The rotator cuff is a confluence of tendons that insert on the superior lateral aspect of the upper arm. The tendons are what permit the shoulder muscles (subscapularis, supraspinatus, infraspinatus, teres minor) to attach to bone, and therefore raise and lower the arm, and rotate it in and out. The tendons are broad, measuring approximately 5 centimeters in width, and form a cuff encapsulating the articular surface of the top of the humerus.
The rotator cuff runs under a bony and ligamentous arch formed by the acromion,(the bone felt when you put your left hand on top of your right shoulder) and is bordered by the acromioclavicular ligament, the coracoid (the bone in front of the shoulder), the acromioclavicular joint (where the clavicle joins the acromion. The rotator cuff muscles are the subscapularis anteriorly, the supraspinatus superiorly, and the infraspinatus and teres minor posteriorly.
Due to the narrowness of the space provided for the cuff, any inflammation or swelling of the tissue leads to pain. Any significant tearing of the cuff, weakens the ability of the muscle to move the arm, and eventually permits the articular cartilage in the shoulder joint to impact against the bony confines of the space, leading to pain and arthritis.
When a person lands on the shoulder, the acromion bangs into the rotator cuff. Depending on the position of the arm, the strength and flexibility of the muscles and tendons, and the shape of the under surface of the acromion, either a bruise or tear of the rotator cuff can commonly occur.
If the cuff is bruised only, bleeding into the tendons occurs, the tendons swell, and pain increases. This entrapment of the swollen cuff may persist for months, increasing and decreasing in intensity usually related to activity. The entrapment of the rotator cuff is called the "impingement syndrome. " The syndrome is typically characterized by pain when the arm is in the overhead position, pain when twisting a screw driver or opening a bottle top, or pulling a cork, or when skiing. For the athlete, the pain is usually at the front of the shoulder.
If the rotator cuff is torn, the problem is significantly more serious. The symptoms are the same as for the impingement syndrome, with pain at night often being more prominent. The size of the tear must be determined by an arthrogram (where radiographic dye is injected into the shoulder joint and x-rays taken; how much leaks out as seen on x-ray, determines the size of the rotator cuff tear) or by Magnetic Resonance Imaging (MRI) (where pictures are taken in a magnetic field showing the internal structures of the joint.) If the cuff tear is significant, then surgery is generally recommended in order to prevent the humeral head from poking up through the rotator cuff tear to rub against the bony acromion. This superior migration not only produces pain and limited motion, but leads to significant arthritis of the shoulder joint. At surgery, the torn cuff is sewn back to itself, and reattached to the bony insertion on the lateral border of the humerus. Fortunately, many times this can be performed arthroscopically (using a small incision through which a thin tube is inserted to do the procedure). We routinely repair torn rotator cuffs under local (regional anesthesia with the patient awake) as an outpatient (no overnight stay required). Exercises are started the next day and the patient usually can return to full activities within months.
Rehabilitation and Treatment
Treatment of inflammation of the rotator cuff begins with an accurate diagnosis to rule out a tear of the cuff, followed by a combination of anti-inflammatory and strengthening maneuvers. An anti-inflammatory agent such as ibuprofen or aspirin is ingested daily and continued for six weeks. Regular dosing is required to build up blood level and to maintain that level throughout the initial treatment time to obtain the optimum anti-inflammatory effect. By diminishing the inflammation, further strengthening and stretching exercises can be performed.
Stretching of the shoulder rotator cuff muscles is easily performed both as treatment for inflammation and as a warm up before activity. Specific stretches are targeted to the desired activity. For example, for skiing, with a ski pole held firmly with one hand at the basket and one hand on the handle, with the arms held out straight, bring the pole from the waist to above the head, repeating the motion slowly to the limits of the range of motion. With the arms above the head, lean the ski pole as far as possible to the left and then to the right. This motion should be repeated with the arms in front of the body, both held out straight and in the flexed position. Many other shoulder stretches are available and most are helpful as long as sharp pain is avoided.
Strengthening of the shoulder rotator cuff muscles is best performed by isolating each muscle group and selectively training that muscle. The subscapularis is the anterior stabilizer of the rotator cuff and responsible for internally rotating the shoulder. It is best strengthened by holding a hand weight in front of the body, with the arm flexed to 90 degrees, and rotating the hand to touch the belt. The exercise can be performed while lying on your back with the elbow close to your side and flexed ninety degrees. Lift the weight until it is pointing toward the ceiling and then lower it slowly. The supraspinatus is strengthened by holding a light weight (initially 3-5 lbs) out straight in front of the body, with the thumbs pointed toward the floor. Slowly elevate the weight to above the head. Stop if pain is produced in any portion of this motion, as the rotator cuff is under maximal stress in this position. The infraspinatus is strengthened by holding the weight in the position of the ski pole just prior to planting the pole. By rotating the arm from the neutral straight ahead position, to the externally rotated (out to the side) position, the infraspinatus and teres minor are strengthened. Again, this exercise can also be performed while lying on your side with the elbow close to your hip, and flexed ninety degrees. Rotate the weight until it is pointing toward the ceiling. Shoulder exercises are best performed with relatively light weights and multiple repetitions.
The logic behind stretching and strengthening the inflamed rotator cuff in order to speed healing and functional performance is as follows: the inflamed tissue is characterized by increased fluid between the cells, increased numbers of new blood vessels and inflammatory type cells. As a result of this inflammatory reaction, new collagen tissue is laid down in an effort by the body to heal the injured tissue. If the shoulder is immobilized during this time, the new collagen is laid down in a disorganized fashion, creating scar. The goal of gentle stretching, strengthening and anti-inflammatory medication, is to stimulate the cells to lay down collagen along the lines of stress, forming normal strong tendons. The combination of a good warm up, gentle stretching, strengthening below the limits of pain, icing after working out and anti-inflammatory medication has been consistently shown to speed recovery time in the strongest possible fashion.
Shoulder injuries can be diminished by careful warmup, stretching, and strengthening of the shoulder muscles. The exercises described above for treatment of the injured shoulder are superb for a general conditioning program. When shoulder injury symptoms begin, early evaluation and treatment can prevent mild inflammation from becoming full blown rotator cuff impingement, or worse, a tear of the rotator cuff. A program of twenty minutes a day of shoulder stretches and muscle strengthening exercises is recommended to increase performance and decrease injuries. As “chance favors the prepared mind”, so does injury haunt the unprepared athlete.
The rotator cuff muscles are susceptible to injury from falls. The injuries are usually treatable with stretching, strengthening, and anti-inflammatory medication with full return to sports expected. Careful differentiation between inflammation and tearing of the rotator cuff is mandatory. If the cuff is torn, early arthroscopic or open repair is often helpful. Preventive conditioning exercises can diminish the frequency of these injuries.