Thanks, Brett, and thanks for the program committee for the opportunity to share some of our work in the military and posterior shoulder instability. I think you'll see it ties together a lot of the principles we've talked about during this session, including operative and nonoperative indications, some tricks, some associated lesions. So without further ado, we'll get started here. This is Dr. Lance LeClaire from Vanderbilt University Medical Center with Drs. Benjamin Hoyt, Kelly Kilcoyne, and John Dickens from Walter Reed National Military Medical Center and Duke University Medical Center. This video will demonstrate our current approach to posterior shoulder instability. Posterior shoulder instability was once thought to be a rare form of shoulder instability. However, multiple recent studies have shown that may not be the case, especially in young active patients. Our review of operatively treated patients at the U.S. Naval Academy found that over half of all shoulder instability surgeries involve repair of the posterior labrum, and nearly 20% of all patients have pure posterior instability. Our team recently performed a retrospective review of posterior shoulder instability in order to evaluate success and failure rates of attempted nonoperative treatment of posterior shoulder instability. With minimum two-year follow-up, approximately half of all posterior shoulder instability patients with MRI arthrogram confirmed posterior labrum tears required surgical treatment in our series. Several key imaging findings predicted failure of nonoperative treatment. These included increased linoid retroversion, posterior humeral head subluxation, a shallow glenoid fossa, and glenoid dysplasia or hypoplasia. Several key history and examination findings were predictive of the need for surgery, including a history of distinct injury and examination findings consistent with instability, including a positive posterior load and shift, and interestingly, a positive anterior apprehension test. 21-year-old Division I varsity football player presented with complaints of right shoulder pain and multiple posterior subluxation events. His MRI demonstrates a posterior labrum tear with a 5% posterior bony Bankart lesion and anterior extension of the tear. Additional imaging findings include a shallow glenoid as well as static posterior humeral head subluxation. Given his multiple subluxation events, positive physical examination, and desire to return to a contact sport, he was indicated for right shoulder arthroscopy with labral repair encapsulography. We prefer a lateral decubitus position with a balanced suspension device for arm positioning. A bump is placed in the axilla to aid in distraction of the humeral head in order to increase visualization of the inferior portion of the glenohumeral joint. Our typical viewing portal begins in posterior lateral position. Optimal viewing can be obtained by placing the posterior lateral portal skin incision inferior and lateral to the posterior corner of the acromion by one to two centimeters. This allows for excellent visualization of the joint, but also a downward trajectory onto the glenoid face once anchor placement begins. It is ideal to keep the posterior and accessory posterolateral portals high and tight for this reason. The accessory posterolateral portal is approximately four to five centimeters straight lateral to the posterior corner of the acromion. Prior to skin incision, localization with a spinal needle demonstrates appropriate trajectory and accessibility to the inferior aspect of the glenoid. Typically two anterior portals are utilized. The mid glenoid anterior portal is kept somewhat medial in order to allow instruments to reach across the face of the glenoid to the posterior and inferior glenoid. This slide demonstrates our typical cannula setup. The arthroscope is placed in the posterior viewing portal initially. An anterior superior portal is established as well as a mid glenoid portal anteriorly. The accessory posterolateral portal is then placed under direct visualization. After diagnostic arthroscopy, the arthroscope is moved to the anterior superior position and a smooth board cannula is placed in the posterior superior position to allow for instrumentation and suture passage. After diagnostic arthroscopy, preparation of the labral tissue begins. First, a spatula elevator is used to free the labrum of adhesions and scar tissue. Care is taken to fully mobilize the capsular labral tissue in order to allow for anatomic repair. This portion of the procedure is especially critical as it optimizes healing of the repaired soft tissue back to the glenoid rim. After soft tissue mobilization, utilizing the elevator, a serrated rasp is used to prepare the glenoid rim and remove all soft tissue attachments. The arthroscopic sucker shaver also allows for debridement of both the labrum and the glenoid. Following full and adequate preparation, soft tissue mobilization is once again checked. In our case example of the right shoulder in the 21-year-old football player, the bony Bankart lesion is visualized beneath the spatula elevator in this video. Adequate soft tissue mobilization has been performed and will allow for anatomic reduction of the bony Bankart. Also visualized is a posterior glenoid labrum articular disruption or GLAD lesion at the nine o'clock position. This patient also has an anterior GLAD lesion at the three o'clock position. After appropriate soft tissue and glenoid preparation, a curved suture passing device is utilized to pierce the capsule approximately 10 millimeters from the capsule labral junction and is passed underneath the capsule and labrum. This is initially done at the six o'clock position with the suture passing device in the posterolateral cannula. The wire loop is retrieved out of the posterolateral portal and a suture tape is placed into the wire loop. One limb of the suture is then pulled in a retrograde fashion under the labrum and capsular tissue. The free limb of suture tape is then retrieved out of the posterolateral cannula and looped over the top of the soft tissue. Both limbs of the suture tape are then placed into the islet of a 2.9 millimeter peak or biocomposite suture anchor. The drill guide is placed through the posterolateral cannula and onto the corner of the glenoid at the edge of the chondral surface. The drill is started on full power while off the bone and a drill hole is placed. The inferior limb of suture tape that has been passed under the labrum is preferentially tightened in order to evert the labrum. While holding the tape under tension, the labral tissue is translated to the aperture of the drill tunnel. Care is taken to place the anchor at the same angle as the drill tunnel while holding tension on the labral tapes. Excess limbs of suture are then trimmed. We typically begin our posterior repairs at the six o'clock position and march superiorly to complete the posterior repair. The six o'clock anchor is the keystone in anatomic repair as it has been shown to reduce recurrence in arthroscopic instability surgery. Eversion of the labrum and placement of the anchor on the corner of the glenoid will allow for anatomic repair. In addition to allowing for a knotless repair, labral tapes have superior biomechanical pull-through strength as demonstrated in our biomechanics lab. Significantly higher soft tissue pull-through strength when compared to conventional suture. As Jim Bradley and colleagues have shown, the number of suture anchors may be a contributing factor for failure of posterior labrum tears. We strive for a minimum of three anchors in each repair spaced 1.5 hours apart on the clock face. In general, posterior glenoid bone loss occurs in the posterior inferior quadrant in an oblique orientation compared to the long axis of the glenoid. In this particular case, the bony Bankart lesion spanned the 7.30 to nine o'clock position. Given the thickness of the bony Bankart lesion, the drill was used to place a pilot hole through the bony Bankart lesion in order to facilitate suture tape passage and anatomic reduction of the bone fragment. After suture passage, the anchor was drilled and placed down to the face of the glenoid into the GLAD lesion in order to provide soft tissue coverage over the lesion. This technique was also used to cover and address the anterior GLAD lesion as well. Our technique involves recreation of the native anatomy by appropriate placement of a six o'clock anchor with spacing of approximately 1.5 hours on the clock face. Following placement of the six o'clock anchor, 7.30, nine o'clock, and if needed, a 10.30 anchor is placed. Once again, restoration of the native anatomy is critical and this begins with a six o'clock anchor followed by spacing of subsequent anchors 1.5 hours apart. The suture retrieving device can be utilized to assist in optimal suture tape placement prior to tensioning the suture in challenging cases. In this case, a bucket handle tear was debrided and the tension was applied after surcloging the remaining labral tissue at the six o'clock position. The eyelid is then taken to the undersurface of the labrum and the inferior limb of suture can be preferentially tightened in order to evert the labrum and allow for anatomic repair. The anterior repairs are performed next, followed by any Hagel or capsular repair last. Care must be taken to evaluate for atypical lesions, including humeral avulsions of the glenohumeral ligament. When appropriately identified and addressed, as seen here in an offensive lineman that had failed a previous posterior repair, excellent outcomes can be expected. In our prior case example of the 21-year-old football player, a capsular tear was present, but there was no true Hagel lesion. However, a side-to-side repair should be performed in order to prevent recurrent posterior instability. If left untreated, chronic instability from Hagel lesions and capsular tears can lead to early glenohumeral arthritis, as seen in this 40-year-old Marine. In our 21-year-old football player, a side-to-side capsular repair was performed, appropriate capsular tension and anatomy was restored. Also of critical importance is identification and treatment of posterior glenoid bone loss. Our recent series of 66 active duty military patients with posterior instability demonstrated that patients with moderate glenoid bone loss did significantly worse when compared to patients without bone loss. Patients with moderate bone loss presented more frequently with primary complaints of instability and higher degrees of clinical failure and recurrent shoulder instability. Therefore, early recognition and treatment of posterior instability prior to the onset of significant bone loss is optimal. In general, good and excellent outcomes can be expected for the majority of patients treated with arthroscopic surgery for posterior shoulder instability. Our midterm follow-up of over 200 patients with arthroscopically treated posterior shoulder instability from the U.S. Naval Academy demonstrated low recurrence rate at short-term follow-up with a 17.2% failure rate at greater than five-year follow-up. While no statistically significant risk factors for recurrence were identified, younger age was shown to contribute to failure within the first four years of follow-up. Tear size was not predictive of failure. Our current treatment algorithm for posterior shoulder instability is as follows. For patients with new onset or first-time posterior shoulder instability with no bone loss, both conservative and surgical treatment are discussed and offered. For patients with minimal bone loss, surgical treatment is recommended. For patients who had failed primary arthroscopic surgery but do not have bone loss, revision arthroscopic surgery is possible. But if patients have moderate to severe bone loss or have failed prior surgery with mild to moderate bone loss, arthroscopic distal tibia allograft reconstruction is performed. We recently published our preferred technique for arthroscopic distal tibia posterior glenoid reconstruction in the Video Journal of Sports Medicine. This patient demonstrates a typical posterior glenoid bone loss with prior failed arthroscopic posterior labral repair. A diagnostic arthroscopy was performed and the posterior glenoid recipient site was prepared with an arthroscopic burr. A fresh distal tibia allograft was harvested and prepared based on the defect size as measured on a 3D printed model of CT scan imaging. The graft is delivered through the infraspinatus muscle utilizing a three centimeter incision parallel with the posterior glenoid rim. Cannulated screws are placed percutaneously for graft fixation. A capsule of labral repair is then performed at the native glenoid rim in order to make the allograft extra articular to mitigate risk of allograft resorption. Follow-up CT scan at three months postoperatively shows excellent graft incorporation and healing. Clinically, the patient was pain-free, had full range of motion and no complaints of instability. Functionally, he was able to perform push-ups without pain and was cleared to return to full duty a little over four months postoperatively. This procedure may offer enhanced treatment options for patients with posterior glenoid bone loss. Our standard postoperative rehab protocol includes use of a sling for four weeks postoperatively, strength training is initiated at 10 weeks postoperatively and a push-up progression is started at 16 weeks postop. Most patients are cleared to return to full activities and full duty at six months postop. In summary, attempted non-operative treatment can be successful in approximately half of posterior shoulder instability patients. If treated arthroscopically, optimal position of the patient in the lateral decubitus position, appropriate placement of viewing and working portals and diligent preparation and recreation of anatomy is essential. While performing arthroscopic surgery, careful attention must be paid to unique lesions such as Hagels, GLAD lesions and bony Bankarts. Finally, in a revision or bone loss setting, arthroscopic bone augmentation techniques are now available and offer improved treatment options for these challenging patients. Great job, Lance. Thank you very much. That concludes our session. Thank you to our panel and ask everyone to stick around for a special presentation. Thank you.

posterior shoulder instability

treating

nonoperative treatment

arthroscopic surgery

rehabilitation protocols