Early to short-term radiographic follow-up of metal-augmented baseplates in reverse shoulder arthroplasty for treatment of glenoid deformity in glenohumeral arthritis and rotator cuff arthropathy

Hypothesis and background

As reverse total shoulder arthroplasty (rTSA) has evolved, the use of augmented glenoid baseplates has increased. While there are benefits of metal augmentation, literature concerning the mid- to long-term follow-up of these implants is emerging. The purpose of this study is to report early to short-term radiographic follow-up of patients with glenoid deformity treated with a metal-augmented glenoid baseplate. Our hypothesis is that we will see a low incidence of osteolysis, loosening, complications, and revision of these implants regardless of diagnosis, augment type, or patient demographics.

Methods

We performed a single-center retrospective review of all patients undergoing primary reverse shoulder arthroplasty with an augmented metallic baseplate for rotator cuff arthropathy and glenohumeral arthritis. Patients undergoing revision procedures or reverse arthroplasty for fractures were excluded. All patients had a minimum of 1-year radiographic follow-up. Preoperative imaging was reviewed to confirm the diagnosis and glenoid deformity classification. Postoperative radiographs were reviewed for evidence of complications, revisions, osteolysis, baseplate loosening, and failure. Clinical data were reviewed for complications.

Results

Primary rTSA with a metal-augmented baseplate (38 full wedge and 22 half wedge augments) was performed on 60 patients who met inclusion criteria (mean age 74 ± 7). The average radiographic follow-up of all patients was 17 months. In our cohort, there was one patient with aseptic loosening of a full wedge implant that was not revised. There were no other complications, revision surgeries, baseplate failures, or acromial stress fractures. Six patients developed scapular notching, and five patients were found to have asymptomatic glenoid osteolysis. Two patients with full wedge implants developed aseptic humeral loosening. Pearson chi-square post hoc analysis found no correlation between augment type, gender, or glenoid deformity classification and radiographic changes such as glenoid or humeral osteolysis, loosening, or scapular notching. We did find a statistically significant correlation (P = .018) between patients with body mass index > 35 and glenoid osteolysis.

Discussion and conclusion

Primary rTSA for patients with rotator cuff arthropathy or glenohumeral arthritis with glenoid deformity corrected with metal-augmented glenoid baseplates results in a low complication rate and an acceptable outcome at a minimum 1-year follow-up. Compared to other similar cohorts, our patients did not experience any acromial stress fractures, and only one patient had loosening of the glenoid component that was not ultimately revised. Further studies with longer follow-up will be needed, but early outcomes are promising and support the increase in the use of these implants.