The shoulder is a complex, very mobile joint with over twenty muscles involved in its motion. Four of these muscles are involved in the rotator cuff, a group of four tendons that join together and facilitate rotation of the arm bone, or humerus, at the shoulder.
The rotator cuff tendons are subject to a lot of use, and at some point can tear. Rotator cuff tears are usually fairly painful and can occur as degenerative tears in middle age after years of wear and tear, or they can occur in younger athletes such as a baseball pitcher as a result of high demand repetitive usage.
Normal Rotator Cuff Tear
A normal rotator cuff is a complex of smooth tendon which attaches to the humerus. The most commonly injured tendons of the rotator cuff are the supraspinatus and infraspinatus tendons. These two tendons lie just beneath the acromion, which is the bony arch of the shoulder formed by the shoulder blade, or scapula, as it comes forward to meet the collarbone. Between the acromion and the rotator cuff tendons is a bursa, or fluid filled sac, which is a cushion to prevent injury to the rotator cuff.
Rotator Cuff Tears
Rotator cuff injuries have a spectrum of severity, ranging from inflammation of the rotator cuff and bursa, to partial tearing of the rotator cuff, and finally to complete tearing of the rotator cuff. A partial rotator cuff tear occurs when the tendon starts to break down or tear, but has not actually torn completely through the tendon.
A partial rotator cuff tear may gradually worsen over time and eventually become a full thickness tear, or it may suddenly “snap” and become a full thickness tear as a result of trauma, or from trying to lift a heavy object.
A full thickness rotator cuff tear usually starts out as a small tear, which can progress over time to a medium or large tear, or even a massive tear.
Symptoms of a Rotator Cuff Tear:
Rotator cuff tears may be asymptomatic, or they may cause pain and weakness of the shoulder. Rotator cuff tears usually cause pain with shoulder motion, and shoulder motion may actually become limited due to pain. Sometimes the pain is not in the shoulder itself, but refers to the affected arm. It is also very common to have difficulty sleeping or getting comfortable in bed at night because of rotator cuff tears. Because a painful shoulder becomes inefficient in its motions, muscles in the upper back, neck and arm may become painful as they try to compensate for the abnormal shoulder motion. With a full thickness rotator cuff tear, the arm may become weak when trying to lift things in certain positions.
A shoulder MRI (left) with an artist’s enhancement (right) showing a rotator cuff tear.
Rotator cuff tears can usually be diagnosed with a history and physical examination. X-rays are useful in determining if your scapula has a hooked acromion, which may increase your risk of having a rotator cuff tear. MRI (magnetic resonance imaging) scans are very good at showing the extent and severity of a rotator cuff tear. An MRI uses magnetic waves to create a series of pictures in slices to show the bones, tendons, muscles and cartilage in the shoulder. A closed MRI is usually preferred over an open MRI, as a closed MRI is much more accurate at showing details in the shoulder anatomy.
Partial thickness rotator cuff tear:
A partial thickness rotator cuff has a good chance of healing without surgery. Physical therapy is an important treatment option because it will help regain any lost motion, and it will condition the other muscles of the shoulder – allowing more efficient use of the arm, giving a chance for the torn tendon to heal. Icing the shoulder twenty minutes twice daily will also help reduce inflammation and relieve pain – it is especially helpful to ice the shoulder before bed if sleeping is difficult. A corticosteroid injection into the shoulder may be helpful in further reducing pain and inflammation. An arthroscopy of the shoulder (see below) may be a treatment option if pain continues despite physical therapy and a corticosteroid injection. During arthroscopy, the torn portion of the tendon is removed, leaving the healthy, intact fibers of the tendon. The inflamed bursa is removed, and the “hooked” portion of the acromion which pinches the tendons is shaved away, alleviating pain and allowing more space to prevent further tearing of the rotator cuff.
A full thickness rotator cuff tear in most cases is best treated with an arthroscopy. During the surgery anchors are placed in the bone at the location where the tendon should be attached; these anchors have stitches in them, which are passed through the torn tendon and tied. When these stitches are tied, the tendon is pulled back down to the bone, allowing the tendon to heal in place. The hooked portion of the acromion is also shaved away, allowing more space and preventing pinching of the repaired rotator cuff.
After a rotator cuff repair, the tendon must be able to heal in place. While it is important to move the shoulder to prevent scar tissue, or a frozen shoulder, from developing, there should only be passive motion of the shoulder. Passive motion is when a physical therapist moves the shoulder for the patient – the patient should not make any active effort to move the shoulder by himself. Usually, these passive motion only restrictions apply for four weeks. After the tissues have had time to heal, the physical therapist will advance your activities, and you will start strengthening exercises. While recovery is different for every patient, you should expect about four months of physical therapy, two to three times weekly, with additional exercises at home after you are done with therapy.
A very large, full thickness tear of the rotator cuff in some cases in not repairable. If there is very little tendon remaining, or if the tear is old and the tendon becomes very stiff and immobile, a repair of the tendon may not be possible. It is important to know before surgery, that with massive rotator cuff tears, repair may not be the best choice if there is severe muscle atrophy or stiffness of the rotator cuff muscles or tendon. In these cases, the torn edges of the tendon are shaved, and inflamed tissues are removed which can significantly reduce or eliminate your pain.
For a massive rotator cuff tear, with or without arthroscopy, physical therapy is important to maintain motion and condition the many other muscles in the shoulder that remain intact.
Shoulder arthroscopy is generally an outpatient procedure in which the patient goes home the day of surgery. Small incisions (approximately 1cm in length) are made in the shoulder, through which a fiber optic camera and other instruments are inserted to perform the surgery. The shoulder is visually examined, including the cartilage, tendons and bursa of the shoulder. Any necessary procedures, such as a rotator cuff repair, are then performed as described above.