So my lateral hip protocol actually starts with the anterior hip, and this is how I designed it from the beginning, and after a number of years of doing this, it's reinforced that starting with the anterior hip is important to put all the pieces of puzzle together. And so with the anterior hip, I look at the joint, I look at the labrum, and several muscles. It's not as detailed as, let's say, my protocol for an anterior hip exam, and it doesn't take much time, but again, I think it's important. And then laterally, I focus on five structures as the baseline, and that would be the greater trochanter itself, the IT band at two different levels, the gluteus minimus, both bands of the gluteus medius, and then the bursa. So we're going to jump into the anterior hip, and there's two reasons why I choose to start with the anterior hip exam, and the first is that I have learned over time that hip joint abnormalities can present as lateral hip pain. So probably once a month, it's a very common scenario where a patient presents with lateral hip pain, they've already had an injection into the lateral hip with suboptimal results, and they're referred for a GME tear as the cause of not improving with the injection. And it turns out that, most commonly, hip osteoarthrosis is the underlying etiology proven with an injection into the hip joint. A minor reason is, by adding the anterior hip, we more completely meet the criteria for a complete exam, because we're now including in the joint, and if we need to, there's certainly several nerves in the anterior hip. As mentioned in the first couple cases, it's important to obtain and or review radiographs prior to starting the sonographic study, and so this is the radiographs in our gentleman. Right away, we see that there is some hip osteoarthrosis, and so that's one of the first things I scrutinize, is the joint itself, before starting the ultrasound. The second is, I scrutinize the greater trochanter. And we see in this gentleman, it's fairly smooth, and I look at the degree of cortical regularities. I also look for bony ossicles or heterotopic bone that might be adjacent to the greater trochanter, which is oftentimes confusing on ultrasound, unless you already are prepared to see this from the radiograph. So here's images for the anterior hip, and I always start with the long axis of the joint and the anterior recess of the joint, looking for thickening, effusions. And then I slide my probe proximal to look at the anterior labrum and try to get the full width of the anterior labrum. So you see in this gentleman, there is an extensive degenerative type labral tear of the anterior labrum. Then I slide over, I take the long axis orientation and slide medially to get the long axis of the iliopsoas tendon, and then I turn the probe 90 degrees to get the short axis. Now I could argue we probably don't need a long axis if we're evaluating the lateral hip if we have a normal short axis, but I do a fair amount of ultrasounds for patients who have had pain after a hip arthroplasty looking for hip impingement, and so it's just kind of second nature for us to do this, so we just keep it in the protocol. Now it's beyond the scope of this case, but you should think of the iliopsoas as a complex and has a fair amount of heterogeneity, so if you're doing a lot of anterior hip work, it's worth digging into that and understanding the complex. Now after our second case series, one of our colleagues made a comment that it might be useful to present some of the report as you go along, and so I'm going to try that today. So I generally, the majority of my cases for lateral hip have three paragraphs in the body of my dictation. The first paragraph is the anterior hip, and so it would start out, there was no hip joint effusion, and there's a degenerative titerity anterior acetabular labrum present. And then to finish off the anterior hip, we include the rectus femoris, and as you know, there's a direct head to the anterior inferior iliac spine and then a reflected head, and again, this is not the focus of the evaluation. If it looks normal, I just stop right here, and then I slide over to the sartorius and the ASIS and look at that insertion, and you can see here that there are enthesiopathic changes at the sartorius insertion onto the ASIS. So we see this as hypochoic thickening. We have some alteration or loss of fibular echo texture in this case. And so completing the first paragraph of my report, I mentioned that the degenerative type tear, the iliopsoas and rectus femoris muscle tendon units are normal, and then there is hypochoic thickening with alteration of fibular echo texture at the insertion of the sartorius muscle tendon unit onto the anterior superior spine. Now, I think it's quite reasonable and useful when we do ultrasounds to report in a situation like this, whether there's pain with sonopalpation. Obviously, the older a patient gets, the more we're going to find asymptomatic findings, and so I say in my report, there is no corresponding pain with sonopalpation at the ASIS, and I think that's an important piece of information. So that completes my anterior hip, and then I slide over to the lateral hip. I do my anterior hip exam with the patient's supine, and then I'll do my lateral hip exam in this case in the left lateral decubitus. And I always start, as mentioned, with the greater trochanter itself in the bone. So let's just quickly review the bony anatomy, and as you all know, there's four facets of the greater trochanter. We have the anterior, we have a fairly broad triangular lateral facet with peaked on top of the superior posterior facet, and then posteriorly, the posterior facet. Now the tendinous attachments, again, as you most know, just reviewing, on the anterior facet is a tendinous attachment of the gluteus minimus. We have a bare zone where there's no tendinous attachment onto a portion of the lateral facet, and the anterior band of the gluteus medius attaches onto the posterior aspect of the lateral facet. And again, cephalide to that is the attachment of the posterior band onto the superior posterior facet. And again, as you know, the posterior facet itself is bare, but covered by the greater trochanteric bursa. And you can see in our gentleman here that the greater trochanter looks fairly pristine for his age and being a runner. There was really no cortical irregularities or abnormalities. Now I'm going to just, again, review how I get this image. And the natural tendency is when we examine the lateral hip is to stay in anatomic planes. And the lateral hip is often referred to as a rotator cuff of the hip for many reasons. And one of them is when we evaluate the shoulder, we're often not in anatomic planes. And this very much is true for the lateral hip. And so if we have the probe oriented anatomic transverse, we're essentially oblique to all the important structures. We're oblique to the face of the anterior facet. We're oblique to the insertion on the posterior aspect of the lateral facet of the anterior band of the G mead. And so by rotating the probe in an anatomic axial oblique with the posterior aspect of the probe cephalad to the anterior aspect, now we're matching perpendicular the face of the anterior facet. And we're just about perpendicular, which would be, again, the short axis of the insertion of the anterior band of the G mead. And so that's exactly the probe position that I obtained in this structure. Now even though we're focusing on the greater trochanter and the bony cortices, it turns out with this orientation, I have a true short axis of the G mead in this patient and a pretty good short axis, although not optimal, of the G mead itself, posterior band and anterior band. And so just because I'm already at this location, I'm going to slide my probe posterior encephalad and just optimize that image of the G mead, again, posterior band, anterior band. The posterior band oftentimes can even be more prominent and rounded with the muscle itself or musculotendinous junction can be very short and it's not unusual to see muscle here. So even though, again, we're focusing on the greater trochanter, I've already gotten short axis of both the G min and the G mead. And the greater trochanter, again, is the roadmap for understanding the tendinous attachments. So again, I like to start off with the bony cortices of the greater trochanter. Now, a smooth trochanter with G mead problems is unusual. And reality is that we see a fair amount of cortical regularities in these companion cases. In this particular case, we see a very large bony projection between the anterior and lateral facet. Similarly, on this with a fair amount of cortical regularity. Turns out that the extent of bony projections and in my experience with cortical regularities is predictive of the abnormalities you may see in the gluteal tendons. Again, somewhat analogous to the shoulder where if you see a fair amount of cortical regularities of the greater tuberosity, you can expect to see pathology of the rotator cuff. And the second structure I evaluate is the iliotibial band. And I evaluate the iliotibial band in two locations. The first is at the greater trochanter. And you can see the somewhat fibular pattern of the iliotibial band to the right is distal, to the left is proximal. Now there's a fair amount of heterogeneity in the IT band and you can actually see muscle interposed with the IT band here, not to mistake it for pathology. Now distal, the IT band covers the vastus lateralis. And where the vastus lateralis attaches next to the greater trochanter, this is called the vastus tubercle. And I focus on that area there. And in this gentleman, it's fairly unremarkable. But again, in these two companion cases, you see that we see bony projections and hypertrophic changes and essentially tempting and causing an undersurface frame of the IT band. Now any of you that have done a fair amount of ultrasound guided bursal and greater trochanteric bursal injections know when the needle hits the IT band, it hurts the patient. So clearly there's pain fibers in the IT band. And in trying to put this puzzle together, I'm not sure I understand fully what are the pain generators in greater trochanteric pain syndrome. But my suspicion is that the IT band is an important pain generator. And actually in this patient right here, I'd asked him if I could put a small amount of local anesthetic right in this area and they were agreeable. And so I put a very small amount right here so it doesn't spread. Had the patient walk, when they came back, they said they were about 70 to 80% better. So again, I believe that the IT band is an important pain generator in greater trochanteric pain syndrome. And so again, this is the area I scrutinized the most during my sonographic exam. Now after I look at this area, I take the probe and slide it proximally in the same anatomic plane, which is an anatomic coronal plane, and I look at the proximal insertion of the IT band. And our gentleman here, it's abnormal. And we see essentially enthesiopathic changes here where we see bony irregularity, fragmentation of the iliac crest, as well as hypochoic thickening of the insertion of the IT band. And again, it's important to give information, is this a potential source of pain or is it not? It's a fairly superficial structure that we can comment on sonopalpatory pain. So then that completes my second, in a sense, my second paragraph of my report. My first paragraph is the anterior here. My second paragraph generally is commenting on the greater trochanter, the IT band. And so, I start the second paragraph, laterally, the greater trochanter is normal, IT band, the level of the greater trochanter is also normal, and then I talk about the enthesiopathic changes at the iliac crest, and then I also again say there is no corresponding pain with sonopalpation at this location. So after I scrutinize the greater trochanter and IT band, I go to the G-min tendon, which is anterior. And so, we've also already have talked about the short axis image of the G-min, and when we look at the greater trochanter, which is this image here, and so I'm going to rotate my probe 90 degrees, and I'm getting this probe position. And so again, it's a coronal oblique, but also an axial oblique, and the probe is tilted posteriorly to match the face of the anterior facet to get this image right here. So in this image right here, we're seeing the tendon of the G-min, underneath this is the anterior hip capsule, and overlying is the G-med muscle, which I'll talk about a little further. Now one thing I like to do when I first look at the long axis of the G-min is I like to slide my probe anteriorly off the facet and then slide back on. And why do I do this? Because it assures me that I'm on the anterior facet and not the lateral facet, because if there's a tear, especially a large tear of the G-min, it can be confusing. So it orients me and confirms that I'm on the anterior facet. So this is just a video of me doing that in a different individual. So I'm sliding off the anterior, I'm still on it, now I'm off of it, and now I'm going to get back on. I'm 100% sure I'm on the anterior facet, and I'm on therefore the G-min tendon. Now there's a couple of details that I'd just like to talk about. So this is a normal G-min tendon, similar to our gentleman, and I want to focus on two things, and one is the overlying G-min, or G-mead, I'm sorry, muscle fibers. And so we see in this dissection of the lateral hip, the vascular loop is around the G-min tendon, so anterior is to the right and around the back is posterior, and we see the muscle fibers of the G-mead come down and then have this insertion on the posterior aspect of the lateral facet. And it's these anterior fibers that obliquely come to the tendon that go over the G-min tendon. And so we can see that right here, this for me is blocked out a little bit on our screen, but you can see again that the anterior fibers of the G-mead cover that of the G-min tendon. And so you want to see that to confirm that you're in the right anatomic plane when evaluating the long axis of the G-min. And then the second thing I like to focus on is the musculotendinous junction. So here's a dissection now where the G-mead has been removed, and this is all G-min, posteriors to the left, anteriors to the right. Now the anterior fibers take a relatively straight course down to the anterior facet, whereas the posterior fibers have to have a fairly sharp turn to join in to form the tendon of the G-min. In fact, there's a 75 degree difference between the anterior and posterior fibers. So which means that the musculotendinous junction should not look clean because we have different orientation of fibers coming to coalesce to form the G-min tendon. So this appearance is normal. And then the second thing about this area is this is where pathology tends to start the majority of the time. And so I'd like to scrutinize this area because we start to see changes in the echo texture and undersurface tears as the early pathology. And so in this companion case here, we see bony hypertrophic changes at the proximal aspect of the anterior facet, and we start to see increased hypoecogenicity in the undersurface tear develop of this G-min tendon. Here is the same image, but I have a comparison to the other side, which was nice because he was just starting with very early pathology here, and then more advanced on the affected side. So with that in mind, we go back to our G-min tendon, and we see actually it's not quite normal. There's some increased hypoecogenicity here and a very small early partial thickness tear developing. And so my last paragraph discusses the G-min tendons, and there is focal hypoecogenicity in a small partial thickness undersurface tear of the G-min tendon at the proximal border of the anterior facet. So once I go and complete my G-min evaluation, I go to the G-mead, and I actually start with the posterior band and not the anterior band. And why do I do that? Well, let's look at this dissection here. In the posterior band, to the left is posterior, again, a fairly relatively straight fibers, fibers are more in an oblique orientation, inserting onto, again, the posterior aspect of the lateral facet. And so if I was going anterior to posterior, I would hit this bare zone first before I got to the tendinous portion of the G-mead anterior band. And this bare zone can be confused with a tear, especially in the presence of a tear. And so to eliminate that confusion, I like to start posterior and go anterior. And so the orientation of my probe then is almost in a, it would be an anatomic coronal oblique plane in that sense. And so here we see the probe. The probe is tilted anteriorly, oftentimes the cephalad portion is rotated just slightly posterior to optimize it. And then this is the image that we obtain in our gentleman. And we see this is the posterior superior facet, and it's a fairly stout attachment. It has a very strong attachment. When the posterior band tears, patients experience a lot of disability in a Trundall-Bergate. And again, in contrast to the anterior band, which is the cephalad portion of the probe is rotated anteriorly. And so after I assess the posterior band, then I do go to the anterior band and start adjacent to the posterior band. But I do rotate my probe in the expected plane that I'm getting for a long axis of the anterior band. And so again, I'm rotating from the posterior band to the anterior band as I translate my probe anterior to avoid that bare zone as I evaluate the tendon. Sometimes patients, and this model is relatively straight, but if the model is in a fetal position, this rotation is even more pronounced. And the normal appearance should be that of the G-mead muscle. And the anterior band is a central tendon. It's a bipennate configuration. And that central tendon should go deep to superficial, and then it attaches onto the back of the latifacet, as we've mentioned. And again, analogous to the G-min, the pathology typically starts at the proximal border where it goes over the, I call it the superior trochanteric crest, goes over this, and then inserts onto the back of this. And this is exactly what we see in our patients. So we see clear, diffuse hypocoic thickening of the anterior band of the G-mead tendon and an extensive partial thickness undersurface tear right at that proximal border of the latifacet. And so oftentimes, when I see a tear, I like to do dynamic images, and I'll have the patient either just gently abduct, and just contracting the muscle sometimes can be enough. Or if it's too painful, I'll often have one of my staff just very passively abduct the leg, and here we see. And what I'm trying to understand is the extent of the tear. So it's not a full thickness tear here. It's a partial thickness tear of the anterior band of the G-mead. Now one of the tricks I do, as we know, sometimes patients have a large body habitus when we're examining the lateral hip. In the presence of a big tear, we can get lost. So one of the tricks that I do is I'll slide the probe towards the greater trochanter and find the muscle, and I optimize a bipennate appearance, and then follow that central tendon bipennate to the greater trochanter. And oftentimes, we include a panoramic view of the anterior band of the G-mead with our study. And also, the third reason is if there's a large tear, we can see the extent of atrophy of the G-mead muscle. Now I just want to mention that bare zone, because I talked about it. And again, this is a dissection, and the vascular loop is around the G-min tendon. And this is the reflected G-mead tendon muscle. And again, you can see the bare zone pretty clearly. It's between the G-min and the G anterior band of the G-mead. And again, it's nice to avoid this, especially when you're first starting out with this, and not mistake it for a tear. OK, and lastly, after I evaluate the anterior band of the G-mead, I take the probe, and I just slide it distally over, and more of the posterior aspect of the tendon fibers of the G-mead anterior band over the posterior facet. And I look at the IT band, and deep to the IT band is the greater trochanteric bursa. You can see in this patient, it's the thin line. You can follow that down the posterior facet to be sure that you're in the right plane to do that. Now, if I see a large tear, or if I see thickening or fluid of the greater trochanter, I'm very careful to look posteriorly, because the trochanteric bursa is a fairly posterior structure, and you can miss it if you don't purposely look posteriorly. In fact, it's easy to miss a fairly large-filled bursa unless you look posteriorly. And so, the last paragraph, there's diffuse hypocoic thickening and a moderate-sized partial thickness under surface tear of the anterior band of the G-mead. This corresponds to the maximal site of tenderness with sonopalpation. The posterior band of G-mead is normal. Greater troch is normal. So which leads me to my report, and again, there's a lot of preferences in how to do a report, and there's a lot of ways to do this. This is just the way I do it. I try to do my reports the same way every time, so I'm not missing things. And so, here we see we have a diagnostic wholesale on the right hip, attention to the lateral aspect. We've had discussion whether we should be putting complete exam or limited exam, and if you do put that, there's nothing wrong with that, and in fact, it does make it more clear. I put the indications for it, the probe I use, and if I use several probes, I list them. I talk about the correlation with, let's say, if an MR study or radiographs, and then as I mentioned, I divide into three sections, just the way I do it, the anterior hip, the IT band, the greater trochanter, and then the glial tendons and bursa. And so my conclusion, there's a degenerative type tear of the anterior acetabular labrum. Talk about enthesiopathy of the sartorius and proximal IT band, but also qualify that as there was no pain with sonopalpation. It's a fairly superficial structure, so it's easy to evaluate for this. Mild tendinosis with a small partial thickness tear of the G-min tendon, and then a tendinosis and moderate-sized partial thickness tear of the anterior band of G-med, which corresponds to the maximal site of tenderness. So take-home points, again, we've tried to emphasize the importance of reviewing radiographs prior to doing a sonographic evaluation, protocol-driven exams, and I've talked about the rationale for including the anterior exam in the lateral hip. And again, we've discussed our protocols not only address those structures, but the differential diagnosis. In the lateral hip, it's important to understand the planes of the structures and correlate the findings with sonopalpatory information. In our institution, an ultrasound is a first-line advanced imaging for greater trochanteric pain, particularly at the anterior band and the G-med, where it has a fairly acute course as it goes over the greater choke, and that can be easily missed with an MR.

2nd Edition, CASE 24

2nd Edition

Hip

lateral hip protocol

anterior hip examination

hip joint abnormalities

ultrasound diagnostics

greater trochanter

IT band tenderness