plateau, indicating extension of the... Next, I'd like to talk about tibial tubercle fractures. So these fractures, which you can see here, tend to occur more commonly in males as they near the end of their skeletal growth, so about 12 to 15 years old, who engage in athletic activity. You tend to see these in baseball, football, sprinting, and high jump. What you can see here, what I'm showing you on the AP, is that if you look through the blue box, you can see that lucency in the area of the tibial tubercle. And obviously, this fracture is much more evident on the lateral view where, in this case, we have hinging of that fracture fragment. You can see the patellar tendon inserting on the tibial tubercle. These can be associated with compartment syndrome, but fortunately, have a high rate of fracture healing and a low rate of leg length discrepancy. Normal fissile closure is from posterior to anterior and proximal to distal, which leads to this fracture pattern. Next, I'd like to talk about patellar fractures. So here's an example of a normal knee, and just showing you the different ways you can assess the patella. So on the AP through the femur, on the lateral view, we can see the posterior articular surface. And if we can get a good patellofemoral view, we can see the medial and lateral facets. These tend to be from direct trauma, usually a fall. The patellar sleeve fracture occurs in the pediatric population, which we'll talk about separately. And when you're assessing these, you really want to note, are the fragments displaced or non-displaced? Is it transverse, vertical, or comminuted? And if these don't heal properly, these can have significant functional implications. So here's an example of a patellar fracture on the AP. As we look through the femur, you can actually see the lucency between the fracture fragments. This is much more evident on the lateral view, where we can see the marked distraction in this transversely oriented fracture with the effusion that extends through the fracture fragments into the pre-patellar bursa. On the patellofemoral view, you can see the lucency through the patella, but you can see that it's not clearly as evident as it is on that lateral view. And this patient went on to have a CT, and you can see the quadriceps tendon and patellar tendon, which are leading to the distraction between those fracture fragments. And a nice example of an effusion in the two associated facets. Next, I'd like to talk about patellar sleeve injuries. So these are avulsion injuries that occur in skeletally immature patients. And what's avulsing is the unossified epiphyseal cartilage from the patella. What we see in these cases is lucency through the rim of the patella, like we do on this patellofemoral view. And the real tell in this case is the extensive pre-patellar bursitis that we have. Here's a companion case of a different patient with an avulsion involving the patellar tendon and the inferior part of the patella. And just showing you the T2 hyperintense signal that corresponds to the lucency we see on the image. Two common anatomic variants of the patella that we don't want to confuse for a fracture would be the dorsal defect of the patella, which we see in this case here as a lucency in the superlateral margin of the patella on both the AP and lateral views, and the bipartite patella, which we see here. And just a reminder, even though these are normal anatomic variants, these can be symptomatic, like in this case where there's edema on both sides. Next, I want to talk about the intercondylar eminence of the knee, which is an important area to scrutinize when you're reading these x-rays. So this is located between the medial and lateral articular surfaces and serves as a very important attachment site of the ACL, PCL, and menisca. So when we're looking for avulsion injuries here, we're really concerned about functional issues involving those structures. In skeletonally immature patients, we'll tend to see these as more avulsion injuries, whereas in adults, the ligaments are going to insert directly onto the bone, and we have corresponding ligament tears instead of avulsion fractures. When we do have fractures, we want to assess the degree of displacement of the avulsed fragment or hinging. So here's an example of a 17-year-old, I believe, who had a road bike injury. And you can see on the x-rays, there's a lipohemarthrosis and also a little bit of lucency at the posterior margin of that intercondylar eminence. On the AP view, you can see that there's just more lucency in that area than you'd expect. This patient went on to have CTs and an MRI, and you can see a hinged fracture fragment at the posterior margin of the intercondylar eminence, which corresponds with the insertion site of the PCL, which is the low signal ligament inserting on that fracture fragment. So this is an example of a hinged fracture fragment in that area. Another avulsion-type injury around the knee to discuss would be the second fracture. So we want to use whatever tips we can find on the x-rays. So knowing that these x-rays were taken in a ski resort is always a good sign to be on the lookout for trauma. And in this case, what we see here is this avulsion at the lateral margin of the lateral tibial plateau, which on the subsequent MR is shown to correspond to a patient who has a full thickness ACL tear. And we can see that little capsular avulsion on CT and MR in this case. The Sagan fracture itself is not a clinically unstable fracture, but it's more of its association with ACL tear, which can be about 75%. Tends to be seen in ACL tears that occur secondary to internal rotation and varus stress. And then a reverse Sagan would be on the medial side of the tibia, which is associated with the deep fibers of the medial collateral ligament, and tends to be seen in high-velocity injuries, particularly knee dislocation and PCL tears. So that's another sign we don't want. Just to show you a different entity, this is a steata fracture. So this is an avulsion fracture involving the femoral attachments of the deep fiber of a deep component of the medial collateral ligament. It's a very rare injury, but just to show another example of an avulsion-type injury around the knee that's really indicative of ligamentous failure. A very important injury that we need to talk about is the arcuate sign or fibular head fracture. And this is an avulsion of the proximal fibula where the arcuate ligament complex inserts, which is structurally very important for the knee, particularly with posterolateral instability. And this may reflect an avulsion of a lateral collateral ligament, biceps femoris, or both. And here are the numerous stabilizers which insert on the posterolateral corner. Just to show you an example, here's some multi-planar reformatted images from an MR the knee showing the fibular collateral ligament and the biceps femoris and their insertion on the proximal fibula. And this is what we're losing when that piece of bone. Next, I want to talk about a rare but very important injury, the knee dislocation. So here's an example where we have two x-rays showing you an anterior tibial dislocation. You can see the patella is corresponding, aligning with the tibia. The tibia is perched on the femur. You can also see the non-displaced fibular head fracture. And just to give you an idea, here's a couple of MR images from this patient. And just for starters, we see the extensive edema after they've been reduced. But we've got an ACL tear, full thickness, PCL tear, and fibular collateral ligament and its femoral attachment on top of the fibular fracture. So these cases are often associated with multiligamentous injury and really further imaging when they occur. So knee dislocations are high-energy traumatic injuries. The anterior dislocation is more common than the posterior, like we saw before. These have a high rate of vascular injury. And actually, the posterior knee dislocation is most commonly associated with a vascular injury in the popliteal artery. Treatment involves emergency reduction. And then it's really all about perfusion assessment in the limb. Believe it or not, 50% of these may self-reduce and can as a result may be underreported. 60% have associated fractures. And the various soft tissue injuries we can see include patellar tendon rupture, periarticular avulsion injuries, and displaced menisca. So that same patient from earlier after the reduction went on to have a CT angiogram, which is often warranted in these patients to assess for vascular injury. And you can see this focal change in the size of the lumen of the popliteal artery posterior to the knee, which was thought to be secondary to probably an interval injury. This is a subtle case, but just an example of what we would be looking for. And then lastly, I just want to talk about the other joint that can dislocate next to the knee, which is the tibiofibular joint. So this is a case of a proximal tibiofibular dislocation. And on the x-ray, you can see widening between the tibia and fibula. And the MR that we see here corresponds showing that same widening along with disruption of the anterior and posterior tibiofibular ligaments. These are rare injuries, but can be associated with posterior hip dislocation. And just another thing to be aware of that in another area we should be scrutinizing on our knee. So in conclusion, knee injuries range from minor contusions to limb-threatening popliteal artery injuries. The main goal in the ED is to prevent further damage and defer definitive treatment to other settings. So in order to do that, we need to know about the subtle x-ray findings that can be indicative of severe soft tissue injuries and other severe ligamentous and vascular injuries. When we're concerned about those, MRI and CT andriography can play a critical role in further diagnosing and deriving the treatment. And again, we want to get a minimum of two views with additional views. Thank you very much. Hello. I'm Nix Kumaravel. I'm a radiologist at UT in Houston in Texas. I would like to say thanks to RSNA for this opportunity to talk to you today. And my topic is about shoulder trauma. I don't have any financial disclosures. Here's the main objective in the next few minutes. We want to recognize subtle injuries on radiographs. We want to understand less common injuries in the shoulder that can happen. We want to improve diagnostic yield with cross-sectional imaging as such. And then hopefully have a clinical emphasis on the entire spectrum of injuries that we're going to deal with, because that's what matters. And I'm going to share my experience with you from the local hospital here, as well as from my previous training in orthopedic surgery as a resident. Here's the outline that we're going to touch upon. We're going to very briefly talk about radiography, particularly one view, and then we're going to talk about dislocations. We'll talk about scapular fractures and we'll wind up with scapular thoracic dissociation. Given the amount of time, that's all we can do right now. As we all know, these are the common views that we do for a shoulder view. When you look at the AP, these are the images that are being generated, as we're aware. And what we want to see here is the overlap between the oval shape of the glenoid and along with the circular nature of the humal head. That's what we want to know. Here's an example right here. You can see the anterior margins and posterior margin and the humal head. What we're interested in is this overlap over here, which tells us that there's about six millimeters or so, and that's important for you to make sure that the shoulder isn't joint. This also gives you the congruency of the joint and gives you an idea about what the cartilage is doing. A grassy view, 45 degrees away, and you end up with one of these, where you get a good idea of what's happening to the cartilage in between the humal head and the glenoid as such. Here's an example of the grassy view. Look for congruity between the two, talking about the cartilage. A scapular-wide view, when the patient's 45 degrees away in a PA projection. That's how you get this. And you end up with one of these, where you want to identify the coracoid process, the spine of the scapula and the body of the scapula. That gives you the why. And what we're primarily interested in is what's happening to the glenoid and is the humerus sitting on top of the glenoid. And that's basically what you're looking for. I would like to make a plug for this view here. That's an axillary view. This is typically how it's done. I recommend it. But you can imagine how painful this would be for a patient to do this. But I learned from Jose Martinez, who is actually a technologist with us in the ER, that you don't have to do that. You can actually do this, and you can still get a pretty reasonable view of the axillary projection. An axillary projection looks like this. And we want to know where the glenoid and the humeral articulation is going to be. More importantly, we want to know where the coracoid process and then the AC joint, because great foreinjury of the AC ligaments across here would result in a displacement across this joint, and we want to be able to figure that out. Remember, the little prominence here is going to be the lesser tuberosity. Let's move on and talk about dislocations now. When you think about dislocation, pretty much most of it's going to be anterior dislocation. And then we have the smaller subset, which is the pustular dislocation, and even more rare dislocations as well. Let's look at some examples. Here's a patient fall while skinning. This is an obvious dislocation of the entire shoulder, and the humeral head is now sitting at the subcoracoid location, as we can see. So why do we need radiographs? The primary reason for the radiographs is actually to try and assess the glenoid, if you can, here at this location on axillary projection. You can see the margin of the glenoid is your humeral head and the spine of the scapula, and you're trying to figure out if there's any deficit in any of these bones that you're looking at. That's an anterior dislocation, as we can see. Let's look at another example. Bike accident and a shoulder pain patient presenting to the ER. When you look at this example, you can actually see that there is some abnormality rate in anterior fetal position of the glenoid, and that might raise possibilities about what else is going on. And you want to try and see this bony back arm injury is displaced very minimally, and you want to assess one of the different things you want to do with this, and with the realization that 15% of these injuries are seen in initial dislocation. And most importantly, the post-reduction views are very important. You're going to pick up about 35% of them only in the post-reduction view. Let's go on and get some more detail. We can do some CTs, obviously. Here's an axial slice through the upper shoulder. On this view, there are a couple of things that you want to notice. One is a little bit at the back of the humeral head, and that is because there's a small Hill-Sachs deformity. That's the impression of the impaction fracture that you get when the humeral head dislocates anteriorly. The other important thing is to make sure that you're at a good level to pick it up, because you want to identify these at about 2.5 centimeters from the superior aspect of the humerus, and not below that. And you want to be able to see the coracoid process while you're in that region, or at least in the zone of the coracoid process. Because distally, you're going to run into the retrohumeral groove, and you don't want to be able to call that a Hill-Sachs deletion. What do we need to tell our surgeons when we look at these? It's important to talk about the percentage involvement of the humerus. So in this location, you're taking a circle around here. How much of the circle is being involved by this? And this is a small one, a tiny divot. Imagine if there's a large 40% defect, that'll be a large Hill-Sachs deformity that becomes an engaging lesion. That's what we want to know. What about the glenoid and CT? I'm using a volume-rendered image to demonstrate this, and you have a bony Bankart injury where you can see the portion of the glenoid being displaced anteriorly. You can also see it on the axial slices. It gives you an idea about how far the displacement is as far as the glenoid injury is concerned, and you can see it right there, too. What else are we interested in when we talk about the bony glenoid component? What is interesting to a surgeon? The main thing they want to know is how much of the articular surface is involved by this bony injury. Is it approximately 20% to 25% of the articular surface? That's the number that's being used in my institution, and it's about a reasonable number to think about when you think about displacement or involvement of the glenoid margin, because it's going to make the shoulder unstable. How can we measure this? I'm again using a 3D volume-rendered image here, and I'm trying to do a circle on this, and here we go. That gives us an assessment of the glenoid, and you want to try and see how big the fragment belongs to this, and that gives you an approximate idea of what area this is involved, and that's about 20-25% is a reasonable number, because you want to create a bony buffer in front. How do you treat it? Here's another patient presenting with some chronic subluxation. When you look at this, you can start seeing that the glenoid attrition has happened, that there's a large area of glenoid that's missing out there, and when you want to reconstruct that, the commonest approach or one of the processes is to actually put in a coracoid graft, and that's called a Latter-J procedure, and here is how it is done. You take a piece of it, and it's anchored across in the front, creating a new buffer in front of the glenoid so that the head doesn't dislocate, and there's a resection, and that's what it is as a cartoon image. So what is important in anti-dislocation? What do they want to know from us? They want to know, is there a bony component of the glenoid? They want to know if there's actually how much of the area is being involved by this, and what about hillside solution? If there is one, is it a large one or a small one? And obviously, for soft tissue detail, we need MRI, and that's beyond the realm of this particular talk. Moving on, 35-year-old shoulder patient coming in with shoulder pain, sorry, and here's what you're looking at. A cursory examination looks like it's not too bad. When you go a little bit closer and look at it, here's what you can see. The glenoid and the humeral alignment looks okay, but then you get this extra line around here, and you're wondering, what is that? Let me show that again. Sorry. Here's what you're looking at. It's a little line that's running parallel to the humeral articular surface, and that is what is called a trough fracture. It's an impaction fracture that's created by the posterior dislocation. So this is important to realize that this patient had a posterior dislocation at some point in time. And that's what you're seeing right here. And when you look at an axillary projection, you can actually see the divot that's created by this posterior dislocation, and that's called a trough fracture. I can guarantee you, if you go back to your outpatient imaging piles and look at these, you will be able to find a lot of these where patients had a posterior dislocation and never really reported back, except for shoulder instability now. What can you see on MRI is an example. You can see a joint adhesion, and you can also see that little impression that's on the humeral head because of the posterior dislocation and impaction fracture that you can get to see that. Here's a sagittal projection demonstrating the same thing about an impaction fracture in the humeral head, and that's your trough fracture from a posterior dislocation. So what is clinically relevant? It is important to realize a lot of these are missed. So maybe it's a center here. Hopefully not. It's important to realize the patient comes in with an arm, fixed internal rotation is supporting the arm as well. What is important for the surgeons to know, is there a bony glenoid component? Is there a reverse Bangkok lesion? If you see the trough fracture, how big is the trough fracture? It's better to quantify these as much as you can. And obviously, there's soft tissue element that goes along with it, and for that, we need an MRI. Let's move on and talk about a couple of rare dislocations. Luxadia recta. This is when you have a hyperabduction injury resulting in your humeral head being displaced and tearing through your inferior capsule and pushed into your axilla. And when you have one of these, you end up with an axillary vein injury or an arterial injury, and quite a lot of times, the brachial plexus neuropraxia comes along with it because of the injury as well. Moving on, here's an 83-year-old patient coming to the ER, and is, well, let's have a look. The first thing you notice is there's some gas across the right upper shoulder region, and then you see this little faint opacity or a linear opacity in the right upper lobe, and you're wondering, what is that? And that is actually an intrathoracic fracture dislocation. How do we know that? Obviously, CT comes to our help, and you can see that the femoral head is actually dislocated into the thoracic cavity as such. You can see it again in the coronal slice where the head is now displaced inside the thoracic cavity, and a coronal image across here demonstrating where the donor site for this is. So in other words, if you're ever missing a humeral head, look in the thoracic cavity and you'll find it. Here's another one, which I couldn't find an example. We have one example in our institute. I just couldn't find it. Here's one from the literature where the entire humerus can also dislocate into the shoulder. Let's move on and now talk about scapular fractures. The scapula is a well-padded bone, so you need high energy to cause any injuries, which means that you have to look for associated injuries. Here's an example. Fracture. Next question, does it involve the articular surface? And yes, it does. You can see that. Can we show that any better? A grassy view here demonstrating a step off on a radiograph. Just watch out for these and you can get to see them as well. A scapular body fracture extending to the glenoid with depression. CT much more eloquently demonstrates this. Here's your fracture line, and there is your extension to the posterior aspect of the body. Another view that's important, it's a sagittal view that you want to look at in your glenoid surface. Why? Because it demonstrates the extent of injury and where does the fracture actually extend all the way across. In this case, it's a 50% involvement of the glenoid surface. Another thing you want to watch out for, as we said, is high velocity of trauma. So when you see one fracture, you got to go hunting for the rest of them. You get to see the acromion-based fracture here. And on a scapular-wide view, you can also see the body fracture extension all the way down. When you think about the scapula, you want to think about this archaic and downhole zone. So you don't have to remember the names, but it's important to know what fractures matter. Here's an apophyseal fracture at the top, which is unfortunately there, but it's not really surgical most of the time. Same with the bodies of the scapular fracture, unless there's a huge amount of displacement. The most important zone that you want to know is the supralateral angle zone, where it can also extend into the articular zone, as well as going to where the neurovascular structures are sitting here, such as the suprascapular notch or the neck of the scapula across here. So watch out for them and be careful about it. You can see that the 3D volume rendered images demonstrate this much more eloquently and easy for you to see them. So spend a few seconds on them to try and catch where the fractures are extending, just like in the example that I'm showing you right here. It leads us on to talk about another concept called the floating shoulder. What is this? It's a ligamentous complex connecting the distal clavicle, the chromium, and the coracoid process in the superior aspect of the glenoid together, forming a single unit. So if you have a fracture running through that, it's going to separate the superior aspect of the shoulder away from the rest of it. Let's look at an example. Here's what we're seeing across here, a fracture through the neck of the glenoid, extending posteriorly all the way to the base of the spine, and also involving the clavicle, resulting in a single unit out here, and that becomes a floating shoulder. Here's another example, a 30-year-old patient on a motorcycle. You can see the same fractures again at the base of the neck and extending back towards the spine of the scapula, along with a displaced clavicle fracture, and that results in a floating shoulder. A CT makes it much easier to find these fractures and demonstrating it in different projections as well, such as these ones in the sagittal projection, extending posteriorly as well. It's also nice to see it on 3D, and here we are looking at a 3D model, by which you can actually demonstrate it much easier to the clinician and to yourself as well, to get an idea what's happening with the extent of the fracture. The beauty of this is also it tells you if there's any glenoid extension and you don't see one. Typically, fixation is either going to the clavicle first or, in this case, with the scapula, and it's usually a double-stage procedure for this case, along with the clavicle fixation as well. So what do they want to know? Articular involvement. Is there a glenoid neck involvement? Watch out for that. And what about other associated injuries? Let's finally wrap up with something called scapular thoracic dissociation, which is very important to identify because this is a four-quarter amputation. This is where the entire body is being amputated from inside, where the skin is intact, but your muscle, vascular, brachial plexus injury, and that leads to dismal prognosis, so we want to be able to catch it. Let's start with an example. Here's a patient who is coming from a car crash, and here's what you're seeing. You're noticing that the medial margin of the scapula is being shifted away from the midline on the right side. You also have an epipleural hemorrhage across in this region, and you look closely and you start seeing scapular fractures along with this as well. If you wanted to measure things, there's something called a scapular index, where the distance between the affected side and the non-affected side medial margin of the scapula from the midline, it should be a ratio more than 1.07. What are the other things that goes along with it? The findings that you want to look out for, lateral scapular displacement, an associated scapular fracture, typically extrapolar hematoma, or a sternoclavicular dislocation, or a diastatic clavicle fracture is what you're looking for. And this is something that the patient presents with asymmetric pulse, and that's the primary thing that loses most of the time. And imaging certainly helps out by either doing a CT angiogram or a conventional angiogram. In this location, there's a conventional angiogram with a huge block segment of the right subclavian artery as such. Here's another example. I want to at least show you a couple of examples of this so that you don't want to miss this. Here's a 45-year-old patient, and you can see there's your midline. There is your scapula on the right side, and there's your scapula on the left side, and that's being distracted away from the midline as such. Here's a CT image from the same patient, and here there is complete occlusion of the subclavian artery. Unfortunately, the patient died from concomitant injuries as well. And the last example that I want to show you is a 42-year-old patient, which I just saw a couple of weeks ago. And here's what we're seeing, multiple extensive injuries. You can obviously see the pneumothorax and multiple root fractures, but then when you watch the clavicle itself, sorry, I beg your pardon, the scapula itself, there's your left side of the scapula, there's the right side of the scapula being displaced away from the midline, and then obviously they put a chest tube in and all that, and even then you can see that the spread of the scapula onto the way from the midline as such. And here's a CT demonstrating what we want to see, and that's your occlusion segment across in the right subclavian artery at this level. And this is what the primary problem is, and it was fixed with a stent afterwards, and this saved the patient's limb as such. So in summary, it's important to look for adequacy of radiographs. Make sure that you actually spend some time in the auxiliary view if you can, and encourage your techs to get it. When you think about dislocations, think about the bony components, the glenoid component and the humeral component as such, because that's what they want to know, and that helps us out with it as well. The scapula, well-padded bone, so if you have a fracture, look out for other associated injuries as well. The main zone that you want to be interested in is the neck and articular zone, where you can have maximum damage in a fracture of the scapula. Scapulothoracic dislocation, you just need to have a high degree of suspicion. Asymmetric pulse should clue you into the problem. And I would like to acknowledge my colleagues and my boss, Clark West, for a lot of contribution to my knowledge and to the presentation and my colleagues as well. Thank you very much for your attention. Goodbye. Thank you to the organizers for inviting me today to speak about elbow and forearm trauma. I have no relevant financial disclosures. After this presentation, the learner will be able to describe clinical prediction rules that guide imaging after trauma, consider the relevance of elbow effusion after trauma, and identify injury patterns associated with elbow instability. So first, who to image? Clinical prediction rules do exist for adults. One of them is called the East Riding Rule, and this involves tenderness along the radial head, olecranon, or medial epicondyle with high sensitivity. Elbow extension is another way to screen the elbow, and this has reportedly high sensitivity and specificity in some, but not all studies. How to image? Elbow radiographs are sufficient for the diagnosis of the majority of acute elbow conditions. Three views, AP, lateral, and radial head oblique views are essential. CT is generally only used for preoperative planning. MR and also ultrasound can be used to confirm acute tendon ruptures, but MR and MR arthrography are only useful in the setting of chronic elbow pain to assess tendon and ligamentous injuries and osteochondral defects without utility in the emergency setting. Case one is a 62-year-old man after falling outstretched hand. You can see elevation of the anterior fat pad compatible with an elbow joint effusion, but no obvious fracture. So what does this mean for our patient? Post-traumatic elbow effusion has classically been described as indicative of an intraarticular fracture, but can we see effusion in the absence of fracture? Well, in several studies that looked at this question in children using the detection of periosteal reaction on follow-up radiographs, they found that only 17 to 77% of children develop periosteal reaction. Now this may be artificially decreased by the absence of periosteal reaction in completely intracapsular fractures. So perhaps a better way to look at this question is with MRI. And this has been done in a study that included children. And in fact, they found that only 57% of kids with an effusion after trauma had a fracture detected on MRI. So in children, you probably can't be definitive about the presence of a fracture. In adults, though, it was a different story. All of the adults in one study and most of the adults in the second study had definitely a bony abnormality, if not frank fracture seen on the MRI, the majority of these being in the radial head. So the classic teaching of effusion equals fracture in the adult population is probably appropriate. So how should we manage these patients? Well, first of all, we should not be recommending additional imaging. We do not need CT or MR in these patients to identify the location of the fracture. Instead, they should be treated as if they have a non-displaced radial head fracture with collar and cuff sling and active range of motion exercises as tolerated. So moving on to case two, this is a 36-year-old woman who fell after a mountain bike crash. And we can see that she has an anterior fat pedilevation, but a clearly visualized common unit fracture of the radial head. Radial head fractures are the most common fracture in the adult elbow. They can result from low energy falls as well as high energy polytrauma. And the vast majority are minimally displaced, which is good because they have a good outcome. The outcome is most dependent not on the morphology of the radial head fracture itself, but on the presence of additional injuries that cause instability. Here's three different fractures of the radial head. One on the left is minimally displaced, but most importantly, it's marginal involving less than a third of the radial head circumference. And this is the pattern seen in most radial head fractures and can be treated non-operatively. The one in the middle is also minimally displaced, but this one involves 50% of the radial head circumference. And this is important because it has a higher likelihood of needing radial head replacement, or at least fixation due to effects on range of motion as well as common in other injuries. And in the case on the right is a complete and displaced fracture, almost assuredly associated with other injuries and going to need radial head replacement for repair. The classic teaching is that 10% of radial head fractures have dislocation and 10% of dislocations have radial head fractures. So not synonymous, but certainly something to look for should you diagnose one. Radial head fractures may become unstable if there's injury to the medial collateral ligament, and this results in valgus stress positivity, or if there's interosseous membrane and TFCC disruption, and this results in axial stress positivity and has been called the SX lopresti injury. So what is our patient's likelihood of instability? So the increased complexity of a radial head fracture increases the risk of instability. In other words, if you have a comminuted radial head fracture, you have to look for both axial and valgus instability. Whereas a vertical shear fracture of the radial head that's displaced or an impacted radial neck fracture is most often associated with valgus instability. And then if a non-displaced or minimally displaced radial head fracture is seen, more often than not, these are stable. Put another way, if you have a displaced but apparently isolated radial head fracture, consider this quite rare and look for additional findings that may be radiographically occult. So again, going back to our mountain biker, we can see on her wrist radiograph that there is widening of the distal radial ulnar joint and positive ulnar variance in addition to a scaphoid waist fracture. So she has an SX lopresti injury. Unfortunately, at the time of diagnosis at the outside hospital, she was treated just for a scaphoid waist fracture and the radial head was replaced, but the longitudinal stability of the forearm was not addressed. And she went several months with having symptoms of instability before definitive repair was performed at our institution. Radial head fractures can be associated with other fractures involving the elbow, including to the capitellum from valgus stress, to the coronoid process with posterior dislocations, and to the olecranon with dislocations in a variety of directions. So let's talk about coronoid process fractures. They can be difficult to detect radiographically, at least in part because the coronoid tends to be superimposed over other structures, like on the radial head on this lateral view. Any coronoid process fracture can create instability, but the instability is increased in likelihood with the increasing size of the coronoid process fracture fragment. There are several classification systems. The older is the Regan-Mori, which is based on lateral elbow radiographs and the size of the fragment. The oedruscal classification came along later and was based on CT and included extension into the antramedial facet, the oedruscal type 2 shown in the blue image. A more recent paper came out of Minnesota and included Dr. Mori and evaluated coronoid process fractures again on CT. They found five types. The first three are synonymous with the original Regan-Mori, one through three, and comprise about three quarters of coronoid process fractures. The 4AM is the oedruscal type 2 type, the oblique antramedial, and these comprise the remaining, the majority of the remaining one quarter of fractures. But a small percentage of patients had a new fracture pattern that had not been previously described. And this they called the oblique antralateral. So it just has the opposite obliquity. And it's important to note that all of these fractures have an association with radial head or neck fractures, but this association is particularly high in the patients with the oblique antralateral. So the take home here is that it's probably worth doing CT on patients who have a coronoid process fracture on radiographs to more completely describe the morphology of that and to always look for associated injuries in the radial head. All right, case three, a 16-year-old who was playing basketball. He was rejected going up for a dunk and as a result fell very hard onto his outstretched arm, resulting in this posterior elbow dislocation without fracture. Posterior elbow dislocations most commonly occur from a valgus posterolateral rotatory mechanism, which has been shown in the drawing to the right. This can result in dislocation without fracture, as we've seen, or with fractures, including several named variants. All right, so posterolateral rotatory instability starts with injury to the lateral collateral ligament, starting with the ulnar component, then the radial component. And this allows posterior subluxation of the radial head. Stage two progresses to complete lateral collateral ligament detachment combined with a portion of the anterior posterior joint capsule and part of the common extensor tendon. And this allows posterior subluxation of both the radius and ulna. And then stage three, a fully dislocated elbow requires incomplete or complete MCL disruption. All right, getting into some of those named variants, if you have a dislocation combined with a radial head fracture and coronoid process fracture, this is known as the terrible triad of the elbow. An example is shown here where we have a posterior elbow dislocation. And on the AP view, we can see a comminuted complete fracture of the radial head. And on the lateral projection, you might say that the coronoid looks a little bit truncated. However, the true fracture of the coronoid is best seen on the post-reduction CT, where we can see a volition through the tip, probably in the, sorry, a Regan-Mori type one. Posterior elbow fracture dislocations sometimes involve the bones instead of the ligaments, particularly in the setting of osteoporosis. And the result is an olecranon fracture with a posterior radial head dislocation as shown in the image on the right. This has been called the posterior montasia fracture dislocation. Now, elbow dislocations can also occur through a varus force as shown in the drawing. And the varus posterior medial dislocation is overall less common as a cause of posterior dislocations. It also starts with rupture of the lateral collateral ligament, but because of the axial loading force now on the medial side, we get a facet fracture, an intermedial facet fracture of the coronoid process, the adruscal type two injury. It's again, the MCL that may remain intact and prevent complete dislocation of the elbow. So here's an example of an AP radiograph showing a dislocation with medialization of the radius and ulna. And on the post-reduction radiograph, we can see this double density over the coronoid. So this is probably a fracture of the intermedial facet, which is confirmed on the preoperative CT where this would be the classic tip fracture. But we can see in this case, the fracture extends medially into the intermedial facet and the sublime tubercle. Anterior dislocations can also occur. They tend to be from a direct trauma to the flexed elbow though, as opposed to fuchsia injuries, and they tend to be open as shown here. You almost always have an olecranon fracture involving these anterior dislocations. So these are amontasia fracture dislocation, again, the anterior variant. All right, moving on to case four, a 61-year-old female who fell from a ladder. We can see a distracted fracture of the olecranon here. And so when you see distracted fractures of the olecranon, you know they have to go to surgery to fix these, to restore the extensor mechanism of the elbow. But are there associated ligamentous injuries, or is it a fairly simple, straightforward surgery? So unfortunately, on the post-reduction radiographs, we can see that there's some new anterior subluxation of the radial head and of the coronoid. So there is evidence of ligamentous injury here. And so this is an example of amontasia fracture dislocation. Amontasia fracture dislocations are defined as a proximal ulnar fracture and radial head dislocation. And then you may or may not have a proximal radius fracture as well. These were classified by Botto, later modified by Jupiter, based on the direction of dislocation and the location of the ulnar fracture. So here are just a couple examples. This is a Botto 2B, where you have fracture of the proximal ulnar shaft and posterior dislocation of the radial head. Here is a more proximal example, the Botto type 2 morphology, where you have fracture through the level of the coronoid process and fracture of the radial head. This one had to have a radial head repair. And this is the anterior variant, which is Botto type 1, where we have shaft fracture and anterior dislocation of the radial head. So a brief discussion of forearm ring fractures and dislocations is relevant here. So we already discussed the amontasia injury at the elbow, Galeazzi fracture dislocation is seen at the wrist, and Essex-Lopresti injury involves the entire forearm, as we saw in the mountain biker. The key with these is to image the entire forearm, because they can coexist. So starting with the Galeazzi fracture dislocation, this is a fracture through the distal radial shaft with ulnar, sorry, distal radial ulnar joint disruption. They have to involve rupture of the TFCC, but we can't see that directly on radiographs. A variant may include ulnar shaft fracture as well. These are highly unstable and require internal fixation in adults. Here are two different examples, both of which have ulnar shaft fracture, sorry, radial shaft fracture, and then gross widening and positive ulnar variance at the drudge. The case on the left has an ulnar styloid avulsion, but clearly it's not necessary for the diagnosis. Usually they will be repaired with transfixion of the fixation rather of the radial shaft fracture, and then often the dredge has some positional stability, and that's what the patient's allowed to heal in. Essex-Lopresti injury involves radial head fracture with or without dislocation, as well as disruption of the dredge, and the implication is that the entire membrane is disrupted. As you'd expect, these are highly unstable and require repair or replacement of the radial head and then stabilization of the dredge distally. So here's another example, not from our mountain biker, where we have distal wrist injuries, including a intercarpal dislocation, but positive ulnar variance and ulnar styloid disruption as well, and a displaced fracture of the radial neck seen on the elbow radiograph with subluxation or dislocation of the radial head. So this patient underwent radial head replacement as well as transfixation of the dredge. To summarize, radiographs are usually enough for initial evaluation of the elbow after trauma. Post-traumatic elbow effusion should be considered equivalent to a non-displaced radial head fracture, at least in adults, and treated appropriately without additional imaging recommendations. Always consider instability if you have a radial head fracture that's displaced or comminuted, or when you see a coronary process fracture, and remember to image the entire form when the elbow is injured. These are my references for your appraisal, and thank you very much for your attention.

joint injuries

emergency settings

femoral neck fractures

osteonecrosis

imaging techniques

knee trauma

shoulder dislocations

elbow effusion

fracture dislocations

musculoskeletal trauma