Today, I'm going to talk about CAM impingement. It's going to be a WorldWood tour, diagnosis and treatment. Mike Salata from Cleveland, Ohio, so I'm going to get going because there's a lot to cover. These are my disclosures, nothing to do with this talk. We all like to talk about the hip in this layered approach, as Brian Kelly has helped us with. We're going to focus mostly on layer one, which is the osteochondral layer, as it's most important for the mechanics of the joint. In our office, when we're evaluating for CAM impingement, we get a standing AP pelvis, a 45-degree done lateral, and a false profile to look for labral pathology that's associated with it. An MRI or an MRR diagram can be used, in addition to a pain log and then 3D reconstructions from a CT scan can be used, as well as modeling, if needed. The alpha angle has traditionally been used, but I think is an incomplete way to evaluate CAM impingement. It's basically a line drawn down along the neck of the femur and then looking to see where the bone first breaks the circle drawn as a circle of best fit. As you can see here, it's been best shown to be ideally put into profile with a 45-degree done lateral, which is why we choose that X-ray. Certainly you can miss it if you're not looking for it in the right plane. I would really advocate for considering using offset to define CAM, as well as the adequacy of your resection. Normal offset is about 9 to 11 millimeters. And I think sometimes, even if you correct the alpha angle, but you don't restore the offset, patients can certainly have issues with residual impingement. So I think thinking about offset is important. There's always a little less offset on the AP than there is on the done. Optical imaging may be very helpful. 2D imaging may be primitive and may become obsolete. So certainly using some of the imaging software and even some of the modeling software may be helpful for you in your practice, especially if you're early on to identify the area of impingement, which is often more distal on the neck. The CAM lesion, these are slides courtesy of Ashish Bedi. It can be in different locations. Here we see it at the 1 to 4 o'clock position. But here we see it from the 11 to 6 o'clock position. And this may be more amenable to an open approach than an arthroscopic one. You should think about version. Certainly if they're excessively femorally antiverted, the impingement lesion or CAM morphology may be less significant. Or if they're significantly retroverted, you may need to take more of the native neck or consider a derotational osteotomy, as this has been shown to be a source of failure with arthroscopic hip surgery. Certainly patients with more retroversion are at a higher risk of getting arthritis. You're often going to see more significant CAM morphology and articular cartilage damage in these lesions. So that's something to keep your eye open for. Three-dimensional imaging software can be helpful. Certainly I think that it does show you the location of the CAM. Here you can see where the maximal location of impingement is. And so that's what you really want to be sure that you create. You can see that it's much more distal. And we'll talk about some of the techniques later on in this talk about how you can best attack that in terms of removing the CAM impingement, but also maintaining the convexity to concavity relationship to allow for lack of loss of suction seal when you get into deep flexion. 3D morphology, the CAM lesion is three-dimensional. You really want to do a complete CAM resection in the location of the CAM proximally and distally and medial and lateral, being careful to be sure that sometimes you need to go posterior and superior to the vessels in order to fully remove the CAM resection. The difficulty with hip preservation surgery is that it's hard to see it sometimes. So different management techniques of the capsule can be helpful so that you can create a good offset here while still maintaining that sphericity of the head. You know, the biggest issue, this is a slide courtesy of Shane, know about 81% of the time patients that require revision surgery have had an inadequate CAM resection. So being sure you can see it and remove it in its entirety is important. The bigger sin is too much resection. There is no bailout that's reliable for this. Though Mark Philippon has talked about some of these REM plissage techniques. So when in doubt, take less, see what you're doing and be sure that you're taking bone away from the area of maximal impingement. And even if you do an incomplete osteoplasty, as long as you're taking the majority of the bone away from where they're impinging, patients can still do very well. Capsular management, you can use many different strategies. Certainly you can use a T-capsulotomy like you can see here, kind of an interportal capsulotomy with an incision down the neck. This is how a lot of surgeons like to do this. I used to do this in my practice and now we switched to an interportal capsulotomy with retention sutures that I'll show you on the next slide. But here you can see a really good adequate visualization of the CAM all the way down to the vessels. You can see the zona obicularis there. And I think this gives you really excellent visualization of the CAM. You just have to know how to repair this and I'm not going to talk about that in this talk. This is the kind of visualization you can get here with a T-capsulotomy. This is from earlier in my practice. You can see that we can see all the way posterior and laterally here. We can see the bulk of the CAM deformity along the neck. And it really allows you to have really excellent visualization so you can do your resection in an appropriate way. Capsular closure can be technically challenging if you're not accustomed to it. So being sure that you know how to fix the T-limb is certainly important if you're going to choose to use this in your practice. Currently we use an interportal capsulotomy. We like to leave that medial flap intact there. We will sometimes do this little resection here of this little inner flap. We call it an internal T-cut where you kind of take a little bit of that away. Here you can see we're kind of shaving out that little bit of an area there. We use two retention sutures placed through a dollop portal. And then that allows you to have the visualization that you see at the bottom of the screen. We'll use a combination of multiple different options in terms of internal and external rotation of the hip and different flexion angles. Chris Larson and Ashish Bedi have a really nice paper about the around the world view. Here you can see the vascular pedicle. We can carefully work above the vascular pedicle. We can work all the way down the neck. You can see that you have excellent visualization here for a very broad-based osteoplasty where you can work all the way down to the medial synovial fold, all the way down to the lateral synovial fold, and really all the way down to the trochanter. You can hug the vessels here so you can be sure that you get that nice spherical shape. Certainly I think as you kind of come around the corners, you want to lighten up your touch a little bit so you don't gouge them. I like to look at the impingement lesion from multiple angles here. We're working through an anterior lateral portal and working through the modified mid-anterior portal. You can see that we can get all the way down the neck. We can look at it from this view to be sure that we're correcting our slope appropriately. We can work all the way up along the top here, creating a very nice contoured resection, and then we can work all the way down to the inferior lateral aspect of the neck and even above it if necessary. We do use fluoroscopy. I think it's critically important to help you plan your resection and also to identify the location of the impingement on multiple views to be sure that you've corrected for sphericity on multiple views. I think the important thing that we've done more of recently, I'm going to show you a quick video here. Sorry, it's in just for the sake of time. It's kind of sped up, but basically what I like to do here is kind of create a trough proximally and then go far distal about five or six millimeters below that initial trough where I'm going to end my resection. Really you can dig in here to create the offset that's often in the area where they have this really sclerotic bone, so you can get rid of it here. Again, looking at it from multiple angles, I've slid my camera distal down the neck. I'm pinning the capsule out of the way with my camera. This is a view that we've kind of popularized here, kind of an up the neck view. Here you can see looking more down the neck view and you can see we're really working on creating that distal trough and then kind of working up proximally. We like to call it a two-tiered resection because we're doing the majority of the offset work distally and then we're really just sculpting proximally to kind of maintain that sphericity that you saw on our previous image. That really allows you to kind of work quickly and efficiently. I think if you do it this way, your osteoplasty will take you maybe eventually probably about 15 to 20 minutes here. You can see we're just deepening the offset again in the area where we really want to recreate that kind of nice convexity, the concavity relationship. Then at the top here, we're really just kind of sculpting that down so that we don't lose the suction seal when we go into deflection. I think this is a very nice way to do it. I think it's very reproducible and it can help you get really good resections of your CAM morphology. I think here you can see we're just deepening the offset in the areas that we think we need it. Doing it multiple views again can be helpful to be sure that you're adequately decompressing the CAM on all those views. Internal rotation, external rotation, flexion and extension, and a combination of those things really helps you to do this osteoplasty very well. Thank you for your attention and appreciate being included in these talks.

CAM impingement

diagnosis

treatment

hip joint

imaging techniques