Five-year outcomes of anatomic total shoulder arthroplasty with Aequalis Perform+ posterior augmented glenoid implants in Walch B2 and B3 glenoids.

Abstract

Background: Posterior glenoid wear and persistent static posterior subluxation of the humeral head (SPSH) are associated with early failure of anatomic total shoulder arthroplasty (aTSA). In patients with Walch B2 or B3 glenoid types, posteriorly augmented glenoid (PAG) implants have been reported to successfully correct SPSH on short-term follow-up. However, the medium- and long-term clinical and radiological outcomes of PAG remain unclear.

Methods: We prospectively followed ten consecutive patients (mean age, 67.9±8.9 years; 5 females) with primary glenohumeral osteoarthritis and B2 or B3 glenoid types, who underwent aTSA with cemented keeled PAG implants (posterior augments of 15, 25, or 35 degrees, Aequalis Perform+ shoulder system). Clinical outcomes were assessed using Constant and Quick-DASH scores. All patients underwent preoperative shoulder computed tomography (CT) scans with 3D surgical planning combined with patient-specific instrumentation at the time of surgery. Follow-up shoulder CT scans were performed at 3 months and 5 years postoperatively. Glenoid version (GV), inclination (GI), and static humeral subluxation index (SHSI) were measured in 3D, on both pre- and postoperative CT scans, using the same reliable quantitative method. At 5-year follow-up, we estimated the polyethylene wear of the glenoid component. The glenoid implant loosening was defined as the presence of a radiolucent line (thickness >1.5 mm) at the glenoid bone-cement interface, and/or migration (>5 mm) and/or tilt (>5 degrees) of the glenoid component.

Results: Five-year clinical outcomes revealed a Constant score of 78.2 ± 8.9 and a Quick-DASH of 8.4 ± 8.2. GV and SHSI significantly decreased from -17.1 ± 8.9 degrees and 70.3 ± 5.9% preoperatively to -4.2 ± 7.7 degrees and 55.5 ± 8.1% respectively at three months postoperatively (p<0.001). At 5-year follow-up, GV and SHSI only varied by 0.9 ± 3.4 degrees and -1.1 ± 5.5% compared to 3-month postoperative values, while GI increased by 3.6 ± 3.0 degrees. Five patients (50%) had CT signs of aseptic glenoid loosening. Only the preoperative Constant score differed significantly (p=0.016) between patients with and without glenoid loosening.

Conclusion: Our 5-year evaluation revealed excellent clinical outcomes. PAG successfully corrected glenoid retroversion and SPSH over time, but there was a high rate of radiological glenoid implant loosening. Long-term comparative studies between aTSA and reverse shoulder arthroplasty are awaited to determine the optimal implant in patients with B2 and B3 glenoids.