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Updated: Feb 15, 2026

Reverse Total Shoulder Arthroplasty
Published on: July 5, 2011
[The ABC guide for the treatment of posterior shoulder instability]
P Moroder1, V Danzinger2, M Minkus2
1Abteilung für Schulter- und Ellenbogenchirurgie, Centrum für Muskuloskeletale Chirurgie, Charité - Universitätsmedizin Berlin, Campus Virchow Klinikum, Augustenburger Platz 1, 13353, Berlin, Deutschland. philipp.moroder@charite.de.
Background:
Posterior glenohumeral instability (PGHI) is an often unrecognized or misdiagnosed type of shoulder instability due to its heterogenic clinical and radiological presentation.
Classification:
The ABC classification for PGHI is based on the different pathomechanisms and recommended treatment standards and is therefore a guide to finding the correct diagnosis and therapy for affected patients. There are different types of PGHI: A (first time), B (dynamic), C (static). These groups are further classified based on pathomechanical principles: A1: subluxation, A2: dislocation; B1: functional, B2: structural; C1: constitutional, C2: acquired.
Therapy:
In patients with type 1 PGHI (A1, B1, C1) conservative treatment is recommended while in patients with type 2 PGHI (A2, B2, C2) surgical treatment can be considered based on structural defects, clinical symptoms, chronicity, age, functional demand, and patient-specific health status. In addition it has to be considered, that there is the possibility of coexisting or overlapping subtypes as well as the chance of progression from one category into another over time.
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