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Finally a subject-specific model could be useful for predicting clinical outcomes.Friday, October 8, 2010, 13:30-14:10Session B12: Shoulder ArthroplastyReverse Shoulder Prosthesis With Concentric vs Eccentric Glenosphere. aMulticentric StudyCarlo Felice De Biase - - Roma,*Giantony Di Giorgio - Sapienza, University of Rome - Pignataro Interamna, ItaliaRoberto Postacchini - Università Gemelli - Rome, Italy*Email: digiorgiog@aol.comBackground : One of the main concern about reverse shoulder arthoplasty for the treatment ofrotator cuff deficiency is scapular notching that is still an unsolved issue for this particularprosthesis. The purpose of this multicentric retrospective study is to compare two differentconcept of reverse prosthesis, one with a concentric glenoshere and the other one with a neweccentric glenoshere design that aim to minimize scapular notching.Methods: From 2004 to 2009 67 patients were treated with a SMR reverse shoulder prosthesis(LIMA) with either concentric (figure 2) or eccentric glenosphere (figure 1). We selected forthe study patients with criteria as much homogeneous as possible by the age and pathology . Wethen included for the study 25 patients (Group 1) with a concentric glenosphere and 21 (Group2) with a eccentric glenosphere. All baseplates of concentric glenospheres were implanted withthe most inferior aspect of baseplate that matched with the inferior glenoid ream, so that theglenosphere extended 4 mm beyond the glenoid inferiorly in order to minimize scapularnotching. Every patient were followed clinically (Constant and Murley Score [ C.S.] andSimple Shuolder test [S.S.T. ]) and radiographically (notching, loosening and mechanicalfailure) with a minimum follow-up of 24 months. We also evaluated at the final follow-uppsna (prosthesis-scapular neck angle), pgrd (peg glenoid rim distance) and DBSNG ( distancebetween scapular neck and glenosfere).Results: At two years of follow up R.O.M. increased significantly in both groups especially inthose with a eccentric glenosphere. Notably in patients with an eccentric glenosphere elevationimproved from 66° to 148° and abduction from 60° to 115° while in those with a concentricglenosphere improved from 78° to 122° and 71° to 98° respectively for elevation andabduction. Outcomes for external-rotation and internal-rotation were very similar in bothgroups. 14 (56%) patients among those with a concentric glenosphere had scapular notchingwhile we didn’t have any notch in those with eccentric glenosphere even though we didn’t findany significant different between the two groups in term of clinical outcomes and patient’ssatisfaction. The average C.S. increased from 38% to 69% in those with concentric SMR andfrom 30% to 74% in the other group. At the final follow-up PSNA, DBSNG and PGRD wererespectively 88°, 3,2mm and 18,2 mm in group 1, while they were 92°, 4,3 mm and 21,2 mm inthe group 2.Conclusions: Putting concentric glenosphere more inferiorly reduce the incidence of scapularnotching but it doesn’t solve the problem whereas, at medium follow-up, the new eccentricfile:///E|/ISTA2010-Abstracts.htm[12/7/2011 3:15:47 PM]