Thank you to the Arthrospy Association Organizing Committee for the opportunity to present this talk on multidirectional instability, balancing the shoulder all the way around. Here are my disclosures, none appropriate to this talk. I do want to acknowledge Dr. Jeff Abrams, who has kindly allowed me to use some of his audio visual aids in this presentation. In talking about multidirectional instability, we need to define our terms. We need to sort out what, in fact, is the pathology in this syndrome, and the role of the labrum capsule and interval, and how does it play into multidirectional instability. And if we're going to stabilize the shoulder, how much is enough? It'd be impossible to talk about multidirectional instability without acknowledging the great work of Dr. Charles Neer and Craig Foster that was published back in 1980 that introduced us to the concept of inferior capsular shift for multidirectional instability of the shoulder. Subsequent publications by Pollack, Plato, and Bigliani outlined the role of capsular volume reduction in dealing with patients with multidirectional instability through the procedure known as the inferior capsular shift. These principles we need to be aware of, as this is the principles that will be guiding us as we move towards arthroscopic techniques. You'll notice the goal here is to reduce inferior capsular volume, and we can tighten both anteriorly and posteriorly by shifting the posterior and inferior bands of the glenohumeral ligaments up to the rotator interval to over-sew the interval and decrease capsular volumes. Multidirectional instability is really a syndrome. It's a difficult problem to understand and define, but the keys to it is that you must have symptomatic inferior translation with associated anterior-posterior symptomatic translation. So it must be symptomatic. Many patients have translation without symptoms associated with it. So on this slide, on the left-hand side, we see the classic sulcus sign, and as we are doing the sulcus sign, we need to ask the patient, does this happen to you and does this reproduce your symptoms? We look for signs of generalized ligamentous laxity through the Baton score, which is illustrated in the central bottom part of the slide. Often these patients as well will have scapular winging or subtle scapular dyskinesias as part of their syndrome. What in fact is the pathology? Well, the key is really a loss of dynamic glenohumeral stability, and this can be caused by a loss of normal joint position sense or proprioception and control both of the glenohumeral joint and of the scapula. This can be associated with labral tears, but more frequently it is not. Most often these are joints with small labrums, capacious or large volume inside the joint, and for the most part this is genetic. Pain is often a prominent feature in these patients, and the findings are often bilateral in terms of the amount of translation, but symptoms are often unilateral, which makes this problem all the more puzzling. The role of proprioception has been looked at by many as a key to the pathology in the shoulder. As we get to end range, the stretched set of receptors within the capsule should be triggering dynamic control through the cup musculature, and somehow this normal reflex is lost in patients with multidirectional instability, and this can be improved both surgically but also through a non-operative treatment and rehab, and this can be both at the scapulothoracic articulation, but also within the glenohumeral joint. We scope patients with multidirectional instability. We often see this very thin capsule, and you'll often see that the head is subluxed almost completely out the bottom of the shoulder joint, so a very large volume shoulder joint. We may see things like scuffing on the labrum, but not sort of dramatic labral capsular injuries associated with more traumatic type instability. Low profile labrum with a relative lack of concavity of the joint, and once again, large volume in the shoulder is typical. So the indications for surgery would be really a protracted, failed, non-operative, quality physiotherapy program, so not just using local modalities, but dynamic control, proprioceptive retraining, scapulothoracic retraining, and in patients who do fail this, their primary symptom should be of instability and not of pain. So the goals are to decrease capsular volume, to retention capsular stretch receptors, repair labral tears if encountered, and often they aren't there, but balance both anterior, posterior, and inferior superior aspects of the shoulder, and certainly a controlled portion of this through the rotator interval. Our options are to perform suture pleats with an intact labrum, or use small suture anchors to anchor our shifting off the glenoid. We can take down the labrum and shift it, but more often leaving the capsule intact. We can use either PDS or high-strength sutures, and closing the rotator interval is a key part of this procedure. So we're looking here from a posterior view at a left shoulder, and we can see bringing a motorized shaver in to create some healing response on the labrum, and then using crescent-type suture hooks, we can shuttle through PDS and perform placation or imbrications of the anterior and posterior bands of the glenohumeral ligament. And then using a percutaneous approach, we can do the same using a suture anchor to get a more secure fixation to the glenoid, and using this double-loaded anchor, once again, we can shift the inferior pouch, obliterating some of the inferior pouch, and shortening the glenohumeral ligament. By shortening the capsule by one centimeter, we typically lose about 20 degrees of rotation. So these crescent-type hooks are really ideal for getting down into the inferior pouch, and we have to be careful that we take just capsule and not take too big a bite for fear of axillary nerve injury. Another key element of this is rotator interval closure, and taking a bite between the superior glenohumeral ligament and the upper fibers of the middle glenohumeral ligament, without taking the subscapularis, and really closing that capsular interval, which again helps decrease overall capsular volume. Best to use a non-absorbable suture, as you can tether motion significantly through the interval. This is showing the final product, looking from an anterior superior portal, looking at the relative balance between anterior and posterior placation. The rehab should involve immobilization with appropriate support. We don't try to re-establish all pre-operative range, and this is a protracted rehab with at least a six-month return to sporting activities. Thank you for your time and attention.

multidirectional instability

shoulder stabilization

capsular volume reduction

ligamentous laxity

proprioception loss