Comparison of Asymmetric Reaming versus a Posteriorly Augmented Component for Posterior Glenoid Wear and Retroversion: A Radiographic Study

Abstract

Background: Managing posterior glenoid wear and retroversion remains a challenge in shoulder arthroplasty.<br />Correcting glenoid version through asymmetric reaming (AR) with placement of a standard glenoid component and the<br />use of posteriorly augmented glenoid (PAG) components are two methods used to address this problem. Our objective<br />is to report the radiographic outcomes of patients with posterior glenoid wear and/or retroversion treated with either<br />approach.<br />Methods: Patients with posterior glenoid wear and a minimum of 15 degrees of retroversion, treated with AR and<br />standard glenoid component or with a PAG component (3 mm, 5 mm, or 7 mm posterior augmentation), were<br />consecutively identified through retrospective chart review. Pre-operative axillary views were evaluated for version,<br />humeral head subluxation in relation to scapular axis and to mid-glenoid face. Post-operative axillary views were<br />reviewed to measure corrected inversion and humeral head subluxation.<br />Results: There were 48 patients in the AR group and 49 patients in the PAG group. Version improved 6.8 degrees in the<br />AR group. In the PAG group, version improved 8.8 degrees with 3 mm augment, 13.4 degrees with 5 mm augment, and<br />12.8 with 7 mm augments. There were significantly more central peg perforations in the 5 mm PAG group compared<br />to other groups. The humeral head was re-centered within 6.1% of normal in all groups except 7 mm augments.<br />Conclusion: This study demonstrates that AR and PAGs have the ability to re-center the humeral head when utilized<br />in patients with retroversion and posterior wear. Use of a PAG component may allow for greater correction of glenoid<br />retroversion, however, there is an increased risk for central peg perforation with the specific implant utilized in this study.<br />Long-term follow-up is ongoing and needed to understand the clinical implications of these findings.<br />Level of evidence: IV