Late-Onset, Advanced Scapular Notching Associated with a Lateral Offset Reverse Arthroplasty Design - A Case Report

Reverse shoulder arthroplasty, introduced by Grammont et al. [1] in 1987, is commonly associated with scapular notching, [2] an impingement of the humeral cup against the scapula’s inferior border. Although the clinical significance of notching has been debated, 2 studies reported less successful clinical outcomes in its presence [2,3]. A laboratory study showed that a varus humeral neck-shaft angle and a lateral glenosphere offset reduce inferior scapular impingement [4]. The DJO Encore reverse shoulder prosthesis (Encore Medical, Austin, Texas) has a varus, 135° humeral neck-shaft angle and a lateralized offset glenosphere component [5]. A literature search found 1 study [6] (5-year follow-up) and 1 case report [7] describing notching associated with this reverse arthroplasty design, but neither reported more than a Sirveaux [2] Grade 1 notching.