Factors Associated With Humeral Avulsion of Glenohumeral Ligament Lesions in Patients With Anterior Shoulder Instability: An Analysis of the MOON Shoulder Instability Cohort.

Background: Humeral avulsion of the glenohumeral ligament (HAGL) lesions are an uncommon cause of anterior glenohumeral instability and may occur in isolation or combination with other pathologies. As HAGL lesions are difficult to detect via magnetic resonance imaging (MRI) and arthroscopy, they can remain unrecognized and result in continued glenohumeral instability. Purpose: To compare patients with anterior shoulder instability from a large multicenter cohort with and without a diagnosis of a HAGL lesion and identify preoperative physical examination findings, patient-reported outcomes, imaging findings, and surgical management trends associated with HAGL lesions. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Patients with anterior glenohumeral instability who underwent surgical management between 2012 and 2020 at 11 orthopaedic centers were enrolled. Patients with HAGL lesions identified intraoperatively were compared with patients without HAGL lesions. Preoperative characteristics, physical examinations, imaging findings, intraoperative findings, and surgical procedures were collected. The Student t test, Kruskal-Wallis H test, Fisher exact test, and chi-square test were used to compare groups. Results: A total of 21 HAGL lesions were identified in 915 (2.3%) patients; approximately one-third (28.6%) of all lesions were visualized intraoperatively but not identified on preoperative MRI. Baseline characteristics did not differ between study cohorts. Compared with non-HAGL patients, HAGL patients were less likely to have a Hill-Sachs lesion (54.7% vs 28.6%; P = .03) or an anterior labral tear (87.2% vs 66.7%; P = .01) on preoperative MRI and demonstrated increased external rotation when their affected arm was positioned at 90° of abduction (85° vs 90°; P = .03). Additionally, HAGL lesions were independently associated with an increased risk of undergoing an open stabilization surgery (odds ratio, 74.6 [95% CI, 25.2-221.1]; P < .001). Conclusion: Approximately one-third of HAGL lesions were missed on preoperative MRI. HAGL patients were less likely to exhibit preoperative imaging findings associated with anterior shoulder instability, such as Hill-Sachs lesions or anterior labral pathology. These patients underwent open procedures more frequently than patients without HAGL lesions.

Development and Validation of a Short-Form Version of the Western Ontario Shoulder Instability Scale (Short-WOSI).

BACKGROUND: Patient-reported outcome measures (PROMs) have transitioned from primarily being used as research instruments to becoming increasingly used in the clinical setting to assess recovery and inform shared decision-making. However, there is a need to develop validated short-form PROM instruments to decrease patient burden and ease incorporation into clinical practice. PURPOSE: To assess the validity and responsiveness of a shortened version of the Western Ontario Shoulder Instability Index (Short-WOSI) when compared with the full WOSI and other shoulder-related PROM instruments. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 2. METHODS: This study was a secondary analysis of data collected as part of an institutional review board-approved, multicenter cohort of 1160 patients undergoing surgical stabilization for shoulder instability. The following PROMs were captured preoperatively and 2 years after surgery: WOSI, American Shoulder and Elbow Surgeons (ASES) score, the Single Assessment Numeric Evaluation (SANE), and 36-Item Health Survey (RAND-36). The cohort was split into 2 data sets: a training set to be used in the development of the Short-WOSI (n = 580) and a test set to be used to assess the validity and responsiveness of the Short-WOSI relative to the full WOSI, ASES, SANE, and RAND-36. RESULTS: The Short-WOSI demonstrated excellent internal consistency before surgery (Cronbach α = .83) and excellent internal consistency at the 2-year follow-up (Cronbach α = .93). The baseline, 2-year, and pre- to postoperative changes in Short-WOSI and WOSI were closely correlated (r > 0.90), with both demonstrating large effect sizes (Short-WOSI = 1.92, WOSI = 1.81). Neither the Short-WOSI nor the WOSI correlated well with the other PROM instruments before (r = 0.21-0.33) or after (r = 0.25-0.38) surgery. The Short-WOSI, WOSI, and SANE scores were more responsive than ASES and RAND-36 scores. CONCLUSION: The 7-item Short-WOSI demonstrated excellent internal consistency and a lack of floor or ceiling effects. The Short-WOSI demonstrated excellent cross-sectional and longitudinal construct validity and was similarly responsive over time as the full WOSI. Neither the Short-WOSI nor WOSI correlated with more general shoulder PROMs, underscoring the advantage of using instability-specific instruments for this population.

Predictors of Bone Loss in Anterior Glenohumeral Instability.

BACKGROUND: Anterior shoulder instability can result in bone loss of both the anterior glenoid and the posterior humerus. Bone loss has been shown to lead to increased failure postoperatively and may necessitate more complex surgical procedures, resulting in worse clinical outcomes and posttraumatic arthritis. HYPOTHESIS/PURPOSE: The purpose of this study was to investigate predictors of glenoid and humeral head bone loss in patients undergoing surgery for anterior shoulder instability. It was hypothesized that male sex, contact sport participation, traumatic dislocation, and higher number of instability events would be associated with greater bone loss. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A total of 892 patients with anterior shoulder instability were prospectively enrolled in the Multicenter Orthopaedic Outcomes Network (MOON) Shoulder Instability cohort. The presence and amount of anterior glenoid bone loss and accompanying Hill-Sachs lesions were quantified. Descriptive information and injury history were used to construct proportional odds models for the presence of any bone defect, for defects >10% of the anterior glenoid or humeral head, and for combined bony defects. RESULTS: Anterior glenoid bone loss and Hill-Sachs lesions were present in 185 (20.7%) and 470 (52.7%) patients, respectively. Having an increased number of dislocations was associated with bone loss in all models. Increasing age, male sex, and non-White race were associated with anterior glenoid bone defects and Hill-Sachs lesions. Contact sport participation was associated with anterior glenoid bone loss, and Shoulder Actitvity Scale with glenoid bone loss >10%. A positive apprehension test was associated with Hill-Sachs lesions. Combined lesions were present in 19.4% of patients, and for every additional shoulder dislocation, the odds of having a combined lesion was 95% higher. CONCLUSION: An increasing number of preoperative shoulder dislocations is the factor most strongly associated with glenoid bone loss, Hill-Sachs lesions, and combined lesions. Early surgical stabilization before recurrence of instability may be the most effective method for preventing progression to clinically significant bone loss. Patients should be made aware of the expected course of shoulder instability, especially in athletes at high risk for recurrence and osseous defects, which may complicate care and worsen outcomes. REGISTRATION: NCT02075775 (ClinicalTrials.gov identifier).

Psychosocial factors play a greater role in preoperative symptoms for patients with atraumatic shoulder instability: data from the MOON-Shoulder Instability group.

BACKGROUND: Previous studies have demonstrated that psychosocial factors and comorbid depression are associated with worse preoperative baseline measures, clinical outcomes, and recovery in patients undergoing shoulder surgery. It is unknown whether this potential link would differ between those with traumatic vs. atraumatic shoulder instability, as symptoms may persist longer in atraumatic instability prior to surgical intervention. The purpose of this study was to determine if psychosocial factors and/or comorbid depression more heavily influence preoperative symptoms for patients with traumatic vs. atraumatic shoulder instability. METHODS: Prospective baseline data from 1552 patients in the Multicenter Orthopaedic Outcomes Network (MOON) Shoulder Instability cohort were analyzed based on mechanism of injury while controlling for age, sex, and direction of instability. Multivariable linear regressions were performed to determine whether psychological factors (RAND 36 Mental Component Score [MCS], depression diagnosis, Personality Assessment Screener-22) were predictive of preoperative American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) and Western Ontario Shoulder Instability Index (WOSI) scores in the atraumatic group. The same model was repeated for the traumatic instability group, and the model fit was compared between groups, with P < .05 considered statistically significant. RESULTS: Female sex and lower MCS were significantly associated with worse preoperative ASES and WOSI scores for the group with atraumatic instability (ASES R2 = 0.15, P < .001; WOSI R2 = 0.17, P < .001). The same model performed significantly worse (P < .05) for both ASES and WOSI scores in the group with traumatic instability (ASES R2 = 0.07, WOSI R2 = 0.08). CONCLUSIONS: Worse preoperative psychosocial factors were found to be more strongly associated with shoulder-related pain and function for patients with atraumatic instability. Across multiple orthopedic conditions, depression and emotional well-being have been associated with worse preoperative symptoms and inferior postoperative patient-reported outcomes. Despite the stronger and significant association in atraumatic patients, worse psychosocial factors did not have as large an impact as has been seen in other, more chronic conditions such as osteoarthritis or rotator cuff tears. In addition to medically optimizing patients prior to surgery, the current findings identify a subset of shoulder instability patients that may benefit from a behavioral health intervention either prior to surgery or early in the postoperative period to potentially improve postoperative outcomes.

Factors Associated With Shoulder Activity Level at Time of Surgery and at 2-Year Follow-up in Patients Undergoing Shoulder Stabilization Surgery.

BACKGROUND: Patients undergoing shoulder stabilization surgery have been shown to have elevated activity levels. Factors associated with shoulder activity in this patient population at baseline and after surgery are unknown. HYPOTHESIS: Patient-specific variables are associated with shoulder activity level at baseline and at 2-year follow-up in a cohort of patients undergoing shoulder stabilization surgery. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: Patients undergoing shoulder stabilization surgery were prospectively enrolled. As part of the data collection process, patients completed a previously validated Shoulder Activity Scale. A regression analysis was performed to assess the association of patient characteristics with baseline and 2-year follow-up shoulder activity levels. RESULTS: A total of 764 (n = 612 men, n = 152 women) out of 957 patients (80%) undergoing shoulder stabilization surgery with a median age of 25 years had baseline and 2-year follow-up data and were included in the current analysis. The baseline shoulder activity level was associated with race ( P < .0001) and preoperative duration of instability (P < .0001). At 2 years, 52% of the cohort had returned to the same or higher activity level after surgery. Predictors of higher shoulder activity level at 2-year follow-up included higher baseline activity level (P < .0001), male sex (P < .0001), younger age (P = .004), higher body mass index (BMI) (P = .03), more dislocations (P = .03), nonsmokers (P = .04), and race (P = .04). CONCLUSION: A longer duration of preoperative symptoms was associated with a lower baseline activity in this cohort. High baseline preoperative shoulder activity, younger age, male sex, higher BMI, number of dislocations, and nonsmoking status predicted higher shoulder activity 2 years after shoulder stabilization surgery. REGISTRATION: NCT02075775 (ClinicalTrials.gov identifier).

Beach Chair Versus Lateral Decubitus Position: Differences in Suture Anchor Position and Number During Arthroscopic Anterior Shoulder Stabilization.

BACKGROUND: Arthroscopic shoulder capsulolabral repair using glenoid-based suture anchor fixation provides consistently favorable outcomes for patients with anterior glenohumeral instability. To optimize outcomes, inferior anchor position, especially at the 6-o'clock position, has been emphasized. Proponents of both the beach-chair (BC) and lateral decubitus (LD) positions advocate that this anchor location can be consistently achieved in both positions. HYPOTHESIS: Patient positioning would be associated with the surgeon-reported labral tear length, total number of anchors used, number of anchors in the inferior glenoid, and placement of an anchor at the 6-o'clock position. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: This study was a cross-sectional analysis of a prospective multicenter cohort of patients undergoing primary arthroscopic anterior capsulolabral repair. Patient positioning in the BC versus LD position was determined by the operating surgeon and was not randomized. At the time of operative intervention, surgeon-reported labral tear length, total anchor number, anchor number in the inferior glenoid, and anchor placement at the 6-o'clock position were evaluated between BC and LD cohorts. Descriptive statistics and between-group differences (continuous: t test [normal distributions], Wilcoxon rank sum test [nonnormal distributions], and chi-square test [categorical]) were assessed. RESULTS: In total, 714 patients underwent arthroscopic anterior capsulolabral repair (BC vs LD, 406 [56.9%] vs 308 [43.1%]). The surgeon-reported labral tear length was greater for patients having surgery in the LD position (BC vs LD [mean ± SD], 123.5°± 49° vs 132.3°± 44°; P = .012). The LD position was associated with more anchors placed in the inferior glenoid and more frequent placement of anchors at the 6-o'clock (BC vs LD, 22.4% vs 51.6%; P < .001). The LD position was more frequently associated with utilization of ≥4 total anchors (BC vs LD, 33.5% vs 46.1%; P < .001). CONCLUSION: Surgeons utilizing the LD position for arthroscopic capsulolabral repair in patients with anterior shoulder instability more frequently placed anchors in the inferior glenoid and at the 6-o'clock position. Additionally, surgeon-reported labral tear length was longer when utilizing the LD position. These results suggest that patient positioning may influence the total number of anchors used, the number of anchors used in the inferior glenoid, and the frequency of anchor placement at the 6 o'clock position during arthroscopic capsulolabral repair for anterior shoulder instability. How these findings affect clinical outcomes warrants further study. REGISTRATION: NCT02075775 (ClinicalTrials.gov identifier).

Are there racial differences between patients undergoing surgery for shoulder instability? Data from the Multicenter Orthopaedic Outcomes Network (MOON) Shoulder Instability Group.

BACKGROUND: The purpose of this study was to identify differences related to race in preoperative and intraoperative findings of patients undergoing operative treatment for shoulder instability. METHODS: Data from the Multicenter Orthopaedic Outcomes Network (MOON) Shoulder Instability cohort were used. Of 1010 patients, 995 provided race and ethnicity information and were included in the analyses. Demographic characteristics, injury history, radiographic and intraoperative findings, and preoperative patient-reported instability, pain, and function were compared (1) between white and minority patients and (2) in a subgroup analysis between white patients and the 3 largest minority groups. The Distressed Communities Index (DCI) score was recorded for each patient's home ZIP code. Multiple logistic regressions were performed to determine whether models consisting of race/ethnicity, insurance carrier, and/or DCI score were predictive of bone and cartilage loss at the time of surgery. RESULTS: Compared with white patients, a greater percentage of US minority patients had ≥2 dislocations (68.0% vs. 57.1%, P = .01), which corresponded with more frequent articular cartilage lesions (62.2% vs. 51.0%, P = .007) and increased frequencies of glenoid bone loss > 10% (16.2% vs. 8.7%, P = .03) and Hill-Sachs lesions (68.6% vs. 56.0%, P = .004). Specifically, when compared with white patients, African American and Asian patients showed significantly increased frequencies of glenoid bone loss > 10% (19.7% of African American patients, 18.4% of Asian patients, and 8.9% of white patients; P = .01) and Hill-Sachs lesions (65.6%, 71.7%, and 52.4%, respectively; P = .02). Race was an independent predictor of articular cartilage lesions (P = .04) and the presence of Hill-Sachs lesions (P = .01). A higher DCI score (P = .03) and race (P = .04) were both predictive of having glenoid bone loss > 10%. CONCLUSION: We found that minority race was associated with increased number of preoperative dislocations and increased frequency of articular cartilage and Hill-Sachs lesions at the time of surgery, and both minority race and an increased DCI score were associated with glenoid bone loss > 10%. Further research is needed to understand the underlying reason for these differences and to optimize care for all patients with shoulder instability.

Surgical Stabilization of Shoulder Instability in Patients With or Without a History of Seizure: A Comparative Analysis.

PURPOSE: To compare patients from a large multicenter cohort with a history of seizure and those without a history of seizure regarding preoperative and intraoperative findings and surgical procedures performed. METHODS: Patients undergoing shoulder stabilization from 2011 to 2018 at 11 orthopaedic centers were prospectively enrolled. Those with a history of seizure were identified and compared with non-seizure controls. Preoperative demographic, history, physical examination, and imaging findings were collected. Intraoperative findings and surgical procedures performed were recorded. The Mann-Whitney test, χ2 test, and logistic regression analysis were used to examine differences between the groups and define independent risk factors. Owing to the number of statistical tests performed, the false discovery method was used to determine adjusted P values to achieve α < .05. RESULTS: During enrollment, 25 of 1,298 shoulder stabilization patients (1.9%) had a history of seizure. The sex ratio and age were similar between groups, as was posterior instability incidence (23.2% in control group vs 28.0% in seizure group). Seizure patients more frequently had more than 5 dislocations in the year preceding surgery (P = .016) and had increased preoperative radiographic evidence of bone loss (P < .001). Intraoperatively, seizure patients had a higher prevalence of reverse Hill-Sachs lesions (P < .001) and large (>30% of glenoid fossa) bony Bankart lesions (P < .001). Arthroscopic Bankart repair was the most common procedure in both groups. However, open procedures were performed in 15.6% of controls and 40.0% of seizure patients (P = .001). These procedures were most commonly bony procedures. CONCLUSIONS: Seizure patients had more prior dislocations, had more preoperative bone loss, and underwent more open stabilization procedures than controls because of bone loss. Studies examining recurrence after stabilization will help establish appropriate management practices in this population. LEVEL OF EVIDENCE: Level III, retrospective review of prospectively collected cohort.

Surgical outcomes in the Frequency, Etiology, Direction, and Severity (FEDS) classification system for shoulder instability.

BACKGROUND: The Frequency, Etiology, Direction, and Severity (FEDS) system was developed as a simple but reliable method for classifying shoulder instability based on 4 factors attainable by history and physical examination: frequency (solitary, occasional, or frequent); etiology (traumatic or atraumatic); direction (anterior, posterior, or inferior); and severity (subluxation or dislocation). This study investigated the epidemiology and 2-year surgical outcomes for the FEDS categories in the prospective Multicenter Orthopaedic Outcomes Network (MOON) Shoulder Instability cohort. METHODS: At the time of surgery, 1204 patients were assigned to the FEDS categories. Follow-up data were available for 636 of 734 patients (86.6%) who had undergone surgery at least 2 years prior to analysis. The most common categories were further analyzed by patient-reported outcomes (PROs) (American Shoulder and Elbow Surgeons, Western Ontario Shoulder Instability index, Single Assessment Numeric Evaluation scores) and rates of recurrent subluxation, recurrent dislocation, and revision surgery. RESULTS: Of the 36 FEDS categories, 16 represented at least 1% of patients. Occasional traumatic anterior dislocation (OTAD) was the most common category, with 16.4% of patients. Five other anterior categories (solitary traumatic anterior subluxation, occasional traumatic anterior subluxation [OTAS], frequent traumatic anterior subluxation [FTAS], solitary traumatic anterior dislocation, and frequent traumatic anterior dislocation) and one posterior category (solitary traumatic posterior subluxation [STPS]) represented at least 5% of patients. PROs improved significantly for each category. The highest rates of recurrent subluxation occurred in FTAS, OTAS, and OTAD cases; dislocation, OTAS and FTAS cases; and further surgery, OTAD cases. The lowest rates of failure occurred in STPS cases. Downward trends in PROs and higher failure rates were noted with an increasing number of preoperative dislocations. CONCLUSION: Different FEDS categories showed varying degrees of improvement and failure rates, indicating that the system can be used to provide prognostic insight for presurgical education. Overall, outcomes decreased with a higher number of preoperative dislocations.

Risk Factors for Intra-articular Bone and Cartilage Lesions in Patients Undergoing Surgical Treatment for Posterior Instability.

BACKGROUND: Patients with posterior shoulder instability may have bone and cartilage lesions (BCLs) in addition to capsulolabral injuries, although the risk factors for these intra-articular lesions are unclear. HYPOTHESIS: We hypothesized that patients with posterior instability who had a greater number of instability events would have a higher rate of BCLs compared with patients who had fewer instability episodes. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Data from the Multicenter Orthopaedic Outcomes Network (MOON) Shoulder Group instability patient cohort were analyzed. Patients aged 12 to 99 years undergoing primary surgical treatment for shoulder instability were included. The glenohumeral joint was evaluated by the treating surgeon at the time of surgery, and patients were classified as having a BCL if they had any grade 3 or 4 glenoid or humeral cartilage lesion, reverse Hill-Sachs lesion, bony Bankart lesion, or glenoid bone loss. The effects of the number of instability events on the presence of BCLs was investigated by use of Fisher exact tests. Logistic regression modeling was performed to investigate the independent contributions of demographic variables and injury-specific variables to the likelihood of having a BCL. Significance was defined as P < .05. RESULTS: We identified 271 patients (223 male) for analysis. Bone and cartilage lesions were identified in 54 patients (19.9%) at the time of surgical treatment. A glenoid cartilage injury was most common and was identified in 28 patients (10.3%). A significant difference was noted between the number of instability events and the presence of BCLs (P = .025), with the highest rate observed in patients with 2 to 5 instability events (32.3%). Multivariate logistic regression modeling indicated that increasing age (P = .019) and 2 to 5 reported instability events (P = .001) were significant independent predictors of the presence of BCLs. For bone lesions alone, the number of instability events was the only significant independent predictor; increased risk of bone lesion was present for patients with 1 instability event (OR, 6.1; P = .012), patients with 2 to 5 instability events (OR, 4.2; P = .033), and patients with more than 5 instability events (OR, 6.0; P = .011). CONCLUSION: Bone and cartilage lesions are seen significantly more frequently with increasing patient age and in patients with 2 to 5 instability events. Early surgical stabilization for posterior instability may be considered to potentially limit the extent of associated intra-articular injury. The group of patients with more than 5 instability events may represent a different pathological condition, as this group showed a decrease in the likelihood of cartilage injury, although not bony injury.

Are Patients Who Undergo the Latarjet Procedure Ready to Return to Play at 6 Months? A Multicenter Orthopaedic Outcomes Network (MOON) Shoulder Group Cohort Study.

BACKGROUND: The Latarjet procedure is growing in popularity for treating athletes with recurrent anterior shoulder instability, largely because of the high recurrence rate of arthroscopic stabilization, particularly among contact athletes with bone loss. PURPOSE: (1) To evaluate return of strength and range of motion (ROM) 6 months after the Latarjet procedure and (2) to determine risk factors for failure to achieve return-to-play (RTP) criteria at 6 months. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: A total of 65 athletes (83% contact sports, 37% overhead sports; mean ± SD age, 24.5 ± 8.2 years; 59 male, 6 female) who enrolled in a prospective multicenter study underwent the Latarjet procedure for anterior instability (29% as primary procedure for instability, 71% for failed prior stabilization procedure). Strength and ROM were assessed preoperatively and 6 months after surgery. RTP criteria were defined as return to baseline strength and <20° side-to-side ROM deficits in all planes. The independent likelihood of achieving strength and motion RTP criteria at 6 months was assessed through multivariate logistic regression modeling with adjustment as needed for age, sex, subscapularis split versus tenotomy, preoperative strength/motion, percentage bone loss, number of prior dislocations, preoperative subjective shoulder function (American Shoulder and Elbow Surgeons and Western Ontario Shoulder Instability Index percentage), and participation in contact versus overhead sports. RESULTS: Of the patients, 55% failed to meet ≥1 RTP criteria: 6% failed for persistent weakness and 51% for ≥20° side-to-side loss of motion. There was no difference in failure to achieve RTP criteria at 6 months between subscapularis split (57%) versus tenotomy (47%) (P = .49). Independent risk factors for failure to achieve either strength or ROM criteria were preoperative American Shoulder and Elbow Surgeons scores (per 10-point decrease: adjusted odds ratio [aOR], 1.61; 95% CI, 1.14-2.43; P = .006), Western Ontario Shoulder Instability Index percentage (per 10% decrease: aOR, 0.61; 95% CI, 0.38-0.92; P = .01), and a preoperative side-to-side ROM deficit ≥20° in any plane (aOR, 5.01; 95% CI, 1.42-21.5; P = .01) or deficits in external rotation at 90° of abduction (per 10° increased deficit: aOR, 1.64; 95% CI, 1.06-2.88; P = .02). CONCLUSION: A large percentage of athletes fail to achieve full strength and ROM 6 months after the Latarjet procedure. Greater preoperative stiffness and subjective disability are risk factors for failure to meet ROM or strength RTP criteria.

The Prevalence and Clinical Implications of Comorbid Back Pain in Shoulder Instability: A Multicenter Orthopaedic Outcomes Network (MOON) Shoulder Instability Cohort Study.

BACKGROUND: Understanding predictors of pain is critical, as recent literature shows that comorbid back pain is an independent risk factor for worse functional and patient-reported outcomes (PROs) as well as increased opioid dependence after total joint arthroplasty. PURPOSE/HYPOTHESIS: The purpose of this study was to evaluate whether comorbid back pain would be predictive of pain or self-reported instability symptoms at the time of stabilization surgery. We hypothesized that comorbid back pain will correlate with increased pain at the time of surgery as well as with worse scores on shoulder-related PRO measures. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: As part of the Multicenter Orthopaedic Outcomes Network (MOON) Shoulder Instability cohort, patients consented to participate in pre- and intraoperative data collection. Demographic characteristics, injury history, preoperative PRO scores, and radiologic and intraoperative findings were recorded for patients undergoing surgical shoulder stabilization. Patients were also asked, whether they had any back pain. RESULTS: The study cohort consisted of 1001 patients (81% male; mean age, 24.1 years). Patients with comorbid back pain (158 patients; 15.8%) were significantly older (28.1 vs 23.4 years; P < .001) and were more likely to be female (25.3% vs 17.4%; P = .02) but did not differ in terms of either preoperative imaging or intraoperative findings. Patients with self-reported back pain had significantly worse preoperative pain and shoulder-related PRO scores (American Shoulder and Elbow Surgeons score, Western Ontario Shoulder Instability Index) (P < .001), more frequent depression (22.2% vs 8.3%; P < .001), poorer mental health status (worse scores for the RAND 36-Item Health Survey Mental Component Score, Iowa Quick Screen, and Personality Assessment Screener) (P < .01), and worse preoperative expectations (P < .01). CONCLUSION: Despite having similar physical findings, patients with comorbid back pain had more severe preoperative pain and self-reported symptoms of instability as well as more frequent depression and lower mental health scores. The combination of disproportionate shoulder pain, comorbid back pain and mental health conditions, and inferior preoperative expectations may affect not only the patient's preoperative state but also postoperative pain control and/or postoperative outcomes.

Preoperative Validation of the Patient-Reported Outcomes Measurement Information System in Patients With Articular Cartilage Defects of the Knee.

PURPOSE: To validate the Patient-Reported Outcomes Measurement Information System (PROMIS) physical function computer adaptive test (PF CAT) with current patient-reported outcome (PRO) instruments in patients with cartilage injuries of the knee. METHODS: Patients scheduled for osteochondral autograft or allograft transplant, microfracture, autologous chondrocyte implantation, allograft cartilage resurfacing, and chondroplasty were prospectively enrolled in the study and completed PROMIS PF CAT, Knee Injury and Osteoarthritis Outcome Score (KOOS activities of daily living, pain, symptoms, sport, and quality of life), Short Form-36 Health Survey (SF-36 physical function [PF] and Physical Component Summary), and EuroQol-5 Dimension questionnaires. The Spearman correlation coefficient was used to compare instruments. Instrument correlations were defined as excellent (>0.7), excellent to good (0.61-0.69), good (0.4 to 0.6), and poor (<0.39), with significance defined as P < .05. RESULTS: A total of 293 knees in 275 patients (54.5% male) undergoing 319 cartilage procedures were analyzed. The most commonly performed cartilage procedure was chondroplasty (n = 118; 37.0%), followed by microfracture (n = 100; 31.3%). The mean age was 34.0 ± 14.7 and the mean body mass index was 30.0 ± 6.9. The PROMIS PF CAT had an excellent correlation with the SF-36 PF (r = 0.819; P < .001), SF-36 Physical Component Summary (r = 0.766; P < .001), KOOS activities of daily living (r = 0.733; P < .001), KOOS Sport (r = 0.709; P < .001), and EuroQol-5 Dimension (r = 0.752; P < .001) instruments; an excellent-good correlation with the KOOS pain (r = 0.662; P < .001), and KOOS quality of life (r = 0.640; P < .001) scores; and a good correlation with the KOOS symptoms (r = 0.519; P < .001) scale. The PROMIS PF CAT had no floor or ceiling effects and the smallest question burden (mean 4.17 ± 0.93 questions). Dimensionality analyses demonstrated that the smallest amount of unexplained variance was present in the PROMIS PF CAT (3.6%). CONCLUSION: The PROMIS PF CAT is an effective tool for preoperative outcome assessment in patients with cartilage defects of the knee. It correlates strongly with legacy PRO measures of physical function with no ceiling and floor effects and a minimal time burden for completion. Further study is warranted to determine postoperative performance and to evaluate the responsiveness of PROMIS to change within a patient. LEVEL OF EVIDENCE: III; Prognostic retrospective comparative study.

Clinical Outcomes After Anterior Shoulder Stabilization in Overhead Athletes: An Analysis of the MOON Shoulder Instability Consortium.

BACKGROUND: Traumatic anterior shoulder instability is a common condition affecting sports participation among young athletes. Clinical outcomes after surgical management may vary according to patient activity level and sport involvement. Overhead athletes may experience a higher rate of recurrent instability and difficulty returning to sport postoperatively with limited previous literature to guide treatment. PURPOSE: To report the clinical outcomes of patients undergoing primary arthroscopic anterior shoulder stabilization within the Multicenter Orthopaedic Outcomes Network (MOON) Shoulder Instability Consortium and to identify prognostic factors associated with successful return to sport at 2 years postoperatively. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Overhead athletes undergoing primary arthroscopic anterior shoulder stabilization as part of the MOON Shoulder Instability Consortium were identified for analysis. Primary outcomes included the rate of recurrent instability, defined as any patient reporting recurrent dislocation or reoperation attributed to persistent instability, and return to sport at 2 years postoperatively. Secondary outcomes included the Western Ontario Shoulder Instability Index and Kerlan-Jobe Orthopaedic Clinic Shoulder and Elbow questionnaire score. Univariate regression analysis was performed to identify patient and surgical factors predictive of return to sport at short-term follow-up. RESULTS: A total of 49 athletes were identified for inclusion. At 2-year follow-up, 31 (63%) athletes reported returning to sport. Of those returning to sport, 22 athletes (45% of the study population) were able to return to their previous levels of competition (nonrefereed, refereed, or professional) in at least 1 overhead sport. Two patients (4.1%) underwent revision stabilization, although 14 (28.6%) reported subjective apprehension or looseness. Age ( P = .87), sex ( P = .82), and baseline level of competition ( P = .37) were not predictive of return to sport. No difference in range of motion in all planes ( P > .05) and Western Ontario Shoulder Instability Index scores (78.0 vs 80.1, P = .73) was noted between those who reported returning to sport and those who did not. CONCLUSION: Primary arthroscopic anterior shoulder stabilization in overhead athletes is associated with a low rate of recurrent stabilization surgery. Return to overhead athletics at short-term follow-up is lower than that previously reported for the general athletic population.

Sex-related differences in patients undergoing surgery for shoulder instability: a Multicenter Orthopaedic Outcomes Network (MOON) Shoulder Instability cohort study.

HYPOTHESIS AND BACKGROUND: Male sex has been identified as a risk factor for both primary shoulder dislocation and recurrent instability, and male patients more often undergo surgery for instability. Despite published discrepancies between sexes regarding the incidence and surgical rates of shoulder instability, there is little detail on the differences in presentation, mechanism of injury, and intraoperative findings. The purpose of this study was to explore these differences. METHODS: Prospective baseline data from 1010 patients in the Multicenter Orthopaedic Outcomes Network (MOON) Shoulder Instability cohort were analyzed for sex-related differences using demographic characteristics, patient-reported outcomes, radiographic findings, intraoperative findings, and surgical procedures performed. Two-tailed t tests and χ2 tests were used to compare the continuous and categorical data, respectively. Patients were categorized using the Frequency, Etiology, Direction, Severity (FEDS) classification system. RESULTS: Male patients comprised 81.3% of the cohort. Male patients had a significantly higher rate of traumatic instability and rate of initial instability while playing sports, as well as significantly higher activity scores. Female patients had significantly lower preoperative American Shoulder and Elbow Surgeons, Western Ontario Shoulder Instability Index, 36-Item Health Survey, and Single Assessment Numeric Evaluation scores. No difference in the number of dislocations was found between male and female patients. Intraoperatively, male patients had higher rates of labral pathology and bone loss whereas female patients had higher rates of capsular laxity. These differences resulted in more Latarjet procedures for male patients and more soft-tissue procedures for female patients. CONCLUSION: There are differences between male and female patients in the etiology of their instability, baseline patient-reported outcomes, and associated shoulder pathology, likely reflecting intrinsic and activity-related variation. These differences may influence clinical decision making and patient outcomes.

Descriptive Epidemiology of the MOON Shoulder Instability Cohort.

BACKGROUND: Shoulder instability is a common diagnosis among patients undergoing shoulder surgery. PURPOSE: To perform a descriptive analysis of patients undergoing surgery for shoulder instability through a large multicenter consortium. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: All patients undergoing surgery for shoulder instability who were enrolled in the MOON Shoulder Instability Study were included. Baseline demographics included age, sex, body mass index, and race. Baseline patient-reported outcomes (PROs) included the American Shoulder and Elbow Surgeons (ASES) score, Shoulder Activity Score, Western Ontario Shoulder Instability Index (WOSI), 36-Item Health Survey (RAND-36), and Single Assessment Numeric Evaluation (SANE). The preoperative physician examination included active range of motion (ROM) and strength testing. Preoperative imaging assessments with plain radiography, magnetic resonance imaging (MRI), and computed tomography were also included and analyzed. RESULTS: Twenty-six surgeons had enrolled 863 patients (709 male, 154 female) across 10 clinical sites. The mean age for the cohort was 24 years (range, 12-63 years). Male patients represented 82% of the cohort. The primary direction of instability was anterior for both male (74%) and female (73%) patients. Football (24%) and basketball (13%) were the most common sports in which the primary shoulder injury occurred. No clinically significant differences were found in preoperative ROM between the affected and unaffected sides for any measurement taken. Preoperative MRI scans were obtained in 798 patients (92%). An anterior labral tear was the most common injury found on preoperative MRI, seen in 66% of patients, followed by a Hill-Sachs lesion in 41%. Poor PRO scores were recorded preoperatively (mean: ASES, 72.4; WOSI, 43.3; SANE, 46.6). CONCLUSION: The MOON Shoulder Instability Study has enrolled the largest cohort of patients undergoing shoulder stabilization to date. Anterior instability is most common among shoulder instability patients, and most patients undergoing shoulder stabilization are in their early 20s or younger. The results of this study provide important epidemiological information for patients undergoing shoulder stabilization surgery.

Surgical stabilization for first-time shoulder dislocators: a multicenter analysis.

BACKGROUND: Anterior shoulder dislocations in young patients are associated with high rates of recurrent instability. Although some surgeons advocate for surgical stabilization after a single dislocation event in this population, there is sparse research evaluating surgical treatment for first-time dislocators. METHODS: Patients undergoing surgical stabilization for anterior shoulder instability were prospectively enrolled at multiple institutions from 2015-2017 and stratified by number of dislocations before surgery. Demographic data, preoperative patient-reported outcomes, imaging findings, surgical findings, and procedures performed were compared between groups. Analysis of variance, χ2, and multivariate logistic regression were used for statistical analysis. RESULTS: The study included 172 patients (mean age, 25.3 years; 79.1% male patients) for analysis (58 patients with 1 dislocation, 69 with 2-5 dislocations, 45 with >5 dislocations). There were no intergroup differences in demographic characteristics, preoperative patient-reported outcomes, or physical examination findings. Preoperative imaging revealed increased glenoid bone loss in patients with multiple dislocation events (P = .043). Intraoperatively, recurrent dislocators were more likely to have bony Bankart lesions (odds ratio [OR], 3.26; P = .024) and biceps pathology (OR, 6.27; P = .013). First-time dislocators more frequently underwent arthroscopic Bankart repair and/or capsular plication (OR, 2.22; P = .016), while recurrent dislocators were more likely to undergo open Bristow-Latarjet procedures (OR, 2.80; P = .049) and surgical treatment for biceps pathology (OR, 5.03; P = .032). CONCLUSIONS: First-time shoulder dislocators who undergo stabilization are more likely to undergo an arthroscopic procedure and less likely to have bone loss or biceps pathology compared with recurrent dislocators. Future studies are needed to ascertain long-term outcomes of surgical stabilization based on preoperative dislocation events.

Patients Undergoing Shoulder Stabilization Surgery Have Elevated Shoulder Activity Compared With Sex- and Age-Matched Healthy Controls.

BACKGROUND: Shoulder activity level may be a risk factor for shoulder instability, an indication for surgical intervention, and a risk factor for failure of operative stabilization. HYPOTHESIS: Patients undergoing shoulder stabilization surgery have a higher activity level compared with sex- and age-matched healthy controls. STUDY DESIGN: Cross-sectional study. LEVEL OF EVIDENCE: Level 2. METHODS: Patients undergoing shoulder stabilization surgery aged 18 to 50 years were prospectively enrolled. As part of data collection, patients completed a previously validated shoulder activity scale, which generates a score reporting frequency of activity ranging from 0 (least active) to 20 (most active). The activity level of these patients was compared with sex- and age-matched norms for a healthy population with no history of shoulder disorders. RESULTS: A total of 409 subjects (343 male, 66 female) undergoing shoulder instability surgery completed the activity scale. Seventy-seven percent of patients had higher shoulder activity level than sex- and age-matched controls. Seventy-nine percent aged 18 to 30 years had a higher shoulder activity level than controls, with an identical distribution for men (79%) and women (79%). Among patients aged 31 to 50 years, 70% had higher activity than controls. However, men were more likely to have a higher activity level than controls (72%) versus women (59%). In patients aged 18 to 30 years, median activity level for instability patients was 14 in men compared with 10 in controls, and 13 in women compared with 8 in controls. In patients aged 31 to 50 years, median activity level was 13 in men compared with 10 in controls and 10 in women compared with 8 in controls. CONCLUSION: Patients undergoing shoulder stabilization surgery have a higher activity level than sex- and age-matched healthy controls. CLINICAL RELEVANCE: Shoulder activity is especially elevated in younger, male instability patients.