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The RSA angle ("Reverse Shoulder Angle") : A Novel Measurement of Glenoid Superior Inclination for Reverse Shoulder Arthroplasty
By Pascal Boileau, Marc-Olivier Gauci, Nicolas MORIN-SALVO, Bryan SEETO, Eric Wagner, Gilles CLOWEZ, Mikaël CHELLI, Gilles WALCH in category TOPICALITY
Superior inclination is an important consideration in reverse shoulder arthroplasty (RSA), given its association with scapular notching, glenoid loosening and decreased shoulder mobility. The traditional measures of glenoid inclination ("TSA angle") are based on the sclerotic line of the floor of the supraspinatus fossa and the entire glenoid surface (Beta angle). However, there is evidence that in RSA, the baseplate should be placed as low as possible, ie on the inferior aspect of the glenoid. Thus, surgeons should be aware that there are two different types of glenoid inclination: the global inclination, useful for positioning of glenoid implant in anatomic TSA, and the Inferior inclination that should be measured to determine the positioning of the baseplate in RSA (Figure 1).
The purpose of this study is to describe and assess the reproducibility of a novel measurement of inclination centered on the inferior portion of the glenoid.
Materials and Methods
Forty-five shoulders with rotator cuff tear arthropathy (CTA) were included, with a mean age of 74 years (range, 48-91). The TSA and RSA angles required the identification of several points: R = intersection of the line of the...
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