I am Janelle Thomas, I'm from Penn State, and we're going to talk about shoulder arthroplasty. So first I just want to give you four unknown cases. I'll give you about 30 seconds in your seat. Just silently look at the case and make a decision of what you think the findings are. Here is case 2. Here is case number three. And finally, here is case number four. Okay. So as you saw, three of the four cases I showed you were of the reverse total shoulder arthroplasty design. And this graph explains why I'm going to focus on that for the majority of this talk. If you look back in the 1990s and early 2000s, the majority of implants placed by surgeons were the hemiarthroplasty or the anatomic total shoulder design. And just as a review, the anatomic design includes this metal humeral implant, metal humeral implant, and a radiolucent polyethylene glenoid component. With the FDA approval of the reverse total in 2003, you can see it is now implanted in nearly 50% of cases while there's been a significant drop in the use of hemiarthroplasty and a plateau of the anatomic total shoulder. And RTSA really revolutionized who can have a shoulder replacement by allowing patients with a full thickness rotator cuff tear to now have an implant. These allow the deltoid to take over rotation of the shoulder. Additional indications have been added over the years. So I want to review the components. And this is a real case. I was looking at this case with a resident and this was the impression. And I said, well, I agree with you. The humeral component is not articulating with the glenoid components and this glenosphere. I don't really think it's attached to the metaglene anymore. And she said, well, that's not the metaglene, Dr. Thomas. And I said, well, what do you mean? And so I pulled up this image and I asked her to point to the metaglene and she pointed to that. And so I asked her, well, who told you that? She said, Dr. So-and-so. And I said, are you sure? And she said, yes. But they've been practicing much longer and they're wiser than I am. And then I looked back at that person's reports and I talked to them and indeed, they had been miscalling the components. And it's very easy to do. I'm not trying to call a colleague out. I'm just saying with all of the new designs and hardware, it's very challenging to keep up and we should make sure we're all on the same page as we talk about it. So the metaglene is this base plate here that should be attached to the glenoid and flush with the bone. This convex glenosphere, you can imagine, reverses the normal concavity that you see of the glenoid. There is a humeral cup with a polyethylene liner that is concave and this polyethylene liner can vary in thickness. So you can have varying degrees of space between your glenosphere and your humeral cup. So I want to review these five main complications that occur with reverse total shoulders. So this is a case that one of my colleagues called me over about two months ago and said, Janelle, do you think this coracoid is fractured? I said, absolutely. You can see it's inferiorly displaced. There may even be some callus there. And so we looked back at the month prior and it had been there, but it had not been called. And it's very easy to miss things for a lot of reasons. Most are perceptual. They can be subtle. It can be due to a lack of experience. I'm hoping at the end of this session I'll give you a little bit more experience so you won't miss some of these. And then later we'll also talk about poor positioning as a cause of missing. So this was case number one. How many of you noted the inferior scapular notching? Good. How many of you saw this coracoid fracture that was also there? Good job, Kirkland. But it's very easy to miss. And I'll tell you that this is the third coracoid that I've seen with reverse total in the last year. Probably more have seen me than I have actually seen because I wasn't looking for these, right? Traditional teaching is scapular fractures, scapular spine and acromion, not coracoid. So I think it's just imperative to always look at the entire film. This was case number two. How many of you noted this scapular spine fracture there? A little bit subtle, but if you know to look for it, then you should be able to find it. Scapular spine and acromion fractures are a unique complication with the reverse design. They're often non-displaced, so we often miss them on that first study. We often see them on the subsequent study when they are healing or displaced. And what makes it even more challenging, they're more often seen in osteoporotic patients, so it's hard to identify those fractures. The best X-ray projection to detect them is actually your axial image. You can see such a nice profile of your acromion as well as your entire spine. CT is a great adjunct modality to confirm as well as assess the degree of healing and displacement. There is a grading system for those interested. Type one is anterior. Type two is as seen in this picture, this posterior to the AC joint. This was the initial radiograph where I think it would be very, very easy to have missed that, and that's why this patient ended up having a CT, which confirmed there was a fracture there. And type three is that scapular spine that I showed you earlier. So why do these occur? The RTSA biomechanics shift your center of rotation inferior medially, and that increases the length of your deltoid to abduct the arm. But as it does that, excessive deltoid elongation can stress your acromion, and that can lead to these fractures. Similarly, the biomechanics of shifting that center of rotation inferior medially causes abutment of that humerus on the inferior glenoid, leading to the scapular notching, which we saw earlier. Here's a case where you have this kind of smooth, chronic reparative process with a sclerotic margination of the notching. It's important to recognize this. Most likely you'll see this at the four to five year mark, and typically it's going to be a grade one to two just abutting that inferior screw. It's important to note because it does impact patient outcomes with loss of range of motion and strength. Now in order to combat both of these complications, you may see a new trend in RTSA. They are trying to lateralize that center of rotation, and they're doing that in two ways. They're either adding an increased humeral offset, so in this diagram you can see the polyethylene liner is thicker more inferiorly than it is superiorly. Additionally, you may add a thickening on the offset for the glenoid side, and that's been shown to decrease notching in up to 35% of cases, so you may see this as a new trend. This was case number three. Now I had this case a few weeks back, and it was the first post-op image, and it was the same alignment as the intraoperative image, and I see teeth gritting in the front, and I thought back to an article I read in Radiographics by Cat Roberts, which was a great article on reverse shoulder where the metaglene is supposed to be flush with the bone, and the screws are supposed to be interosseous, but I don't know where these screws are hanging out, right? So I looked at the operative report, and I spoke to the surgeon, and he actually put it in on purpose like this, which was, I was a little surprised, so I had to do my homework, and it seems that they're now recommending that you do an inferior translation, an inferior tilt, and a lateralization of that glenosphere position. So this one is what you do not want. You do not want it superiorly tilted or translated. Now what I would say is that if it changes, if it's neutral and it goes to a tilt, that's abnormal. If it's in this tilt and it's the immediate post-op, I still would look at the operative report. I would still talk to the surgeon. My gut is I don't think this patient's gonna have a good outcome, but some of the surgeons are starting to change the way that they place these. So here's an example of what you do not want. This one is superiorly tilted. You have a fractured screw, and the metaglene is not flush along that inferior margin. Instability is one of the other early complications you can see with this design, but because of the unopposed contraction of the deltoid, you have what's called an anterior superior escape. So if you think about a traditional shoulder, the hubris goes inferior medial in the anterior dislocation, but in the reverse design, it actually goes superior. So one other topic I wanna talk about that's been in the orthopedic literature and discussed at their meetings is infection in regards to reverse total. And I know this is an ugly picture, but it's meant to represent the fact that in a reverse shoulder, you have no rotator cuff. It's torn, and it's usually retracted. So you now have a potential space, and in that potential space, you get a hematoma, and that's a brewing ground for bacteria to form and to lead to an infection. And the problem is is that patients often have nonspecific symptoms. Your ESR and CRP may not be elevated. Additionally, radiographs are nonspecific. Probably the best finding to suggest it is progressive humeral osteolysis or radiolucency, but again, this can be seen with aseptic loosening. So often, we're called upon to aspirate these patients, fluoro or ultrasound guided. At our institution, we take whatever the first available slot is. My preference is ultrasound because I can look for the fluid collection. I remember in fellowship, Felix Chu telling me that if you think about it, most of the day, you're laying back, and the fluid's going to collect posterior. So with ultrasound, you can actually find that posterior pocket of fluid, whereas with an anterior approach fluoro guided, you may miss it, and that may explain why the literature is showing that aspiration only has a sensitivity of 33% for infection in these cases. And I've been in cases where I think the patient really has an infection. I think it's there, and I get a dry tap. So then it begs the question, how often do you perform a saline irrigation in these patients? Our surgeons do not want us to do this, at least our shoulder surgeons. Some of our hip guys do, but not our shoulder. And the literature supports our surgeons. A recent study showed that irrigation in 43 yielded no further bacteria, and thus, it was felt to be worthless. Now, the typical teaching is P. acnes is the bacteria to worry about with these shoulder arthroplasties. The new name that's out there is C. acnes, in case you get any test questions on this. And I will tell you, I was embarrassed. I was giving a lecture, and my astute resident asked me, well, why C. acnes? And I didn't know the answer. I had just read that I needed to worry about it. And so I'm gonna give you the answer, so hopefully you sound smart to your resident. It's found in your sebaceous glands, particularly in your axilla and chest wall. So the proximity to the shoulder surgery allows it to actually play a role in up to 70% of these infections. Now, you have to hold it in the lab for 14 days because the mean time for it to start showing on a culture is eight and a half days. We're now gonna move on to some other topics about anatomic and hemiarthroplasties. So this was case number four. Hopefully you agree with me that this humerus looks anteriorly subluxed in respect to this glenoid. This is an anatomic total, right, with this radiolucent polyethylene liner. This is my, I'm gonna harp on positioning. So one of our surgeons told me that a lot of the times we get these really poor axial views. The arm is bent posteriorly 90 degrees and it makes it look like a pseudo subluxation. So before you call a subscap tear from an anterior subluxation, just make sure it's appropriately positioned. And so he sent me these two images, this one being a really poorly positioned study, and this one being a better one where your humerus is in line with your glenoid and your scapula. So anterior subluxation suggests an injury to the subscapularis. We prefer ultrasound to confirm that. And you might see two findings. Some of the surgeons will perform a lesser tuberosity osteotomy. And what we see is that that osteotomy fragment actually evolves back off, but the tendon is still attached to it. Alternatively, you may see hypo or anechoic defects in the tendon fiber, such as in this image. And you can see the suture material is medialized. Here's another image with a nice focal hypoechoic retear of that subscapularis. And these figures show you why ultrasound's a great modality for diagnosing these. Now one finding we've been seeing, and it's not published, this is just anecdotal. We've been seeing the sutures elongated even in the absence of a hypoechoic area. And when the surgeon has taken these patients back in, they've actually had a tear. And so it's almost a little secondary sign we're seeing to suggest that there might be a tear there. You can have a suprasmedius tear, which is going to show up as progressive narrowing of your chromohumeral distance or superior subluxation of your humerus. And again, ultrasound is preferred for confirmation. I didn't talk a lot about these also because not much has changed in the literature. Your most common complication after an anatomic total is glenoid loosening. Here is the marker of that polyethylene liner. It's extraosseous. And your most common complication with a hemiarthroplasty is progressive narrowing of that glenohumeral joint with erosions of the glenoid. One trend you may see is some surgeons are starting to use a stemless humeral component in the total shoulder arthroplasty. And the thought is you'll have a lower rate of fractures as well as humeral lucidating. And studies show it's normal within the first year to have about two millimeters of radial lucency around that humeral component. So let's briefly talk about indications for cross-sectional imaging. We already talked about ultrasound, the use for infection as well as rotator cuff integrity. I find not a lot of use for MRI in these. Infection, if you really have a whopping infection and you wanna look at the degree of joint collections, CT is a workhorse in these patients. It's great for looking at the osteolysis, periprosthetic fractures, scapular notching, erosions as well as a preoperative assessment. And you can try a metal artifact reduction or dual energy. This is an example where you can really nicely see the bone just adjacent to the prosthesis and it gives you great visualization for osteolysis. One other indication I wanted to add is that we're seeing patients present with nonspecific neurological conditions. And when we're working these patients up, these screws are extra osseous and they're extending into either the spinal glenoid or the suprascapular notch. And these patients have to be revised. And CT is nice for this. I think ultrasound, depending upon habitus, it may be very hard to penetrate down and visualize that very tiny nerve branch. An MR would be very limited by artifact. I just wanna touch on preoperative CT. So this is often used for planning. The most important factors that you wanna include in your report are the degree of retroversion. So you can perform that with a typical 2D or a 3D reconstruction. This arrow is just showing you that retroversion. Drawing that line along the axis of the glenoid, drawing a line perpendicular, and you wanna be at the level or just below the coracoid process. Additionally, you want to comment on any significant erosions that you see within the glenoid. A general comment on bone stock, as well as any posterior subluxation and soft tissue findings. Obviously, if they're considering a reverse total, you also want to look at the integrity of the rotator cuff, as that may determine what type of shoulder implant they can use. Finally, our surgeons told me they don't want measurements. There are articles out there about measuring bone stock, superior, central, and they said with all of our templating software, we can do that. Save yourself the time, save yourself the headache. Just give us a generic report. So today we'll be talking about MRI of traumatic lower extremity emergencies. MRI traditionally hasn't had much of a role in the acute setting for lower extremity trauma. In most cases, radiographs and CT are all we need to make the diagnosis. However, as we've seen increasing scanner availability and shorter scan times, we're seeing a lot of growth in the use of MR in both the adult and pediatric populations in the orthopedic injury clinic and through the emergency department. The real value of MR in this setting compared to radiographs and CT is its excellent soft tissue contrast resolution. This is great at picking up certain injuries that we don't see with radiographs and CT, especially when it comes to detecting bone marrow edema, disruption of the cartilage, and injuries to muscles, tendons, and ligaments. The categories that we'll touch on today, these selected topics, include radiographically occult bone and cartilage injuries, muscle contusions and strains, tendon rupture and laceration, and finally, we'll touch on Lisfranc ligament tears. Now, both bone contusions and occult fractures are injury that are by definition not detected with radiographs. In a bone contusion or what we call a bone bruise, there's a blunt trauma to the bone that causes bleeding into the bone marrow cavity and disruption of the trabeculae, but the cortex remains intact. An occult fracture has a non-displaced break in the cortex or a band-like line that might be complete or incomplete across the bone. Here we see different examples of bone contusions in the knee of one patient and in the ankle of a second patient on T2 fat-suppressed sequences. Here's a bone contusion in a hockey player who was hit in the ankle by a puck at high speed. On MR, we see here the typical features of a bone contusion. There's a reticular pattern of bone marrow edema that's just below an intact cortical surface. The presence of soft tissue edema overlying the bone marrow edema is an important clue to make this diagnosis. Now, bone contusions near a joint occur in very predictable patterns that can clue us in to the presence of other coexisting injuries. So in this teenage boy who twisted his knee, the location of bone contusions here in the lateral femoral condyle and lateral tibial plateau would indicate a pivot-shift type of injury, and they're gonna direct our attention to the ACL, which in this case was torn. Bone contusions will gradually resolve after several months in most cases, and these are treated non-operatively. We should know that contusions that involve this subcondyle plate are more likely to be associated with chondrocyte injuries and worse clinical outcomes, and probably a precursor to degenerative arthritis. MR is also very important when we're trying to detect occult fractures in the hip. We know, and it's been well shown in the literature, that radiographs lack sensitivity for hip fractures, especially in elderly patients and those with osteoporosis, and when the fracture is non-displaced. If the radiographs are negative for fracture, an MR will pick up essentially all of these fractures in the femoral neck, including in up to a third of patients who have negative radiographs but a clinical suspicion for fracture. Here's a common example from our emergency department. This is a 68-year-old man who had a same-level fall, presents with right hip pain. He had some limited radiographs in the ED that were read as negative. MR was done the same day, and it shows the features that are diagnostic of an occult femoral neck fracture with a cortical break, band-like bone marrow edema, and a hypo-intense fracture line. MR should be done in the acute setting for these patients because if the diagnosis is delayed, there's a higher risk of fracture displacement, a longer hospital stay, and greater morbidity and mortality. At our institution, we perform a quick four-sequence pelvic MR exam using T1 and T2 fat-suppressed sequences in the axial and coronal planes. And in some places, even do a shorter or more abbreviated exam with just two coronal sequences. So the exam can be done rapidly. Even if the patient doesn't have a fracture, MR shows an alternate explanation for their pain about three-quarters of the time, so it does add value. Now let's look at a 65-year-old woman who has hip pain after a same-level fall. The radiograph here shows a nondisplaced fracture of the greater trochanter. MR was subsequently done for this patient, and it shows a hypo-intense line indicating intertrochanteric extension of the fracture. It turns out that most patients who are thought to have an isolated greater trochanter fracture actually have intertrochanteric fracture that we can't appreciate with radiographs. So MR is indicated for these patients to detect a colt extension of that fracture line. I find that the coronal T1-weighted sequence is very helpful for detecting these injuries where we can see the fracture line as a hypo-intense band. Detecting these fractures does make a difference because treatment varies. A patient who has truly an isolated greater trochanter fracture is going to be weight-bearing right away, and they can go home, whereas someone who has intertrochanteric extension needs surgical fixation or nailing in this case. Now let's shift to cartilage injuries. This case is a 28-year-old woman who twisted her knee and reported knee pain and locking. The bone marrow edema in this case is normal, but notice there's a full-thickness cartilage defect in the articular surface of the medial femoral condyle that has sharp marginated edges. This is a chondral fracture. MR is great for detecting injuries both to the articular cartilage and pediatric growth plate cartilage. These injuries can't be seen with radiographs. Cartilage injuries are especially common in patients who have twisting injuries to the knee, either in the setting of a torn ligament or a patellar dislocation. These cartilage fractures usually occur in the lower extremity on convex surfaces like the femoral condyles, the patella, and the talar dome. We'll look here at impaction and shearing injuries that affect the articular surface, and then we'll talk briefly about growth plate injuries in kids. So here's a shearing chondral fracture. A shearing fracture is seen in the lateral femoral condyle in this case. Notice that unlike degenerative damage to the cartilage, the chondral fracture has sharp shouldered edges. When we see this, we want to look for a corresponding loose body, which in this case is found anteriorly. These injuries happen when there's a shearing force that's tangent to the cartilage and the subchondral plate, so there tends to be little to no subchondral bone marrow edema. And this pattern is more common in adults and usually is treated arthroscopically. So here's an arthroscopic photograph of the lateral femoral condyle fracture in this patient showing the full thickness chondral defect. The pink surface you see there is the exposed subchondral bone. The figure of H shape of that cartilage fracture is mirrored nicely on the axial MR image on the bottom right. In this patient, the surgeon first removed the loose bodies that you can see on the bottom image and then performed a procedure called a microfracture. This involves using a pick to perforate the subchondral plate in multiple places, which creates a blood clot that fills the defect with fibrocartilage. Impaction injuries can also involve the articular surface through a different mechanism. These occur when there's an axial force that's directed perpendicular to the cartilage and the bone surface. This will cause a linear crack in the cartilage and the subchondral plate and is associated with a reticular pattern of bone marrow edema. We see this injury more commonly in adolescence, and it's usually treated nonoperatively if there's no other injuries and if the articular surface is congruent. MR is also great in detecting pediatric growth plate injuries, which we tend to miss completely or underestimate on radiographs. These injuries occur most commonly in adolescence, and they can involve the growth plates of the distal femur and the proximal tibia or the patellar cartilage before it's completely ossified. Here are some radiographs of a 14-year-old boy who hurt his knee while sledding. No fracture was initially seen on the radiographs, but there was a large joint effusion. His MRI shows a Salter-Harris III fracture in the distal femur with widening of the medial physis and a fracture line in the epiphysis that's extending to the trochlear articular surface. You can see here at this arthroscopic image there was a gap in the trochlear articular surface. The surgeon manipulated this and reduced the fracture and then stabilized it with lag screws across the epiphysis. This next case is a patient with a patellar sleeve fracture. This is an important injury to be aware of in kids because it tends to be more severe than we see radiographically. In this case, the clues that we have a patellar sleeve injury on radiographs include a low-lying patella and a small fleck of bone that's superior to the joint. The MR here shows the full extent of the injury in this case. Outlined in green, we can see the ossified portion of the patella. Notice that this is surrounded by a large area of unossified cartilage that we can't see radiographically. The cartilage is fractured and there's a superior cartilage fragment that's retracted with a large gap. This was treated surgically. Now let's shift to talk about traumatic muscle injuries. We're gonna talk about two types, muscle strains and contusions. These are both very common sports injuries and they're usually diagnosed clinically based on the typical findings, pain, swelling, bruising, limited strength and range of motion. MRs can be done in patients if the diagnosis is uncertain, if there's a delayed presentation and for high-performance athletes. The first injury pattern is a muscle contusion which we see here. A contusion occurs when there's a direct blunt force injury to the muscle that causes intramuscular bleeding and sometimes hematoma formation. We see this most often in the quadriceps muscle group in the lower extremities in contact sports like football and rugby. The key finding to make this diagnosis is edema that's centered at the point of impact both in the overlying soft tissues and in the underlying muscle belly. The edema in this case can cross fascial planes too. For these injuries, we're gonna rely on our axial T2 fat suppress sequences to determine the amount of cross-sectional muscle involvement and we use the long axis images to look for gaps in the fiber. T1 weighted images are most useful to detect intramuscular hematoma which in this case has a T1 bright rim from subacute methemoglobin. Now unlike muscle contusions that we get from direct blunt trauma to the muscle, muscle strains are eccentric injuries that happen when the muscle's contracting while being stretched out. The rectus femoris and biceps femoris and gastroc muscles are most commonly involved. And what these all have in common is that they have large muscle bellies with pinnate architecture. They cross two joints and they each contain a high percentage of fast twitch fibers. It's important to note also muscle strains take about twice as long to heal and for people to return to their activities compared to contusions. Now here's a hamstring muscle strain in a football player. The axial image shows edema in the biceps femoris muscle belly. Unlike a contusion where the edema is centered at the point of impact, in a muscle strain the edema is centered at the myotendinous junction. We see that well here on the coronal image where there's feathery edema at the myotendinous junction as well as some fibers that are disrupted in this grade two strain. So when we're describing these injuries we want to talk about the location of the strain, the percent of cross-sectional area involved, the length of muscle that's affected and the integrity of the myotendinous junction. Now let's talk about tendon injuries. In the lower extremity that's primarily gonna include the quadriceps and Achilles tendon as they're the most commonly injured tendons. It's said that normal tendons don't tear. Tears happen after there is prolonged repetitive loading that damages the tendon and causes tendinopathy followed by an acute load that causes rupture of the weakened tendon. A less common tendon injury pattern that we can see is also due to sharp penetrating trauma that can lacerate an otherwise healthy tendon. The diagnosis of a tear is usually made clinically but MR will be done to confirm the diagnosis, to determine the location and the size of the tear and then to plan surgery. So MR gives us some important diagnostic information both on the type of tear and the quality of the tendon. Here insertional Achilles tendon tears in two different patients. MR shows the difference between a partial thickness tear which we see on the left with torn superficial fibers and some intact deep fibers and the full thickness tear at the insertion on the right. Notice also that the tendon on the right is severely thickened distally and several centimeters of this abnormal tendon had to be debrided before it could be reattached to the bone. For tendon tears, the sagittal fluid sensitive sequence is what we use to measure the gap in the torn tendon. If the tendon tear occurs outside the routine field of view or extends outside the routine field of view on an ankle or knee MR which is often the case, we've trained our MR technologists to move the coil proximally, change the field of view. This allows us to detect retraction of the myotendinous junction and on T1 weighted images to look for muscle atrophy. Now let's talk about tendon lacerations. We said that normal tendons don't tear but the exception to that is when there's penetrating trauma by a sharp object like a knife or a piece of broken glass. The tendons in the dorsum of the foot and ankle run right under their skin and they're especially vulnerable to lacerations. So for these cases, MR is often done unless a primary repair is performed. This case shows the typical appearance of a tendon laceration on MR in this girl who was cut by broken glass while she was taking out the trash. On the axial image, notice that the flexor digitorum and flexor hallucis longest tendons are both normal. However, the posterior tibial tendon is not seen and its sheath is filled with fluid. Looking at the saggial image, we see the retracted stump of the posterior tibial tendon which has a sharply cut edge and no evidence of tendon apathy. Now the last injury we'll discuss involves the Lisfranc ligament. There are two main injury patterns that we see here. The first is a high energy midfoot fracture dislocation that's easily seen with radiographs and CT. No role for MR in these cases. However, in low energy midfoot injuries where there's a twisting injury to the Lisfranc complex, the foot radiographs might be normal or there might be very subtle findings. So if there's clinical suspicion in these cases for a midfoot sprain, MR is indicated to make a rapid diagnosis because the patient, if they require surgery, it should be done quickly to prevent post-traumatic osteoarthritis. So the medial midfoot gets its stability from the bony structure and the soft tissue supports. The bones of the first through third metatarsal bases and the three cuneiforms will form an arch structure. We can see here that the middle cuneiform is recessed compared to its neighbors and this creates a mortise joint that stabilizes the midfoot. In addition to this bony anatomy and the joint capsules themselves, the Lisfranc ligament complex is a key stabilizer. The ligament is made up of dorsal fibers which are thinner and weaker and then the most biomechanically important fibers which are the interosseous and plantar bundles. We see the Lisfranc ligament best on images obtained in the long axis and in the short axis of the midfoot. Between the medial cuneiform and the second metatarsal base, the Lisfranc ligament looks like a trapezoidal bundle of fibers that we see both in the long axis and short axis planes quite well. It's important in setting up the images off of the short axis image to obtain the correct long axis plane. If the axis is malaligned, we don't see the Lisfranc ligament fibers very well. We found that setting up the long axis imaging plane along a line parallel to the three medial metatarsal bases gives us a nice view of the intact ligament. Now let's look at the case of a young man who was running and twisted his foot and has midfoot pain. The initial radiographs of the foot were read as normal. Here's his MR. On the long axis image, there are multiple bone contusions in the midfoot with thickening of the dorsal Lisfranc fibers indicating a sprain of the dorsal fibers. However, the interosseous and plantar ligament fibers are intact both on the long axis and the short axis images. His midfoot was also stable to exam under fluoroscopy, and so he was treated with immobilization and a boot and did not need surgery. Here's a contrasting case of a complete Lisfranc ligament rupture in a patient who also had normal radiographs, had a similar clinical presentation, similar physical exam. Here the MR shows complete disruption of the ligament fibers in both the long axis and in the short axis planes. Notice also there's mild dorsal subluxation of the second metatarsal base that couldn't be seen radiographically. This patient had an unstable midfoot and was treated with surgical fixation. So to recap, we've discussed briefly some topics in the role of MR in diagnosing acute traumatic lower extremity injuries. MR is helpful to detect bone contusions and occult fractures, to identify the location and type of cartilage injury, to stage muscle injuries and their complications, to demonstrate degenerative and penetrating tendon injuries and in characterizing midfoot sprains. Thank you for your time. Excellent, well, I just want to start by thanking the RSNA and thanking Dr. Strohlo for inviting me here to speak and thanking all of you for coming to this session here today. So I'm going to talk to you all about imaging of the wrist and hand. Okay, so for starters, we pretty much have the most experience in radiology imaging the hand and wrist, going back to the beginning. And the hand is the most commonly injured body part. When we are looking at the hand and wrist, we've got 29 bones and 29 major joints. So there's a lot to look at, a lot to think about. Unfortunately for patients and for us, there are long-term consequences if diagnosis is delayed or incorrect. The good news is that in most cases, X-rays are sufficient for diagnoses, but wrist fractures and various trauma in the hand and wrist account for more delayed diagnoses than any other traumatized region in patients with initially normal ER X-rays. So there are cases where we do miss things in this setting. So starting with recently revised ACR appropriateness criteria, for any hand and wrist trauma, the initial examination is going to be X-ray. And we'll talk about that, but you really want three views, whether it's focused on the wrist or the hand or the fingers, whatever that may be. In cases where you suspect acute hand and wrist trauma, but the X-ray is interpreted as normal, you pretty much have three options which are appropriate. MRI without contrast, repeat X-ray in 10 to 14 days, or CT without contrast. And in my institution, generally, we lean towards treating patients and repeating in 10 to 14 days. And here's just a nice example showing you on top, X-ray of a patient with trauma initially interpreted as normal. One month later when they return for follow-up X-rays, we can see that sclerotic band of a healing non-displaced fracture through the metathesis. And then in the ACR appropriateness criteria, most recently, if you're suspecting trauma with a foreign body and the X-ray is normal, your two options are ultrasound for foreign body evaluation or CT without contrast. Okay, so now I'm going to talk a little bit more in particular about those imaging techniques. So when we're starting with X-rays, we really want three views of the area of interest, PA, oblique, and lateral. And in the research, an oblique adds clinical impact and helps your diagnosis about 5% of the time. So very important to do that. And it's also very important you train your technologist to limit your X-rays to the area of concern. So if it's a wrist, focus on the wrist. If it's fingers, making sure those individual fingers are being displayed properly. So when we look at the wrist in particular, just a couple of things to highlight are your three carpal arcs of galula. So we want to make sure we can trace out these three lines and that they're continuous without any breaks or evidence of dislocation. I think it's always good to take a good look at the hook of the hamate to make sure we see that nice continuous cortical ring representing that bone. And I always make a point to scrutinize the metacarpal bases as this is an area that I think a lot of trauma and issues can hide. Some soft tissue findings on our PA view, want to look at the navicular fat pad. This can be a nice secondary sign if we're concerned about scaphoid fractures. And just in general, I think abnormal soft tissue swelling anywhere in the hand and wrist can really be helpful to guide you towards the pathology and the symptoms, especially in these days of computerized order entry where everyone has trauma coming in from the ED or other settings, no matter really what's going on. On our lateral view of the wrist, we want to make sure we've got the wrist in neutral position with the elbow flexed to 90 degrees for a good lateral. Again, if we're concerned about the fingers, we want to remove overlapping digits. We want to make sure we see nice alignment between the base of the third metacarpal, the capitate, the lunate, and the radius, like we see here. Again, I would scrutinize the metacarpal bases. We can look at our pronator quadratus sign to make sure we have a nice fat pad highlighted here to exclude any distal radial fractures. And in general, I always make a good point of looking dorsally for soft tissue swelling, again, as another good secondary sign. The PA with ulnar deviation is a great tool to help elongate and evaluate the scaphoid. And since the scaphoid fractures are most common carpal fracture, this is a great tool. So in a case like this, we've got a PA with ulnar deviation highlighting that little avulsion fracture of the distal pole of the scaphoid. Some other views that are helpful, your clenched fist view to look for scapholunate ligament injury. So in a case like this where we clench the fist, drives the capitate proximally and stresses the scapholunate interval, you can do these bilaterally to have a nice side for comparison. And then our carpal tunnel view, which can be challenging for technologists to do well. But when they do, you can really see the hook of the hamate, and particularly the base of the hook of the hamate, where we can have fractures. So you may see a lot of overlapping bones in these kind of views. But the two structures you need to see are the hook of the hamate and the trapezoidal ridge. And usually, you can see those well. When we go to CT, ideal position would be putting patients in the Superman position, with their hand above their head. Alternatively, you can do it with the hand resting on the abdomen. But I think in those situations, you just want to make sure you've got a good technologist giving you the right reformats. Coverage should be from the distal radio ulnar joint to the MCP or the fingers. And you definitely want three planes of bone reformats and two to three millimeter slices, at least one plane of soft tissue reformats. And for cases of scaphoid fracture, it's very helpful to do an oblique sagittal reformat, like you see here, to really elongate the scaphoid and see it in its entirety. And this is particularly helpful for follow-up of these fractures. Dual energy CT in the hands has actually been a huge benefit for us for evaluation of gout, and particularly in the emergency setting, where the ER asks us to perform, and they want us to perform a joint aspiration. These are challenging procedures and very painful for patients. So here's an X-ray of the hand that was initially interpreted as normal. The ER had a high concern for gout, so we did this dual energy CT. And you can see on the standard CT images, you can see the radiodense tophi. And on the color-mapped images, where the gout, the uric acid stands out with green coating, very evident the extent of disease here. And in a case like this, you can actually look back on the X-rays and see that there are some tophi on the images, particularly in the small finger. But it's much, much easier to see on these dual energy CT images. We thought we might find some promise in dual energy CT to look for bone marrow edema. We personally have had less success with this. But the idea with this is you remove the calcium using dual energy technique. And if you have a fracture or bone marrow edema, the fluid will replace the normal fatty marrow. And it may help you see occult scaphoid fractures like in a case like this. But we've had limited clinical success with that. For MRI, again, we want to have patients ideally in the Superman position. And if we're really looking for basic diagnoses like fracture, 1 and 1 half teslas is more than adequate. And with multi-planar T1 and PD-FATSAT images, we can see occult fractures like in a case like this, where the x-ray was interpreted as normal. And it's pretty clear on the T1-weighted images and the PD-FATSAT that this is an intra-articular distal radial fracture. And in this particular case, there was actually a layering of fusion in the dorsal extensor compartment with fat, blood, and fluid, like a lipohemothorosis. This is just a nice example showing you that even in a patient where motion is an issue, you can make these diagnoses pretty confidently. OK, so diving into some cases. So case number one, we've got three views here of the distal radius showing a distal radial fracture. These are very common, about 1 6th of all fractures presenting to the ED. The history is generally going to be a fallen and outstretched hand. You definitely want three views to evaluate these kind of injuries. And I'm personally not a fan of eponyms, but I think if we just talk about the components of the fracture, like location, articular involvement, comminution, displacement, and articular surface tilt, we'll provide all the information that the referring team needs to treat these. So again, here's just a list of some of the eponyms we have for distal radial fractures. And I just want to talk about some of the things that determine treatment. So again, we can pay attention to these when we're interpreting these studies. So in general, they can be treated with closed reduction and casting if they're extra articular, less than 5 millimeters of radial shortening, which we'll talk about, dorsal angulation less than 5 degrees. And if they're intraarticular displaced fractures, or greater shortening or angulation, or in cases of failed reduction, these are going to go on to surgical fixation. So radial height is measured by drawing two perpendicular lines, one through the distal ulna and one through the radial styloid process like this and measuring that distance. Normally, this should be 10 to 13 millimeters. Radial inclination is going to be drawn through the angle of that same line to the distal ulna and then a line paralleling the radial articular surface. That should be about 21 to 25 degrees. And if you think about it, decreased values will have abnormal pressure on the lunate and abnormal wrist biomechanics. And then radial tilt is measured on our lateral view where we draw a line perpendicular to the radius and then a line along the radial articular surface. And this should normally be between 2 and 20 degrees of volar tilt. And here's just an example of one of our fractures where we've now got dorsal tilt of that articular surface. Here's another case just showing that radial fracture I showed you earlier, showing how in the acute setting we have decreased radial height. And after it's been reduced, that's restored. And again, showing pre-reduction, we've got dorsal tilt. And on the post-reduction images, we've still got some dorsal tilt, but it's much improved. And again, I don't measure these, but these are things I look for when I'm evaluating these cases. So case number two is another very common entity, our scaphoid fracture. So here's two very different cases where we happen to be able to see these on the x-rays. The white arrows are showing you a case through the waist of the scaphoid. The black arrow through the proximal pole of the scaphoid. This is the most commonly fractured carpal bone. Tends to be in younger patients. Older patients who have more osteoporotic bone will be more likely to fracture their distal radius. Most of these will be through the waist of the scaphoid. 10% in children are more likely to be in the distal third, and about a quarter in the proximal third. And one of the things we worry about with these injuries are avascular necrosis. And so if you see here, we see the blood supply to the radius to the scaphoid enters distally and tracks back proximally. And so you can see the more proximal the fracture, the higher the risk of avascular necrosis because of that limited blood supply. 75% of these will be visible on the PA and PA ulnar pronated views. 25% of these will be visible on all views, but approximately 2% to 5% of these are gonna be radiographically occult. So inevitably, we will miss some of these initially. So it's important that these are treated even if the x-rays are normal. And unstable fractures that may require treatment generally have higher amounts of displacement, more complicated injuries such as fractures with perilunate dislocation, or patients who require an accelerated return to work or sport. So this is that same case of the patient who had an avulsion of the proximal pole of the scaphoid. And if you look at the lateral view of this hand, you can just see a soft tissue swelling dorsally that's just really out of proportion and out of proportion for location for what you'd expect for a scaphoid fracture. And if you look closely, there's actually another fracture through the small finger metacarpal head. So just wanna highlight a point here, multiple fractures. So approximately 8% of hand fractures are multiple. So wanna make sure we definitely don't avoid satisfaction of search in these cases. And we've done, we really work hard to train our technologists to give us notes and put markers in the site of pain. And in a case like this, that might help you, draw you to the right area. Okay, so just another common fracture we've probably all seen, but triquetral fractures. So here we've got a lateral view of the wrist. There's an ossific fragment in the dorsal margin of the carpal bones. You can see that it's not completely, it doesn't have a complete ossific rim yet. And most importantly, we've got a lot of soft tissue swelling here, which leads me to believe, you know, in the appropriate setting, this is an acute fracture. You're really gonna see these best on the lateral view. Wanna make sure you look in this area and recognize these. And these generally heal with immobilization, but again, just something we wanna make sure we catch and don't miss. Okay, case number four, we've got a lateral view of a finger here with a dorsal fragment with minimal displacement. So this is a mallet finger. These are caused by forced flexion of an extended DIP joint. And these can be some combination of an injury to the terminal extensor tendon, plus an osseous avulsion. These can be traumatic or laceration. And your operative indications here are really gonna be volar subluxation of the remainder of the bone, greater than 50% articular surface involvement, or greater than a two millimeter articular gap. And just to show you an example of what this looks like on MR, so here we've got two fingers of the same patient, one where we've got the torn terminal tendon inserting on that distal phalanx, and one where you see that thin low signal tendon intact. And here you can see that that tendon, that because of that tendon failure, we've got some flexion at the DIP, despite surgical fixation in this case. Here's just a case of a different patient who has a similar type injury involving the base of the middle phalanx. And here you can see where the central slip is inserting. This patient, the white arrow is showing you an intact terminal tendon. But again, just showing you how when that fragment is large enough, you'll end up with volar subluxation of that middle phalanx, and the reason why these need surgical treatment. And here, these orange arrows are just showing you the intact central slip on the other fingers. Okay, case number five, hook of the hamate fractures. These tend to happen, these are rare, but I think something you just wanna make sure you're aware of, you're aware of the appearance, and again, always look out for. History on these is usually gonna be some sort of racket or club sport, so golf, baseball, and hockey, usually a direct blow to that area. You can have bipartite hamates as a mimicker. These'll be well ossified completely around, and may not have that history of trauma. And again, on the second image here, we see the carpal tunnel view showing us that lucency through the base of the hamate. This is that same patient, just showing the follow-up imaging. This patient went on to non-union, but ultimately didn't need surgery. But just showing you again, nice examples of that. Okay, here's another case of a patient who had a trunk of the car closed on their hand, and just wanna point out here that we see a lot of soft tissue swelling on the ulnar side of the wrist. And as we look closely, we see some offset at the base of the fifth CMC joint, and small little avulsion fragments on that middle image. I think here you can see it well when we compare the original images to the intra-op reduction images. You can see there's that offset dorsally that's subsequently reduced. So this is a case of a CMC fracture dislocation. These are rare, but one of the reasons I like to show this case is that if you look in the orthopedic literature, they say that most of these are missed on x-ray. So the bar is very low for us. The expectation is that we're gonna miss it. But the reason these happen at the fourth and fifth CMCs is because we've got relatively mobile ring and little fingers compared to the rest of our hand. The ECU in the joint capsule may complicate reduction in these. So you do wanna scrutinize your follow-up films to make sure they are reduced. Here's another case where we don't have a dislocation, but if you look closely, we have that same soft tissue swelling. And you can see some cortical irregularity involving the base of the fifth metacarpal. Interestingly, this patient had wrist x-rays and forearm x-rays. And on the forearm x-rays, we can actually see much better that there's this comminuted fracture at the base of the fifth metacarpal. And here we see it on CT. So similar injury pattern. Hard to see on our initial images, but it shows up well if we follow our soft tissue findings. Here's a similar case of a 21-year-old male who actually dislocated his second through fifth CMC joints. And pre-reduction and post-reduction, we can now see he's got some of those residual osseous fragments in that area. This was another interesting case that we had. So here you can see some flexion deformity of the index finger at the DIP, and maybe some narrowing at the PIP. But when we look on our middle image here, there's actually some subluxation. And on the lateral view, it's a little bit confusing at first to figure out what's going on. If we compare our pre-reduction and post-reduction films, we can see that we had a dislocation at the PIP joint, which has subsequently been reduced. And the post-reduction is much more normal appearance of what we're used to seeing. So this was a PIP dislocation. Again, in these injuries, you may have a combination of dislocation, fracture, dislocation, and avulsion fracture. This is a case that we had where a patient came in no trauma. We saw these diffuse calcifications around the metacarpals bilaterally, kind of interestingly. And on the lateral view, we see that this is predominantly located in the dorsal soft tissues. And this actually took some digging to figure out, but this was a cosmetic procedure. So you may have seen some of this in your practice. This is something we see a little bit more where I am, and we've become quite familiar with this. But this is actually calcium hydroxyl apatite microsphere injection. So a cosmetic injection into the dorsal soft tissues of your hand to get rid of the veiny or tendinous appearance that you might see. So again, a nice little trauma or injury mimicker that you just wanna be aware of. Lastly, I wanna point out calcific tendonitis or abnormal calcifications that you can see within the tendons of the carpal tunnel. So gout, CPPD, and hydroxyapatite deposition can all affect tendons in the carpal tunnel and are a not uncommon mass that hand surgeons will see and treat. Lastly, just wanna point out this normal variant, which I've seen misinterpreted as fractures in some of our more junior trainees. And this is the epiphyseal scar. So this is a thin radiopaque band at the site of the former growth plate. This is very common in patients between 20 and 50, and even in the published literature, there is no maximum age where we can no longer see an epiphyseal scar. So something to be aware of and one of our trauma mimickers. So in conclusion, just a reminder that the hand is the most commonly injured body part. Fortunately, x-rays are usually sufficient, but we may have delayed or missed diagnoses, which can have significant clinical impact on patients. Soft tissue findings can really aid in the diagnosis and guide you to the right area. Be aware of your indications for follow-up imaging. Be aware of some of these pitfalls and trauma mimickers. And just remember some of the goals of reduction so we know what we're looking for on our follow-up studies. Thank you. I really love this session because it's such disparate but great talks, and so we can all stay awake with four totally different talks. Hopefully, I'll keep you awake. This hardware sounds boring, but I find it interesting and hope that you will as well. So let's talk about some basics of screws. Okay, so back to residency. And in my residency, we had two screws to talk about. I was trained to recognize cortical screws, and you can recognize cortical screws because they have small threads. And the space between the threads is called the pitch. Cortical screws have narrow pitch between the threads. Versus cancellous screws, cancellous screws really like to take a bite into cancellous bones, so they have big threads that are more widely pitched there. And so forever, those have been the two main types of screws. Then they kind of messed with us about a decade ago and started showing us locking screws, and we'll get to that in a few minutes. So just to make sure we're on the same page with what we learned in residency, this screw in a calcaneus fracture has narrow threads that are narrowly pitched, and that's a cortical screw as opposed to this cancellous screw with bigger threads with a little wider pitch. Most cancellous screws are partially threaded and not fully threaded as well, and that can help. Okay, so let's talk about the evolution of extremity fixation plates. Sort of, if you look back, way back in the last millennium, the basic concepts and ideas that they were trying to accomplish with these plates included neutralizing forces, buttressing, and compression. And those are the basic types of plates that they use. When you talk about compression of fractures, one of the principal concepts in fracture treatment is that if you can, if it's the type of fracture that can be compressed and you apply compression, that can actually augment healing. And so surgeons want to apply compression in the appropriate fractures, and some plates do that. All of these plates from the last century were cortical plates, and they did their work by being smashed down on the cortex by screwing the screws tight on there, and that's how they achieved their friction and force. They weren't necessarily all flat plates, which was a term that was bandied about in the reading rooms during my residency. So here's sort of the schema of the kind of basic stabilization or neutralization plate. Basically, all you're doing is putting this plate down, screwing it down on bone to try to hold two pieces of bone, whether it's a fracture, an osteotomy, whatever. And then it will hopefully heal itself, and most of the time it does that just fine. A typical example of one of these that's still in common use today is the 1 3rd tubular plate. So it's not flat, it's actually got a little curved contour because 95% of these are used on the fibula, and the fibula's got a real small radius of curvature. Flat plates would not be flush with this, so they use the 1 3rd tubular plate, and that's just a neutralization plate. Now you can modify that as is done here. Notice how these plates have these notches in the side, and so surgeons can take special pliers and basically mold these and contour them. And so these are called reconstruction plates or contoured plates. They use these most common for acetabular and pelvic fractures where the bones are all curved and none of the fractures is the same as the one before and the one after, and so they have to contour these to maintain contact with the bone. Buttress plates, how do you recognize a buttress plate? The idea here is you're trying to cradle or buttress multiple fragments of bone together, hold them together, provide a buttress fracture, or a buttress function, excuse me. So this tends to happen in metaphyseal and epiphyseal fractures where you have lots of fragments that need to be cradled together, and these fractures or these plates are distinguished because they get wider near the joint surface there. So they're narrow by the diaphysis and wide down near the joint, and that's classic for a buttress plate. Okay, so the next evolution in these plates was in the early 90s, and that's when LCDC plates came along, excuse me, and I use that term actually in my reports. Stands for low-contact dynamic compression plate. So these use both of those features, so let's look at that. So this is so-called dynamic compression plate, and if you look from overhead, these plates have oval holes, and if the surgeon drills a screw in eccentrically within that hole, away from the fracture, then when the head of that screw comes down eccentrically, it hits the plate, the beveled edge of the plate. That wants to push the head toward the center of the hole, meaning toward the fracture, but the head is connected to the rest of the screw, which is embedded in bone. So the entire screw and that whole piece of bone then wants to push itself centrally toward that fracture fragment, and if you do that on both sides, then that creates compression across the fracture margin, and that can augment healing. This is a typical LCDC plate with these eccentrically placed screws away from the fracture on either side, and then as they actually screw those into the plate, then that means that it will apply compression across the fracture. The LC, again, is low contact or limited contact. Here we see a close-up of this plate, and you can see how these plates are sort of scooped away from the bone in between the screws. There are places where the plate doesn't actually contact the bone in between where the screws come in, and the reason for that is if you're smashing one of these plates down on the cortex, then you express away all the periosteal blood supply there. People have thought that when designing these that if they can actually preserve some of the periosteal blood supply by having portions of the plate not touch the bone, then that may augment healing again because you have better blood supply and cut down on the number of infections that happen periodically and postoperatively. So that was the idea with the low contact thing. It turns out it probably doesn't help a bit, the latest literature shows, but they're still making all these plates these ways, so that's the low contact deal. Okay, so let's move into modern plates. We're talking about this century, this millennium. We're talking about locked plates or locking plates. These are fixed angle devices, which we'll see in a minute, and they include three main types of plates, combi plates, locked condylar plates, and list plates. I'd be happy if any of you in this room, once you walk out of here, can just call them locking plates, okay? So you don't have to remember all three of these names. But all of these have locking screw technology, so a locking plate has locking screws. And so because they have locking screw plates, these screws actually fit into the plate, and they act like pins from an external fixture. They're very rigid in their fixation. And so sometimes surgeons, and you'll see this in the literature, call them internal fixtures because they're like external fixtures because they're so rigid, but they're on the inside. So let's look at how you can recognize that. Well, so what does a locking screw do, or what's its special design feature? It's this. It has threads on the head of the screw. That's new. And the plates have threads in the holes that you screw the screw into. So when a surgeon screws this and fits it in just right, then the threads of the head engage the threads of the hole there. And so that screw is truly locked in there. It engages it there. It's not going to toggle. So your typical screw, standard screw, could loosen and then start to wiggle and come out. This thing can't wiggle out because it's fully engaged with those threads. The only way for it to come out is to turn itself seven full revolutions to come out. That's never going to happen. So only a surgeon would get that thing out of there. So that's what a locking screw is, and it's fit tightly in there, and it will be very stable. These screws have very small threads, and they are very narrowly pitched, which we will see in a minute, like right now. So this is an extreme blowup here, and you can still barely see these threads. Locking screws have the very smallest threads and the very narrowest pitch between the threads, and that's how you can recognize the vast, vast majority of locking screws and differentiate them. So, again, smallest threads, narrowest thread pitch. And here you can see an example here of a locking screw next to a cortical screw. These threads are so tiny, it makes the cortical screw look like a Kancella screw. It's not. This is a cortical screw there, so really tiny threads there. The first key point I would like you to remember is locking plates use locking screws, and you can recognize the screw itself because it has these tiny threads that are narrowly pitched. So what's a combi plate? This is where you basically take locking screw technology and add that to a standard LCDC design. That's why I had to explain LCDC plates. So these use combination holes or combi holes, and that's where it got its name. A combination hole looks not like an oval. It's not circular, but it's got a figure-eight shape. As we see in here, there's a figure-eight-shaped hole. A portion of this hole is the locking portion, and it has threads that you can see, and a portion is non-locking, so a regular hole that accepts cortical or Kancella screws in there if you want to use those as well. And so you can use either type of screw, and the surgeons often will use a combination. The combi plates per se are only used in the diaphysis. So these are for the shaft of the bone and not the end of the bone. So again, combi plates, as you see here with a figure-eight-shaped hole, are actually made with the regular part of the hole, the non-locking part, away from the fracture so the surgeons can still employ dynamic compression the same way they do in a standard LCDC plate. And again, they still have low contact because the funny shape of the holes, then the scooped-out portions are a little bit irregular there. So let's look at a couple of examples here. So all the surgeons just leave these humerus fractures to go on to nonunion, and they never fix them primarily, and then they never heal, and so then they come back and plate them six months later. And now our surgeons are using these combi plates. It's a diaphysial plate. Notice here where we don't have a screw at all, you can tell figure-eight-shaped hole. So that should be your clue. And some of these screws are cortical screws, so you can see the threads pretty well. Some of these are locking screws. You can barely, even from up here on my monitor, I can barely see the threads on that thing. Here's another, okay, humerus fracture, kind of a broken record, and using a combi plate. So again, figure-eight-shaped holes where the screws are. It turns out that they used all cortical screws and no locking screws. I don't know why they use this plate. I mean, they don't have to. I think the main reason is it's got a low profile, and these are really nice plates for a lot of other reasons that we don't have time to discuss. They can get fancy with these things, so it's a real bad problem if you've got hardware on the hip, hardware on the knee, and two inches of space, and then they go and fracture through that thing. How do they fix that? You can't nail it. Most plates don't work well. Well, these combi plates, actually, they can put in some short screws where they have to, long screw here, surclise cables, and then these fixations actually do pretty well. Here's one where they contoured a combi plate and bent it. That's off-label. Sorry, but they do it all the time. Again, you can recognize figure-eight-shaped hole. That hole looks a little different. It's just a different manufacturer. I don't know whose this is. So the diamond part of the hole is the locking hole, and then the round hole is the regular hole on that. And again, you see a couple of locking screws, a couple of regular screws there. Okay, so if you see those figure-eight-shaped holes, they're combi holes, and the important thing is you know that they can use locking screws in there or regular screws in there, depending on which side of the hole they use. I saw this case about a year and a half ago, and I looked at this thing, and I was like, what is that? So it's a plate that's got figure-eight-shaped holes, but it doesn't look like a combi plate. It's got the notches on the side. So it's locking. It has locking capability, and indeed, they have locking screws here and a cortical screw here, but it looks like a reconstruction plate because it's got the notches on the side. So the op note wasn't out, and I have to read the X-ray, and I like to call them what they are, and so I said, well, this is a locking reconstruction plate and screw device. And sure enough, that's exactly what the surgeon called it in his or her note as well. And so you just apply these principles. If you called it this and instead it was something else, they'd just be happy that you knew what was going on. They're making all kinds of new plates, and so this plate is like a year and a half old. You can see it's curved. They didn't have to contour this. It comes out of the box this way. It's curved to fit the pubic symphysis, and it's got locking screws in there. So this is a locking symphysial plate, or the surgeons just call it a symphysial plate. So they're not using a standard recon plate. They're using this fancy one with these little notches that show them where to put that thing to have it centered on the pubic symphysis. So these things are changing all the time, which for me is actually good because it keeps me interested. If this all stayed the same, I wouldn't be as interested. So just keep interested in this and keep looking at your op notes. Okay, so we talked about combi plates. Now what about locked condor plates? That's a complex name. Don't worry about it. Just call it a locking plate. It is a locking plate. These ones are not diaphysial specifically but periarticular. They look like buttress plates. They're wider near the joint just like buttress plates. But the key thing with that is they don't actually have to touch the bone. To do a true buttress function, you have to be on the bone with that metal, and these things aren't required to do that. So technically they're not buttress plates even though they look like old-style buttress plates. And each one of these is made for a specific anatomical site. And you've got like six vendors and like 58 sites. So just do the math on how many of these there are. But like proximal humerus, proximal femur, distal femur, whatever, different anatomic sites. And all of these locking plates, they use a minimally invasive insertion technique, which makes them nice for healing as well. And we don't have a lot of time to talk about that. So here's a distal femur plate. And you can say locking distal femur plate when you see this. You know it's a locking plate because, again, it's got the combination holes for regular or locking screws to go in. Down by the joint where it winds out, these are all threaded holes, round holes. They only take locking screws. The big one in here is a locking screw as well, and it does have bigger threads. So that's the one screw that's a locking screw that violates this tiny thread sort of situation I told you about. They make like four different lengths, just one company for the proximal humerus. Again, only locking screws up by the end of the bone, combi holes down by the diaphysis so they can use locking or regular screws. They're obligated to use locking screws up by the joint. This looks like a standard L-shaped buttress plate for the tibial plateau, which we see all the time, except it's a locking plate. It's one of these locked condylar plates. Actually, you can see the threads in the holes there, so you know that, and then the teeny tiny threads there. Now, notice that these screws are placed on this image in the brochure in three different angles. That's intentional, and that's the way those holes are machined. They go in at specific fixed angles. And importantly, this one from the metaphysis comes up at an angle. So your Schatzker 5 and 6 tibial plateau fractures, we know this medial fragment exists here, and they want to capture that from two different directions with two fixed angles there, and then that helps really make that fixation be stronger, they think at least. And so that's what we're talking about with fixed angle devices. In older plates, there's nothing to keep those screws at particular angles because they're not locked into the plates. So, this is a plate on the distal radius. It's on the volar side, like 98% of them are, so you can call this a locking volar distal radius plate and screw device, and you'll be totally right. Again, you see the figure 8 shaped holes, they used all cortical screws there, and then down by the joint, it's all locking screws, and that's the way these locked periarticular plates are. All locking screws, teeny tiny threads, as opposed to the cortical screws. Proximal radius locking plate, done, you know that one as well now. And so, locking screws, regular screws, figure 8 shaped holes, and so even if you couldn't see the locking screws down here, you know that's what's going on. And so that's a locking proximal radius plate. Locking distal femur is so long, I hate to say it, but it's a locking distal femur plate and screw device. Notice how far this thing is off the bone. These plates do not have to be smashed on the bone, okay? Old tummy plates do, that's where they get their friction. All of the friction is here, and they're essentially welded into the plate there. Locking, locking, locking screws all the way up and down. Look at those threads there. But again, this, like if you saw a circa 1990 plate that was doing this, and it just came in and you got this x-ray, that's lift-off. That's a loose, those are loose screws in a lifting-off plate. Not so much with modern plates. The final plate that I'll mention here is the LIS plate, okay? This is the one that started it all off, actually. Not commonly used, but I just saw a new one about a month ago, so they still use them occasionally. They transfer less invasive stabilization system, only designed for the distal femur and the proximal tibia, so around the knee. They can make small incisions, like with all these plates. They put them in in a submuscular fashion, which is nice to the periosteum. And some of the screws go in percutaneously without having to make a big incision there. These ones actually only use locking screws, so they have round holes, not combi holes, not figuration holes, circular holes. These three features in here, again, don't have a lot of time to talk about it, but these help the surgeon to preserve blood supply. So that's why they like all of these locking plates. Another reason, actually. So the tibial LIS plate comes in three lengths and bilateral design, so right versus left. They're labeled in case the surgeon forgets, okay, R. Three different lengths obviously depends on how long the fracture goes there. And look at this. The holes are all round and not figure-eight shaped. They have these cool jigs that they attach to this thing. So the black thing is a jig, and they attach it to the plate. They make a shorter incision. The incision is not as long as the plate. And then they just slide the thing in under the muscle next to the bone. And then it's got holes to stab in percutaneous screws so you don't have to extend your incision all the way down there to get screws in there. And so it's awesome for preservation of blood supply. They always leave room for a raft of screws up by the plateau to lag those bones together if needed. Here's an example from one of our trauma surgeons. That's a huge incision. It's shorter than the plate by about six or eight centimeters. So it's not nearly as big as a typical incision. You can see them jigging it in there and putting in screws percutaneously there. And so that's a lot less exposure, and it's awesome. Here's where you might want to use it. Huge diaphysial component of a tibial plateau fracture. And then they put the list plate on there. So again, can't even see the threads because they're so tiny. Round holes only, so they only use locking screws, and they left room for screws up by the plateau. They make these for the distal femur as well. Same sort of cartoons here, jig on that sucker. They leave room intentionally in certain locations for these lag screws to go in. So you've got to think about it. They lag the fractures together first before they lock down the plate because once they lock down the plate, the fragments are not moving. The screws go in, and again here, nasty periarticular fracture, too low to nail it, and so they put in a list plate, round holes, locking screws only. Again, not touching the bone there over almost the entire length because all of the force is along the threads there. So again, just remember these locking plates do not have to touch the bone, and that's not a complication. Okay, in the last couple of minutes here, I just want to talk about a couple of devices, two or three devices in the foot and ankle there and get out of the long bones. So we've got a plate here on the first metatarsophalangeal joint which is used. This is somebody who needs arthrodesis here, and if you look on this lateral image, you can't even see the threads. Those are locking screws except for that one. This is a locking plate used for arthrodesis on the metatarsophalangeal joint. Guess what she called it? A locking MTP arthrodesis plate. So you just say this stuff and pop it out, and they'll love it. The surgeons just love it. Here are a couple of locking tarsometatarsal arthrodesis plates there, and this is a patient that had this injury, had these plates put in. That's different. What is going on with that thing? So that's actually been around for a while, probably since the mid-2000s. So again, don't have to remember this name, but it's an arthrodesis plate. The trade name is Charlotte Claw arthrodesis plate. Only one company makes these. They're really cool, though. So they stick this spreader device in between these two flanges, and then once they get it screwed in, then they spread these flanges apart, and what that's supposed to do, shown on this cartoon, is pull the two screws closer together. By widening this space, you pull the ends together, and that applies compression across the joint and enhances your arthrodesis. They often use these in calcaneal osteotomies as well to augment healing there. So Charlotte Claw arthrodesis plate, or you could just call it an arthrodesis plate. Pretty neat stuff. They make these with two holes and three holes. Guess what they call them? Two-hole arthrodesis plate and three-hole arthrodesis plate. There's a four-hole arthrodesis plate not pictured here, so you can get those as well. Okay, so it almost looks like they took hardware out of this thing. Did they take a screw out? So many of you have seen these things by now. This is not new. This stuff has been out for about four or five years. This is not where a screw was, but there's actually something in there right now. This is the tightrope syndesmosis stabilization, and if you don't want to use trade names, just say syndesmotic stabilization. That's fine. But everybody knows the name tightrope. So what they're using is suture or bands made of high molecular weight polyethylene, just like they use in joint prostheses there, but they make them thin so they're a little pliable. Why would they do that? You can't even see it. What's going on? What's the point of this? Well, this is the point. Surgeons used to always stabilize the syndesmosis when they needed to with screws, often through a one-third tubular plate. Well, the syndesmosis is not designed to be rigidly fixed, and so it's kind of a race for your ligaments to scar down before this thing can loosen. This is the most common screw in the body to loosen is a syndesmotic screw, and it just kind of wiggles around and starts coming out. Not every time, but it happens a lot, and then sometimes it hurts, and the surgeon has to go get it. So maybe if they could do a more physiologic sort of fixation, then that's where the tightrope comes in, and maybe that will work better. So far the jury is still out. Here's one of our former tailbacks, really messed up his ankle, tore his anterior tibiofibular ligament and the interosseous membrane, and so they did a double-level tightrope on him, and that's awesome. So that was like September or October. He comes back in August at the beginning of fall camp, and his ankle starts hurting on like day three, get an X-ray, and like this all looks fine, but notice the periosteal reaction. What's up with that? The screw doesn't look loose. That was my first guess. It's not loose. Instead, there's a stress fracture through the hole for the tightrope. So this is a stress riser, and he had a stress fracture. Bummer, because he has to miss a whole other season there. He came back and plated the stress fracture and had to put in another syndesmotic stabilization. So next to last case I'll show you is this one. So this is a distal clavicle fracture, but look at the distance between the clavicle and the coracoid. Not so great. So they have shredded the coracoid clavicular ligaments, but the clavicle fracture is right out the end. If they just plate the clavicle fracture or maybe put a little rod or something through there, that's not going to treat the ligament there, and that's a problem. So somebody came up with this system, again, using a tightrope. They have a special plate they put on top, and then a tightrope running from the plate down to the coracoid. And so this is another tightrope fixation coming through a specialized plate. They thought this little endo button-looking thing looked like a dog's bone, so they call it the dog bone clavicle fixation system. You can just say clavicle plate and screw device locking, by the way, with a tightrope on it, and then that's awesome. Final case here. So this patient had great toe surgery. Clearly it looks like they lopped off something. We can confirm that. Giant osteophyte in somebody with hallux rigidus. I looked down at the head of the first metatarsal, and I was like, that looks square. That does not look like your father's subchondral cyst there. So what's up with that? It was not there pre-op. So she did something to this. Our foot and ankle surgeon did something to this that I didn't understand. So I went digging in and found out about it. So in some people, they're doing this now. This is coming to a medical center, foot and ankle center near you soon. What they've done is essentially like a small version of a hemiarthroplasty. They have resurfaced a portion of this with a synthetic cartilage implant. So it's like a hemiarthroplasty. It makes it stop hurting, and that's great, and maybe they can sort of keep this person from having to go on to arthrodesis early like they otherwise would have to do. Okay, so the final thing. Like, you're going to fall asleep if you look at all your post-op films and don't get curious. I just want to encourage everybody to maintain your curiosity, pull aside the requisition for all, you know, print off your report when you don't understand something and go digging in the op notes, and hopefully you'll find this interesting. It actually can be. So thank you very much.

shoulder arthroplasty

reverse total shoulder arthroplasty

RTSA

rotator cuff tear

glenosphere

metaglene

scapular notching

coracoid fractures

osteoporotic patients

implant infections

C. acnes

MRI imaging