Comparison of Intra-articular Findings and Clinical Features Between Patients With Symptomatic Anterior Instability After Recurrent Shoulder Subluxation and Dislocation

Abstract

Purpose: The purpose of this study was to compare the prevalence of concomitant intra-articular pathologies and clinical manifestations after arthroscopic stabilization between patients with symptomatic anterior instabilities following recurrent shoulder subluxations and dislocations. Methods: Among patients who underwent arthroscopic stabilization, 28 patients who experienced shoulder subluxations (subluxation group, 26.7 +/- 1.8 years) and 84 who had shoulder dislocations (dislocation group, 25.9 +/- 2.2 years) were included. Recurrent shoulder subluxation was defined as instability caused by repeated injuries without a history of frank dislocation or manual reduction maneuver. Common inclusion criteria were positive clinical test of anterior instability and Bankart lesion with less than 25% of glenoid bone loss. The pathoanatomies in radiologic and arthroscopic examinations and postoperative clinical outcomes were compared. Results: The number of instability events was significantly fewer in the subluxation group (5.0 +/- 1.3) than in the dislocation group (12.1 +/- 2.0; P = .01). The pathologic findings in preoperative radiology demonstrated no intergroup differences, except for the prevalence of Hill-Sachs lesions. In the subluxation group, the Hill-Sachs lesions were significantly less commonly detected with computed tomography and magnetic resonance arthrography (28.6%) than in the dislocation group (63.1%, 60.7%; P = .001, P = .003, respectively). There were no significant differences in arthroscopic findings in both groups including superior labral anterior to posterior lesion (subluxation group, 39.3%; dislocation group, 45.2%), anterior labral periosteal sleeve avulsion lesion (21.4%, 29.8%), and bony Bankart lesion (21.4%, 28.6%). Preoperative and postoperative functional outcomes also did not differ between the groups. There was no statistical difference in terms of the rate of revision or postoperative subjective instability. Conclusions: Patients who had anterior instability after recurrent shoulder subluxation demonstrated a similar rate of concomitant intra-articular pathologies requiring the same level of management as recurrent shoulder dislocation. Recurrent shoulder subluxation also displayed similar functional outcomes and failure rate after arthroscopic stabilization procedures as recurrent dislocation. Thus, the clinical importance of symptomatic recurrent subluxation should be considered comparable with that of recurrent dislocation.