High Incidence of Combined and Posterior Labral Tears in Military Patients With Operative Shoulder Instability

Background: Anterior shoulder instability is the pattern most commonly reported in the civilian population, but military servicemembers may represent a unique population. At 1.7 per 1000 person-years, servicemembers not only have a higher incidence of instability events compared with civilians (reported rate of 0.2-0.8), but the distribution of labral tears in the military may differ significantly as well. Hypothesis: The incidence of combined and posterior labral tears in the military population will be greater than numbers previously reported. Study Design: Cross-sectional study; Level of evidence, 3. Methods: The Wounded, Ill, and Injured Registry, a Department of Defense patient reported outcomes data collection platform that includes all military branches, was queried retrospectively for all patients who had undergone a primary arthroscopic or open shoulder stabilization procedure (Current Procedural Terminology codes 29806, 23455, 23462) between October 2016 and January 2019. Demographic information was obtained through intake forms completed by patients at the time of enrollment into the Military Orthopaedics Tracking Injuries and Outcomes Network. Tear location was determined arthroscopically and labeled as anterior, inferior, posterior, superior, or any combination thereof. Chi-square analysis was used to compare the percentage of patients with isolated anterior, isolated posterior, isolated inferior, or combined labral tears in the current study cohort with those in a previously reported cohort of patients with operative shoulder instability at a single military treatment facility. Results: A total of 311 patients were included who had undergone primary shoulder stabilization during the study period. Of these patients, 94 (30.2%) had isolated anterior tears, 76 (24.4%) had isolated posterior tears, and 136 (43.7%) had combined tears. We observed a higher percentage of combined tears in our data set than in a data set from a single military treatment facility (χ²(2) = 48.2; P <.00001). Chi-square analysis demonstrated that significantly more female patients had an isolated anterior labral tear (51.2%) compared with male patients (27.1%; χ²(2) = 9.4; P =.009). Conclusion: The incidence of combined and posterior labral tears in the military population is greater than numbers previously reported in both military and civilian populations.