Instability of the shoulder involves painful abnormal translational movement or subluxation and/or recurrent dislocation
Aetiology
Traumatic instability
Instability following a traumatic anterior dislocation - patient develops recurrent dislocations and subluxations
Age at time of first dislocation predicts the likelihood of further - 80% re‐dislocation rate in under 20s, and 20% re‐dislocation rate in over 30s
Atraumatic instability
Patients with generalized ligamentous laxity (idiopathic, Ehlers‐Danlos, Marfan’s) can have pain from recurrent multidirectional (anterior, posterior or inferior) subluxations or dislocations
Clinical features
Symptoms
Atraumatic laxity/subluxations
Not painful
Signs
Abnormal shoulder contour
Muscle wasting
Tenderness
Muscle spasm
Good ROM
Scapular winging/dyskinesia
Tests - sulcus sign, anterior and posterior draw tests, anterior apprehension and relocation test, posterior apprehension test, RC strength, general laxity