Scapular Positioning in Standing Position Using Sonography

This study is measuring the position of the shoulder blade (scapula) using ultrasound in patients undergoing reverse shoulder arthroplasty — a type of shoulder replacement surgery used when the rotator cuff muscles are severely damaged. Knowing the exact position of the scapula is important for properly placing the implant and predicting how well the shoulder will function after surgery. The study aims to determine whether ultrasound-based scapular positioning measurements are accurate and useful for surgical planning and outcomes assessment. You may be eligible if: - You are 18 years of age or older - You are having a reverse shoulder replacement on a native (non-previously-replaced) shoulder joint - You agree to participate after receiving information about the study You may NOT be eligible if: - You are under 18 years old - You refuse to participate - You are unable to provide informed consent - You are under legal protection measures or deprived of liberty - You do not have health insurance coverage Talk to your doctor to see if this trial is right for you.