The clinical and radiographical results of reverse total shoulder arthroplasty with eccentric glenosphere

Scapular notching is a common worrying finding after reverse total shoulder arthroplasty (RSA). Eccentric glenospheres have recently been developed in an attempt to prevent notching. The purpose of this study was to evaluate the clinical and radiological results of RSA with an eccentric glenosphere and compare the incidence and the severity of scapular notching using a concentric glenosphere.

A prospective evaluation was performed of 57 consecutive RSA performed over a two-year period. At a minimum of two years postoperatively, 47 RSAs with a mean 30.4 months follow-up were evaluated clinically and radiographically and compared to a historical control group of concentric glenospheres performed by the same surgeon.

The mean Constant score significantly increased (from 32.4 to 71.8) postoperatively (p < 0.0001). Active forward flexion and external rotation also significantly increased (p < 0.0001). Overall, scapular notching was present in 19 shoulders (40.4 %). Grade 1 notching was observed in 13 shoulders (27.7 %), grade 2 in five shoulders (10.6 %), grade 3 in one shoulder (2.1 %), and grade 4 in no shoulders. There was no significant difference in the incidence (p = 0.289) of notching between the eccentric and concentric glenospheres. However, the severity of notching was significantly decreased (p = 0.011) with an eccentric glenosphere. The postoperative Constant score was not significantly different between patients with or without notching (p = 0.651).

A Grammont type RSA with eccentric glenosphere can result in good clinical outcomes. An eccentric glenosphere does not prevent notching, but decreases the severity of scapular notching at early follow-up.