This study tests the safety and performance of the AETOS Shoulder System, a device used in shoulder replacement surgeries. The study involves 220 people at 15 places in the USA. The AETOS system has been approved since June 2023 and is used in two types of shoulder surgeries: anatomic and reverse. The device is made by Smith & Nephew, Inc. and has special fins and a coating to help it stay in place in the shoulder bone.

To join this study, you must be at least 18 years old and having a primary shoulder replacement for issues like arthritis or joint disease. You must also be able to attend all checkups and understand the study's rules. You cannot join if you've had shoulder surgery before, have certain health problems, or are pregnant. The study does not include comparisons between different devices and does not involve any random selection of participants.

• Study involves multiple visits to the site.
• Participants must commit to follow-up visits and procedures.
• Eligible participants are adequately informed about risks and requirements.