Nonoperative management of anterior shoulder instability can result in high rates of recurrent instability and pain at long-term follow-up

Background: Data on the long-term outcomes of nonoperative treatment of anterior shoulder instability are lacking, particularly for the US population. The purpose was to (1) describe the characteristics of patients with anterior shoulder instability treated nonoperatively, (2) assess the long-term outcomes of nonoperative management in a US population, and (3) identify risk factors for poor outcomes following nonoperative management. Methods: A geographic cohort of >500,000 subjects was used to identify patients treated nonoperatively for anterior shoulder instability. Only patients aged <40 years at the time of initial instability with minimum 10-year follow-up were included. Medical records were reviewed to obtain demographic characteristics, physical examination findings, clinical history data, imaging results, treatment details, and clinical and/or radiographic progression. Recurrent pain, recurrent instability, and the development of symptomatic osteoarthritis (OA) were the primary outcomes evaluated. Results: The study included 254 patients (73% male) with a median age of 19 years (range, 16-26 years) at the time of initial instability. At median 17-year follow-up, 37.5% experienced recurrent instability, 58.4% had recurrent pain, and 12.2% had symptomatic OA development. Factors associated with recurrent pain at final follow-up were multiple instability events prior to presentation (hazard ratio [HR], 2.43; P < .01) and increased pain at the initial visit (HRs of 0.79 for mild, 1.74 for moderate, and 1.39 for severe; P < .01); patients with multiple instability events prior to presentation also had an increased risk of recurrence (P < .01). Factors increasing the risk of the development of symptomatic OA included increased pain at the initial visit (P = .05), seizure disorder (HR, 27.01; P < .01), and smoking (HR, 5.15; P < .01). Conclusions: At long-term follow-up of 17 years, a high rate of poor outcomes was observed following nonoperative management of anterior shoulder instability. Overall, 37.5% of patients experienced recurrent shoulder instability, 58.4% had recurrent shoulder pain, and 12.2% had symptomatic OA development. Risk factors associated with adverse clinical outcomes included increased pain at the initial visit, recurrent instability prior to presentation, seizure disorder, and smoking.