Diagnosis and conservative treatment of atraumatic posterior shoulder instability

Posterior shoulder instability is an entity of low prevalence. An atraumatic etiology makes its diagnosis more difficult owing to the absence of inciting factors. A specific clinical and diagnostic examination is required to make the correct diagnosis. Scapular dyskinesis offers insight into the pathogenesis and thus helps rationalizing conservative treatment as the first choice in most cases. The rehabilitation protocol should be analyzed and customized to correct the abnormal biomechanics of the shoulder, providing a strengthening program to avoid persistence of symptoms or recurrence. Failure of conservative treatment warrants surgical interventions such as arthroscopic stabilization, posterior bone block, or, rarely, shoulder arthrodesis.