Hi everyone, I'm Shelby Johnson from Mayo Clinic in Minneapolis, and this is an ultrasound consult for lateral epicondylopathy. So for the lateral elbow, I generally use a high to mid frequency linear probe depending on the patient's body habitus. I'll have the patient positioned supine with their forearm pronated and then their elbow in slight flexion. A very good palpatory reference point is actually the bony prominence of the lateral epicondyle, which I use as a proximal anchor to start my scan. And you can see that in this picture on the right. Additionally, throughout this lecture, I will have little red boxes to indicate the position of my probe. So using that lateral epicondyle as my proximal anchor, I can then visualize the nice ski jump appearance of the lateral epicondyle. The top 50 to 70% of the tissue coming off of that ski jump is the common extensor tendon, and then that deeper tissue is the radial collateral ligament. Sometimes it can be hard to distinguish these two layers, and that's where transducer movement, tilt and heel-toe can help. I have shaded in these two structures to help with visualization, with the teal blue being the common extensor tendon, and then this lime green being the radial collateral ligament. And both of these we're seeing in long axis. In this view, we can also see the radiocapitellar joint, slightly distal. And then you may see some smuck in the joint, which is a lateral synovial fringe. In this individual who has a normal common extensor tendon, you can see these really nice, homogenous, hyper-echoic structures with nicely aligned fibers. There's no significant tendon thickening associated, cortical irregularities, calcifications or hyperemia. One note with tendon thickness is that there's really not a great number to hang your hat on to use as a cut-off for thickening. But what I generally use is this border of the lateral epicondyle, and if the tendon protrudes above that, then it's probably thickened. You can also compare the tendon to the contralateral side, which can be helpful as well. So as always, you want to view structures in two views. So here we've changed to a short axis view of the common extensor tendon and the radial collateral ligament. And so this dashed line right here separates those two tissues with the ligament below and the tendon above. Now in a longitudinal view, it's often very hard to distinguish the different components of the common extensor tendon because it's so interwoven. In a short axis view, however, you can see those different components by just sweeping distally to see the muscle bellies bloom off of each part of the tendon. Keep in mind that with lateral epicondylopathy, the most common tendon affected is the extensor carpi radialis brevis. And so in short axis, again, we will look for echogenicity and architectural change, and thickness and presence of any enthesophytes, calcifications, or hyperemia, which we're not seeing here. So now I'm moving on from normal to an individual with common extensor tendinopathy. In these two images here, we are in that original view with the lateral epicondyle to our left and the common extensor tendon in long axis. And in contrast to our previous images, we can see how this tendon is much thicker. It requires areas of significant hypoechogenicity, and the echo texture is just much more heterogeneous. We can also see that the tendon architecture is no longer those nicely linear aligned fibers. You can also see an area of anechogenicity in the mid portion consistent with an intrasubstance partial thickness tear. Be careful with calling tears because partial tears, especially if small, can be difficult to distinguish from tendinosis. So always be sure to visualize those in two planes. If there's a complete tear, this is a little bit more obvious because fluid will typically fill that gap between the bone and the tendon. So looking in short axis view, we can again visualize how that tendon is just much thicker. And this video on the right, we can see those areas of hypoechogenicity and anechogenicity right there. And then we can also see that these tendon fibers are disrupted compared to normal. Now this individual does not have any significant enthesophytes or intertendinous calcifications, but that is something that you may see, especially in someone with long standing tendinopathy. So with tendinopathy, we also want to evaluate for intertendinous hyperemia. So with power doppler here, we can see that there's moderate hyperemia with the tendon visualized in long axis here and short axis on the right. A couple of things to keep in mind when you are evaluating an individual with lateral elbow pain is that not all lateral elbow pain is due to the common extensor tendon. So especially in someone with recalcitrant pain, you should also consider radial collateral ligament injuries, which can co-occur with extensor tendinopathy. And then you also want to think about radial nerve entrapment, as well as any intraarticular process. And that concludes this ultrasound consult.

3rd Edition, CASE 13

3rd Edition

Elbow and Forearm

lateral epicondylopathy

ultrasound consult

common extensor tendon

tendinopathy

radial nerve entrapment