The rotator cuff is a series of four muscles that run from the shoulder blade (scapula) around the shoulder socket (glenoid) and attach to the ball of the shoulder (humeral head) by their tendons. The muscles of the rotator cuff work to keep the humeral head centered in the socket as the arm moves. Injury or degeneration (wear and tear) can result in a tear of the rotator cuff tendon. Rotator cuff tears affect the ability to keep the humeral head centered on the socket, subsequently causing weakness and pain. Therefore, as the arm elevates, the rotator cuff tendons and subacromial bursa (which sits on top of the rotator cuff) come into contact with the coracoacromial arch that serves as the bony roof of the shoulder joint. This contact can cause pain and inflammation, resulting in further rotator cuff weakness and creating a cycle of pain with repeated use of the shoulder. Untreated rotator cuff tears retract, get larger, the muscle atrophies, (turns into scar tissue and fat) with disuse, and eventually becomes irreparable.
Treatment depends on the patient’s medical health and demands (activity level), the presence of arthritis and the reparability of the tear. For large possibly irreparable tears, elderly patients with low demands, or poor surgical candidates because of other health conditions, restricting activity to prevent symptoms combined with physical therapy to optimize the function of the remaining intact (not torn) rotator cuff muscles is the most appropriate initial treatment. For irreparable tears with shoulder arthritis (rotator cuff arthropathy), initial treatment is the same except in rare cases when a reverse shoulder replacement may be warranted. For irreparable tears that have failed the initial activity restriction and therapy, arthroscopic surgery to debride (clean-up) the rotator cuff and shoulder joint, release or use the damaged biceps tendon to partially repair the rotator cuff, remove the inflamed bursa or decompress the bony space between the humeral head (ball of the shoulder) and the acromion (bony roof of the shoulder) may be helpful to relieve symptoms.
There are many other options including superior capsular reconstruction, muscle transfer, and experimentation options such as inflation balloon insertion to help keep the humeral head (ball) centered and moving in the glenoid (socket).