Okay. Let's keep going. All right. Good morning, everybody. As usual, happy Friday. Hope everybody's having a good summer, at least here in the Midwest. It's quite warm right now, so hopefully everybody's getting to spend some time outside and enjoying the weather. One quick housekeeping point, and I'll make the point at the end as well before I introduce our speaker, this is the last of our quote-unquote fellowship block of presenters, and so we will be taking a break for a week or two, I believe. I'll get the exact date. I have it in front of me. And then we'll get restarted in early August, transitioning back to our faculty presentations. Just like last fall, it'll be the same format, just this block of presenters will be faculty docs, and then again, we'll hopefully transition back to fellows later in the year. So with that, I want to introduce our presenter. So we're fortunate to have Dr. Allie Warrick presenting today. She no longer is a fellow, but she was kind enough to stay and do this presentation for us, so I appreciate that, and she, like we were talking about earlier, she is California through and through. She's from Lafayette, California. She did medical school, her residency and fellowship at UC Davis, and she is now currently on staff at UC Davis with their PMR and sports medicine department, and today she's going to be talking to us about a case of distal IT band syndrome, so with that, I will let Allie take it away. All right. Good morning, everyone. Thank you very much for the introduction. All right. I have no disclosures, but I would like to thank everyone at UC Davis sports medicine department, and special thanks to Alberto Pinero. Thank you to the AMSSM Sports Ultrasound Committee with Dr. Cruz, Hoffman, and Hall, and thank you all for joining us this morning. My objectives today are to review the distal IT band anatomy and lateral knee anatomy. I will describe a case and the sonographic approach to this patient, highlighting pertinent ultrasound structures. Let's review the scanning protocol for the distal IT band and lateral knee. I will identify pertinent sonographic structures and describe a structured diagnostic ultrasound report. Let's start with the case. Chief complaint of left lateral knee pain that began in a 36-year-old male recreational runner, both road and trail runner, who presents with four months of left lateral knee pain, insidious onset, pain when running, who is training for the California International Marathon that takes place here in Sacramento. He is running 40 miles per week. He's a heel striker and denies any of these symptoms. On physical exam, there is no visible or palpable knee effusion, and there is normal knee alignment. With the single leg squat, on the left, there is less control, and he appears somewhat unsteady. On physical exam, there is tenderness to palpation over Gertie's tubercle and the distal IT band, and there is no tenderness to palpation to other structures. There is full range of motion. Stability testing is all negative. However, there is tightness in the IT band and pain over the distal IT band, demonstrated by Ober's and Noble's compression tests, respectively. Other history is non-contributory. The differential diagnosis includes these conditions, which may be present with lateral knee pain. Let's review the anatomy before beginning our diagnostic ultrasound evaluation. First, the iliotibial band, commonly referred to as the IT band, is a fibrous band that runs longitudinally along the lateral aspect of the thigh from its origin with connections to the tensor fascia lata at the iliac crest, gluteus maximus, medius, and vastus lateralis. Although it is known to insert a Gertie's tubercle at the anterior lateral tibia, it also inserts onto the femur, patella, and tibia, as reviewed on the left. While highlighting the complex anatomy of the IT band, today's ultrasound scan will focus on the insertion of the IT band at Gertie's tubercle. The biceps femoris muscle includes both the long and short head, which insert onto the head of the fibula, as well as the lateral condyle of the tibia. The lateral collateral ligament originates from the lateral femur and extends over the popliteus to insert on the lateral aspect of the fibula. On the right is the anterolateral ligament, which connects the anterolateral tibia with the femur. I encourage you to review Kentaro Onishi's wonderful AMSSM lecture on posterior lateral knee ultrasound, which describes the structure being more aptly named the anterolateral complex, and describes how to scan this region, including anchoring the distal end of the transducer between Gertie's tubercle and the fibular head, and orienting the proximal end of the transducer slightly posteriorly. The RSNA, or Radiological Society of North America, has excellent content listed online if you are interested. The popliteus tendon originates at the lateral aspect of the femur, lies within the groove of the lateral femur, encourses obliquely, and inserts on the posterior surface of the tibia. There are three layers to the lateral knee, described by their orientation from outward to inward. The first, most superficial structures include the IT band and the biceps femoris. The second layers include the LCL and the patellar retinaculum, which is the fibrous expansion of the IT band, an extension of the fascia of the vastus lateralis, and includes the deeper layers of the lateral patellofemoral ligament, patello-tibial band, and transverse ligament. The third and final layer of the knee includes these stabilizing structures. Please note how integral the head of the fibula is for orientation when finding these structures on ultrasound. To review, the biceps femoris, long head and short head, arcuate ligament, LCL from the second layer, popliteofibular ligament, fabellofibular ligament, all insert onto the head of the fibula. The fabellofibular ligament can be found deep between biceps tendon and the lateral head of the gastrocnemius. The popliteofibular ligament originates at the myotendinous junction of the popliteus and attaches to the fibula. Here's an axial MRI to review the anterior to posterior relationship, starting anteriorly with the IT band and the LCL, biceps femoris, and finally common peroneal nerve most posteriorly at the level of the patellar tendon. To briefly review ITB biomechanics, the three images include progressively increasing angles of knee flexion. IT band is under greatest tension at 30 degrees of knee flexion with friction of ITB rubbing across the lateral femoral epicondyle. As the knee is flexed, the tension in the ITB shifts from its anterior to its posterior fibers. Here are T1 weighted MRI scans of the knee that depict the movement of the IT band from extended knee on the left to a knee in 30 degrees of flexion on the right with the contracted quadriceps. The IT band slopes laterally as it passes from the femur to the tibia. However, at 30 degrees of flexion, it slopes immediately. This depicts that the IT band is compressed against the lateral epicondyle at 30 degrees of flexion. Contracting the vastus lateralis with the flexed knee also reduces the space occupied by the fat pad deep to the IT band and compresses the blood vessels and nerves. Thank you for reviewing the anatomy with me. Let's review the AMSSM recommended diagnostic sports ultrasound protocol. It includes scanning the IT band, the lateral meniscus and tibiofemoral joint space, the LCL with various stress as indicated, biceps femoris, palclitius, the lateral patella retinaculum and patellofemoral joint, which can also be included with an anterior region scan. Proximal tibiofibular joint and additional structures may be included as listed here below. There's some overlap with the posterior knee ultrasound. To start the scan, the patient is positioned supine with the femur tibia internally rotated. The knee is flexed with bolster or rolled up towel under the knee. Alternatively, the lateral decubitus position can be used with the pillow between the knees. The transducer is a linear array reducer, 15 to 6 megahertz, and here are the ultrasound machines used. Scanning strategy includes using orthogonal planes for a full diagnostic evaluation and using sonopalpation for clinical correlation. I'll be using key landmarks and scanning strategies that will hopefully make it easier to scan the lateral knee. First, for orientation, the transducer may be placed over the patellar tendon in long axis. This is an easy landmark to locate. Then the transducer is translated laterally towards Gertie's tubercle. The first structure in long axis will be the IT band. Here is the IT band long axis. To obtain this view from the patellar tendon, rotate the proximal end of the transducer posteriorly so that the fibers of the IT band line up in a linear orientation. The IT band in Gertie's tubercle can be palpated for orientation. Next, let's evaluate the IT band in short axis by rotating the transducer 90 degrees. This video depicts the proximal to distal scan of the IT band. You can see the IT band over the femoral condyle and moving distally towards Gertie's tubercle. Ekman et al. in the literature reported a normal thickness of 2.5 millimeters plus or minus 1.5 millimeters at the lateral femoral epicondyle. This patient's IT band size at this location is 4.8 millimeters. Thicker IT band over the lateral femoral epicondyle is characteristic of IT band syndrome. Now here we also have the IT band in short axis and this video depicts the IT band at the level of the lateral femoral condyle with and without sodium palpation pressure and demonstrates some hypoecogenicity deep to the IT band. To evaluate for a fluid collection, there are two possible spaces. So I'll repeat this again. One is the lateral peripatellar recess of the knee joint which can be seen overlying the femur and connects intra-articularly. This patient for reference had a trace effusion ultrasound and literature reviews how the synovium can fold into the lateral recess and appear to be the IT band versopathy. And then secondly, the IT band versa is just deep to the IT band and is likely pathologic and related to IT band syndrome. Here is an anechoic space that appears to be a suctated versa. Given its close proximity to the femur, this is likely from the lateral recess and the space just inferior to the IT band would be consistent with IT band versopathy. In summary, as part of a diagnostic scan, please evaluate the IT band for IT band thickening, surrounding fluid, and tenderness with sonopalpation. Next, let's reorient within the long axis of the IT band and translate laterally to the tibiofemoral joint line. So here we have the joint line. You can evaluate the joint line including the meniscus and the coronal plane for any type of meniscal tear which would appear as a hypoechoic or anechoic cleft and evaluate for any perimeniscal cysts which can be associated with a meniscal tear. Meniscal displacement or extrusion which may or may not be in the setting of osteoarthritis may also be evaluated. Go ahead and move the transducer anteriorly and posteriorly. Wag the transducer to account for anisotropy. In contrast to a medial meniscus extrusion, extrusion of the anterior horn and body to lateral meniscus may be a variation of normal. Ultrasound evaluation is limited for evaluating meniscal tears. Due to complete visualization, therefore MRI is the method of choice for thorough evaluation. The pulsatile structure that we see here is not a cyst. It's the lateral inferior geniculate artery adjacent to the meniscus and can be visualized with color doppler. Next let's translate the probe superiorly to the groove for the popliteus. The popliteus tendon may be followed as it curves posteriorly around the knee joint in a coronal oblique orientation. Because of the curved arrow of the popliteus tendon, now this tendon is assessed in segments given that it is prone to anisotropy. A prone position will help to localize the posterior popliteus between the tibia and vasculature as part of the posterior knee evaluation. Next let's evaluate the structure overlying the popliteus, the LCL. Briefly reviewing the distal insertion of the LCL and biceps femoris, the LCL inserts onto Gertie's tubercle. The biceps femoris tendon inserts around the LCL. Long head is superficial and short head is deep to the LCL. The image on the left and right both demonstrate how the LCL inserts on fibula between the distal insertions of the biceps femoris. Because of this overlap, do not overhaul tendinopathy within either of these structures as they are prone to anisotropy with this overlap. To review, there is also a tibial insertion of the biceps femoris that can cause anisotropy when evaluating for the LCL. So to orient the LCL on long axis into the proximal end of the transducer just above the groove of the popliteus, next locate the head of the fibula and rotate the distal end of the transducer towards the fibula, placing the transducer across the joint line is prone to error because the distal end of the transducer will likely be too interior given how posterior the fibular head is. You need to be able to visualize the head of the fibula, see the tib-fib space. So this structure is part of the biceps femoris that will attach the tibia and is causing anisotropy given the orientation of the fibers here. So you can see the LCL coming across here and the biceps femoris here causing the anisotropy. Also the LCL can appear lax, more so with knee flexion. You can assist by adjusting patient positioning and putting the knee into some varus with pillows. You may also do a dynamic varus stress test performed to evaluate for any additional laxity. The LCL in short axis is followed from the proximal to distal, from the lateral femoral epicondyle to the fibular head. So here is the LCL, I'm going to be pointing to it first. So you can see it coursing distally here. Let's review that again. So here's the LCL, so you can see it deep to the popliteus, posteriorly right here, the LCL. And you can see the biceps femoris, that's tendon and muscle coming from posterior to anterior. You can see it wrapping around the LCL here. And then you can see the LCL as it inserts onto the fibular head. Let's watch it one more time without me pointing. All right, next let's evaluate the biceps femoris. So to orient the probe, anchor the distal aspect of the probe on the head of the fibula and rotate the superior part of the transducer distally. You can palpate the biceps femoris tendons as well. So how can you tell what's the LCL versus biceps femoris? Well, the LCL is deep to the biceps femoris and the biceps femoris has a myotendinous junction when followed proximally. So here we are. This video of the biceps femoris is in long axis, which further demonstrates how this insertion onto the tibia can cause this relative anisotropy here. Next, let's evaluate the biceps femoris in a short axis. So it can be seen coursing posteriorly to the IT band and LCL respectively. And the common fibular nerve is reliably found posterior to the biceps femoris tendon, the common fibular nerve being the bifurcation of the sciatic nerves into it and the tibial nerve. This can be further evaluated in the posterior evaluation. So to systemically scan the structures, there is a scanning technique or a Z technique, which includes how we scan this case, starting with the IT band and long axis, keeping the proximal transducer anchored on the lateral femoral condyle, moving the distal aspect of the transducer posteriorly to the fibular head to visualize the LCL, and then anchoring on the fibular head and rotating the proximal transducer long axis to the biceps femoris tendon. This is the Z pattern of the IT band, LCL, and biceps femoris. Next, the tib-fib joint. You can orient the transducer as depicted above from anterior to posterior. You can look for an effusion, tenderness with soma palpation. And lastly, the last two structures to be scanned in this case would be best evaluated in a prone position. So to evaluate the palpatiofibular ligament, I recommend palpating the fibular head as depicted on the left and orienting the probe at an oblique longitudinal orientation. Superiorly, the transducer is medial and inferiorly, the transducer is lateral and anatomic long axis of the palpatiofibular ligament. And you can see the palpatiofibular ligament on the right and the palpateus next to it as depicted here. And lastly, let's evaluate the lateral gastrocnemius. So go ahead and translate the probe more superiorly and the probe will be oriented in long axis to the lateral gastrocnemius muscle, myotendinous junction and tendon of the femoral condyle. We evaluate this thoroughly. And lastly, let's move forward with our summary and our ultrasound report. Here's our diagnostic ultrasound report. It includes a description of who the referral is from, the clinical indication, the laterality, comparison studies and technique, detailing the type of transducer and ultrasound machine. The findings include that the iliotibial band was scanned from the proximal thigh to its insertion at Gerd's tubercle with evidence of fluid in the lateral recess and inferior to the iliotibial band in the distal iliotibial band bursa. There is tenderness to sonopalpation over the distal iliotibial band at the level of the lateral femoral epicondyle, which is consistent with the location of his pain running. The iliotibial band measured 4.8 millimeters in thickness at the level of the lateral femoral epicondyle. Normal thickness 2.5 plus or minus 1.5 millimeters referenced below and 3.8 millimeters in thickness at the level of the lateral femoral epicondyle with this normal thickness listed. These are case series here that I have depicted for reference. And the lateral meniscus ultrasound evaluation is normal. However, ultrasound is limited in visualizing the entirety of the lateral meniscus. Findings also include that the lateral collateral ligament is normal. There is no laxity with various stress testing. The remainder of the ultrasound exam, including the patellar tendon, tibiofemoral joint space, distal biceps femoris, including the long and short head muscle and tendon, popliteus muscle and tendon, lateral patellar retinaculum, proximal tib-fib joint, popliteofibular ligament, and common peroneal nerve at the level of the femoral epicondyle was normal. So overall, the impression of this ultrasound findings and clinical presentation are consistent with distal iliotibial band syndrome. The plan is a referral to physical therapy to focus on strengthening, including, but not limited to, hip abductors, hip girdle, and core with gradual return to running. So to share some follow-up, this patient's symptoms gradually improved. He returned to running. He was able to compete in the California International Marathon, and he set a new personal record. So in summary, for a scan of the lateral knee and distal IT band, recommend palpation of bony landmarks, which aid in ultrasound evaluation, including the head of the fibula. The Z approach helps to localize the IT band, LCL, and biceps femoris. And it's important to correlate clinically with sonal palpation, the area of where your patient may or may not be tender. And in summary, ultrasound is useful for a dynamic evaluation, yet limited to scanning the entirety of the lateral knee. So consider MRI as needed. Here are my references. Thank you very much. Here's my email address, if you'd like to contact me. And I'd be happy to hear comments and answer any questions. Thank you. All right. Thanks. Thanks, Allie. Great job. It's a complex area, at least in my opinion, the lateral knee. There's a lot of structures out in that area. And so, you know, your review of the anatomy out there was well done. And I think, you know, as folks are beginning to scan this region, or as, you know, they continue to scan this region, just knowing the anatomy is critical out here. I have a couple of points to make here, you know, for my protocol, there's, for the lateral knee, and there's a lot of crossover with lateral knee and the posterior knee, and even the anterior knee for that matter. And so I think this is an area where using, you know, your clinical judgment can really help narrow down the structures that you're evaluating in that region. You know, I have a similar protocol as to what you're doing what you presented, you know, common fibular nerve is always part of my scan out in the posterolateral knee. So always keep that in mind. One point as you're trying to navigate this area, you know, you brought up the point about the Z technique, or some folks will call it the zigzag technique, or there's different names. I think, you know, that's certainly helpful for some folks starting out to give you a reference point as how to move your transducer, at least for me personally, it was not helpful. And it's probably just because I'm not smart enough to figure out when I'm supposed to zig and when I'm supposed to zag and which part of the Z am I on. And so it was never helpful for me. I think just knowing your anatomy, you know, where a structure comes from and where it goes to can be really helpful, but the Z technique certainly, you know, can provide at least some sort of guidance for the lateral knee. The other point, I guess, two other points is regarding the FCL. You know, patient positioning for this is critical. If you don't have the patient in, you know, a decent amount of various stress, that FCL is going to be rather lax and wavy and evaluation can be a little challenging. So I always bolster their knee to put them in a decent amount of various to help me with scanning. And then the other point is regarding the rather intimate, you know, correlation or relationship between biceps and FCL. And there's a decent amount of variability with the anatomy of the biceps femoris. And as you mentioned, you know, oftentimes those two limbs of biceps will essentially core superficial and deep to FCL. And so you're going to have differential fiber orientations in that region. And so it's somewhat challenging to not over call pathology down there because you're going to get a bit of anisotropy. So really, you don't need to convince yourself that what you're seeing is actually pathologic both within FCL and biceps and, you know, try to not over call pathology in that area. That's what I have. Doug, do you have any points? Yeah. Ali, nice job. You know, it's a complex area and you took a nice methodical approach to it, which is one of the goals of this case series is to discuss protocols. Just to comment on the protocol. So, and I think I've mentioned this before, almost, I would say the majority of my protocols start with joint. And so in the knee, for example, my medial, my lateral, my posterior protocols start with the anterior super patellar synovial recess. And I do that long and short axis. One, looking for a joint effusion because being able to accurately assess for a joint effusion is going to help with your differential diagnosis and interpreting other pathology that you see. And then the other thing I look for is not only the presence of an effusion and I'll flex the knee looking for small effusions. I'll look at the, just the morphology of the super patellar synovial recess. And then oftentimes I'll look at synovial, synovium at the medial lateral patellofemoral gutters. And the reason why I do that is thickening suggests that there's a chronic disorder within the knee. And so the most common would be osteoarthrosis. And so not only is anatomy of the lateral knee complex, but so is a clinical evaluation of it. You know, people can present with lateral posterior lateral knee pain and non-traumatic can be very difficult. And in my experience, lateral interarticular pathology is the most common, particularly as, you know, the aging athlete. And so when I see a thickened synovium, I see a little effusion, I'm starting to wonder about interarticular pathology. So for example, if I'm doing a lateral elbow protocol, my first images are always the anterior elbow looking for a joint effusion. And so again, that's my protocol. The only other thing I add in my protocol to the lateral knee I agree with. Ryan, I do add the common fibular nerve. I also add the proximal tibiofibular joint. And just scrutinize that joint as well, because that can be a pain generator, or, you know, as we know, can affect the other structures around the knee. And then the last thing is, and you alluded to this, it can be very difficult sometimes to differentiate a small bursa between the IT band and lateral femorificondyle. And then that lateral synovial recess, which is a lax recess. And so it can fill with fluid, and in the normal state can have a very small amount of fluid. And so I find that to be, you know, can be difficult. And then sometimes with people who have clinically, obviously distal IT band friction syndrome, the ultrasound findings can be really subtle, just some slight increase in thickening and hypoepigenicity of the IT band itself, which can be really subtle and often comparison views can help with that. And sometimes I don't even really see much of a thickened bursa or thickening of the soft tissue between the IT band and the lateral femorificondyle, but just a little bit of hypochloric thickening of the IT band itself, but they're paying their risk on a palpation. So it can be hard sometimes to see the sonographic abnormalities with distal IT band friction syndrome. So nice job. Again, a nice approach to methodically, you know, sticking with the protocol, because it's easy to get lost in the lateral knee area. Thank you. Yeah, great job, Allie. Anybody else have any thoughts or questions? I had a nice job, Allie. It's Jay. Yeah, it's a difficult part of the knee. I don't know whose knee you scanned for that FCL biceps femoris, but I think if I saw correctly, it might've been, you know, I've seen uncommonly variations where the biceps femoris may actually go through the FCL or the LCL, and at least in part, and that's clearly not the usual anatomy, but I think I saw a part of it on that one. And I guess I would just be, let everyone be aware that it can, although we commonly discuss the biceps going around the FCL, sometimes it can go through the FCL. And I thought I caught a piece of that. It's just, you know, just an interesting curiosity, but really, really nice job on the scan. Great, thank you. All right. All right, well, thanks again, Allie. Great job. Again, it's a really complex area with a lot of anatomic variation. So like Doug mentioned, and like you mentioned as well, you know, sticking to the protocol is important to, you know, not only make sure you evaluate everything you need to evaluate, but just to kind of keep a checklist in your mind as you're going through those structures. So great job. So as I mentioned previously, we are off next week and we will restart actually on August 6th. We'll restart the staff or faculty presentations. I'll be presenting on that date. That'll be a case of a sports hernia slash athletic pubalgia slash core muscle injury. Pick your favorite term and we will go from there. So everybody have a good Friday, a good weekend, and we'll see you back on 8, 6.

3rd Edition, CASE 28

3rd Edition

Knee

distal IT band syndrome

lateral knee pain

sonographic examination

Z technique

ultrasound diagnostics

anatomy review

biomechanics