How do I plan for a Reverse Shoulder Replacement?

Patrick Denard, MD. So I'm gonna go over the steps that I take to plan before a reverse shoulder arthroplasty. I take several steps to really ensure the best outcome possible. The first thing I do is kind of look at the big picture. Then I size the components. I pick the position of the components, assess the contact. Then I decide if I need to use an augment or bone graft depending on if somebody has deformity. And then finally, I'll pick the fixation of the actual base plate. The base plate is the component that's used to secure the sphere side or the ball side of reverse shoulder replacement into the socket or glenoid. And these steps are really important because we want to plan in advance The idea is to create a flight plan so that the surgery is performed almost virtually prior to doing that, and that really ensures consistency of the position of the implants to help provide the best outcome possible to the individual patient. And the technology I use is a web-based platform. It's based off a CT scan that's obtained before the surgery, and I can use a guide if necessary to place the components to really help ensure the position. So the first thing I do is I try to get the big picture. You know, there's individual patient needs, but also not just get too honed into the x-ray. So I like to look at everything in advance. This is an example of the web-based platform I use. So we have a CT scan that's uploaded, and I can look at the components here and see where they would go. But then I'll also kind of look at the bony deformity. You can see here over on the left I can look at, um, the overall picture, see how large the bone spurs are, uh, see if there is wear of the socket or glenoid side. In this case, there's quite a bit of wear. Normal version is about 7 degrees. This particular example, there's 28 degrees of version. So there's a lot of deformity to address. Once I get the big picture, I'm going to size the glenosphere. The glenosphere again is that ball size. And we have 5 sizes we can use here. I can use a 33, 36, 39, 42, or 45. And I want to match that to the individual patient. So oftentimes for a woman, I'll use a size 33 or a 36. And most commonly for a man, it's going to be between a 36 and a 42, but we can adjust that up and down as needed. And I want to see that there's good match from the front to the back of the shoulder. Because it doesn't— we don't want it to be too large so that you actually get more bony impingement. It has to be just right. And then I'll typically lateralize. That means we move it out to the side to take it away from the socket to remove impingement. The next thing I do is I look at the base plate position. That is the component that is secured into the socket itself. So I have the sphere sized here, and now I can adjust the position. I can zoom in on my view here, and I can pick the correct angle that I want to put this base plate in, in order to match what I predict would be the normal native anatomy. That's often, often also called the pre-morbid anatomy, because I want to try to put things back where they were before the arthritis developed. And I'll look at both the version, which is the orientation from front to back, and then also the inclination, which is the orientation from top to bottom. And these, these positions are important to ensure that the component is stable. If these components are placed in improper version or inclination, one can get loosening of these components, and we want to achieve long-term fixation so that we lower the risk of anyone having to do this again. Then I'll look at the contact. The contact is how much the base plate is in contact with the native bone. So in a case like this, if I was to use a standard base plate, I would have a gap in the back of about a centimeter, and that's too much. So in this particular case, I'll have to build up with an augment. An augment is essentially a metal wedge that goes on the back of the base plate. One can also use bone graft, but if I can, I will use an augment because an augment has metal, and metal has better stability than bone graft, and you don't have to achieve healing on two sides. You only have to have that occur between the base plate and the bone itself. So this augment in particular has 20 degrees. This allows me to build up about 9 millimeters in the back, so it's perfect for this individual. I kind of orient that augment toward the back and top. As you can see here, this is what we call an oblique augment. And now over on the seating on the left, You can see as I adjust the position, I can get good seating of the implant. I'm going to aim for at least 75%. In this case, I'm able to achieve 95%, in fact. So this will biomechanically provide a very, very stable construct, restoring the joint line and letting somebody get back full function. The last step I do is then I select my fixation. So there's a post that goes into the bone, and I want to make sure that that is through the native socket or glenoid. Oftentimes we also call this the vault. And then I'll use screws on the outside, and I'll pick the position and length of the screws around the base plate. And I do this so that they just go beyond the bone But I'm picking positions that avoid any risk of nerve injury in particular, especially on the top and in the back. If the screws are too long, we can run into issues. So I'll, I will use what are called locking screws on the front, back, and top holes. And the bottom one, I use what's called a compression screw in this case to really bring the base plate down and the locking screws interdigitate with the base plate itself, and those are really, really strong constructs. And all these steps I take in every patient who I plan with a reverse shoulder arthroplasty. And again, the, the idea is to just look ahead of time so we have that flight plan and know what to expect. That makes the surgery itself more efficient, which is good for the patient because We're spending less time in the operating room, but also having a patient-specific approach where we're matching anatomy both in terms of the orientation of the socket and the size of the components. And I think taking these steps is very important when somebody has a reverse shoulder replacement because it's a very serious proposition, and I really want to have my patients get the best outcome possible. So I hope those steps are interesting to you, and if you have any questions, please put those in the comments section. Thank you.