The rotator cuff is a group of tendons and muscles that connect the upper arm bone, the humerus, to the shoulder blade. Their function is to stabilize the shoulder and help to lift and rotate the arm. When a rotator cuff tear occurs those arm movements are limited and/or significant pain may be associated with shoulder motion.
The shoulder joint is a large ball and socket joint housing the rounded head of humerus, which fits into a shallow socket in the shoulder blade. The four muscles and their corresponding tendons that comprise the rotator cuff attach the humerus to shoulder blade (scapula) with the purpose of stabilizing and keeping the arm in the socket. The shoulder is capable of extensive motion due to the complexity of the hard and soft tissues in the joint.
Damage to the rotator cuff is a common source of pain and disability in adults. The most common problems are tears, strains, tendinitis, and bursitis. In the case of a torn rotator cuff, one or more of the rotator cuff tendons are no longer fully attached to the head of the humerus.
A rotator cuff tear can happen as a result of a single traumatic event or can develop gradually as a due to repeated micro-traumas. An acute tear occurs abruptly as the result of a fall, lifting a heavy object with a jerking motion, or along with other injuries sustained in an accident such as a broken collarbone and dislocated shoulder. Acute tears are typically accompanied by immediate and intense pain.
Most rotator cuff tears fall into the category or degenerative tears. These are a result of overuse and repeated rotator cuff injury due to straining or irritating the tendons. While degenerative changes to the rotator cuff occurs naturally with age, some occupations and hobbies that involve repetitive stress put one at greater risk for rotator cuff tears. With this type of tear, symptoms may develop or worsen gradually.
The symptoms of a torn rotator cuff range from mild to severe. In the case of a partial rotator cuff the presenting symptoms may be mild, while with a complete tear the pain, weakness, and decreased range of motion are more severe. Symptoms can include varying degrees of:
Shoulder pain and weakness
Pain in the shoulder when lying down at night or at rest
Limitations in range of motion
Crackling in the shoulder with certain movements
To diagnose a rotator cuff tear the doctor will first to a complete medical history. This will include questions about prior injuries to the shoulder, work and home activities, as well as a discussion of the symptoms. A physical exam will include checking which movements cause symptoms, range of motion, as well as arm strength. Further diagnostic tests such as imaging tests, nerve conduction, and muscle function studies may be ordered.
As a rotator cuff tear can get larger over time, it is a good idea to pursue treatment in a timely manner. While some cases respond to conservative non- surgical therapy if chronic pain persists, if large or acute tears are present, and if there is a loss of function and significant weakness, surgery may be indicated.