Radiologic, clinical, and patient-reported outcomes in stemless reverse shoulder arthroplasty at a mean of 46 months

Abstract

BackgroundThe humeral stem can be a cause of problems in shoulder arthroplasty, for example loss of bone stock, intraoperative and postoperative periprosthetic fractures or postoperative infections involving the medullary canal. Therefore, stemless reverse shoulder arthroplasty (slRSA) has gained popularity, particularly in terms of preserving bone stock. However, there is limited data available on the mid-term outcomes of slRSA. The objective of this study was to evaluate the clinical, radiological, and patient-reported outcomes of slRSA at a minimum follow-up period of two years. MethodsData on all stemless reverse shoulder prostheses implanted between January 2016 and October 2020 were collected. Patients were followed up at 6 weeks, 6 months, 12 months, and 24 months postoperatively. Clinical and radiological data as well as patient-reported outcomes measures (PROM) were assessed with validated questionnaires (UCLA, ASES, Quick-Dash, VAS pain, Subjective Shoulder Value (SSV), Constant-Murley Score (CS)). All patients had a minimum follow-up of 2 years. ResultsDuring the observation period, 26 shoulders in 25 patients fulfilled the inclusion criteria. The mean follow-up was 46.8 (range 25 -66) months. The mean age was 70.1 years (range 59.9 – 86.4 years). At most recent follow-up, a significant improvement was noted in the ASES score (55.9±19.9 vs. 85.6±10.7, p<0.001), SSV (44.3±18.7 vs. 85.3±10.4, p<0.001), Quick-Dash-Score (40.6±22.0 vs. 17.8±13.9, p<0.001), VAS pain score (4.6±3.2 vs. 0.9±1.2, p<0.001) and ROM in flexion (66±53 vs. 154±22, p<0.001) as well as in the absolute (44.1±18.7 vs. 83.1±10.1, p<0.001) and relative CS (62.1±27.8 vs. 111.9±13.3, p<0.001). Scapular notching was observed in 16% of cases, and radiolucent lines were detected in 28% of cases without symptoms of implant loosening. No revision was necessitated by any causes related to the stemless humeral component. ConclusionsWith an ASES score showing a 30-point improvement and thus exceeding the MCID of 21 points and no revisions due to the stemless component, these results indicate that slRSA is a viable option, providing good to excellent mid-term outcomes that are comparable to those of stemmed reverse shoulder prostheses, with the added advantage of bone stock preservation.