The aim of this retrospective study is to evaluate clinically and radiographically the effectiveness of implanting an eccentric glenosphere and if a correct glenosphere positioning would avoid the occurrence of notching. since 2006 40 patients with shoulder eccentric osteoarthritis were treated with reverse shoulder arthroplasty with a 36 mm eccentric glenosphere. We have selected 25 patients, with a minimum follow up of 24 months. The patients were clinically evaluated with the Constant score and SST and with X-ray, MRI and/or CT before and after surgery. At the follow up we evaluated the presence or absence of notch, and we measured the PSNA (prosthesis-scapular neck angle), the DBSNG (distance between the scapular neck angle and glenosphere), the PGRD distance (peg glenoid distance). Stastistical analysis was performed with a paired t test.INTRODUCTION
METHODS
Reverse shoulder prosthesis may lead to scapular notching, caused by attrition of the upper humeral component with scapular neck. We compared the clinical and radiographic results obtained with a SMR prosthesis, which allows a concentric or an eccentric glenosphere to be applied. 67 patients, mean age 73 years, were treated with reverse prosthesis using concentric and eccentric glenosphere. In patients with concentric glenosphere, the glenosphere extended about 4 mm below the glenoid. The eccentric glenosphere protected the upper glenoid neck by its inferior prolongment. Patients were followed for a mean of 33 months. At final F-U the Constant Score (C.S.) and the score with the Simple Shoulder test (S.S.T.) were calculated. Radiographs were obtained to evaluate the presence of scapular notching, psna (prosthesis-scapular neck angle), pgrd (peg- glenoid rim distance) and DBSNG (distance between scapular neck and glenosfere). Included in this study were patients, as much homogeneous as possible by age and pathology, 25 with concentric (Group I) and 30 with eccentric (Group II) glenosphere, who had a minimum F-U of 24 months. Statistical analysis was performed with a paired test.Purpose
Patients and methods
