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

Background: Managing posterior glenoid wear and retroversion remains a challenge in shoulder arthroplasty.Correcting glenoid version through asymmetric reaming (AR) with placement of a standard glenoid component and theuse of posteriorly augmented glenoid (PAG) components are two methods used to address this problem. Our objectiveis to report the radiographic outcomes of patients with posterior glenoid wear and/or retroversion treated with eitherapproach.Methods: Patients with posterior glenoid wear and a minimum of 15 degrees of retroversion, treated with AR andstandard glenoid component or with a PAG component (3 mm, 5 mm, or 7 mm posterior augmentation), wereconsecutively identified through retrospective chart review. Pre-operative axillary views were evaluated for version,humeral head subluxation in relation to scapular axis and to mid-glenoid face. Post-operative axillary views werereviewed to measure corrected inversion and humeral head subluxation.Results: There were 48 patients in the AR group and 49 patients in the PAG group. Version improved 6.8 degrees in theAR group. In the PAG group, version improved 8.8 degrees with 3 mm augment, 13.4 degrees with 5 mm augment, and12.8 with 7 mm augments. There were significantly more central peg perforations in the 5 mm PAG group comparedto other groups. The humeral head was re-centered within 6.1% of normal in all groups except 7 mm augments.Conclusion: This study demonstrates that AR and PAGs have the ability to re-center the humeral head when utilizedin patients with retroversion and posterior wear. Use of a PAG component may allow for greater correction of glenoidretroversion, however, there is an increased risk for central peg perforation with the specific implant utilized in this study.Long-term follow-up is ongoing and needed to understand the clinical implications of these findings.Level of evidence: IV