[Diagnostics and treatment of posterior shoulder instability]

Posterior shoulder instability has a markedly lower incidence than anterior shoulder instability. It has a wide spectrum of clinical symptom manifestations and the overwhelming number of patients lack a traumatic primary dislocation. In addition to a detailed medical history, a specific clinical examination with the help of standardized provocation tests is essential for the diagnostics. For the detection of structural posterior capsule and labral lesions in cases of chronic courses, magnetic resonance imaging (MRI) should be used with an intra-articular contrast agent. Relevant bony defects of the humeral head (reverse Sachs-Hill lesion) are frequent, whereas critical posterior defects of glenoid cavity are relatively rare. Both lesions should be quantified using 3D computed tomography. The choice of therapeutic procedure should be based on the underlying pathology of the defect. Conservative therapy is useful in patients with scapular dyskinesis, voluntary dislocation and pathological muscle patterning. In isolated soft tissue pathologies, arthroscopic labrum fixation and capsule plication are the standard treatment. In the case of insufficient soft tissue relations or critical posterior glenoid defects, bony stabilization of the glenoid using an iliac crest bone graft is the recommended therapy.