Rotator Cuff Full-Thickness Tear

A 66-year-old right-hand-dominant male painter presents with 8 months of progressive right shoulder pain, weakness on arm elevation, and night pain. He has a positive drop arm test and weakness on resisted abduction (Jobe empty can test). Musculoskeletal ultrasound performed in the modified Crass position shows the supraspinatus tendon in long axis. The structure marked **A** in the diagram demonstrates a well-defined anechoic to hypoechoic defect extending from the articular to the bursal surface, located in the critical zone 1–2 cm medial to the greater tuberosity insertion. Which of the following best describes the clinical significance of this finding?