Posterior Shoulder Instability: Surgical Outcomes and Risk of Failure in Adolescence.

Background: Arthroscopic capsulolabral reconstruction has proven to be effective in treating posterior shoulder instability. Few studies have examined the risk factors that may contribute to poor outcomes in the adolescent population. Purpose: To identify risk factors for surgical failure by comparing anatomic and subjective variations in children who underwent surgical intervention for posterior shoulder instability. Study Design: Case series; Level of evidence, 4. Methods: All patients undergoing arthroscopic shoulder surgery at one institution between 2011 and 2018 were reviewed. Patients >18 years old at presentation and those with Ehlers-Danlos syndrome were excluded. Posterior instability was defined as unidirectional subluxation on posterior drawer testing while under anesthesia. Two-year minimum follow-up was required, but those whose treatment failed earlier were included for calculation purposes. Demographics and intraoperative findings were recorded, as were Single Assessment Numeric Evaluation (SANE) scoring, Pediatric and Adolescent Shoulder Survey (PASS), and the short version of the Disabilities of the Arm, Shoulder and Hand (QuickDASH) results. Major complication was defined as revision arthroscopy or redislocation, and minor complications included self-reporting a poor outcome score (eg, SANE score <65). Results: A total of 48 children (23 girls and 25 boys) met criteria, with a mean age of 16.5 years (range, 12.4-17.9 years) and a mean follow-up of 3.75 years. Fifteen (31.3%) patients had a complication by our criteria, including 12.5% with surgical failures; regarding major complications, boys were treated successfully 96% of the time and girls 78% of the time (P = .049). Of the anatomic and subjective variables tested, only younger age (P <= .001) and presentation type (P < .05) were correlated with complications. SANE scores differed significantly (P < .002) by presentation type, with mean scores of 52 (trauma), 94 (recurrent instability), and 81 (pain). QuickDASH scores demonstrated patients with a history of trauma (mean, 37), instability (mean, 9), and pain (mean, 11). Conclusion: Adolescents treated surgically for posterior shoulder instability are at risk of treatment failure (when including outcome scores), and it appears that patients of female sex, younger age, and traumatic presentation are at the highest risk to require revision surgery or experience continued limitations secondary to their shoulder.