The rotator cuff is a group of four muscles that run from the scapula (shoulder blade) and attach to the humeral head (top of upper arm bone) by their tendons. Rotator cuff surgery is indicated for people who have a symptomatic rotator cuff tear that affects daily activities due to pain or weakness. When the rotator cuff is torn, the tendon usually tears off of the humerus, retracts, and cannot heal back on its own. Rotator cuff tears tend to progress over time and become larger and mores symptomatic. Additionally, with time, the rotator cuff tendon retracts further and the rotator cuff muscle atrophies and degenerates, becoming weaker and turning into dysfunctional scar tissue. This makes the repair technically more difficult and the rotator cuff becomes less likely to heal and function normally.