Concomitant Glenohumeral Instability and Rotator Cuff Injury: An Epidemiologic and Case-Control Analysis in Military Cadets

INTRODUCTION: Concomitant rotator cuff tear and glenohumeral instability in a large cohort of young and active patients has not been examined. The purpose of this study was to investigate the incidence, associated variables, and outcomes in military cadets undergoing shoulder stabilization procedures with these concomitant pathologies. METHODS: A retrospective cohort study of a consecutive series of collegiate patients who underwent shoulder stabilization from 2014 to 2018 at a single service academy was conducted. Exclusion criteria were noncadets, revision instability cases, multidirectional instability, and prior rotator cuff repair. A nested case-control analysis was done in a matched series of patients with and without MRI evidence of rotator cuff tear. Baseline demographics, VAS pain scale, physical therapy duration, and time to surgery were analyzed. Postoperative metrics included rate of recurrent instability, subjective outcomes, VAS pain scale, and military-specific criteria. RESULTS: Three hundred twenty-four cadets met the inclusion criteria, including 272 men and 52 women averaging 20.53 ± 1.80 years of age. MRI demonstrated concomitant rotator cuff tears in 5.56% of cases. A matched case-control comparison between patients with (rotator cuff tear group) and without (no rotator cuff tear group) rotator cuff tear showed no differences in preoperative data, recurrent instability rate, or postoperative VAS pain scores (0.24 versus 0.88, P = 0.207) at mean 44-month follow-up. Fifteen of 17 patients (88.2%) in each group returned to full activity (P > 0.999). No patients failed to graduate due to shoulder concerns. No patients in the rotator cuff tear group underwent a medical board for separation from the military compared with 2 (11.8%) in the no rotator cuff tear group (P = 0.163). CONCLUSIONS: The incidence of concomitant rotator cuff tears in this study of military cadets undergoing shoulder stabilization was 5.56%. In a matched cohort comparison, the presence of a rotator cuff tear on preoperative MRI was not associated with inferior clinical outcomes.