Inferior scapular notching following encore reverse shoulder prosthesis.

Abstract

Inferior scapular notching following reverse shoulder arthroplasty has been described using devices with a center of rotation located at the glenoid. Notching is typically seen within the first few months. To date, the only prosthesis without a reported case of scapular notching is the Encore Reverse Shoulder Prosthesis (RSP) (DJO Surgical, Austin, Texas). We present the first reported case of inferior scapular notching with the Encore RSP seen in a patient treated using an alternative glenosphere (36 minus 4) with a center of rotation 2 mm lateral to the glenoid. The glenosphere was implanted using previously described techniques to avoid scapular notching: inferior tilt and inferior translation with overhang of the glenosphere. Inferior scapular notching was not observed at 1-year follow-up. However, at 2-year follow-up, radiographs revealed Sirveaux Grade 2 scapular notching. This case illustrates that using a glenosphere with a center of rotation at or near the glenoid places the shoulder at risk for scapular notching. When choosing this type of design, the treating surgeon must maintain a high index of suspicion for scapular notching as intermediate and long-term follow-up radiographs are reviewed. Scapular notching for these devices may develop later than devices with a center of rotation at the glenoid.