Short-Term Radiographic Outcomes of Bone Versus Metallic Augmented, Central Screw Type Baseplate in Reverse Total Shoulder Arthroplasty: Matched Case-Control Study.

Background: Although glenoid bone grafting and metallic augmented baseplates have demonstrated success in restoring the glenohumeral joint line in the recent literature, there remain no consensus guidelines defining the use of one versus the other.

Methods: Between 2017 and 2020, 15 primary RTSA with screw-in metallically augmented glenoid baseplates were identified and 2:1 matched by age, sex, and body mass index with primary bony-augmented glenoid baseplate patients. Patients with previous glenoid implantation or fracture were excluded. Charts, routine radiographic series (Grashey, Scapula Y, Axillary lateral), and 3-dimensional computed tomography (3D CT) scans were retrospectively reviewed. Structural patient-specific metal or bony augmentation was indicated based on preoperative glenoid morphology as identified by 3D CT. Aseptic failure was identified as hardware breakage and/or shift in glenoid baseplate component position.

Results: There were 45 eligible cases with mean age of 65.7 years (range 44-85 years) and 65.5 years (range 42-82 years) for the metallic-augmented and bone graft group, respectively. Correspondingly, mean follow up was 22.6 months (range 12-53 months), and 27.3 months (range 11-53 months). At latest follow up, there were no baseplate failures in the metallic augment group and 2 baseplate failures (7%) in the bone graft group at a mean of 42.5 months (range 32-53 months) postoperatively. Mean age of the bone failure group was 64.5 years (range 64-65 years).

Conclusion: Contemporary reversed shoulder arthroplasty glenoid baseplate designs appear to have low incidence of failure. Further analysis is necessary to determine if a critical degree of glenoid retroversion or inclination is preferable with a specific form of augmentation.

Level of evidence: III; Retrospective Cohort Comparison.