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.

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.

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.

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.

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 c 2 tests were used to compare the continuous This study was approved by the Institutional Review Board at the University of Iowa (Department of Health & Human Services registration No. IRB00000099). y The MOON Shoulder Group Collaborators are as follows: Matthew J.