Can small glenospheres with eccentricity reduce scapular notching as effectively as large glenospheres without eccentricity? A prospective randomized study

Abstract

The objective of this study was to analyze whether small glenospheres with eccentricity were comparable to large glenospheres in scapular notch development. This prospective randomized study included 82 patients who had undergone a reverse shoulder arthroplasty with a 2-year follow-up period. After randomization, 43 patients were allocated to receive a 42-mm glenosphere and 39 patients were allocated to receive a 38-mm glenosphere with 2 mm of eccentricity. Scapular notch development was defined after examination of an anteroposterior radiograph at the end of follow-up. Functional outcomes were recorded using the Constant score before surgery and at the end of follow-up. Scapular notchdevelopment was present in 16.6% of patients who received a 42-mm glenosphere and 34.2% of patients who received a 38-mm eccentric glenosphere. No significant difference was found between the groups with the number of cases available (P = .07). Functional outcomes significantly increased from preoperatively to postoperatively in both groups, with no significant difference found between them (P = .77). The mean glenosphere overhang measure was 6.3 mm in patients with a 42-mm glenosphere and 6.0 mm in those with a 38-mm eccentric glenosphere (P = .68). No significant differences were noted between patients with a scapular notch and patients without a scapular notch in terms of functional outcomes. Small glenospheres with eccentricity fared slightly worse than large glenospheres regarding scapular notch development, even though no significant differences were noted. Functional outcomes were comparable between the 2 designs.