Posterior Instability Research Articles

Subscapularis Muscle Radiographic Integrity and Patient-Reported Outcomes Following Arthroscopic Anatomic Glenoid Reconstruction With Distal Tibial Allograft.

Shoulder stabilization surgery has evolved over time, and bony augmentation procedures on the glenoid side are being performed more often. The Latarjet procedure modifies subscapularis anatomy because the conjoined tendon divides the subscapularis muscle fibers through a split/takedown, which has structural and functional implications. Arthroscopic anatomic glenoid reconstruction (AAGR) re-creates anatomy. This technique uses the Halifax portal to deploy and fix a distal tibial allograft (DTA) through the rotator interval, thus preserving the subscapularis anatomy. The purpose was to analyze the radiographic properties of the subscapularis muscle after AAGR. It was hypothesized that the subscapularis muscle structure remains preserved postoperatively. Case series; Level of evidence, 4. A retrospective review was performed comprising a consecutive series of patients treated with AAGR with DTA between November 2012 and April 2021 for traumatic anterior shoulder instability with glenoid bone loss. Patients were excluded if they had posterior instability, glenoid fracture, missing pre- or postoperative computed tomography (CT) scans, or only CT arthrogram available. Radiographic variables measured on CT scans included estimates of subscapularis muscle volume, subscapularis/infraspinatus muscle ratio, and fatty infiltration according to the Goutallier classification. Pre- and postoperative Western Ontario Shoulder Instability index scores were collected as a secondary outcome of this study. Ninety-three patients were included in the study with a clinical follow-up of 2.3 ± 1.5 years (mean ± SD). The subscapularis volume increased from 185.91 ± 45.85 mL preoperatively to 194.1 ± 49.0 mL postoperatively (P = .006). The subscapularis to infraspinatus muscle ratio showed a significant increase from 0.96 ± 0.27 to 1.05 ± 0.30 after surgery (P = .002). All patients had a Goutallier stage of 0 before and after surgery. The Western Ontario Shoulder Instability scores showed a significant improvement from 64.8 ± 15.5 preoperatively to 28.2 ± 24.0 postoperatively (P < .001). Patients who undergo AAGR with DTA for traumatic shoulder instability with glenoid bone loss have a preserved subscapularis muscle volume with no fatty infiltration, while showing a significant improvement in clinical outcomes.

Nonoperative Treatment of Isolated Posterior Glenohumeral Instability in an Active Military Population: Effect of Glenoid and Acromial Morphology

Background: Nonoperative management of posterior shoulder instability is common. However, limited data are available to assess the pathomorphologic factors associated with its failure. Purpose/Hypothesis: The purpose of this study was 2-fold: (1) to determine glenohumeral pathomorphologic features predictive of nonoperative management failure of posterior instability; and (2) to determine the relationship between nonoperative management failure and posterior glenoid bone loss (pGBL) progression. It was hypothesized that greater posterior acromial height (PAH) would adversely affect nonoperative survivorship and that shoulders treated nonoperatively would have pGBL progression compared with those undergoing surgical stabilization. Study Design: Case-control study; Level of evidence, 3. Methods: This was a retrospective review of a consecutive series of patients with isolated posterior shoulder instability, defined as isolated posterior labral tear on magnetic resonance imaging (MRI) with corresponding physical examination findings, who underwent nonoperative management for 6 months and had no previous related surgical history. The primary outcome of interest was the failure of nonoperative management, defined as the inability to return to full military duty or requiring surgical intervention. The morphologic features assessed for association with nonoperative management failure included pGBL, glenoid version, acromial morphology, and posterior humeral head subluxation. We secondarily sought to determine the progression of pGBL on serial MRI scans. Cox proportional hazard analysis was used to evaluate risk factors for failure. Results: In this study, 42 of 90 (46.7%) patients had failed nonoperative management and went on to receive an arthroscopic stabilization procedure. The group with failed treatment demonstrated a greater humeral head subluxation ratio than those with successful nonoperative management (0.65 ± 0.2 vs 0.62 ± 0.2; P = .038). Cox proportional hazard analysis identified pGBL, greater PAH, less posterior acromial coverage, and posterior humeral subluxation as significant risk factors for failure. Of those with failed nonoperative management, 17 had repeat MRI scans at a mean of 488.2 ± 87 days after index MRI for comparison, demonstrating a statistically significant progression of pGBL (index MRI, 2.68% ± 1.71%) versus after nonoperative treatment failure (6.54% ± 1.59%; P = .003). Conclusion: Failure occurred 47% of the time in patients who underwent nonoperative management for isolated posterior glenohumeral instability for a minimum of 6 months, and it was associated with a greater posterior humeral head subluxation, less posterior acromial coverage, greater PAH, and greater amounts of glenoid retroversion on index MRI. Additionally, those who had repeat MRI approximately 1 year after the index MRI demonstrated greater pGBL compared with the index MRI.

Comparison of the MIPPO technique and the modified Stoppa approach in the treatment of unstable anterior pelvic ring injuries: a retrospective cohort study

BackgroundAnterior pelvic ring injuries have gradually become common. Using a minimally invasive technique to treat this injury may be feasible if the reduction and stability can be effectively achieved. We describe a percutaneous technique, minimally invasive percutaneous plate osteosynthesis (MIPPO), to fixate the anterior pelvis via establishing a subperiosteal tunnel between two limited incisions over the iliac crest(s) and pubic ramus in this research.MethodsA retrospective cohort study comparing the MIPPO technique (n = 60) versus the modified Stoppa approach (n = 53) for anterior pelvic ring injuries with posterior ring instability was performed from September 2016 to January 2023. The relative surgery variables, follow-up function evaluation, and complications were compared in two groups. The reduction quality of fracture was assessed according to the Matta criterion, and the functional score was evaluated using the Majeed score.ResultsAll patients completed follow-up, with an average interval of 39.90 ± 17.53 months (range 12–78). In the MIPPO technique group, the surgery interval and blood losses were lower compared to the modified Stoppa approach group (P<0.05). The mean procedure times and intraoperative blood losses were 69.56 ± 14.04 min/side (range 50–110) and 156.23 ± 49.75 mL/side (range 90–250) for unilateral anterior ring MIPPO fixation separately. All patients got a satisfactory reduction of the fracture. In the follow-up, earlier ambulation, shorter postoperative hospital stays, and lower complication rates were observed for patients using the MIPPO technique compared to the modified Stoppa approach (P<0.05). However, there is no statistical difference in these indicators including fracture union interval, full load time, the Majeed score, patient satisfaction level, and return to pre-injured work rate between the two groups.ConclusionThis clinical experience gives support for the use of the MIPPO technique to stabilize the anterior pelvis. This minimally invasive technique was an effective and safe surgery method and could obtain satisfactory function results, particularly fitting to part of patients with resistance using the modified Stoppa approach.

Arthroscopic Fixation of Posterior Cruciate Ligament Tibial Bony Avulsion Fractures: The Double Suture Bridge Technique and Evaluation of Results

Background: Surgical fixation is required for displaced posterior cruciate ligament (PCL) tibial bony avulsion fractures or with fractures having grade 2 or more posterior instability. The purpose of this study is to evaluate the results of arthroscopic fixation of PCL tibial bony avulsion fractures using the double suture bridge technique. Methods: A retrospective study was done involving 24 patients having displaced PCL tibial bony avulsion fractures. The arthroscopic double suture bridge technique was used to fix these fractures. Patients were followed up for three years and assessed for knee-related symptoms, signs, Lysholm Knee Score, and satisfaction. Results: The study group consisted of 21 men and three women. Fracture union was achieved in all cases two months postoperatively. The mean Lysholm Knee Score at follow-ups of three months, six months, one year, two years, and three years was 86.6, 96.5, 98.8, 99.1, and 99.4, respectively. At the latest follow-up, all the patients were satisfied with their knee function with respect to pain, range of motion (ROM), stability, and resumption of pre-injury activity level. Conclusion: The arthroscopic double suture bridge technique is an effective method for the fixation of PCL tibial bony avulsion fractures with respect to knee stability, ROM, and resumption of pre-injury activity level.

Anterior ultrasound approach for evaluating posterior shoulder instability in brachial plexus birth palsy: A novel diagnostic technique

Brachial plexus birth palsy (BPBP) often leads to shoulder deformities, such as posterior subluxation and internal rotation of the humeral head, which can severely impact a patient’s quality of life. Traditional imaging techniques such as magnetic resonance imaging, while effective, often require sedation or anesthesia, limiting their routine use in pediatric patients. This technical note explores using ultrasound as a non-invasive alternative for evaluating and monitoring shoulder deformities in BPBP patients. We introduce a novel ultrasound method that focuses on the alignment of the coracoid process and the humeral head, revealing significant differences between affected and unaffected shoulders. This technique offers a reliable and accessible tool for early diagnosis and intervention, improving outcomes for patients with BPBP-related shoulder deformities.

The Efficacy of Conservative Management of Micro-traumatic Posterior Shoulder Instability

The Efficacy of Conservative Management of Micro-traumatic Posterior Shoulder Instability

Arthroscopic Repair for Posterior Shoulder Instability is Associated with Favorable Outcomes and High Return to Sport or Work: A Systematic Review and Meta-Analysis

PurposeThe purposes of this systematic review and meta-analysis were to assess clinical outcomes of primary arthroscopic repair for unilateral PSI in all patients, to evaluate clinical outcomes in athletes, and to compare clinical outcomes between contact and overhead athletes. MethodsA systematic review was performed using PRISMA Guidelines. Included studies reported on primary arthroscopic treatment of PSI with at least 1 year of follow-up. Studies were excluded if they were not in English, included revisions/open procedures or anterior/multidirectional instability, had fewer than ten patients or no full text available, or were biomechanical analyses/descriptions of surgical technique. Primary outcomes were rates of return to sport (RTS), return to preinjury level (RTPL), recurrent instability, and revision surgery. Outcomes were evaluated in all patients and all athletes, with further subdivision for contact and overhead. ResultsOf the 1,504 screened studies, 30 met inclusion criteria (1,649 shoulders). Mean age at surgery was 23.3 years (range: 12.4-65 years), and mean follow-up was 35.5 months (range: 12-140.4 months). There were 1051 males and 196 females. RTS rates were 91.7% among all patients and 90.9% in all athletes, with no statistical difference between contact and overhead athletes (92.8% vs. 88.1%, P=.176). RTPL rates were 78.7% among all patients and 75.6% in all athletes, with no statistical difference between contact and overhead athletes (90.8% vs. 62.3%, P=.072). Recurrent instability rates were 7.0% among all patients and 8.0% in all athletes, with no statistical difference between contact and overhead athletes (7.3% vs. 7.4%, P=.981). Revision rates were 3.7% among all patients and 3.3% in all athletes, with no statistical difference between contact and overhead athletes (6.8% vs. 0%, P=1). ConclusionPrimary arthroscopic treatment of PSI is associated with favorable outcomes and high return to sport and work rates. Recurrent instability and pain were the most common reasons for revision. Level of EvidenceLevel IV: Systematic review and meta-analysis of Level II to IV studies

Open Posterior Capsular Reconstruction Using Acellular Dermal Allograft

Posterior shoulder instability accounts for a minority of shoulder instability cases. There is a lack of data and treatment algorithms compared to anterior shoulder instability; moreover, many of the proposed techniques focus on bony reconstruction. We describe an open technique of capsular reconstruction in the absence of glenoid bone loss using dermal allograft tissue secured with knotless fixation. This technique offers the advantage of direct visualization of graft placement and simplifies suture management.

Posterior Stabilization and Reverse Hill-Sachs Remplissage Using Linked Knotless Anchors

Posterior glenohumeral dislocation can result in impaction fractures to the anteromedial humeral head, known as a reverse Hill-Sachs lesion. They may also cause damage to the posterior capsuloligamentous structures. This can lead to ongoing posterior instability and altered biomechanics resulting in early degenerative changes. Ongoing symptoms may result in challenges to a patient’s day-to-day and sporting activities. Early intervention to stabilize the shoulder may help avoid these. We present a reproducible technique for posterior stabilization using linked knotless anchors to perform a remplissage of the subscapularis into the reverse Hill-Sachs lesion defect that avoids the need for exposure of the subcoracoid bursa.

Posterior Glenoid Bone Grafting in the Setting of Excessive Glenoid Retroversion Does Not Provide Adequate Stability in a Cadaveric Posterior Instability Model

Background: Excessive glenoid retroversion is a known risk factor for posterior shoulder instability and failure after soft tissue stabilization procedures. Whether excessive glenoid retroversion is a risk factor for failure after posterior glenoid bone grafting is unknown. Purpose: To evaluate the biomechanical effectiveness of posterior iliac crest bone grafting (ICBG) for posterior shoulder instability with increasing glenoid retroversion. Study Design: Controlled laboratory study. Methods: Six fresh-frozen cadaveric shoulders had a posterior glenoid osteotomy allowing the glenoid retroversion to be set at 0°, 10°, and 20°. At these 3 preset angles, 4 conditions were simulated consecutively on the same specimen: (1) intact glenohumeral joint, (2) posterior Bankart lesion, (3) 20% posterior glenoid bone defect, and (4) posterior ICBG. Stability was evaluated in the jerk position (60° of glenohumeral anteflexion, 60° of internal rotation) by measuring (A) posterior humeral head (HH) translation (in mm) and (B) peak translational force (in N) necessary for translation of the HH over 25% of glenoid width. Results: At 0° of retroversion, the ICBG restored posterior HH translation and peak translational force to values comparable with those of the intact condition (P = .649 and P = .979, respectively). At 10° of retroversion, the ICBG restored the peak translational force to a value comparable with that of the intact condition (22.3 vs 24.7 N, respectively; P = .418) but showed a significant difference in posterior HH translation in comparison to the intact condition (4.5 vs 2.0 mm, respectively; P = .026). There was a significant increase in posterior HH translation and significant decrease in peak translational force with the ICBG at 20° of glenoid retroversion compared with the intact condition (posterior HH translation: 7.9 vs 2.0 mm, respectively; P < .006; peak translational force: 15.3 vs 24.7 N, respectively; P = .014). Conclusion: In this cadaveric study, posterior ICBG was able to restore stability to a level comparable to that of the native condition at 0° and to some extent at 10° of retroversion. However, posterior ICBG was not able to provide adequate stability at 20° of glenoid retroversion. Clinical Relevance: Posterior glenoid bone grafting with ICBG should be used with caution when performed in isolation in the setting of posterior instability associated with glenoid bone loss and combined glenoid retroversion of >10°.

Arthroscopic selective approach to dynamic posterior shoulder instability: long-term follow-up insights

AimsEvaluate outcomes of arthroscopic capsulolabral repair in patients with structural dynamic posterior instability (Moroder classification B2), analyzing factors associated with inferior clinical outcomes or recurrence. The primary hypothesis is that this surgical approach in patients without static structural changes such as excessive glenoid retroversion or dysplastic glenoids will result in satisfactory clinical outcomes and low failure rates. MethodsObservational retrospective analysis in patients diagnosed with posterior structural dynamic instability who underwent arthroscopic capsulolabral repair. Demographic, clinical and radiologic characteristics were registered as well as patient reported outcomes, satisfaction, complications and failure with a minimum 2-year follow-up. Association between these outcomes and preoperative factors was investigated. Results21 patients were included, with an average age of 38.1 years (range 27-51) and a mean follow-up of 68.7 months (range 24-127). At final follow-up the degree of instability was 0 in 19 (90.5%) patients. Overall outcome assessment demonstrated a mean SSV of 82.3 (±15.2), mean WOSI score of 460.1 (±471) and a mean 91.5 (±13) ROWE score. Furthermore, a significant portion of patients returned to sport 71.4% at any level and 57.1% at previous level, and 71.4% reported satisfaction with treatment, while 5 patients (23.8%) had criteria for failure. ConclusionArthroscopic capsulolabral repair in selected patients with type B2 posterior shoulder instability without static posterior findings yielded satisfactory clinical outcomes and low failure rates.

Using an Intraoperative Stress Exam to Direct Treatment in Posterior Femoral Head Fracture-Dislocations.

To examine the results of a treatment algorithm incorporating an EUA performed intraoperatively after fixation of the femoral head through a Smith Petersen approach to determine need for posterior wall or capsule repair. Design: Retrospective review. Two Level 1 trauma centers. All acute, traumatic femoral head fractures from posterior hip dislocations treated at participating centers over a 5-year period from 2017-2022. Injuries were classified according to the Pipkin system. The primary outcome was the result of intraoperative EUA performed after femoral head fixation to determine the need for Kocher-Langenbeck exposure for posterior wall and/or capsule fixation. The secondary outcomes included rates of avascular necrosis, heterotopic bone formation, late instability, and conversion to total hip arthroplasty. Studied were 63 males and 22 females with mean age 32.5 (range 18-71). 79 of 85 (92.9%) patients had a stable EUA after fixation of the femoral head through a Smith-Petersen approach. Six (6/85, 7.1%) underwent an additional Kocher-Langenbeck approach for posterior wall or capsule fixation. This included 1 Pipkin I, 1 Pipkin II, and 4 Pipkin IV injuries. Of the Pipkin IV injuries, 51/55 (92.7%) had stable EUA and did not require fixation of their posterior wall. This included 7 patients with wall involvement >20%. Five patients were excluded because of planned fixation of their posterior wall based on preoperative imaging. Of patients with at least 6 months follow up, 16 of 65 (26.4%) developed radiographic evidence of AVN and 21 of 65 (32.3%) evidence of heterotopic bone formation. Seven out of 65 (10.8%) were converted to total hip arthroplasty over the study period. When comparing patients with a single exposure with those with additional KL exposure, they did not vary in their rate of AVN (27.1% vs. 0.0%, P=0.3228), HO formation (30.5% vs. 50.0%, P=0.3788), or conversion to total hip arthroplasty (10.2% vs. 16.7%, P=0.510). This study found residual posterior hip instability after femoral head fixation in patients with and without posterior wall fractures after posterior dislocations. The results of this study support use of an EUA after femoral head fixation to identify residual posterior hip instability in all femoral head fractures from posterior hip dislocations, regardless of Pipkin type. Use of the Smith-Petersen exposure remains a viable surgical option and may be improved with incorporation of an EUA after femoral head fixation. For Pipkin IV injuries with posterior wall fractures with indeterminate stability, an EUA accurately identifies residual instability. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Repair of Isolated Subscapularis Tears With Concurrent Biceps Tenodesis Using a Single Anchor Results in Satisfactory Clinical Outcomes: Minimum 2-Year Follow-Up

PurposeThe aim of the present study was to investigate the clinical outcomes of patients treated with isolated subscapularis tear repair and biceps tenodesis using a single anchor. MethodsPatients diagnosed with subscapularis tear and underwent arthroscopic surgery by a single surgeon between February 2017 and January 2022 were retrospectively evaluated. Inclusion criteria were patients who underwent repair of isolated subscapularis tear along with tenodesis for LHBT pathologies such as superior labrum anterior posterior (SLAP) lesion, instability, partial tear or tenosynovitis, with a minimum follow-up of 24 months. Assessment included active and passive range of motion (ROM), single-assessment numeric evaluation (SANE), visual analog scale (VAS),Constant-Murley score (CMS), and specific subscapularis and biceps tests. Improvements were analyzed using Minimum Clinically Important Difference (MCID) values. ResultsA total of 20 patients were included. The mean age was 48.5±7 years, and the follow-up period was 43.1±12.7 months. Significant improvements were observed at the final follow-up in active forward flexion, active abduction, active internal rotation, as well as VAS, SANE, and CMS (p< 0.001). The MCID analysis showed that 100% of patients met the MCID for CMS, 90% for SANE, and 100% for VAS. ConclusionIn the presence of an isolated subscapularis tear associated with LHBT pathologies, favorableclinical outcomes could be achieved by performing both tear repair and biceps tenodesis with a double-loaded single anchor. A majority of patients (>90%) achieved the MCID for the CMS, SANE and VAS, indicating significant clinical improvement and satisfactory patient outcomes. Level of EvidenceLevel IV, Case series

Poster 108: Arthroscopic Posterior Labral Repair Patients Experience Less Instability Events and Full Dislocations Yet Are More Commonly Male Contact Athletes that Require Concomitant Procedures When Compared to Arthroscopic Anterior Labral Repair Patients

Objectives: Direct comparisons between the direction of shoulder instability as it pertains to clinical and demographic risk factors are lacking. The purpose of this study is to identify and compare demographic, clinical, and peri-operative variables in patients receiving arthroscopic treatment for anterior and posterior shoulder instability. Methods: A retrospective chart review was performed for consecutive patients who underwent primary arthroscopic labral repair surgery for anterior and posterior shoulder instability with a minimum 2-year follow-up. Surgeries were performed by six surgeons at a single institution between 2012-2020. Patients with prior shoulder instability surgeries of any kind were excluded. Demographics and operative variables included sex, body mass index (BMI), Contact/collision sports, tobacco use, ASA grade, number of dislocations (&lt;1, 1, 2, &gt;2), tear size (120, 240, and 360 degrees), age, time from first dislocation to surgery, number of anchors, and concomitant procedures. Study groups were compared using student’s t-tests and Mann-Whitney U test for continuous variables and Chi-Square or Fisher’s Exact tests for discrete variables with a significance of 0.05. Results: Five hundred and twenty-four (524) patients met inclusion criteria. Overall, there were 133 females (25.4%) and 291 males (74.6%) with a mean age of 27.1 years at the time of surgery (SD ± 9.9) and a BMI of 26.6 (SD ± 5.6). Posterior instability patients were less likely to have experienced a dislocation (15.1% without prior dislocation) than patients with anterior instability (3.4%). Additionally, posterior instability patients that did experience a dislocation (22.6%) were less likely to have greater than two dislocations when compared to anterior instability patients (53.6%). Posterior instability was more frequently associated with males (85%), higher BMI (mean = 28.25), and contact/collision sports (41%). Posterior instability patients were more likely than anterior instability patients to have concomitant procedures performed at the time of labral repair, including capsular plication, (31.6%) biceps tenodesis (14%), and distal clavicle excision (8.8%). Lastly, posterior instability patients typically required fewer anchors (3.4) than anterior instability patients (3.98) at the time of labral repair. Conclusions: Despite having fewer instability events or dislocations, patients that receive a posterior labral repair are more likely to have additional injuries in their shoulder requiring treatment when compared to patients that have received an arthroscopic anterior labral repair. Interestingly, posterior labral repair patients are more commonly male, and contact athletes, as well. With posterior shoulder instability being less common, we speculate that these findings could correlate with a more significant amount of energy/mechanism involved when a shoulder does dislocate posteriorly, thus leading to injuries to additional shoulder structures. It also correlates with the repetitive microtrauma mechanism that can happen with posterior labral tears. Whereas patients may be more likely to experience symptoms over a longer period of time without ever having a full instability event and additional shoulder structures become injured.

Paper 41: Does MR Arthrography Improve Evaluation of Patients with Posterior Shoulder Instability? An Analysis from the MOON Shoulder Instability Group

Objectives: Posterior shoulder instability is an uncommon injury, accounting for 2-12% of shoulder instability patients. Magnetic resonance imaging (MRI) is often utilized to non-invasively evaluate the joint for labral, cartilage, and bony injury. MR arthrography (MRA) may improve the evaluation of these intra-articular structures, but requires additional cost, time, and an invasive procedure. Moreover, its benefits for patients with posterior shoulder instability are unclear. Accurate imaging is critical in patients undergoing surgery because certain findings may influence the surgical approach. Thus, the purpose of this study is to compare the accuracy of MRA and non-enhanced MRI in detecting labral, chondral, and osseous lesions in patients with posterior shoulder instability. Methods: There were 291 patients with unilateral posterior shoulder instability who had preoperative MRA or MRI between 2006 and 2021 in the MOON database. Images were reviewed by a fellowship-trained musculoskeletal radiologist with 10+ years of experience and an orthopaedic surgeon. Evaluators were blinded to age, gender, medical history, MR report, and arthroscopic findings, but were aware of the patient's history of posterior shoulder instability. Examinations were evaluated for presence, location, morphology, and length of glenoid labral tears. Tear length and localization were noted using a standard clock face. The presence and size of humeral/glenoid osseous and cartilage lesions was also noted.Intraoperative findings from arthroscopic evaluation were documented by the surgeon using a standard response questionnaire. Diagnostic performance of standard MRA and MRI were evaluated using sensitivity and specificity with arthroscopic evaluation as the gold-standard. Chi-squared or Fisher’s exact tests were used to compare the sensitivities and specificities of MRA and MRI. Significance was defined as P &lt; 0.05. Results: 200 patients (69%) had MRA, while 91 patients had non-contrast MRIs of the shoulder. On imaging evaluation, 273 (94%) patients had labral tears with a mean tear size of 156º. 39 (13%) patients had humeral cartilage lesions, whereas 40 (14%) patients had glenoid cartilage lesions. 34 (12%) patients had glenoid bone loss greater than 5%. The mean glenoid bone loss was 12% (range, 5% - 26%). A reverse Hill-Sachs lesion was present in 35 (12%) patients. 16 (6%) patients had bipolar bone loss. The sensitivity for detection of labral tears was high for both MRA (0.95) and standard MRI (0.98) (Tables 1 and 2), though the specificity was low for both modalities (0.25 and 0.40, respectively). There was no difference in the sensitivities or specificities of the two imaging modalities in the detection of labral tears. MRA had a lower sensitivity than MRI in the detection of glenoid cartilage lesions (0.31 vs 0.88, p &lt; 0.001), but no difference was observed for specificity. There was no difference in the sensitivities and specificities of MRA and MRI for humeral cartilage lesions (p = 0.354).MRA had a higher sensitivity than MRI in assessing glenoid bone loss (0.78 vs 0.50, p &lt; 0.001), though there was no difference in specificity. There was no difference between imaging modalities in the evaluation of humeral bone loss (p = 1.000). Conclusions: In this multicenter study, MRA was the most commonly utilized preoperative advanced imaging study for patients with posterior shoulder instability. MRA had a higher sensitivity in detecting glenoid bone loss but lower sensitivity in detecting glenoid cartilage lesions compared to standard non-contrast MRI. There was no difference in diagnostic performance between MRA and MRI in the diagnosis of labral tears and humeral chondral and osseous lesions. MRA may provide an advantage over standard MRI in the evaluation of glenoid bone loss, which can influence the treatment plan for patients undergoing surgical management of posterior shoulder instability.

Single anterior shoulder dislocation patients demonstrate higher rates of posterior labral repair and biceps procedures than multiple dislocators at the time of arthroscopic stabilization surgery

IntroductionThe purpose of this study is to identify and compare demographic, clinical, historical, and intra-operative variables in patients who have received arthroscopic treatment for single versus multiple anterior shoulder dislocations. MethodsThis is a retrospective chart review of patients who underwent arthroscopic labral repair of the shoulder by six surgeons at a single institution between 2012-2020. Patients with a documented anterior shoulder dislocation were included. Patients with pain-only, subluxation-only, multi-directional or posterior instability, and prior shoulder surgeries of any kind were excluded. Studied variables included age, sex, laterality, body mass index, contact/collision sports, Charlson Comorbidity Index, tobacco use, number of dislocations (1, >1), labral tear size, time from first dislocation to surgery, anchor number, and concomitant procedures. Study groups were compared using student’s t-tests and Mann-Whitney U test for continuous variables and Chi-Square or Fisher’s Exact tests for discrete variables with a significance of 0.05. Results633 patients were identified and 351 [85 single dislocators (SD), 266 multiple dislocators (MD)] met inclusion criteria (mean age: 27 years; range: 14-71 years). There were no demographic differences between study groups. SD received surgery significantly sooner at 17 ± 44 months after injury, while MD received surgery 53 ± 74 months post-initial dislocation. SD (30/85, 35%) were significantly more likely than MD (56/266, 21%) to receive concomitant posterior labrum repair. MD (46/266, 17%) were significantly more likely than SD (5/85, 6%) to receive a Remplissage. SD (11/85, 13%) were significantly more likely than MD (11/266, 4%) to receive a concomitant biceps tenotomy/tenodesis. There were no other significant differences in injury or surgery characteristics. ConclusionMD will have more time between their initial dislocation and arthroscopic labral repair and were more likely to receive a Remplissage procedure, yet were less likely than SD to receive a concomitant posterior labral repair or biceps tenodesis/tenotomy despite no differences in age, sex, and activity level. Whether the greater extent of labrum injury in SD is due to a more severe initial injury versus earlier recognition and intervention requires further study.

Return to sport after arthroscopic xenograft bone block associated with Bankart repair and subscapularis augmentation in competitive contact athletes with recurrent anterior shoulder instability

BackgroundOpen Bankart repair and Latarjet stabilization are two of surgical procedures used in the treatment of shoulder instability in contact athletes. The aim of this study is to evaluate the outcomes of bone block arthroscopic procedure, performed with xenograft, in combination with Bankart repair and selective subscapularis augmentation (ASA) for contact athletes with recurrent anterior shoulder instability. MethodsWe retrospectively assessed contact athletes who underwent arthroscopic bone block with xenograft and Bankart repair with selective augmentation of subscapularis for recurrent anterior shoulder instability between January 2017 and December 2021. Shoulders with posterior instability or multidirectional instability were excluded. Recurrence, complications, return to sport, and functional scores (Rowe score, WOSI score, ASES score) were assessed. A CT scan at 2-year follow-up was performed to assess the status of Bone block integration, its displacement and restoration of glenoid surface. Results16 patients were included in the study with a mean age of 24. None of the patients treated with arthroscopic bone block and ASA presented new dislocation episodes. An increase in preoperative scores was observed at the last follow-up, in particular the ASES, Rowe, and WOSI scores increased from 69±7, 31±9 , 1235±46 respectively to 96.1±3.2, 94±6, 119±51. All athletes returned to sporting activity at or near the same level as pre-surgery. The glenoid bone surface increase from 83% to 116% at last follow-up. ConclusionBone block treatment with Xenograft combined with Bankart repair and ASA procedures has been shown to be effective in treating instability in contact athletes with significant glenoid deficit. All athletes returned to athletic activity at a level similar to the pre-intervention period.

Poster 113: Posterior Acromial Bone Block is Biomechanically Superior to Posterior Labral Repair and Favorably Alters Acromial Morphology in a Posterior Glenohumeral Instability Model: A Cadaveric Biomechanical Study

Poster 113: Posterior Acromial Bone Block is Biomechanically Superior to Posterior Labral Repair and Favorably Alters Acromial Morphology in a Posterior Glenohumeral Instability Model: A Cadaveric Biomechanical Study

Paper 42: No Difference in Acromial Morphology in Primary versus Revision Posterior Shoulder Instability Patients

Paper 42: No Difference in Acromial Morphology in Primary versus Revision Posterior Shoulder Instability Patients

Batter's Shoulder: Diagnosis, Management, and Outcomes.

Batter's shoulder is characterized by posterior shoulder instability in the lead (front) shoulder of a batting athlete. This most commonly occurs as a discrete event, particularly a swing and miss at an outside pitch, which leads to an episode of shoulder subluxation. A thorough history and physical examination is key to diagnosis, with patients feeling pain and instability of the lead shoulder when attempting the baseball swing or during pushing-type activities, as well as positive posterior labral signs in tests such as the Kim, jerk, and modified dynamic labral shear tests. Magnetic resonance imaging can confirm the diagnosis of posterior labral tear and may show concomitant pathologies such as a reverse Hill-Sachs lesion. Nonsurgical treatment is directed at rotator cuff and scapular strengthening; however, arthroscopic posterior labral repair is often required for definitive stabilization. Overall, this is a relatively rare diagnosis, but outcomes of surgical repair are favorable with high satisfaction and rates of return to competition.