Anterior Shoulder Instability
Recurrent or symptomatic anterior translation of the humeral head from the glenoid, typically following a traumatic dislocation in a young patient.
Overview
Anterior shoulder instability is the most common form of glenohumeral instability, usually the sequel of a traumatic anterior dislocation in which the humeral head disrupts the anteroinferior labrum and capsuloligamentous complex (Bankart lesion). Subsequent episodes may occur with decreasing trauma.
Epidemiology
First-time anterior dislocation incidence is approximately 23 per 100,000 person-years, with a strong young male predominance. Recurrence risk after non-operative management ranges from 60 to 90 percent in patients under 20 engaged in contact sport, dropping to below 20 percent in those over 40.
Symptoms
After initial dislocation, patients report apprehension and recurrent subluxations or dislocations with abduction and external rotation. Examination employs apprehension, relocation, and surprise tests. Neurovascular examination, particularly axillary nerve, is essential at first presentation.