**5. Conclusions**

IB-RSA is a safe and effective procedure without specific implant-associated complications at mid-term follow-up. Overall, using a 44-mm-diameter glenosphere compared to 40-mm-lead to an improved range of motion. Inverting biomaterials lead to a distinct kind of notching, which mainly showed mechanical features and no observed cases of grade 3 or 4. Scapular notching is associated with a high baseplate position and has a negative influence on range of motion and clinical outcome.

**Author Contributions:** Conceptualization, R.R. and A.C.; methodology, R.R.; software, R.R.; validation, A.C., M.B. and G.D.R.; formal analysis, R.R.; investigation, R.R. and L.D.; data curation, R.R. and L.D.; writing—original draft preparation, R.R.; writing—review and editing, A.C., S.G., M.B. and G.D.R.; supervision, A.C. and M.B. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Institutional Review Board Statement:** The study was conducted in accordance with the Declaration of Helsinki and approved by the Institutional Ethics Committee of IRCCS Humanitas Research Hospital (protocol code 41/22 and 19 July 2022).

**Informed Consent Statement:** Informed consent was obtained from all subjects involved in the study.

**Data Availability Statement:** Not applicable.

**Conflicts of Interest:** Alessandro Castagna declares conflict of interest: Lima consultant and royalties. The other authors declare no conflict of interest.
