Hey everyone, my name is Ryan Nussbaum and I am a sports medicine physician from the University of Pittsburgh Medical Center in the Department of Physical Medicine and Rehabilitation. Today I was going to review an ultrasound case focusing on a high ankle sprain. The first topic we wanted to cover was a normal ultrasound of the anterior inferior tibiofibular ligament, also known as the AITFL, and we're going to look at this in long axis. So if looking at the illustration in the top right, you notice that the transducer is going to be in the location of the black rectangle. With the picture on the way left, you identify the tibia and fibula, and this is in an area that is actually cephalad to the AITFL. As we slide the transducer more caudally, you notice that the AITFL comes into view, and this typically has a fibular appearance and often a homogenous echotexture. What you might notice is that the superficial aspect of the ligament has a hyperechoic appearance, and that is due to the difference in echotexture between the overlying fat and the AITFL. So fat is typically more hyperechoic, which then subsequently makes the AITFL appear more hypoechoic. And it is important to note that this structure is susceptible to anisotropy, so you want to make sure you have an appropriate angle when evaluating. When going more caudally, you will no longer see the AITFL as is seen in the picture on the right, and you are noticing the talus. The video in this slide evaluates the AITFL in long axis with a cephalad to caudal translation. If you have enough time for your scan, you can look at the AITFL in short axis. This slide demonstrates a normal evaluation of AITFL, and the illustration in the top right demonstrates the orientation of the transducer. So moving from left to right, we look initially at the fibula, and as we translate more anteriorly on the ankle, we notice the mid-portion of the AITFL. And as we continue more anteriorly, we eventually see the tibia, and the AITFL is no longer present. This is a video of scanning the AITFL in short axis from the fibula to the tibia. When looking for pathology in the AITFL, there are certain things that can be identified from a qualitative perspective. This includes a heterogeneous appearance, anechoic signal that may be a hematoma, thickening, vascularization on Doppler, dynamic assessment can show discontinuity, and this can be done with dorsiflexion and eversion of the ankle, cortical irregularity of the tibia or fibula. From a quantitative perspective, you can do measurements from the tibia to the fibula at neutral and when stressing the AITFL, which was described previously. Consider contralateral comparison when indicated, particularly if you are concerned about an abnormal finding. If there is concern for an AITFL injury, make sure to evaluate for a more proximal syndesmotic pathology. Next, we wanted to review a companion case of a high ankle sprain. This is a 15-year-old male football player who is an offensive lineman who developed left ankle pain during a play. The mechanism of injury was not seen, but the assessment demonstrated increased swelling and tenderness at the lateral malleolus, intagic gait with pain, limited range of motion, and the examination further showed an anterior drawer, Taylor tilt, and Kliger test that were all positive. During the halftime of the game, we did a screening evaluation of the patient's ankle, which demonstrated no findings of a distal fibula fracture or of an ATFL injury. So from there, we looked at the AITFL ligament, and we are familiar with the long-axis view of a normal AITFL as seen on the right. When comparing to the patient on the left, you'll notice that there is heterogeneous appearance of the AITFL and even anechoic signal within the substance of the ligament, which is concerning for a hematoma. On the left of the slide, there is a video of the patient's AITFL, which demonstrates increased hyperemia within the AITFL. After reviewing all of the images collected, there was findings consistent with an AITFL disruption, which was further confirmed by MRI. This companion case demonstrates how ultrasound can be an effective screening tool for acute ankle injuries. Feel free to utilize the reference on this slide for better understanding the diagnostic value of ultrasound when looking at ligamentous ankle sprains.

3rd Edition, Case 02

3rd Edition

Ankle

ultrasound

high ankle sprain

anterior inferior tibiofibular ligament

sports medicine

diagnosis