**1. Introduction**

Instability-mediated OA is a particular degenerative joint disease after a primary or recurrent dislocation or after instability surgery. In 1982 Neer [1] reported on 26 patients that had been treated with total shoulder arthroplasty due to severe OA after recurrent instability and anterior or posterior surgical stabilization in most cases: "recurrent dislocations and preceding surgery have tensed the capsule and thereby caused a fixed subluxation in the opposite direction of the instability". Since then, it has been discussed whether this unique type of OA is caused by the primary dislocation and thereby is predetermined, or recurrent dislocations, concomitant fractures, other risk factors, and different surgical therapies themselves worsen the prognosis or even cause it. This review clinical article deals with the following aspects: physical examination, diagnostic radiology, causes, prognostic factors, and treatments options and their results so far.
