Joint, Ligament and Muscle Disorders

Shoulder Replacement

Anatomy

The shoulder is a ball-and-socket joint. The ball, or head of the upper arm fits into a shallow socket in the shoulder blade. The shoulder is made up of: the upper arm bone (humerus), shoulder blade (scapula), collarbone (clavicle), and shallow socket (glenoid). The ends of these bones, where they touch, are covered with articular cartilage, a smooth substance that protects the bones and enables them to move easily. All remaining surfaces of the shoulder are covered by a thin lining, or synovial membrane that releases fluid to lubricate the cartilage and eliminate friction. Normally, these components work together in harmony, but when disrupted by disease or injury the result can be pain, muscle weakness and reduced function. Stability and support is provided by muscles and tendons that surround the shoulder. Working together, these structures allow the shoulder to rotate through a greater range of motion than any other joint in the body.

Description

In shoulder replacement surgery, the damaged parts of the shoulder are removed and replaced with artificial components, called prosthesis. Options include replacement of only the ball (head of the humerus bone), or replacement of both the ball and the socket (glenoid).

Symptoms

People who benefit from this surgery often experience one or more of the following: severe shoulder pain that interferes with everyday activities such as reaching into a cabinet, dressing, and washing; moderate to severe pain while resting, day or night, possibly severe enough to prevent a good night's rest; loss of motion and/or weakness in the shoulder; and failure to substantially improve with treatments such as anti-inflammatory medications, cortisone injections, or physical therapy.

Causes

• Osteoarthritis—Usually occurring in those 50 years of age and older, but may also occur in younger people. In osteoarthritis, the cartilage that cushions the bones of the shoulder softens and wears away, allowing the bones to rub against each other and resulting in pain and stiffness. Development of this degenerative joint disease cannot be prevented and it is a common cause of shoulder replacement surgery.
• Rheumatoid arthritis (RA)—The most common form of inflammatory arthritis, this autoimmune disease causes the synovial membrane to become chronically inflamed and thickened, damaging the cartilage and leading to pain and stiffness.
• Post-traumatic arthritis—This can follow a fracture of the bones that make up the shoulder, tears in shoulder tendons or ligaments, or other serious injury that causes damage to the articular cartilage over time, resulting in pain and limited function.
• Rotator cuff tear arthropathy—Changes in the shoulder joint due to a large, long-standing rotator cuff tear may develop cuff tear arthropathy, leading to arthritis and destruction of the joint cartilage.
• Avascular necrosis (osteonecrosis)—When the blood supply to the bone is disrupted, bone cells die, leading to osteonecrosis. This painful condition can ultimately cause destruction of the shoulder joint and lead to arthritis. Chronic steroid use, deep sea diving, severe fracture of the shoulder, sickle cell disease, and heavy alcohol use are risk factors for avascular necrosis.
• Severe fractures—Because a severe fracture of the shoulder may be extremely difficult to piece back together, and the blood supply to the pieces of bone may be interrupted, a shoulder replacement may be recommended. Older patients with osteoporosis are most at risk for this type of fracture.
• Failed previous shoulder replacement surgery—Although uncommon, some shoulder replacements fail due to implant loosening, wear, infection, and dislocation. When this occurs, a second joint replacement, called a revision surgery, may be necessary.

Evaluation and Recommendation

Recommendations for this surgery are based on your level of pain and disability. Before recommending shoulder replacement, your orthopaedic surgeon will provide an evaluation based on multiple factors, including: your medical history; a discussion of your level of pain and ability to perform daily activities; a physical examination to assess the motion, stability and strength; and X-rays to determine the extent of damage in the shoulder, including loss of normal joint space between bones, flattening or irregularity in the shape of the bone, bone spurs, or loose pieces of cartilage or bone floating inside the joint. Occasionally, additional testing such as blood tests or an MRI scan may be needed to determine the condition of the bone and soft tissues of your shoulder. Once the evaluation is complete, your doctor will review the results with you and discuss whether shoulder replacement is the best method to relieve your pain and improve your function. Options such as medications, physical therapy or other types of surgery may also be considered.

The decision to undergo shoulder replacement surgery should be a cooperative one made by you and your family along with your primary care doctor and orthopaedic surgeon. Your doctor will explain the benefits along with any potential risks and complications, both relating to the surgery and that could occur over time.

Shoulder Replacement Options

Shoulder replacement is a highly technical surgery that should be performed by an orthopaedic surgeon and surgical team with experience in this procedure. There are different types of shoulder replacements. Your surgeon will evaluate your situation carefully and discuss with you which type of replacement would best meet your needs. Do not hesitate to ask questions about the type of implant chosen and why it was recommended for you.

• Total shoulder replacement—A typical total shoulder replacement involves replacing the arthritic joint surfaces with a highly polished metal ball attached to a stem, and a plastic socket. These components come in various sizes and may be either cemented or press-fit into the bone. If the bone is of good quality, your surgeon may choose to use a noncemented, or press-fit, humeral component. If the bone is soft, the humeral component may be implanted with bone cement. In most cases, an all-plastic glenoid (socket) component is implanted with bone cement. Implantation of a glenoid component is not advised if the glenoid has good cartilage, the glenoid bone is severely deficient or if the rotator cuff tendons are irreparably torn. Patients with bone-on-bone osteoarthritis and intact rotator cuff tendons are generally good candidates for conventional total shoulder replacement.
• Stemmed hemiarthroplasty—Depending on the condition of your shoulder, your surgeon may replace only the ball, in a procedure called a hemiarthroplasty. In a traditional hemiarthroplasty, the head of the humerus is replaced with a metal ball and stem, similar to the component used in a total shoulder replacement. This is called a stemmed hemiarthroplasty. Some surgeons recommend hemiarthroplasty when the humeral head is severely fractured but the socket is normal. Other indications for a hemiarthroplasty include: arthritis that only involves the head of the humerus, with a glenoid that has healthy, intact cartilage surface; shoulders with severely weakened bone in the glenoid; and some shoulders with severely torn rotator cuff tendons and arthritis. On some occasions, the surgeon will make the decision between total shoulder replacement and hemiarthroplasty in the operating room at the time of the surgery. Studies show that patients with osteoarthritis get better pain relief from total shoulder arthroplasty than from hemiarthroplasty.
• Resurfacing hemiarthroplasty—Resurfacing hemiarthroplasty involves using a cap-like prosthesis without a stem to replace only the joint surface of the humeral head. Because of its bone-preserving advantage, this procedure provides an alternative to standard stemmed shoulder replacement for patients with arthritis. Resurfacing hemiarthroplasty may be an option for you if: the glenoid has an intact cartilage surface; there has been no fresh fracture of the humeral neck or head; and there is a desire to preserve humeral bone. For patients who are young or very active, resurfacing hemiarthroplasty avoids the risks of component wear and loosening that may occur with conventional total shoulder replacements. Due to its more conservative nature, resurfacing hemiarthroplasty may be easier to convert to total shoulder replacement, should it become necessary at a later time.
• Reverse total shoulder replacement—In reverse total shoulder replacement, the socket and metal ball are switched, so the metal ball is attached to the shoulder bone and a plastic socket is attached to the upper arm bone. This allows the patient to use the deltoid muscle instead of the torn rotator cuff to lift the arm. This is typically recommended for patients with: completely torn rotator cuffs with severe arm weakness; effects of severe arthritis and rotator cuff tearing (cuff tear arthropathy); or a previous shoulder replacement that has failed. For these individuals, a conventional total shoulder replacement can still leave them with pain or an inability to raise their arm past a 90-degree angle, which can be severely debilitating.

Preparation

Once the decision to have surgery is made, your orthopaedic surgeon will require some preparations, such as: having a complete physical, including evaluation by your primary care physician for any chronic medical conditions; making sure any skin infections or irritations are treated; blood donations, in the event you may need it after surgery; medication review and management; dental evaluation; urinary evaluation; and a variety of tests, such as blood and urine samples, electrocardiogram (EKG), and chest X-ray, as needed.

• For after surgery—For several weeks after your surgery, it will be difficult to reach high shelves and cupboards, so be sure to go through your home and place any items you may need afterwards on lower, easy-to-reach shelves. When you come home from the hospital, you will need some help for a few weeks with daily tasks as cooking, shopping, bathing and laundry. If you live alone, your orthopaedic surgeon's office, a social worker, or a discharge planner at the hospital can help you make advance arrangements for assistance at your home. You may also arrange for a short stay in an extended care facility during your recovery until you become more independent.

Surgery

Wear loose-fitting clothing and a button-front shirt when you go to the hospital for your surgery. Following surgery, you will wear a sling and have limited use of your arm. After admission into the hospital, you will be evaluated by a member of the anesthesia team. The most common types of anesthesia are general anesthesia (you are put to sleep), a regional anesthesia (you are awake but your body is numb around the surgical), or a combination of the two. The anesthesia team, with your input, will determine the best option for you. Your surgeon will see you before the surgery and sign your shoulder to verify the surgical site. The surgical procedure itself takes approximately 2 hours.

Following surgery, you will be moved to the recovery room where your recovery from the anesthesia will be monitored for several hours. Once you are awake, you will be taken to your hospital room. You can expect to be in the hospital for a few days. You will feel some pain after surgery, but your surgeon and nurses will provide medication to make you as comfortable as possible. Pain management is an important part of your recovery because feeling less pain will allow you to start moving and get your strength back more quickly. If postoperative pain becomes a problem, speak with your surgeon.

Recovery

When you leave the hospital, your arm will be in a sling. You will need the sling to support and protect your shoulder for two to four weeks after your shoulder replacement.

• Rehabilitation—A well-planned rehabilitation program is critical to the success of your shoulder replacement. Gentle physical therapy is usually begun soon after the operation. Your surgeon or physical therapist will provide you with a home exercise program to strengthen your shoulder and improve flexibility.
• Wound care—Stitches or staples will be removed several weeks after surgery. A suture beneath the skin will not require removal. Avoid soaking the wound in water until it has thoroughly sealed and dried. You may continue to bandage the wound to prevent irritation from clothing or support stockings.
• Activity—Exercise is a critical component of home care, particularly during the first few weeks after surgery, and following the home exercise plan your surgeon or physical therapist provides will help you regain your strength. Most patients are able to perform simple daily activities such as eating, dressing and grooming within two weeks after surgery. Some pain or discomfort with activity and at night is common for several weeks or more. Driving a car is not allowed for two to four weeks after surgery.

Your activity program should include: a graduated walking program to slowly increase your mobility, initially indoors and later outside; resuming normal household activities, such as sitting, standing and climbing stairs; specific exercises to restore movement and strengthen your shoulder, performed several times a day. If needed, you may have a physical therapist help you at home or in a therapy center the first few weeks after surgery.

Dos and Don'ts

The success of your surgery will depend largely on how well you follow your orthopaedic surgeon's instructions during the first few weeks after surgery. Here are some common guidelines for when you return home.

• Do—Follow the program of exercises prescribed for you, doing them 2 or 3 times a day for a month or more.
• Do—Ask for assistance if you need it. Your physician may be able to recommend an agency or facility if you do not have home support.
• Do—Avoid placing your arm in any extreme position, such as straight out to the side or behind your body, for 6 weeks after surgery.

• Don't—Do not use your arm to push yourself up in bed or from a chair because this requires forceful contraction of muscles.
• Don't—Do not overdo it! If your shoulder pain was severe before the surgery, the experience of pain-free motion may lull you into thinking that you can do more than is prescribed. Early overuse of the shoulder may result in severe limitations in motion.
• Don't—Do not lift anything heavier than a glass of water for the first 2 to 4 weeks after surgery.
• Don't—Do not participate in contact sports or do any repetitive heavy lifting after your shoulder replacement.

Outcomes

Many thousands of patients have experienced less pain, improved motion and strength, better function, and an improved quality of life after shoulder joint replacement surgery.

You should know that your new implant might activate metal detectors required for security in airports and some buildings. Tell the security agent about your shoulder replacement if the alarm is activated.

Complications

Your orthopaedic surgeon will explain the potential risks and complications of shoulder joint replacement, including those related to the surgery itself and those that can occur over time after your surgery. When complications do occur, most are successfully treatable.

• Infections—Minor or deep, infections are potential complications of any surgery, and may occur in the wound or around the prosthesis and may happen in the hospital or after you return home. Any infection in your body can spread to your joint replacement; so if you suspect an infection, contact your doctor immediately.
• Prosthesis problems—Although designs, materials and surgical techniques continue to advance, you may eventually experience loosening and wear of your prosthesis, or the components of your shoulder replacement may dislocate. Excessive wear, loosening, or dislocation may require additional surgery (revision procedure).
• Nerve injury—Although infrequent, nerves in the vicinity of the joint replacement may become damaged during surgery. Over time, these injuries often improve and may completely recover.