The reverse total shoulder prosthesis provides successful functional outcome in many patients with rotator cuff tear arthropathy.
However, scapular notching, a direct consequence of mechanical impingement between the humeral prosthesis and the glenoid,
remains a major concern. We presumed a better knowledge of the anatomy of the scapula would enable design or placement modifications
to minimize this phenomenon. After establishing a uniform spatial reference system using easy locatable surgical reference
points and planes, we analyzed 200 dry bony scapulae and defined the glenoid and infraglenoid anatomy relative to the reference
system. The bony rim of the two inferior quadrants of the glenoid forms a semicircle the center of which can be used perioperatively
as an easy locatable bony reference point. The infraglenoid tubercle varies in width and length, and can interfere with the
humeral part of the reverse prosthesis, creating scapular notching. To avoid notching, we suggest using a convex base plate
with a smaller radius than currently used, placing it as low as possible with a 42-mm glenosphere eccentrically assembled
to create a posterior offset. If prosthetic overhang cannot be obtained, we suggest removing part of the infraglenoid tubercle.
Each author certifies that he or she has no commercial associations (eg, consultancies, stock ownership, equity interest,
patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article.
Each author certifies that his or her institution has approved the human protocol for this investigation, that all investigations
were conducted in conformity with ethical principles of research.