The shoulder joint has great range-of-motion, but not much stability. The rotator cuff tendons are one of the key reasons that the shoulder is so useful. However, the tendons are prone to damage due to wear and tear and injury, or both.
The tendons can be subject to a considerable amount of wear and tear or degeneration as we use our arms, especially during overhead activities. This wear and tear can lead to weakening of the rotator cuff tendons through a condition known as impingement. The rotator cuff tendons are also subject to degeneration as we age. An injury to these tendons can result in a weak and painful shoulder due to tearing of the rotator cuff tendons.
The shoulder is made up of three bones: the scapula (shoulder blade), the humerus (upper arm bone) and the clavicle (collarbone).
Tendons attach muscles to bones. The tendons of four muscles form the rotator cuff. These muscles are called the supraspinatus, infraspinatus, teres minor and subscapularis. Muscles are able to move bones by pulling on tendons.
The rotator cuff tendons connect the humerus with the scapula (shoulder blade) and helps raise and rotate the arm.
As the arm is raised, the rotator cuff also holds the humerus tightly in the socket (glenoid) of the scapula.
The part of the scapula that makes up the roof of the shoulder is called the acromion. Between the acromion and the rotator cuff tendons, there is a structure called a bursa. The bursa is a lubricated sac of tissue that protects the muscles and tendons as they move against one another. There are many bursae all over the body where tissues must move against one another. The bursa allows the moving parts to slide against one another without too much friction.
Rotator cuff tears usually occur in areas of the tendon that were not normal to begin with and have been weakened by degeneration and impingement. Many studies have shown that the rotator cuff tendons have areas where there is a poor blood supply. Adequate blood supply to the tissue allows it to repair itself from day-to-day wear and tear.
Poor blood supply in the tendon makes the rotator cuff tendons especially vulnerable to degeneration with aging. As we age, our body’s ability to provide an adequate blood supply to the body diminishes so areas already receiving an inadequate supply become further strained.
The weakened rotator cuff tendons can be injured and torn by an excessive force, such as trying to catch a falling heavy object or lifting an extremely heavy object with the arm extended. This can occur even in a young person.
Typically, a rotator cuff tear occurs in people who are nearing the end of their middle-aged years. They have usually experienced problems with the shoulder for some time before the event that causes the tear. A tear usually occurs when lifting something that exceeds the strength of the tendons. The tendon tear usually results in an inability to raise the arm and may be accompanied by pain.
Rotator cuff tears cause two main problems, pain and weakness. In some cases, a rotator cuff tear may involve only a partial tear of the tendons. You may have pain, but can continue to move the arm in a normal range of motion. In other cases, a complete rupture of the tendons occurs, and the arm can no longer be moved in a normal range of motion. A complete rotator cuff tear usually results in an inability to raise the arm away from the side without assistance.
Most rotator cuff tears cause a vague pain in the shoulder area and may result in a “catching” sensation when the arm is moved. The larger the tear in the tendon, the more weakness there is when trying to move the arm. Most people report an inability to sleep on the affected side due to pain.
A rotator cuff tear can usually be identified during a physical examination. A complete tear is usually very obvious. If your doctor can move the arm in a normal range of motion, but you are unable to move the arm using your own strength, there is a high likelihood of a tear in the tendons.
X-rays may show the rotator cuff tear, but a test called an arthrogram is usually required. This test is done by injecting dye into the shoulder joint and taking several X-rays. If the dye leaks out of the shoulder joint where it was placed, it suggests that there is a tear in the rotator cuff tendons.
The magnetic resonance imaging (MRI) scan can also be used to look at the rotator cuff tendons and determine whether or not they are torn. An MRI scan is a special radiological test where magnetic waves are used to create pictures that look like slices of the shoulder. The MRI scan shows the shoulder bones and whether the tendons have been torn. The MRI scan is painless and requires no needles or dye to be injected. The arthrogram is an older test, but the tests are still widely used.
Initial treatment for a suspected rotator cuff tear is rest and anti-inflammatory medication, mainly to control pain. While a true rotator cuff tear will not heal, some partial tears will become very tolerable and may not require a surgical repair. As soon as pain tolerance permits, physical therapy to regain motion can begin.
A cortisone injection may be suggested if you are still experiencing pain after several weeks of conservative care. After a reasonable time, if the pain is not tolerable or the motion of the arm is not acceptable, an arthrogram or MRI scan may be suggested to plan for surgery.
Small tears of the rotator cuff can be sometimes treated with arthroscopic debridement. The surgeon uses an arthroscope to help him see any torn fibers within the tendon and remove (debride) them. An arthroscope is a tiny camera that helps surgeons perform procedures through a small incision.
Surgeons can also use an arthroscope to perform surgery to repair a torn rotator cuff. In most cases, repairing the tendons involves first removing any unhealthy, degenerative rotator cuff tissue. Then, an area of the humerus (the upper arm bone) where the tendon was torn is prepared for reattachment of the tendon. The soft tissue is removed on an area of the humerus to form a raw bony area for attachment of the torn tendon.
Drill holes are made in the humerus to allow sutures to be placed through the bone to re-attach the tendon.
The tear in the tendon is then sewn together. Other sutures are used to attach the tendons to the bone of the humerus by looping the sutures through the drill holes. The tendon heals to the bone over time and reattaches itself. In some cases, surgeons may also use suture anchors which are fasteners that can anchor the rotator cuff to the humerus.
In some instances, rotator cuff repair must be performed by open surgery. Open surgery involves the surgeon cutting through the muscles and tissues at the front of the shoulder to access the rotator cuff and repair the shoulder.
If you are a candidate for arthroscopic repair, you may be able to go home from the hospital the same day. Following open surgery, you may spend one or two nights in the hospital.
Expect to begin physical therapy soon after surgery. The repair must be protected, mainly to keep the sutures from pulling free, but early range of motion exercises will lead to a quicker recovery. Three to six weeks following surgery, the therapist will begin more active exercises to start regaining the strength in the rotator cuff muscles. Recovery from shoulder surgery can take several months. Getting the shoulder moving as quickly as possible is important, but this must be balanced with the need to protect the healing muscles and tissues.
As mentioned earlier, a rotator cuff tear does not usually occur in a normal shoulder. Most shoulders that have suffered a rotator cuff tear have other problems as well. The same problems that caused the rotator cuff tear will most likely affect the rest of the shoulder. These can include acromioclavicular (AC) joint arthrosis and impingement syndrome. When surgery is suggested, the surgical procedure may have to address these conditions as well.
Finally, not all rotator cuff tears are repairable. Sometimes, the tendon has been torn for too long. This can lead to the tendon and muscle contracting. The muscle and tendon cannot be stretched enough to be re-attached to its original position. In other cases, the tendon tissue has simply worn away, and the remaining tendon is not strong enough to hold the stitches necessary to attach the tendon to bone. In these circumstances, simply removing all the torn tissue and fixing any other problems in the shoulder, such as AC joint arthrosis and impingement syndrome, may reduce your pain. It will probably not increase the strength or motion of the shoulder. It may actually decrease the motion.
If all of these attempts to improve your shoulder fail to give you a useable shoulder, there are other more complex and involved procedures that include tendon grafts and muscle transfers. These are rarely necessary, but your doctor will discuss these options with you if suggested by your situation.