Acute Versus Delayed MRI Imaging and Associated Pathology in Traumatic Shoulder Dislocations

Objectives Delayed management of patients with shoulder instability may increase the prevalence and severity of concomitant intra-articular shoulder injuries resulting from persistent instability. We hypothesize that patients with a longer delay from an initial dislocation event to MRI demonstrate a greater degree of intra-articular shoulder damage. Methods We performed a retrospective review of 89 patients from a single institution with clinically and radiographically confirmed traumatic, anterior, primary shoulder dislocations. Patients were divided into two groups: those undergoing MRI less than (N=44; LT6) or greater than (N=45; GT6) 6 months from the initial dislocation event. MRI assessment included evaluation of the severity of cartilage damage and bone loss, in addition to the presence of soft-tissue injuries to the labrum, capsule and rotator cuff. Subsequent treatment including type and method of surgical intervention, as well as recurrent postoperative instability, were evaluated. Results The delayed MRI group demonstrated a greater degree of pathology compared to the early imaging group. A higher percentage of SLAP tears (58% vs. 34%), posterior labral tears (22% vs. 7%) and cartilage damage (73% vs. 27%) were present in the GT6 versus LT6 group. There was no difference in anterior glenoid bone loss. For those patients who underwent surgical stabilization for symptomatic instability, there was a statistically significant difference in recurrence of instability between the early MRI group (0/21) than that of the delayed MRI group (6/33 or 18%). Conclusion Patients who undergo MRI greater than 6 months from the time of primary shoulder dislocation demonstrate a greater incidence and severity of intra-articular pathology including SLAP tears, posterior labral tears and anterior glenoid cartilage damage. Recurrent instability is significantly higher after shoulder stabilization surgery when performed more than 6 months from the primary dislocation event.