Hello and welcome to this AOFAS on-demand presentation. I'm Ben Jackson, and I've been given the task of discussing the evaluation treatment of syndesmotic injuries. I don't have any financial disclosures, but here are my other disclosures. Today we're going to go through syndesmotic injuries, mainly focused on initial case presentation. We're going to talk about the anatomy of the syndesmosis, common mechanisms of injury, physical examination with a special attention of the syndesmosis, imaging modalities, treatment options, and then we're going to review the case. Some of you can relate to this particular patient with the pain diagram that we have here. Some patients present with non-focal symptoms. However, most of the time with syndesmotic injuries, the pain that folks experience or report is fairly focal. So as far as our case presentation, we have a 47-year-old male who two days earlier was performing a martial arts maneuver. He was sparring with his partner, and with his left foot planted, his partner threw him, and he had an external rotation moment onto the leg. On physical examination, he was unable to bear full weight. He had 3 plus edema in the lower extremity. His squeeze test was positive or painful to the middle third of the tibia, and he was unable to tolerate external rotation of the foot. His radiographs here are a mortise and a lateral view of the ankle. This is of the left ankle, and these are weight-bearing radiographs. I'll give everyone some time to look at these radiographs, and we'll revisit the case after discussing more about the features and specific anatomy and some physical examination considerations of the syndesmotic injury. For the anatomy, I think of the syndesmosis having three main ligaments, the anterior inferior tibiofibular ligament, the posterior inferior tibiofibular ligament. This is sometimes subdivided in a transverse portion of that ligament. There's also the interosseous ligament, which generally I see several centimeters above the ankle mortise, best seen on an axial MRI scan. Generally, I evaluate these ligaments on an axial T2 MRI sequence, and it's been noted by some studies when they try and test the strength of these ligaments that the PITFL is the strongest and roughly represents 50% of the strength of the syndesmosis. The most common mechanism of injury, as is shown in this still picture of a collegiate football athlete, generally the foot is planted on the ground or fixed on the ground, and then in this particular sequence, the opposing defensive player is trying to drag the quarterback down. There's an external rotation moment on the foot that is unable to move. The knee essentially goes down straight, and there's a strong external rotation of the foot. Sometimes there's dorsiflexion, and the proinsubination probably don't matter that much to the foot, but mainly it's a foot that is fixed or against the ground in a way that cannot be moved, and there's an external rotation moment. The YouTube video that Dr. Amendola presented, the link is there on the slide. On physical examination, I believe it's important to note echemosis. This is not often present, but if it is, I think it's significant. Particularly when we're seeing these as sports-related injuries on the field, generally there will not be any echemosis. It develops days later. I think the level of echemosis and the severity of echemosis generally correlate with the severity of the injury. I would note edema, how much is present, and how far up the leg does it go. Additionally, when possible, I believe a standing examination is important. Initially, we want to look at foot alignment and position, its comparison to the contralateral side. For those with more subtle injuries, they will be able to perform a hop test. However, most patients with a grade 2 or grade 3 injury, which we'll discuss that in more detail later, will be unable to perform a hop test. One of the other most important tests, I believe, particularly with standing examination, is a standing single limb extramarotation stress test. What happens in this particular physical examination maneuver, typically I start with the patient's contralateral limb. They face that at you. They put all their weight on the unaffected limb, and they rotate their pelvis externally as far as they can. You then ask them if they have pain associated with this. You then have them stand on their injured leg, if they can stand on a single limb stance, and do that same maneuver. If that causes pain, that is associated with a syndesmotic injury. For more chronic syndesmotic injuries, I will often simply grab my hands around the lower part of their lower leg. I will squeeze their syndesmosis together, have them repeat the maneuver, and see if that decreases their pain. For most folks with a chronic syndesmotic injury, it's very similar to taping, which has been described in the literature. If you don't have an athletic trainer and ability to tape the patient's leg in the clinic, if you simply perform this squeeze while they do the external rotation, often that will improve their symptoms for more chronic injuries. In an acute situation, most patients are not able to tolerate this. In addition on physical examination, when they're seated, you can perform the squeeze test. That's where you place generally the heel of your hand on the medial tibia and on the lateral fibula and squeeze them together. I typically start at the upper portion of the lower leg and go down. When they start to have pain over the anterior compartment, that's when I consider the squeeze test to be positive. Many folks will track this with time, as generally speaking, the pain will decrease and go lower down the leg about 1 cm per week. You can also do direct palpation over the anterior fibula and over the lower portion of the anterior compartment. These two tests have been reported to have 88 and 92% sensitivity respectively. Additionally, when patients have a syndesmotic injury, frequently they have an injury to the deltoid ligament as well. You can perform direct palpation over the deltoid ligament, over the medial malleolus and just distal to that. You can also examine the patient for tenderness of the proximal fibula to see if they have a mason-new type of injury, which is associated with a proximal fibula fracture. Again, we mentioned the single limb external rotation stress test in more detail previously. There is a seated external rotation stress test as well, as well as a single limb hop test that can be performed, again, with patients with a more subtle injury, or where they are trying to determine if the patient has a grade 1 stable injury versus a more severe grade 2 type of injury. On imaging, typically I get three weight-bearing views of the ankle and the patients are able to tolerate it. There are many different areas that can be measured. I'll describe that in more detail later. One measurement is tip-fib overlap, and whether or not that is more or less than 6 mm at 1 cm above the ankle mortis. Additionally, you look at medial clear space. If there is proximal tenderness over the fibula, I will obtain apion lateral views of the tibia as well. Additionally, I think MRI scans are incredibly helpful, not only to confirm the diagnosis of syndesmotic injury, but also determine the extent of the injury. For folks that have available, in-office fluoroscopy is reasonable. Some folks will take the patients that they're concerned for a potential grade 2 versus grade 3 injury and do an exam under anesthesia fluoroscopically. Additionally, an emerging modality is a weight-bearing CT scan. I think there are several studies that have shown that syndesmosis is different from patient to patient and the size of the incisura as well as the position of the fibula in the incisura differs from patient to patient. Thus, I believe if you are going to get a weight-bearing CT scan, getting a comparison contralateral view is critical. These are some of the measurements that can be measured on an AP view of the ankle. They're described in more detail below. I believe there are specific papers on these, although I think that the rotation of the ankle, where they don't have a true AP view, can make these very difficult to interpret, and that's why there is no perfect measurement for syndesmotic stability, mainly because it is a three-dimensional joint that is difficult to try and assess that three-dimensional joint on two-dimensional plane radiographs. Then we go to the diagnosis here, and I think this is where things become very important and become the trickiest. Grade 1s are generally incomplete injuries. They do have a pain with an extra rotation stress or squeeze test. Typically, grade 1 injuries, there is only a partial syndesmotic injury. In my mind, this is one out of the three ligaments are injured. Generally, the ligaments are injured from anterior to posterior with the AITFL first injured, and the PITFL generally is the last ligament injured. Generally, with grade 1 injuries, there is only one portion of the ligament injured, and two out of three are intact. Typically, when it gets to grade 2, they have two out of three ligaments that are injured. Sometimes you'll see three ligaments injured, but this is generally not associated with a grade 2 type of injury. Generally, a grade 3 injury is a complete injury to all portions of the syndesmosis, and there can be an increase in medial clear space. These are generally considered to be unstable even without stress, whereas grade 2 injuries can be stress positive, which is why sometimes folks will do in-office fluoroscopy or weight-bearing examination or stress radiographs. For the treatment options, grade 1 injuries are virtually always treated non-operatively because they're stable. In my hands, I typically cast patients for one week. This can be a weight-bearing cast, and I transition them into a boot, and ultimately they return to activity as tolerated. When they do return to activity, particularly if it is a high-risk sport such as football or something that has running and cutting, such as soccer or basketball, typically they are taped, and we use syndesmotic-specific bracing to help protect them from future injury to this limb. We'll now go to grade 3. Grade 3s are almost always managed operatively because these are inherently unstable. They're unstable even without stress. Operative management includes potential repair of the deltoid ligament. I think in general, the literature is turning towards more commonly repairing the deltoid ligament. You can fix the syndesmosis. There are multiple options for this, including flexible fixation, screw fixation, as well as some direct suture tape fixation of the syndesmosis. I believe that most commonly folks are using flexible fixation and using one or two points of flexible fixation. Additionally, authors have described hybrid constructs as well that can involve flexible fixation as well as screw fixation. The other important part of this type of injury, if there is a proximal fibula fracture, many surgeons advocate fixing that. If it is from the middle third or more distal, fixing the fibula so that you make sure that you obtain the appropriate length rotation alignment of the fibula prior to fixing the syndesmosis. Again, grade 2 injuries are the most controversial, not only to diagnose but decide how to treat them. I think there are several different options for treating these. I think some of this depends on the age of the patient, the functional level of the patient, if they are an athlete, where are they in their season or contract. All should be considered as well as their ability to at the collegiate level obtain a medical red shirt. At the high school level, are they going to be playing at the next level and are they a one or multi-sport athlete. There are multiple factors that I think are important for how to manage these injuries. For grade 2 injuries, if you are going to manage them non-operatively, in my mind I treat them with a short leg cast anywhere from 4 to 6 weeks. I use a physical examination, their ability to tolerate a syndesmotic squeeze test as well as their ability to do a single extramutation stress test or tolerate a seated extramutation stress test determines how long they are in a cast. Most commonly it is around 4 weeks, it can be up to 6 weeks then I transition them into a boot. For some of our elite level athletes, we can consider early operative intervention. Again, I think this is a risk and benefit discussion with the patient as well as the collegiate level with the coaching staff. At the professional level, more with the agent. At the high school level, it is more with the parents. For these folks, the goal of operative management is to turn a grade 2 injury into a grade 1. You make it stable by stabilizing at least one additional portion of the syndesmosis such as the interosseous ligament with the placement of flexible fixation. Generally, they are in a splint for 2 weeks. The sutures are removed at 10 to 14 days. Then placed into a boot and allowed them to weight bear as tolerated and returned to sport as tolerated. Again, I think at this point that treatment is controversial. Hopefully there is more evidence that is shown upon this and whether or not there can be a quick return to play. What are the true risks and benefits to performing early operative intervention on these cases that could be managed unoperatively with rest and immobilization? For me, the grade 3 injuries, again, in my hands are nearly always operative. I splint these patients for 2 weeks. Sutures out at 10 to 14 days. Then place them into a short leg non-weight bearing cast for 4 weeks. They are in a boot with progressive weight bearing or full weight bearing by 8 weeks. Out of the boot by 10 weeks. Ultimately, they are in an ASO lace-up brace decreasingly for 6 weeks after that. Now let's go back to our case in these radiographs. Maybe there is some widening of the tibial fibular space. I do not believe there is any increase in the medial clear space that is significant on this examination. Again, there may be a subtle difference there. There was no proximal tenderness to the fibula and there was not an associated fibula fracture. Here is one pertinent cut of the MRI scan. This is up a little bit higher, but I think you can clearly see the edema in the anterior compartment. There is edema in the posterior compartment. I think you can clearly see there is injury to the interosseous ligament as well. You cannot see down lower to be able to assess the AITFL or PITFL. Ultimately, I believe this patient will benefit from operative intervention. I believe there is a role for arthroscopy for the diagnosis of both acute as well as particularly chronic syndesmotic injuries. There is a nice Yellow Journal article where some of our military colleagues explain this well and the role of arthroscopic not only diagnosis, but management and ensuring accurate reduction of the syndesmosis. I believe the most accurate way to look at the syndesmosis is arthroscopically. For me, there are two very important tests that I perform. One is which is illustrated on the picture to the right. I typically place the probe in the syndesmosis. The probe should be able to go into the syndesmosis in the mid portion. It should not be able to pull out the front of the syndesmosis. If you can pull out the front of the syndesmosis, I believe there is an injury to the AITFL and that indicates at least partial syndesmotic instability if not complete syndesmotic instability. This is how I assess both the acute and chronic syndesmotic injury. Notice that the fibula appears to be better reduced with relation to the other tissue that is present when we compare that. A post-operative protocol for this particular patient was a splint for two weeks. Again, suture removal in 10 to 14 days. They were in a short leg weight-bearing cast for an additional four weeks for a total of six weeks out from their injury. Then I converted them into an ASO brace. I wait to start physical therapy until approximately 10 weeks and the physical therapist will help guide their return to activities. This is different in my elite athletes that I've actually worked with. In my elite athletes that have access to an athletic trainer, typically we'll start things like blood flow restriction therapy. At the six-week mark, I do have them get involved with our athletic trainer. I simply don't have them do any resisted external rotation stress. They start band work, they continue to do quad and hamstring strengthening, and they do BFR work, which is blood flow restriction treatment, with our athletic trainer. If they don't have that level of supervision and what I believe high level of competence, either an athletic trainer or physical therapist, I typically wait until 10 weeks before we start that. I did want to show the final radiographs of this particular patient. This is roughly six months out from their injury. A couple of key points here. I do believe you're going to use flexible fixation. Ideally, they're in two different planes. The more inferior suture button fixation is directed anteriorly. This is specifically because the fibula with the fibular shock examination was more unstable posteriorly. That's why it doesn't appear to be completely on the medial cortex on this mortise view. Then we have one placed a little bit more centrally, more in line with the tibiofibular joint, which does go roughly from posterior to anterior approximately 20 degrees, but again, that's variable from patient to patient. I also picked this particular case in radiograph because even despite fixation, because of the patient's severe injury, they did develop a small amount of heterotopic bone in the syndesmosis as well. I only see this typically with a more severe type of injuries. If these are stabilized early, I typically don't see that again, except for the more severe type of injuries. This patient had tenderness going all the way up to the middle third of the tibia with a syndesmotic squeeze test. They really had difficulty with weight bearing. There's clearly a more severe type of injury. We also demonstrated on that axial T2 MRI scan that was further up the ankle. The same amount of edema that was present, they also had fluid around their FHL tendon as well, which also is concerning for more severe syndesmotic type of injury. In summary, this is a spectrum of injury. From the subtle, not unstable grade 1s, they can simply be treated with potentially a shorter period of immobilization and back to activity is tolerated. We typically have a partial injury to the syndesmosis to the grade 3s that are clearly unstable and clearly need operative intervention. I believe there is a lot of controversy over these grade 2 injuries, whether they should be treated operatively or not operatively. I believe there's still further investigation that is being undertaken by multiple authors across the country for critical rehabilitation protocols and whether or not we can find more accurate ways to determine not only return to participation, but also return to full performance and whether or not early operative intervention is helpful in treating these grade 2 injuries and getting folks back to performance more quickly and whether or not they're able to return to full performance while also understanding what the risks are to that type of early operative intervention. Please let me know if you have any questions. I appreciate you listening to this syndesmotic talk. Hopefully this was able to provide more information so you can understand both how to diagnose, classify, and treat these syndesmotic injuries, which can often be complex. Thank you for your time.

syndesmotic injuries

evaluation

treatment

physical examination

radiographs