Rotator Cuff Tear Arthropathy
What is cuff tear arthropathy?
The rotator cuff is a unique structure in the shoulder that is formed by four tendons. These four tendons attach to four muscles that help keep the shoulder stabilized in the socket (or glenoid) and help rotate the upper arm inward and outward. If the rotator cuff is torn and is not repaired, a type of wear and tear arthritis of the shoulder can develop over time. This condition is sometimes called arthropathy and the term cuff tear arthropathy is used to describe this type of arthritis of the shoulder that develops when the rotator cuff is damaged.
What parts of the shoulder are involved?
The bones of the shoulder are the humerus (the upper arm bone), the scapula (the shoulder blade), and the clavicle (the collar bone). The roof of the shoulder is formed by a part of the scapula called the acromion. The shoulder joint is also called the glenohumeral joint. One of the bones of the glenohumeral joint is the humerus (the long bone of the upper arm). It has a ball, called the humeral head on the top end. The humeral head fits into a small, shallow cup called the glenoid fossa. It makes up the other part of the glenohumeral joint. The glenoid fossa is part of the shoulder blade.
The rotator cuff is made up of tough, fibrous tissue. It forms a cuff (or capsule) covering the shoulder joint. There are four tendons that help form the rotator cuff. The muscles that form the tendons are the supraspinatus, infraspinatus, teres minor, and subscapularis. These muscles rotate the shoulder outward and inward. Along with another muscle, the deltoid, they also help lift the arm away from the body.
The rotator cuff slides between the humeral head and the acromion as we raise our arm. As this sliding occurs over and over, the rotator cuff tendons will often be pinched as you use the shoulder everyday. This pinching is called impingement. Over time this pinching can lead to damage and weakening of the rotator cuff tendons.
What causes it?
Cuff tear arthropathy is actually a type of wear and tear, or degenerative arthritis of the shoulder that develops over time after the rotator cuff is damaged. Normally, when the rotator cuff muscles contract, they pull the head of the humerus tightly into the socket of the shoulder. This stabilizes the shoulder and allows the large deltoid muscle to raise the arm over the head. When the rotator cuff is torn, the shoulder can become unbalanced. This causes an abnormal sliding motion that causes wear and tear on the joint surfaces. Arthritis develops and any motion becomes painful. The shoulder becomes weaker and weaker until you can no longer raise the arm above the head.
What are the symptoms?
The most common symptom of rotator cuff tear arthropathy is pain in and around the shoulder. The pain can also radiate into your neck, arm, even into your wrist or hand. The shoulder can be especially painful when trying to lift the arm, or rotate it outward. The pain is usually worse at night. It can interrupt your sleep, especially if you try to sleep on the affected shoulder. If untreated, the pain can be nearly continuous and can be severe. Weakness of the shoulder makes it difficult, if not impossible to lift the arm overhead. Often, even starting this motion can be difficult. The tendency is to shrug the shoulder in order to lift the arm part of the way. With time, weakness of the rotator cuff muscles will worsen. Range of motion can be quite limited. You will often find it difficult to do routine things, like reaching behind your back, reaching into a cabinet, or combing your hair. You may notice a crackling or popping sensation. When there is arthritis of the glenohumeral joint, there is often a creaking or grating sound.
How is it diagnosed?
Your doctor will want to do a history and physical examination. He will ask you about activities or trauma that could have injured your shoulder. He will want to know the level of your pain, and what limitations you have. A physical examination is done. Range of motion and strength of the shoulder muscles will be evaluated. Your doctor will want to look at your shoulder to see if there is bony deformity, or atrophy (shrinkage) of the muscles. With a complete rotator cuff tear, moving the arm away from the body can be nearly impossible. If your doctor lifts your arm for you, and you cannot hold it up, this is called a positive Drop Arm Test. This usually means the rotator cuff is torn.
Your doctor will request X-rays of your shoulder. X-rays show the shape of the bones and joints. When the rotator cuff is torn, the shoulder will often ride high, meaning that it sits higher in the joint than it should. It can also show how much damage has occurred to the joint surfaces. Magnetic resonance imaging (MRI) or a computerized tomography (CT) scan may be necessary to complete the evaluation or plan treatment.
What is the treatment?
Care that includes physiotherapy, ice, heat, and anti-inflammatories is tried first. The goal of treatment is to reduce pain, and increase range of motion and function. Corticosteroid injection into the shoulder joint is also sometimes helpful. Steroids are very powerful anti-inflammatory medications that can reduce pain temporarily. These injections will not heal the tear but may give pain relief for several weeks to months. If arthritis of the shoulder is advanced, and pain is continuous and severe, surgery may be the best option available.
Cuff tear arthropathy is the result of long standing lack of rotator cuff function. In almost all cases, repair of the rotator cuff tear is no longer an option. Surgery for cuff tear arthropathy is done when pain and decreased motion continue after conservative care. The simplest surgical procedure to try and improve the situation is a debridement. During a debridement, the surgeon will surgically remove (debride) any inflammed tissue, bones spurs and loose flaps of tendon tissue that may be catching in the joint and causing pain. This procedure may reduce pain, however, it does not always improve range of motion, strength, or function of the shoulder.
Patients with this type of arthritis would seem to be good candidates for a shoulder replacement, but replacing the shoulder in the traditional fashion has not been successful. Replacing the shoulder with a special type of artificial shoulder joint is becoming more popular. This procedure is called a reverse shoulder replacement. The "normal" artificial shoulder was designed to copy our real shoulder. In the "reverse" replacement, the artificial socket is put where the native ball, or humeral head, use to be, and the artificial ball is put where the native socket, or glenoid, used to be.
This new design leads to a much more stable shoulder joint that can function without a rotator cuff. The final result is a shoulder that functions better, is less painful and can last for years without loosening.