This is Dr. Joe Toro from Ocean County Sports Medicine and Rutgers Medical School, and I'm going to talk to you about some tricks you should know and you might find helpful for doing arthroscopic instability surgery. I have disclosures and they can all be found at the AAOS website. My final goal with any instability procedure is to restore normal anatomy and stability without losing range of motion and function. When I look at the final arthroscopic appearance after I'm done with the repair, the humeral head should be centered in the glenoid by the soft tissue repair with the traction removed. Bone loss has to be addressed, but that's a subject for another talk. I always discuss the stress versus strain curve as a precursor to discussing tricks for instability surgery. Stress is the amount of force you're adding on the ligament, and the strain is the actual length of the ligament. Every ligament, when you pull on it, goes through an elastic region where the length of the ligament recovers after you release the stress. Then it goes through a plastic region as you continue to add more stress. That means in that region, the length of the ligament is never going to recover back to its original number. It's going to be longer before it goes on to a Bankart lesion, i.e. failure in the end. Every Bankart lesion has a plastically deformed capsule. That means that every time you do an instability operation in the shoulder, you've got to anatomically re-tension the capsule to compensate for that plastic deformation. I'd like to talk about the circle theory the glenoid first taught to me. When you pull on one side of that capsule, it always affects every part of the capsule. So here, I'm translating the humeral head by pulling it anteriorly, which means I'm elongating the anterior capsule a bit, but I'm tightening the back of the capsule. That's how the circle theory of the glenoid works. When you have a Bankart lesion, it's the similar situation. When you pull on the front of the capsule, the anterior translation is increased, but if you pull back, posterior translation is also increased, even with an anterior Bankart. When you repair the capsule, a similar thing happens. When you tighten the anterior capsule with your Bankart repair, it tightens the capsule all the way around the glenohumeral joint. Slap lesions are a similar situation, and if you close a slap lesion, you have to be very careful not to take too much capsule, and you just want to repair the labrum, otherwise you wind up with a stiff shoulder. My repair portals for instability surgery are pretty standard. There's a posterior portal, an anterior superior portal right next to the biceps, usually an 8mm mid-anterior cannula right above the subscapularis. A posterior inferior portal, the so-called 7 o'clock portal, can be very helpful, especially when working low down on the glenoid. And then there's various percutaneous portals. If you look at that yellow arrow in the lower right-hand part of that picture, that would be a trans-subscap portal, which we're going to discuss. So every arthroscopic anterior instability procedure that I do begins with a complete dissection of the middle glenohumeral ligament and the anterior inferior glenohumeral ligament off the glenoid neck and the underlying subscapularis. This example here is a left shoulder. The patient actually has an ALPSA lesion, where the capsule and the labrum have torn off and healed inferiorly and medially on the glenoid neck. And this is one where dissection off the underlying glenoid neck and the subscapularis is mandatory. And we'll look around the back of this shoulder, and you can see the capsular volume in the back of the shoulder is pretty normal and just a bit inflamed. Most people teach this using an arthroscopic elevator, as you can see here. But what I find with these arthroscopic elevators is that they tend to cause a lot of bleeding, and I wind up having to come in with my radiofrequency device to coagulate the bleeders. So I'll usually just use the radiofrequency device to do the whole dissection. It's fine to do that as long as you point the device towards the glenoid neck and bone and away from the capsule. If you point it at the capsule, you're going to cross-link and damage the fibers. So you want to come all the way around, down to the 6 o'clock position, exposing the subscapularis all the way around. And once I get to that 6 o'clock position, I'll come in with a grasper and see how much I can translate the ligament complex. And as you can see here, I'm only pulling that ligament complex up by about 5 millimeters, which is not enough. I'll use a surgical technique called a capsular split shift. It allows for more capsular advancement and allows you to tighten the entire capsule and what you do is if you look at that right hand picture you come in with a narrow basket punch and you're gonna make a little snip at the inferior capsule right at the six o'clock position. By doing that if you look at the picture on the left that point B is the end of your split usually about three quarters of a centimeter and as you pull on that capsule now B will advance up the glenoid neck by three quarters of a centimeter. C will wind up 1.5 centimeters up so there's your shift as you can see in the right hand picture. So here is a capsular split about to be performed. I'm coming in with my narrow basket punch through my mid-anterior portal and I'm gonna just make a snip under direct vision right into the capsule going straight down and this rarely needs to be more than three quarters of a centimeter because that's going to give you a one and a half centimeter shift sometimes even a little bit less a half a centimeter sometimes will do it but you'll see what happens now is when I pull on this capsule it really advances up the glenoid and you can see that V opens up and we get our one and a half centimeter capsular shift and to show you that this is the circle theory in action as we pull on that shift you can see the posterior capsule also pull around and tighten. Here's another trip for you it's using a trans subscapularis percutaneous portal and sometimes when you are trying to get your very low anchor in down at the five o'clock position the angle is not so good from the mid-anterior portal and you can insert that anchor into the soft tissue by accident or even in and out of the bone. So by using a percutaneous technique we just come in with a large spinal needle and different manufacturers make versions of this you come in right through the subscap and as long as the arm is abducted less than 40 degrees it's safe from a point of view of the musculocutaneous nerve and you follow that spinal needle with a guide wire followed by a slightly larger diameter dilator and then over that dilator we're going to insert our little percutaneous cannula for inserting our anchor. So again this is safe to do as long as the arm is not overly abducted. The rest of this is pretty much standard anchor insertion you want to have your guide right up on the articular cartilage to put in your anchor and we'll drill and then put in our anchor. This happens to be an all suture anchor any anchor works for this and although you'll see in this case it's a single loaded anchor most of the time now I use a double loaded anchor down here so I can get two sutures into that very important anterior inferior capsule and get my shift. One other little trick is you can put a guide wire back into that portal and leave that guide wire in there for putting in your next anchor. I thank you very much I hope those a couple of tips are helpful to you and your arthroscopic instability surgery.

arthroscopic instability surgery

capsular split shift technique

circle theory of the glenoid

trans subscapularis percutaneous portal

stress versus strain curve