Well, it's a pleasure to be able to meet everybody in person at the upcoming Anna Shoulder course. My name is John Dickens. I'm the Chief of Orthopedic Sports Medicine at Walter Reed and co-chair with Pat Denard for this outstanding course. Before we get started, I just want to say thank you to Anna. Thank you to Alex for all the incredible work putting this on, both leading up to and then this weekend. And certainly, Pat Denard for all the incredible work that he's done in this. It's been a pleasure working with him and the entire staff, and we're looking forward to getting together this coming weekend. So my task is to talk about arthroscopic posterior glenoid reconstruction, graft options and techniques. We know that arthroscopic posterior instability is relatively common and increasingly recognized between 10% and 27% of posterior instability cases, whether it be in a military or a civilian setting. And we know that non-operative management is generally unsuccessful. Two different studies, both in the military population as well as civilian populations, between 50% and 70% of these undergo operative stabilization after a period of non-operative treatment. Generally speaking, arthroscopic posterior capsule labral repair is successful, a 6% to 12% failure rate, and in Jim Bradley's study, 89% return to a sport, albeit two-thirds are returning to the same level. So generally good outcomes with arthroscopic stabilization. However, there is a population that does have posterior glenoid bone loss, and perhaps it's something that we are seeing more often and not recognizing it. We looked at this in the military academy population, which is a unique population where we've been able to MRI cadets before they have an event when they enroll at the academy and then follow them up as they have an instability event. What we've seen in these scenarios is up to 10% posterior glenoid bone loss in these symptomatic posterior instability patients, and then those with recurrent instability, up to 16% posterior glenoid bone loss in this patient population. Overall in the military, measurable posterior glenoid bone loss is seen in about 60% of our patient population with posterior instability, and about 14% of those have bone loss of between 13.5% and 20%. JT's group looked at this as well. No difference in return to duty, whether they had bone loss or did not have bone loss, and there is no difference in WOSI subscale scores as well. Posterior glenoid bone augmentation, therefore, is really only indicated, and this is certainly being evaluated now in the revision posterior instability patient that's failed a prior surgery and has posterior glenoid bone loss of 20%. Perhaps it can be considered in those with 13.5% to 20%, but certainly not a primary treatment option, or in those with multidirectional instability, and in a recent study that is coming out in arthroscopy, Andy Sheehan, Albert Lin, and Rob Hartzer looked at this in a systematic review. Certainly not high-quality studies, given the relatively infrequent nature in which these are done, but overall recommendation was not favorable for posterior glenoid bone augmentation as a general procedure, in part because of its technical demand and high complication rate. Certainly when considering this, these can be done with either iliac crest, a clavicle, or a distal tibia allograft. Iliac crest may be a little bit more common in the European population as the advantage of being able to obtain large grafts, certainly maximum healing potential and no risk of antigenicity. Donor site morbidity, no articular surface, a relatively incongruous surface, and a risk of undersizing are all disadvantages of this particular option. The distal clavicle is popularized by JT as advantages of good healing potential, again, no risk of an antigenetic response. It does have an articular surface, although variability in that surface and its size is not perfect. Donor site morbidity, although less than iliac crest and limited size availability and mismatch are both disadvantages. The distal tibia allograft is certainly one that's been used for large anterior bone loss and works as well for the posterior glenoid bone loss scenario. It does have good articular congruity. It can be worked with in a variety of different sizing to match the bone loss. It certainly does not have donor site morbidity, but brings with it unknown healing potential, risk of aft resorption, cost, and difficulty with availability. So this is a case example that highlights our current practice pattern as dealing with these patients in the military unit at Walter Reed. This is a 32-year-old Marine Corps male who's had recurrent posterior instability and pain of note. He's had two prior arthroscopic posterior labral repairs and revision labral repairs that have failed. He is unable to perform his Marine Corps required physical demands, pull-ups, push-ups, overhead lifting, and is pending a medical discharge from the Marine Corps if he's unable to address this. His exam is significant for a grade 3 posterior load shift on this side versus a grade 1 on the contralateral side. He certainly has a very, frankly, positive apprehension, jerk, and kim, and no hyperlaxity. These are his x-rays, and I think you can appreciate on the axial the degree of posterior bone loss. It's notable this is different from our anterior counterparts. This is his CT scan, again, appreciating the early glenohumeral arthritis as well as the posterior bone loss in previous anchor placements. Our equipment for this, we use a basic arthroscopy shoulder set. A 70-degree scope is helpful. We use the distal tibia allograft as it facilitates the prep. The 10-millimeter sagittal saw, very important for us as a 3D model. This helps understand and preoperative plan for location sizing. We do wash these with pulse lavage and use PRP for all of these. Standard arthroscopic anchors are useful because arthroscopic labral repair can be performed nicely over the top of the bone graft, and certainly, hip scope sleds can be helpful. This is just the graft, and as you can see here, this is the graft prep set. We like to, again, use the allograft distal tibia prep station here. After fixing, we'll generally size this to a size 10-millimeter thickness. We prepare the flush side and then create a five- or 10-degree scarf cut, which will be facing the articular side. We place our depth here, and using this system, you can check the articular congruity. We go ahead and place then, before making our final cuts, our preliminary pin fixation, which we can overdrill with a four-millimeter cannulated reamer seen here. These will help with going ahead and preparing our distal tibia for graft insertion. Once this is complete, we'll then go ahead and move to completing our distal tibia cuts and taking our graft for eventual pulse lavage and then PRP. Here you can see our sizing, which will either size these from superior to inferior at either a 20- or a 23-millimeter length. Again, this is our final graft preparation, which we perform right before the arthroscopy to facilitate the case creation. We like to perform these in the lateral decubitus position. This demonstrates our arthroscopic portal placement. We use a high posterior lateral viewing portal. You can see our glenoid placement for our graft, which is slightly more medial and in line with the glenohumeral joint. Then our accessory posterior lateral portal is placed at the end, as you see here, for a more posterior labral repair. In this case, you can see here, this is a previous failed posterior labral repair, as we mentioned earlier. You can start to appreciate here the capsule and labrum, which is generally maintained. We can take these sutures out. Once we've prepared the labrum and capsule and elevated this, we're viewing from the anterior superior portal. We're working from our high posterior lateral portal here. This gives us a good trajectory down to the articular surface. We're perpendicular here. We'll take a burr and we'll prepare our donor site. Again, we've prepared this and templated this with our 3D CTs. We like to use this guide here to help us measure our depth. You can appreciate the scapular spine here. We removed our previous anchors, as you can see. Then once our donor site is prepared, we then make our posterior glenoid portal. We like to place this sizing guide again here just to confirm our placement, that everything is perpendicular, we have a nice smooth surface. We do place this posterior to our capsule and labrum. We feel like this provides a nice access in both trajectory for our screw placement, as well as facilitates a later capsule labral repair. After preliminary fixation with K-wires, we'll then overream with our four millimeter drill. After this is placed, you can see here, we can then place our two four millimeter screws that are cannulated. We can actually observe these compress at the articular surface. We get excellent time zero stability. The screws can be visualized on the far posterior surface as well to confirm the location of the screws and that they are well seated. These cannulated guide pins are then removed. Final checks are then performed. You can see based on our templating, the restoration of the glenoid humeral joint. We create our accessory posterior lateral portal at this point. Then we can perform a standard capsule labral repair using anchors of your choice to imbricate the capsule back over our reconstructed glenoid for a nice final fixation. As you can see here, this restores tension on those posterior capsular structures. Again, this can be continued up from inferior to superior, creating an excellent posterior shift. This is our follow-up x-rays at the day of surgery here on the top. Then at three months, you can already appreciate our early graft incorporation. Then at five months follow-up, these patients are doing quite well. In fact, I can tell you that they've actually experienced less pain than the arthroscopic procedures. Although we don't normally encourage them to go back to push-ups, they feel excellent stability and have returned to push-ups generally by the five months mark for all of our patients without any difficulty. In summary, posterior glenoid bone loss is common. It may be observed at up to 69% of those with posterior instability. It is associated with decreased return to function. Bone loss is associated with persistent instability despite soft tissue procedures. As we continue to recognize both the prevalence as well as the impact of posterior bone loss, techniques are evolving to better treat these. Posterior osseous augmentation procedures certainly may provide a future clinical treatment, although its uses are really indicated only in those revision cases with significant critical bone loss at this time. Thank you for the opportunity and I look forward to seeing everyone in Chicago. Thank you.

arthroscopic posterior glenoid reconstruction

prevalence of arthroscopic posterior instability

failure of non-operative management

posterior glenoid bone loss

surgical technique using distal tibia allograft