Well, hello, this is Steve Aoki. I'm currently faculty at the University of Utah in the sports medicine department. I have been tasked today to speak on how to treat the painful snapping iliopsoas tendon. These are my disclosures. Now, let's talk about the anatomy. The iliopsoas is primarily a powerful hip flexor, but also aids in femoral external rotation and assisting in truncal balance. It's made up of the iliacus, psoas major, and minor, with the iliacus originating on the iliac crest fossa and the sacral ala, and is innervated by the femoral nerve in the L1 to 2 distribution. The psoas major originates from T12 through L5 along the spine and is innervated by the lumbar plexus of L1 through 3. Both insert onto the lesser trochanter. Now, the psoas minor is not always present, but when it is, it originates from T12 and L1 and inserts onto the iliopectinal eminence. The iliopsoas complex runs directly over the front of the hip in a groove located between the AIS laterally and the iliopectinal eminence medially. The myotendinous junction occurs right around this transition as iliopsoas passes over this bony prominence of the hip. The distal insertion point of the iliopsoas is located at the lesser trochanter, but what's interesting about this dissection taken from the Baylor group is the size of the distal muscular extension. On these fresh frozen cadavers, the size of the muscle belly extending distally is much larger than what we were led to believe with most animated drawings. We'll talk about this later when we get into the surgical options. Looking at the cross-sectional area of the hip, one of the most important anatomic findings related to the iliopsoas is a close proximity of the tendon to the hip joint. Now just as it crosses over the pelvic brim, the muscular tendinous complex sits directly over the anterior capsule. This close proximity is important from a surgical standpoint, but it's also important to note that some feel that the iliopsoas may be responsible for intra-articular pathology, particularly at that three o'clock location in the hip joint. It's also important to note that there's some variability in the muscular tendinous unit as there can be multiple slips of a tendon at the level of the hip joint. Dr. Philippon's study noted a single slip in 28%, a double in 64%, and a triple slip tendon in 7.5% of the cadaveric dissections that they did. Again, another anatomic variation that's important to note when we're talking about surgical management. Internal snapping hip is typically seen in individuals that participate in super physiologic activity and kicking sports. This occurs predominantly in females. They describe a mechanical snapping that could be painful. Typically, it radiates as anterior groin pain and usually it's activity or positionally related symptoms. On physical examination, I typically evaluate by doing three maneuvers. I'll test muscle strength as well as evaluate for pain with resisted hip flexion, both in the supine position as well as sitting. Also, most importantly, I'll look at the internal snapping hip maneuver where you bring the leg from an extended position, have it bring up to a flex position, externally rotate an abduct, and bring it back into an extended position. Patient actively does this. The maneuver will typically recreate that pop and will sometimes be audible but can also be palpated in the front. Radiographs, MRI, and CT, while helpful in the workup of hip pain, may not be as fruitful in evaluating this iliopsoas and internal snapping hip, although sometimes there may be pathologic findings around the musculotendinous complex. An ultrasound can be helpful as the study can be dynamic and look at the iliopsoas and identify the site of the snapping during dynamic exam. A diagnostic injection into the psoas sheath can also be helpful in identifying the location of pain and may also be therapeutic. Now, what is actually snapping with internal snapping hip? This is a little challenging to answer as we don't have a lot of data out there, but there are numerous areas along the length of the iliopsoas complex where the hip flexor may be mechanically flipping over the various anatomic landmarks. In this ultrasound, specifically, this is an example of a tendon that's snapping within the musculotendinous interface where the tendon is rolling over the muscle belly. So what you see in the video is that the tendon is sitting inside the muscle belly and as the leg is moved, the tendon goes into—it flips into a more posterior position behind the muscle belly, and that's the popping that we see here. One of my partners, Joy English, who, by the way, gave me this video, and so thank you for providing this, Joy. She's an expert in ultrasound and does a lot of diagnostic evaluations, and she would say that this is one of the most common type of snapping that she sees when she's evaluating individuals with internal snapping hip. Conservative treatment begins with your typical rest, ice, activity modification, and anti-inflammatories. The goal of non-operative treatment is to decrease the irritation at the site of those mechanical snapping. Physical therapy is the mainstay of conservative management with a program that focuses on hip flexor stretching to lengthen the musculotendinous complex as well as focus on the core and pelvic stabilization muscles and progressing to a focused, comfortable activity program. Most patients seem to get better with conservative treatment and will not require anything surgical. If surgical treatment is necessary, a tendon lengthening can be performed. While open and arthroscopic techniques have been described, most individuals in 2022 would advocate for an arthroscopic release, just given the ease of approaching this area endoscopically. There are three common locations that have been described when releases have been performed. They can be done centrally at the level of the hip joint, peripherally at the level of the zona obicularis, or distally at the lesser trochanter. A classic paper from back in 2011 described the size of the tendon compared to the muscle belly in embalmed specimens at each level. At the level of the central location, there's a 40% tendon and 60% muscle. Peripherally, it was about a 50-50 split, and at the lesser trochanter, it's a 60% tendon, 40% muscle ratio. This has implications when doing a tendon release and the amount of musculotendinous complex that's released at each level. Getting back to the paper published by the group out of Baylor in 2020, they looked at fresh cadavers and the ratios of tendon to muscle were much different with more muscle volume seen at all three areas of release compared to the classic paper using embalmed specimens. And this is probably due to the fresh specimens and the preservation of the size of the muscle belly. But even a release at the most distal location at the lesser trochanter, according to this paper, the tendon release only involves 30% of the musculotendinous complex. The first video here is an example of an iliopsoas release done at the level of the joint in conjunction with FAI surgery. You see that the iliopsoas tendon is just superior to the capsule, and this is sitting right around that three o'clock region of the clock face of the acetabulum. I like to use electrocautery to do my release of the tendon, but you can also use a sharp blade if that's your preference. The second example here is of a left hip undergoing a release at the lesser trochanter. So proximal, the head is located to the right, and the feet are located to the left. You can see the lesser trochanter, the iliopsoas tendon, and I just peel it off with the electrocautery until I get that tendon to fully release itself from the lesser. Arthroscopic release outcomes have been good when done with appropriate indications. In a recent systematic review looking at 20 studies, approximately 10% of patients still reported continued pain after a release. There was recurrent popping in approximately 5%, which is higher in patients undergoing a central compartment release, potentially because of the multiple slips of the tendon at this level. Weakness was noted to be higher with the lesser trochanter release, potentially due to more of the complex being violated with a release. The complication rates for surgery were quite low. There is, however, a potential risk for hip instability, but overall the results for a release for painful popping were quite good. Now our group published a paper back in 2016 looking at individuals from my practice during a time when I was slightly more aggressive with treating internal snapping hip at the time of FAI surgery. We evaluated patients at a mean of 21 months after the surgery, and we noted a 19% reduction in seated hip flexion strength, as well as on MRI follow-up, we noted a 25% muscular volume loss after undergoing a iliopsoas release. Getting back to the issue of potential risks of instability with a psoas release, a paper that was published back in 2016 looking at a review of patients with gross instability after hip arthroscopy. Most of these were in unrepaired capsulotomies, but 33% of these also had an iliopsoas release. With the iliopsoas being a dynamic stabilizer anteriorly, releasing the tendon may potentially add to the instability picture. One other issue worth mentioning is iliopsoas pain after a total hip. Currently in my practice, 2022, this is the most common reason where I would go in from an indication standpoint and do an iliopsoas release. The concept with iliopsoas irritation after a total hip is that that acetabular component is prominent anteriorly, which allows that iliopsoas tendon to directly rub over that prominent acetabular component lip. In an uncontained lip, if you see that on your radiographs, then an iliopsoas release might be helpful if they're complaining of anterior hip pain that seems to localize to the iliopsoas. Now, I'd caution others to make sure that the full workup has been completed and make sure that there's no signs of an infection or prosthetic loosening, kind of those common reasons for pain after a total hip. Diagnostic injection might be helpful in identifying whether the pain is coming from the iliopsoas, and it's worthwhile to do that before considering a release. When looking at the literature for a psoas release after a total hip, continued pain has been noted in about 10 to 30 percent of individuals after doing a release. So when taking on a procedure like this, I do counsel my patients that if a release doesn't help, then they're most likely looking at being evaluated for revision arthroplasty. This is a good example of an iliopsoas release done in a total hip that had that undercovered region of that anterior lip of the acetabular component. You can see the beaded surface of the acetabular component and the close proximity to the tendon, along with that synovitis on the undersurface and the fraying of the tendon. So once I've cleaned up the synovitis and the area around the tendon, then I do a formal release, and I usually do this with electrocautery. I'll do it until I see that the tendon is removed and I see muscle belly. So my final thoughts, it's very important to understand that internal snapping hip and iliopsoas-related pain should be treated conservatively first. In fact, there are a lot of individuals that have internal snapping hip where it's not painful, and it's just mechanical. Most individuals improve without surgery, and if not improved, then we as surgeons can potentially help out. In fact, the literature looking at releases all show pretty good results as far as improving pain, although I certainly would have to say that my personal bias today in 2022, I'm relatively conservative with considering doing anything with the iliopsoas. These are references if you'd like to look at this any further. Thank you so much.

snapping iliopsoas tendon

diagnosis

treatment options

arthroscopic release

conservative treatment