Michael Troiano, DPM discusses the anatomy of an ankle fracture as well as reviews common classifications of these fractures. Dr Troiano also addresses treatment options and possible surgical interventions available.
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Michael Troiano, DPM
Center for Foot and Ankle Disorders
University of Pennsylvania - Penn Wound Care
Adjunct Clinical Professor, TUSPM
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Michael Troiano Dr. Michael Troiano has disclosed that he has a financial relationship with HealthPoint
Male Speaker: Ankle fracture. Someone breaks their ankle, I usually see them pre or post-op. You turn around and you say, “Okay. Well, first I’m going to fix this ankle.” Then I’m probably going to inject their ankle a couple of times once arthritis starts to set in. Probably scope their ankle after that. Maybe some PRP or amniotic injections in between there. After I scope it, I’ll probably do some microfracture. After microfracture, then you’re probably looking at diastasis, arthrodiastasis of some capacity. I’ll probably replace or fuse the ankle after that. This is a nice little profession. This is like a little game we have going on, right? Kind of neat. This is not meant to insult you as residents. I’m sure you’re all very, very familiar with the classification systems of ankle fractures or what have you. I put this together in the hopes that you’ll have something when you graduate your residency or take your boards and look at and something that will prepare you. Just a quick rehash that we can all get to dinner, I’m sure you guys are starving. Anatomy of the ankle. Obviously you have the medial malleoli. But when I was in your position, I really did not understand what the anterior and posterior colliculi were. The anterior colliculi, it’s just the anterior portion of the tibia. When people talk about posterior colliculus fracture, what, have you, it’s just the back-bend of the tibia, and of course the intercollicular grooves where that deltoid sits. If you look at an ankle joint, it’s actually about five different surfaces that give triplanar motion to the ankle joint. We always think of it as a hinge joint but it’s not. It is a triplanar joint. Believe it or not, it has just as much motion as a subtalar joint, the talocalcaneonavicular. But because of the soft tissue structures, it makes it function mostly as a hinge joint. The posterior malleolus is the third malleolus in the trimalleolar fracture. It’s injured with a pull of PITFL, which is common board question that you’ll be asked over and over. The posterior inferior tibiofibular ligament is what causes posterior malleolar fractures. What I consider to be important is in red in the following slides. Lateral ankle ligaments are very commonly injured in sprain. It’s a definition of a sprain but infrequently injured and ankle fractures. Although we have to document that this person doesn’t have pain over the ATFL or what have you, most of the time the bone breaks and the ligaments stay intact with the exception of the calcaneofibular ligament which we’ll get into in a second. If you look at these ligaments, ankle plantar flexion, you have tout ATFL and relaxed CFL. In dorsiflexion, CFL is tout and the ATFL is relaxed. CFL will stabilize that subtalar joint in the frontal plane, which is the reason why ankle fractures can lead to damage of the CFL. Diastatis on an x-ray indicates obliteration syndesmosis. Very infrequently do you not prepare syndesmosis when there’s diastasis. Obviously, comorbidities will play in. But deltoids will, by and large, prevent the lateral talar excursion. Deltoid ligaments on the inside or on the medial side are actually the tightest ligaments. As you know, lateral portion, they’re not injured too much, so syndesmosis is really the biggest ligament complex that you have to be concerned about in the routine ankle fracture. Clinical findings. History trauma, pain, ecchymosis, edema, fracture, blisters, pain in ambulation. If you take one thing home today, recognize that when you call your attendant 2 o’clock in the morning because there’s an ankle sprain in the ED, make sure you document that there’s no high fibular pain. Absolutely essential. Number one cause of negative outcome is a Maisonneuve fracture, which we’re going to get into in a second. Second thing, don’t pop the fracture blisters, alright? Put the patient on antibiotics and compress them. Don’t pop those blisters. You’re obviously going to take x-rays. But not just your three views that you’re going to get in your emergency room, you also want to get tress external rotation view. Now, that in itself can be a little challenging because a lot of it is depending on the C-arm tech, the position, the operating room, how the bed is air-planed when you’re doing it. CT scan always for pilon fracture. It will you how many pieces that pilon is in, how far it has to go out. MRI not really indicated for acute fractures. Compartment syndrome is a major problem with ankle fractures. Obviously be cognizant of your telltale signs, right? Pain out of proportion, numbness, tingling, and of course patients who are just eating through a PCA or [Indiscernible] [05:07] or what have you.
Now, one of the things that makes compartment syndrome difficult to identify is the presence of the popliteal block. A lot of our anesthesiology residents and students or what have you, everybody wants to do a pop block for some reason. Recognize that that will significantly compromise your ability to make a diagnosis about compartment syndrome. Classification system. Lauge-Hansen accounts for 95% of ankle fractures and it’s the one that you’re most commonly going to be tested on. Danis-Weber is a lot easier to understand. When you’re explaining things, you’re attending or other co-residents, that’s probably the ones you’re going to use. But Lauge-Hansen is absolutely essential to your long-term success as far as boards go and tests go. Another key point. The first word denotes the foot’s position. Second is the force applied to the ankle. When we talk about pronation, external rotation, we’re talking about pronation of the foot, external rotation of the leg or the force that’s placed upon it. Both of those classification systems basically identify the fibular fracture. Danis-Weber separating type A, B, and C, A is below the level of the ankle joint, B is at the level of the syndesmosis or ankle joint, and C is above. Pictorial display, again, A is below, B at, and then C above. B and C is where syndesmosis is injured. I’ve seen a fair amount of legal cases, malpractice cases, where the syndesmosis is violated clearly, and the surgeon doesn’t recognize, doesn’t document that it was tested, doesn’t document it that it’s stable or unstable. Always document that syndesmosis is intact if you believe it is. Mechanism of injury for supination-adduction. This is the Danis-Weber type A. Ten to 20% of all ankle fractures. This is going to begin laterally with a CFL rupture. Again, this is the only really concerning ankle fracture where the CFL or lateral ankle ligament complex is damaged. It’s because, really, the subtalar joint, as the force continues moving medially or vertical fracture, the medial malleolus may occur. Because of the kind of low velocity to this injury, it’s not often indicated to repair. On the other side of the coin, usually that piece fits so nicely into there even if it’s just a couple millimeters displaced, it accepts screws very well percutaneously. It’s probably worth it to repair, unless the person has significant comorbidities. The Weber A, again, weigh bearing [Indiscernible] [07:50] and short leg, walking boot, repeat x-rays 10 to 14 days. Minimally displaced short leg cast but most of them have even 1 or 2 millimeters of displacement. You can put it back together so easily with two screws successfully, is probably worth it so the patient can weight-bear earlier. Sometimes that fracture when it’s too vertical across the medial malleolus is difficult to pass screws on. Then that occurs, obviously you can use either a buttress plate. I’ll oftentimes use a fibular plate, just a small fibular plate on the medial malleolus because it’s not a great medial malleolar plate out there that’s thin enough to not be prominent underneath the skin. And of course tension banding. If you do a little hang screw and pass to K-wires parallel to one another with a tension band people do well. But again, that hardwire always has to come out because it’s become prominent. Here’s a typical fracture that you could just toggle back into position with a K-wire, visualize it on C-arm. Throw the K-wire up and then one or two screws across. Supination-external rotation. When in doubt say SER. If you’re ever asked on a test or what have you, it’s always SER, right? Seventy percent of the time it’s an SER fracture. Corresponds to the Danis Weber classification system B. Injury begins at the level of the joint. Now, just because it’s at the level of the joint and not above the level of the joint, does not mean that syndesmosis is not damaged. In fact, most of these with enough velocity do have syndesmotic damage and need to be repaired. First step, lateral-anterior syndesmotic ligament rupture. In order to have an SER fracture, you by default have to have an AITFL injury, alright? AITLF in itself is not reason to fix the syndesmosis, but oftentimes the next step after that fibular fracture obviously is the PITFL. You can imagine how many of these have injury to the syndesmosis. Second take-home point. When in doubt, fix the syndesmosis. There’s no reason not to. You can only get in trouble from not. If you have a bimalleolar ankle fracture, chances are you want to fix that syndesmosis.
Weber B, again, is a spiral oblique fracture of the lateral malleoli. That is the pathognomonic sign. That’s a hallmark sign of the SER fracture at the level of the joint. Then the fourth step, obviously, is that posterior malleolar fracture that you can see. Actually the third step is the posterior malleolar fracture that you can see. Then finally fourth, goes into injury of the deltoid ligament or the transverse fracture of the medial malleolus. Classically, this fracture on the lateral view. If ever you’re in doubt, the PER starts proximal anterior and spirals down to distal posterior, whereas the SER starts proximal and posterior and continues down anteriorly and inferiorly. This is a classic sign for the SER. When you see this kind of down swoop, that is an SER. Pronation-abduction is a rare ankle injury pattern, but when it happens, boy, is it trouble. Also along this posterior abduction or PAB type is the Logsplitter fracture, right? Rare injury pattern but the Logsplitter fracture is when the tail is kind of bulldozed itself. The continuation of that will be the PER but the pronation-adduction is kind of like the lower velocity version of this. It begins medially, progresses laterally at the level of the joint. Again, this corresponds to the Danis-Weber B. This is deltoid ligament rupture, medial malleolar fracture, anterior tib-fib ligament rupture. Then the fibula because that tail is just kind of bulldozing itself, bends with a moment arm to the point where it can’t plastically deform anymore and cracks. Usually about 1 centimeter proximal to the plafond. There’s a prime example of it. Very similar to Logsplitter fracture which is the higher velocity version of this. Mechanism of injury for the PER is 19% of all ankle fractures. Most of the time this requires surgical intervention because of the shear force that the PER is associated with. In other words, this is a lot of twisting moment, bending moment. It’s like a breadstick. If you take a hard breadstick and twist one in one way and one the other way, it will snap. That’s what this happens to fibula. There are a lot of butterfly fragments, oftentimes triangular in shape. This is when you want to take your cerclage wire and try to circle them back into position. If they’re too small, get rid of them and just pack them with some Vitoss or some sort of bone graft. Technically, this isn’t stable ankle mortise. If you ever see a PER, you can guarantee you’re going to fix that syndesmosis. Higher up, you don’t necessarily have to go after unless you can’t reduce your syndesmosis. Once when you get your syndesmosis down in position, you have to fix it. We’re going to get into some of the fixation techniques. PER Danis-Weber C, again, it starts in this case medially and moves posteriorly. Medially, then the syndesmosis, then the fibula, then posteriorly. There it is. Step one, medial fracture or rupture of the deltoid. Step two is the AITFL. Step three is above the level of the syndesmosis fracture. Then step four is the posterior colliculus along with the PITFL. Classic PER. A lot of people don’t want to fixate this. They say, “Oh, the ankle joint looks well aligned.” This is trouble. This needs to be fixed. Nice comparison slide for your boards or what you. It shows you the Weber versus the Lauge-Hansen with the exception that the PAB is not in Weber B in this picture. Molar medial malleolar fractures. It’s a classification system that’s probably gained a little bit of headway. It’s probably worth knowing, avulsions of the tip of the medial malleoli, level of the ankle joint is B, and then oblique and vertical fractures are C and D respectively. The Maisonneuve fracture. Fibular neck fracture, obviously, the energy of rotation transfers through the interosseous ligament. So then everything distal to that Maisonneuve fracture is separated syndesmosis. When it’s up this high, you’re not going to go after it at any cost, right? Because, obviously, the common peroneal nerve is there. But midshaft fibular Maisonneuve fractures, there’s some question, right? There’s a literature up on Japan favoring fixing it. There are some that say don’t fix it. It depends who you read, what you subscribe to. But my rule of thumb is if you can get that fibula down without going after a midshaft fracture, then leave it alone. If not, you’re unstable, go ahead and go after it. Recognize that obviously just like IM nails which we talked about before, you’re further away from the fracture, the more stable it is, so you do want to be able to fixate across that fracture pretty far. Obviously in a scenario like this, even if we weren’t worried about the nerve, in reality, we wouldn’t have enough real estate to land any meaningful proximal screws through a plate.
The Volkmann’s fracture. You’re always taught that 25 to 30% of our articular surface involvement should be fixed. More recent literatures indicating like 10%. Again, my rule of thumb is if I can land one or two threads from A to P and have them grab the posterior portion, then I’ll fixate it. Otherwise I’ll throw that screw from P to A, but more likely to fixate than not. I recently saw a lady who went to an orthopedic surgeon. And I’ve never seen anything like it. I wish I included her slide but I think it’s going to end up in litigation. But the posterior malleolus displaced and with it went the talus backwards and north. Her distal tibia was articulating with the neck of the talus. It’s really, really impressive. That made me especially want to fix these a whole lot more often than not. Talus foot fractures happen mostly in children. Very important because you’re taught that it happens in adults. Talus foot is mostly in children. It’s a growth plate injury. Avulsion forces the anterior tib-fib ligament. Lateral tibial epiphysis fracture. The Wagstaffe fracture is the adult version except for not off the tibia off of the fibula. Anterior distal margin insertion of the anterior tib-fib ligament. Treatment parameters. Non-displaced fractures can be cast or placed on a boot non-weight bearing but rarely is a bimalleolar fracture non-displaced. If it’s totally non-displaced and you have documented no syndesmotic instability, then you can cast it. But I have not really seen many of these where you don’t need fixation. Closed fractures should be treated within three weeks. Soft tissue window will shrink after that. Anybody tell me how many milliliters of blood a distal tibia can lose in a fracture? 750 milliliters of blood, alright? Recognize with a lot of these fractures, especially if there is tibial involvement, you can almost put a liter of blood in that soft tissue, which is the reason why you really want to wait for the soft tissue window to relax, otherwise you’re setting yourself up for wound infection failure of surgery. Again, you don’t want to cut through the fracture blisters. But when you see fracture blisters, you can pretty much guarantee that you’re out of the woods for compartment syndrome, right? Because the fracture blisters, are actually the third spacing finding its way out of the pressure area. Treatment parameters reduction of a closed ankle. Hematoma block, conscious sedation, this of course will be on your boards. You’re going to distract or recreate the injury, reduce the injury reversing the mechanism of the action of the injury and then of course stabilize. If you want to use a cast, if you want to use an AO sugar tong, if you want to use a posterior splint, it doesn’t really matter as long as you have the ankle back under where it belongs. Vassal’s Principle. This is the principle that you will be tested on over and over. It is the idea that once you fixed the dominant fracture, all the smaller fractures will come around hails from the serfs and vassals time in Europe and European culture, basically where the serfs follow the vassals around vassals or likely the prominent people in society. It’s not named after a certain person but actually a way of living. As Dr. Lenora identified, 2 millimeters of displacement will require ORF because there is about 42% decrease in tibiotalar contact. That is setting the train on the track for arthritic condition going forward. Complete disruption of the syndesmosis with disruption of the deltoid causes 40% decrease in that tibiotalar contact area, 36% increase in tibiotalar contact pressures. Basically what you’re doing when that deltoid sprung or when that syndesmosis sprung, is you’re guaranteeing medial arthritis and a medial basis to the weight of that ankle. So you’re guaranteed that you’re going to degenerate the medial column of the foot. Here you can see that the 2 millimeters step off with 4 millimeters of displacement, which we’re looking to, to measure. Talocrural angle, we’re going to get into a second. Before we get into the talocrural angle, recognize that all of the pictures, the measurements that you’re taking, the AP is where you’re going to measure distal tibia overlap. That should be 10 millimeters, less than 5 millimeters between the medial fibular and lateral tibia.
Talocrural angle is going to be measured on a standard AP view. Now, as residents, I’m shocked to how many people don’t know the talocrural angle. This is the best way to assess if you’ve lengthened your fibula, have your fibula out to length. What you’re going to do is basically you’re going to draw a line between the medial and lateral malleoli and then a second line across the top of the talus. If the bisection of those lines, so if you drop a perpendicular down, medial, think measure medial, MM, that angle not worth says 83 degrees but on the other side of that angle is the talocrural angle. It’s 83 degrees plus or minus 4 for normal. Here residents all the time say, well, the dime sign is good, what the hell is a dime sign? Nobody can tell, right? It’s a principle that if you have a dime, the fibula and lateral portion of the talus will add up. It’s not scientific. It’s very dependent on the C-arm if it’s tethered one way or another, rainbowed too much, measure the angle. It’s a lot faster, a lot easier, and you can feel a whole better. You can do it right there real time in the operating room, which I oftentimes do. It will tell you any shortening, do you have it out to length enough, what have you, give you a myriad of wealth in information. Here’s your fibular-tibial overlap of 10 millimeters. Obviously, again, in this case, you’re looking at medial oblique. Surgeons’ goals for absolute stability, no motion through the fracture sites. This is the principle of primary bone healing. Obviously, we would like no motion, no secondary bone healing. But screw fixation alone can only tolerate minimal loading. This is the reason why you go forward with the plate. When you think about it, you can fix an angle fracture with one or two screws. Oftentimes in children I will do that because the plate, there’s no need to have it but it heals so quickly. But in an adult, that plate is to protect the screws. Just a neutralization plates to stop torsional forces. This whole construct for all these screws is just to protect the main character, which is that interfrag screw right there. Posterior plating, it’s a common way to do things, I think in Europe. I don’t know many people that do it here. I put it in there because it seems like you’re tested on a lot. This is the principle where you just put posterior plate with two screws proximally. In theory, you weight-bear these people from beginning. What happens is the lateral ligament complex almost serves to piston or dynamite the fracture. Obviously this person is not going to heal with primary bone healing. This is not rigid internal fixation. But the idea is you can’t really get into trouble if the fibula can’t slide anywhere, can’t displace dorsally or proximally up the legs. It holds it into position. In some cases, people will insert what’s called a track screw which is a screw on the bottom of the plate to hold everything into position as well. The hook test or cotton test, every resident wants to do the hook test. Can we stress the syndesmosis? Sure, after you put the plate on. Don’t stress that syndesmosis until you put the plate on. For two reasons. Number one, the plate is very unlikely to deform when you’re hooking, alright? Not when you’re [Indiscernible] [23:27] when you’re doing the hook test, right? When you take that plate and you pull, you’ll be able to tell if the C-arm is cocked a little bit. In other words, if you see more screws than you did initially, you know that when you’re pulling on the hook, you’re actually displacing the C-arm picture. Other reason is very difficult once you get your interfrag screws and you want to try the hook test, very difficult to maintain that fracture. You’re on the risk of displacing everything. Absolutely, that hook test should not take place. Syndesmosis should be the last thing you fixate before you saw up. It should not be the first thing. Syndesmotic screws. Principles in syndesmotic screws, you have your choice, either two or three cortices screws or one cortex screw. Why is that important? Because sometimes you just can’t put more than one screw in. On the other side of the coin, if you can’t really drop your hand to the angle where you’re going to catch all four cortices, you can just use another screw above it and catch three. Another take-home point is when you use locking technology, that place, that interface between the plate and the screw, counts as one cortex. In theory, you really only need one screw, three cortex if you’re using a locking plate. That’s more of a testament to, I think, Dr. Caleb’s this morning talking about internal/external fixation with a locking plate. That is like an external fix because of the construct that makes. Controversy exists as to whether or not the screws must be removed, that’s patient-specific, independent.
I usually give them the option. I usually say, “Hey, listen. At 12 weeks these are probably going to break. We can take them out in a minimal surgery.” Some people claim that the screws feel better when they break and then leave them in. Totally patient-dependent. I let them do the research and get back to me as to what they want to do. The only time that broken screws become pathologic is if the break is not in the syndesmosis. Sometimes it will break a little bit into the fibula and then the fibula will be tethered. Sometimes you can get some biologic failure or [Indiscernible] [25:31] of the screw which is going to be painful. Sometimes it’ll actually break a little bit of the medial tibial cortex which can be painful. By and large, I let the patient decide what he or she wants, standard construct for syndesmotic repair. Conrad Budd trapping. This is what they call the Chinese finger traps, right? This is the inability to reduce the dominant fracture because the posterior tibial tendon runs right behind that medial colliculus. Oftentimes when the talus displaces a little bit, posterior tibial tendon will force itself into that space. Once it does, if you don’t recognize it, you’ll be playing with this thing all day long trying to figure out why this ankle won’t get back into position. Here you can see obviously it’s poorly fixated ankle fracture because that posterior tibial tendon is lying in that hole Whenever you’re doing this case is bound to failure for multiple reasons, tethering the posterior tibial tendon in inadequate reduction of the ankle joint. That is it. We are on time. And it’s dinner time. Alright, thank you.