Clinical and radiological results of reverse total shoulder arthroplasty with or without lateralization as revision procedure for failed arthroplasty.

BACKGROUND

As reverse total shoulder arthroplasty (rTSA) becomes a common treatment option in the revision setting, common problems associated with Grammont's design such as scapular notching, instability, and rotator cuff weakening occur. Design changes associated with superior outcomes in primary rTSA, such as glenoid or humeral lateralization have not yet been examined in the revision settings. The purpose of this consecutive series of revision rTSA is to evaluate the clinical and radiological short-term results after aseptic and septic revision rTSA and explore potential benefits of metallic glenoid and humerus lateralization.

METHODS

In this study, patients treated with an rTSA between 2014 and 2020 after failed shoulder arthroplasty were included. Forty-five consecutive patients were divided into comparative groups using lateralized rTSA with metallic baseplate augmentation (latrTSA) and additional humeral lateralization using a 145° onlay curved stem (bi-latrTSA); or no baseplate offset with a Grammont-type 155° stem (non-latrTSA). Further, outcome of postinfection revision rTSAs was compared to aseptic loosening. Constant-Murley-Score, subjective shoulder value, shoulder range of motion including Apley's scratch test, abduction strength, and pain levels were assessed. Radiographs were reviewed for implant loosening, scapular notching, fractures, and osteolysis. Lateralization and distalization shoulder angle were measured at the final follow-up.

RESULTS

Thirty-eight patients showed significant improvement in all functional measurements at the final 2-year follow-up compared to the baseline ( < .01). There were no significant differences in favor of glenoid or bipolar lateralization. However, no scapular notching was seen in patients with both humeral and glenoid lateraliazion (non-latrTSA: 33%; latrTSA: 8%; bi-latrTSA: 0%;  = .103), with no signs of implant loosening. Patients with bi-latrTSA showed significantly greater lateralization shoulder angle ( = .017); distalization shoulder angle was lower, but not significantly ( = .230). Postinfectious rTSA after aseptic loosening (n = 19; 55%) presented better internal rotation ( = .036) compared to postinfectious rTSA. The overall complication rate was 16% and 8% leading to revision.

CONCLUSION

rTSA is a viable option for revision cases and presents good results after failed shoulder arthroplasty, including the infected shoulder. The effect of metallic augmentation on clinical results is not comparable to those in literature in primary rTSA setting due to advanced preoperative medialization. However, scapular notching was prevented in all cases with bipolar lateralization.