"Oh, My Aching Shoulder!"
by Arif Saleem, M.D.

Shoulder pain is one of the most common reasons that patients see an orthopedic physician. When an orthopedic surgeon evaluates a shoulder, he is determining the source of pain, which could be due to several factors. The shoulder joint is made up of the humer-al head or ball at the top of the bone of the upper arm, the glenoid or socket of the shoulder joint, the acromion or upper part of the shoulder blade, and the clavicle or collar bone. The muscles that power movement of the shoulder include the muscles of the rotator cuff and the large deltoid muscle that provides the rounded contour of the shoulder. Any one of these bones or muscle groups can potentially be a source of shoulder pain. Furthermore, when the articular cartilage (the smooth covering over the ends of the bones) of the humerus and the glenoid is destroyed, patients have shoulder arthritis. A typical presenting symptom of shoulder arthritis is the gradual onset of dull aching pain which usually worsens as the arthritis progresses. Often patients have difficulty sleeping at night due to an inability to lie on the affected shoulder. As the arthritis progresses, patients notice a decrease in their ability to perform tasks overhead or with the arm away from their body. In addition, patients usually report a locking, catching, or grinding sensation when moving the shoulder joint. X-rays are used to confirm the diagnosis and show a loss of joint space, osteophyte formation (or bone spurs), and irregular joint surfaces. The following are some common questions patients have regarding shoulder arthritis.

What causes arthritis of the shoulder?

There are many causes for shoulder arthritis but ultimately all result in a painful, stiff joint. The normal humeral head (ball) is covered with smooth cartilage which slides on the smooth cartilage covering of the glenoid (socket). An arthritic condition destroys these layers of cartilage and results in bare bones sliding against each other.

The most common form of arthritis is osteoarthritis which has traditionally been thought of as “wear and tear” arthritis; however, current research suggests a biochemical process as well as a mechanical degeneration of the joint. X-rays of osteoarthritic shoulders show not only joint space narrowing but also bone spurs on both the humeral head and the glenoid. Other common forms of shoulder arthritis include inflammatory or rheumatoid arthritis, arthritis due to avascular necrosis, and arthritis due to a chronic massive rotator cuff tear. Rheumatoid arthritis is a chronic inflammatory joint disease which affects the lining of the joint, also called the synovium. Inflammation of the synovium destroys the cartilage surfaces of the shoulder joint, resulting in deterioration of the joint and sometimes even erosion of the bone. Rheumatoid arthritis is a systemic disease which can affect multiple joints throughout the body. Avascular necrosis is the result of an impairment of the blood supply to the humeral head, which can be due to trauma or a number of other causes including the use of steroid medications. Avascular necrosis causes death and deterioration of the bone, resulting in subsequent deterioration and destruction of the overlying cartilage surface. In the shoulder this form of arthritis usually only affects the humeral head, except in advanced disease when the glenoid may also be affected. Arthritis due to a massive rotator cuff tear results from joint instability caused by nonfunctioning rotator cuff muscles. This instability allows the humeral head to rub eccentrically on the glenoid socket, causing abnormal wear on the top of the glenoid.

What are my treatment options if I am diagnosed with shoulder arthritis?

The first step in treating an arthritic condition is to decrease the stress on the joint by modifying daily activities and avoiding painful positions. For example, to help avoid shoulder aches and pains, items used daily should be placed at waist-level rather than at shoulder-level or above. If activity modification alone does not offer substantial relief, an anti-inflammatory medication may be prescribed by a physician. These medications are designed to decrease the inflammatory response in an arthritic joint, which will often allow return to an increased level of activity. There are a number of over-the-counter remedies marketed to the public which may not effectively treat arthritic conditions. It may be prudent to seek the advice of a physician before investing in these remedies. Physical therapy for an arthritic joint has limited goals such as maintaining mobility and muscle tone. In advanced arthritis, physical therapy is prescribed sparingly because it often increases pain without increasing shoulder mobility or patient function.

If the shoulder is persistently painful despite medications and activity modification, consideration may be given to the use of a corticosteroid injection into the shoulder joint. A physician would administer this injection directly into the joint, and it is usually quite well tolerated. The injection would help to decrease joint inflammation and may offer quick relief for a chronic condition. The length of pain relief from the injection is variable, with some patients having long standing relief from a single injection while others report only several days of improvement. If the previous options fail to improve the pain and loss of function from the arthritic condition satisfactorily, surgery may be a reliable option to control the pain of shoulder arthritis and improve shoulder mobility and daily function.

What are the surgical options for shoulder arthritis?

In very early arthritic conditions a small operation, such as a shoulder arthroscopy, is occasionally considered. A shoulder arthroscopy is used to “wash out” the joint and smooth roughened surfaces and release tight structures to allow for greater shoulder movement. Ultimately, however, the most reliable treatment for relief of pain and restoration of function in an advanced arthritic shoulder joint is a shoulder replacement. A standard shoulder replacement uses a metal ball with a stem (the humeral component) to replace the arthritic humeral head, and a plastic socket to replace the arthritic glenoid socket. Once the smooth surfaces of the joint are restored, pain relief is usually quite prompt. Even thought the most predictable outcome after a successful shoulder replacement is pain relief, improvement in shoulder function also results in the ability to perform many more tasks with greater ease and comfort.

How is shoulder replacement surgery performed and how will I recover?

An orthopedic surgeon will perform the surgery by first creating an incision in the front of your shoulder from the collar bone to the front of the arm. Usually, general anesthesia is required for this surgical procedure. In order to expose the shoulder during surgery, one of the rotator cuff tendons must be cut and subsequently repaired at the end of the surgery. Next, the humeral component is inserted into the humerus after the arthritic humeral head is removed. Finally, the glenoid socket is shaved down and contoured to fit a new plastic glenoid socket which is usually cemented in place. After surgery an immobilizer will help minimize shoulder movement and promote soft tissue healing by keeping the operated arm close to the body. The hospital stay is routinely two to three days. To allow proper healing of the rotator cuff muscles, the orthopedic physician will recommend limited shoulder motion for several weeks. However, a physical therapist may move the operated arm to maintain motion in the shoulder joint. Once the physician is comfortable that the repaired rotator cuff tendons have healed, the patient will be allowed to gradually begin movement of the arm. Typically, three months after surgery, shoulder motion will be substantially improved at which point the physician will allow further strengthening and use of the shoulder muscles.

What are some risks of shoulder replacement surgery?

As with any surgical intervention, risks of anesthesia are present. Specific risks associated with shoulder replacement include infection, injury to blood vessels and nerves, instability of the joint, and long-term failure of the shoulder prosthesis. Infection can be a serious complication, and further surgery may be required to eradicate the infection. Several precautions are taken to prevent infections during surgery including the use of antibiotics before and after surgery. Injury to blood vessels and nerves is fairly uncommon but have been reported. Most cases of nerve injury result in temporary loss of function and most recover fully spontaneously. The most common reason for developing postoperative instability of a shoulder replacement is failure of the rotator cuff tendons to heal properly after surgery. Therefore, it is extremely important to comply with physician restrictions on shoulder movement after surgery to maximize healing. Lastly, long-term studies of shoulder replacement have shown that loosening of the shoulder replacement prosthetic parts, especially the glenoid socket, could occur. New designs and cementing techniques seem to be decreasing the former potential long-term complications.

The physicians at Castle Orthopaedics & Sports Medicine, S.C., are dedicated to providing you with optimal care for your shoulder problems by using the latest proven technology to restore your shoulder’s function. Should you have further questions regarding shoulder arthritis or shoulder replacement surgery, please ask your Castle Orthopaedics physician.

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