Advances in Joint Replacement
September 14, 2009
Dr. Christie and Dr. Hodrick
The number of total knee replacements performed in the U.S. will leap by 673% -- reaching 3.48 million -- by the year 2030. Hip replacements will increase by 174% to 572,000 by 2030, according to the new findings, which are based on historical procedure rates from 1990 to 2003 and population projections from the U.S. Census Bureau.
"There is a huge swell of elderly patients from the baby boom who will come through the system and be candidates for artificial joints," explains researcher Steven M. Kurtz, PhD, office director and principal engineer at Exponent Failure Analysis Associates in Philadelphia.
Affecting close to 21 million people, OA of the knee and hips is the most common cause of arthritis-related disability in the U.S, according to statistics from the Arthritis Foundation.
What is Total Joint Replacement Surgery?
Joint replacement surgery, considered when pain and disability have not been controlled by conservative treatments such as exercise and medicine, and joint damage is visible on X-rays.
Joint replacement involves surgery to replace the ends of bones in a damaged joint. This surgery creates new joint surfaces. A person may want to consider joint replacement surgery if they have a stiff, painful joint that prevents them from performing even the simplest of activities and other treatments are no longer working.
Causes for Joint Replacement Surgery
Osteoarthritis is a condition in which the cartilage that protects and cushions the joints breaks down over time. Eventually, the bones-formerly separated by the cartilage-rub against each other, resulting in damage to the tissue and underlying bone and causing painful joint symptoms.
Osteoarthritis is the most common form of arthritis and is a major cause of disability in older adults. It most often affects the spine, fingers, thumbs, hips, knees, or toes.
The symptoms of osteoarthritis can usually be successfully managed with medication and home treatment. Although osteoarthritis usually gets worse, in some cases symptoms may not get worse or may even improve slightly with time. Lifestyle changes like weight loss may also be necessary to reduce stress on weight-bearing joints. Joint replacement surgery may be necessary in severe cases.
Rheumatoid arthritis (RA) is a relatively common disease of the joints. In rheumatoid arthritis, the membranes or tissues (synovial membranes) lining the joints become inflamed (synovitis). Over time, the inflammation may destroy the joint tissues, leading to disability. Rheumatoid arthritis affects women twice as often as men, and frequently begins between the ages of 40 and 60.
Exactly what triggers rheumatoid arthritis is not known, but it is in part due to abnormal immune system activity. Rheumatoid arthritis is an autoimmune disease, meaning the body's own immune system attacks the joint tissues. An inherited factor in some families (genetic predisposition) may increase the risk of developing rheumatoid arthritis.
The main symptoms of rheumatoid arthritis are pain, stiffness, and swelling in the joints of the hands, wrists, elbows, feet, ankles, knees, or neck. Rheumatoid arthritis usually affects both sides of the body at the same time. In rare but severe cases, rheumatoid arthritis may affect the eyes, lungs, heart, nerves, or blood vessels.
Types of Joint Replacement Surgeries
Knee Replacement Surgery
In knee replacement surgery, the ends of the damaged thigh and lower leg (shin) bones and usually the kneecap are capped with artificial surfaces lined with metal and plastic. Usually, doctors replace the entire surface at the ends of the thigh and lower leg bones. Doctors usually secure knee joint components to the bones with cement.
In knee replacement surgery, doctors remove the damaged cartilage and replace it with new joint surfaces in a step-by-step process.
Joint changes caused by osteoarthritis may also stretch and damage the ligaments that connect the thighbone to the lower leg bone. After surgery, the artificial joint itself and the remaining ligaments around the joint usually provide enough stability so that the damaged ligaments are not a problem.
Doctors most often use regional anesthesia for joint replacement surgery. That means you can't feel the area of the surgery and you are sleepy, but you are awake. The choice of anesthesia depends on your doctor, on your overall health, and, to some degree, on what you prefer.
What Happens During Knee Joint Replacement Surgery?
Once you are under general anesthesia (meaning you are temporarily put to sleep), spinal, or epidural (numb below the waist) anesthesia, an eight- to twelve-inch cut is made in the front of the knee. The damaged part of the joint is removed from the surface of the bones, and the surfaces are then shaped to hold a metal or plastic artificial joint. The artificial joint is attached to the thigh bone, shin and knee cap either with cement or a special material. When fit together, the attached artificial parts form the joint, relying on the surrounding muscles and ligaments for support and function.
What Are Recent Advances in Knee Joint Replacement Surgery?
Minimally invasive surgery (MIS) has revolutionized knee replacement surgery as well as many fields of medicine. Its key characteristic is that it uses specialized techniques and instrumentation to enable the surgeon to perform major surgery without a large incision.
MIS knee joint replacement requires a much smaller incision, three to five inches, versus the standard approach and incision, which is typically eight to twelve inches. The smaller, less invasive approaches result in less tissue trauma by allowing the surgeon to work between the fibers of the quadriceps muscles instead of requiring an incision through the tendon. It may lead to less pain, decreased recovery time and better motion due to less scar tissue formation.
Currently this less invasive procedure is performed by only a small percentage of orthopaedic surgeons in North America. Because this type of surgery is still relatively new, research has been initiated to determine how the immediate and long-term results will compare to traditional surgery.
What Happens After the Surgery?
The average hospital stay after knee joint replacement is usually three to five days. The vast majority of people who undergo knee joint replacement surgery have dramatic improvement. This improvement is most notable one month or more after surgery. The pain caused by the damaged joint is relieved when the new gliding surface is constructed during surgery.
After knee joint replacement, people are standing and moving the joint the day after surgery. At first, you may walk with the help of parallel bars, and then a walking device -- such as crutches, walker, or cane -- will be used until your knee is able to support your full body weight. After about 6 weeks, most people are walking comfortably with minimal assistance. Once muscle strength is restored with physical therapy, people who have had knee joint replacement surgery can enjoy most activities (except running and jumping).
How Long Will I Need Physical Therapy After Knee Joint Replacement?
After you are discharged from the hospital, you are usually sent home or to a rehabilitation facility, depending on your condition at that time. If you are sent to a facility, the average rehabilitation stay is approximately seven to ten days. If you are sent directly home from the hospital, your doctor will usually have a physical therapist come to treat you at home. Your doctor also may have you go to an outpatient physical therapy facility as the final stage of the rehabilitation process. Outpatient therapy may last from one to two months, depending on your progress.
Rehabilitation (rehab) after a knee replacement is intensive. The main goal of rehab is to allow you to bend your knee at least 90 degrees-enough to do daily activities, such as walking, climbing stairs, sitting in and getting up from chairs, and getting in and out of a car. Most people can get considerably more bending than 90 degrees after surgery. However, one of the factors that affects how much bend you get after surgery is how much bend you had before surgery. To get the most benefit from your surgery, it is very important that you take part in physical therapy both while you are in the hospital and after you go home from the hospital.
Will I Have to Avoid Certain Movements and/or Activities Following Surgery?
After knee joint replacement surgery, you should not pivot or twist on the involved leg for at least six weeks. Also during this time, when lying in bed, you should keep the involved knee as straight as possible. Kneeling and squatting also should be avoided soon after knee joint replacement surgery.
Your physical therapist will provide you with techniques and adaptive equipment that will help you follow guidelines and precautions while performing daily activities. Remember, not following the given precautions could result in the dislocation of your newly replaced joint.
How Can I Manage at Home During Recovery?
The following tips should make your recovery at home easier.
You should ask your doctor before returning to such activities as driving, sexual activity, and exercise.
Is Knee Joint Replacement Surgery Safe?
Knee joint replacements have been performed for years and surgical techniques are being improved all the time. As with all surgeries, however, there are risks:
How Long Will My New Joint Last?
When joint replacement procedures were first performed in the early 1970s, it was thought that the average artificial joint would last approximately 10 years. We now know that about 85 percent of the joint implants will last 20 years. Improvements in surgical technique and artificial joint materials should make these artificial joints last even longer.
Doctors may not recommend knee replacement for people who:
SOURCE: The Cleveland Clinic Department of Orthopaedic Surgery. American Academy of Orthopaedic Surgeons
Hip Replacement Surgery
Hip replacement surgery is a procedure in which a doctor surgically removes a painful or damaged hip joint and replaces it with an artificial joint. It usually is done when all other treatment options have failed to provide adequate relief. The procedure should relieve a painful hip joint, making walking easier.
What Happens During Hip Replacement Surgery?
Hip replacement surgery can be performed traditionally or by using what is considered a minimally-invasive technique. The main difference between the two procedures is the size of the incision.
During standard hip replacement surgery, you are given general anesthesia to relax your muscles and put you into a temporary deep sleep. This will prevent you from feeling any pain during the surgery. A spinal anesthetic also may be given to help prevent pain.
The doctor will then make a cut along the side of the hip and move the muscles connected to the top of the thighbone to expose the hip joint. Next, the ball portion of the joint is removed by cutting the thighbone with a saw. Then an artificial joint is attached to the thighbone using either cement or a special material that allows the remaining bone to attach to the new joint.
The doctor then prepares the surface of the hipbone -- removing any damaged cartilage -- and attaches the replacement socket part to the hipbone. The new ball part of the thighbone is then inserted into the socket part of the hip. A drain may be put in to help drain any fluid. The doctor then reattaches the muscles and closes the cut.
While most surgeries today are performed using the standard technique (one 8 to 10 inch cut along the side of the hip), in recent years, some doctors have been using a minimally-invasive technique to perform hip replacement. In the minimally-invasive approach, doctors make one to two cuts from 2 to 5 inches long. The same procedure is performed through these small cuts as with standard hip replacement surgery.
The small cuts are thought to lessen blood loss, ease pain following surgery, shorten hospital stays, reduce scar appearance, and speed healing.
What Happens After the Surgery?
You will likely stay in the hospital for 4 to 6 days and may have to stay in bed with a wedge-shaped cushion between your legs to keep the new hip joint in place. A drainage tube will likely be placed in your bladder to help you go to the bathroom. Physical therapy usually begins the day after surgery and within days you can walk with a walker, crutches or a cane. You will continue physical therapy from weeks to months following the surgery.
What Activities Should I Avoid After Hip Joint Replacement Surgery?
For anywhere from six to 12 months after hip replacement surgery, pivoting or twisting on the involved leg should be avoided. You should also not cross the involved leg past the midline of the body nor turn the involved leg inward and you should not bend at the hip past 90 degrees. This includes both bending forward at the waist and squatting.
Your physical therapist will provide you with techniques and adaptive equipment that will help you follow any of the above guidelines and precautions while performing daily activities. Remember, by not following your therapist's recommendations you could dislocate your newly replaced joint and may require another surgery.
Even after your hip joint has healed, sports or heavy activity should be avoided. The replacement joint is only designed for usual day-to-day activity.
Will I Need to Take Special Measures to Manage at Home After Hip Replacement Surgery?
There are a few simple measures that you can take to make life easier when you return home after hip joint replacement, including:
You should ask your doctor before returning to such activities as driving, sexual activity and exercise.
Is Hip Replacement Surgery Safe?
Hip replacements surgeries have been performed for years and surgical techniques are being improved all the time. As with all surgeries, however, there are risks. Since you will not be able to move around much at first, blood clots are a particular concern. Your doctor will give you blood thinners to help prevent this from occurring. Infection and bleeding also are possible, as are risks associated with using general anesthesia.
Other less common concerns that you and your doctor must watch out for are:
How Long Will My New Joint Last?
When hip joint replacement surgeries were first performed in the early 1970s, it was thought that the average artificial joint would last approximately 10 years. We now know that about 85% of the joint implants will last 20 years. Improvements in surgical technique and artificial joint materials should make these implants last even longer. If the joint does become damaged, surgery to repair it often is very successful.
Living with a Hip Replacement
Your health professional will probably want to see you at least once every year to monitor your hip replacement. Gradually, you will return to most of your pre-surgery activities. If you drive a car, your health professional will probably allow you to start driving an automatic shift car in 6 to 8 weeks, provided the seat is not too low and you are no longer taking pain medication.
Because of the way the hip is structured, every added pound of body weight adds 3 pounds of stress to the hip. Controlling your weight will help your new hip joint last longer.
Stay active to help maintain strength, flexibility, and endurance. Your activities might include walking, swimming (once your wound is completely healed), dancing, golf (don't wear shoes with spikes, and do use a golf cart), and bicycling on a stationary bike or on level surfaces. More strenuous activities, such as jogging or tennis, are not advised after a hip replacement.
SOURCE: National Institute of Arthritis and Musculoskeletal and Skin Diseases.
In shoulder replacement surgery, doctors replace the ends of the damaged upper arm bone (humerus) and usually the shoulder bone (scapula) or cap them with artificial surfaces lined with plastic or metal and plastic. Shoulder joint components may be held in place with cement, or they may be made with material that allows new bone to grow into the joint component over time to hold it in place without cement.
The top end of your upper arm bone is shaped like a ball. Muscles and ligaments hold this ball against a cup-shaped part of the shoulder bone. Surgeons usually replace the top of the upper arm bone with a long metal piece, inserted into your upper arm bone that has a rounded head. If the cup-shaped surface of your shoulder bone that cradles your upper arm bone is also damaged, doctors smooth it and then cap it with a plastic or metal and plastic piece.
Surgeons are now trying a newer procedure called a reverse total shoulder replacement for people who have painful arthritis in their shoulder and also have damage to the muscles around the shoulder. In this procedure, after the surgeon removes the damaged bone and smoothes the ends, he or she attaches the rounded joint piece to the shoulder bone and uses the cup-shaped piece to replace the top of the upper arm bone. Early results are encouraging.
Surgeons do most joint replacement surgeries using regional anesthesia. That means you can't feel the area of the surgery and you are sleepy, but you are awake. The choice depends on your doctor, on your overall health, and, to some degree, on what you prefer.
Your doctor may recommend that you take antibiotics before and after the surgery to reduce the risk of infection. If you need any major dental work, your doctor may recommend that you have it done before the surgery. Infections can spread from other parts of the body, such as the mouth, to the artificial joint and cause a serious problem.
You will have intravenous (IV) antibiotics for about a day after surgery. You will also receive medications to control pain, and perhaps medications to prevent blood clots (anticoagulants). It is not unusual to have an upset stomach or feel constipated after surgery. Talk with your doctor or nurse if you don't feel well.
When you wake up from surgery, you will have a bandage on your shoulder and probably a drain to collect fluid and keep it from building up around your joint. You may have a catheter, which is a small tube connected to your bladder, so you don't have to get out of bed to urinate. You may also have a compression sleeve on your arm, which squeezes your arm to keep the blood circulating and to help prevent blood clots.
A physical therapist may begin gentle exercises of your shoulder on the day of surgery or the day after. These exercises are just passive motion; you relax and let the therapist move your arm for you.
Most people who have shoulder replacement surgery are able to sit up and get out of bed with some help later on the day of surgery.
Your health professional may teach you to do simple breathing exercises to help prevent congestion in your lungs while your activity level is decreased.
The First Few Days
You will probably still be taking some medication. You will gradually take less and less pain medication. You may continue anticoagulant medications for several weeks after surgery.
A physical therapist will move your arm for you to keep your shoulder loose as it heals. The therapist will also show you how to use a pulley device so you can move your arm when you go home from the hospital. Your therapist may also begin some simple exercises to keep the muscles of your other arm and your legs strong.
Rehabilitation (rehab) after a shoulder replacement starts right away. It is not too demanding early on, but it is very important that you do it. Most doctors will not allow you to use the shoulder muscles for several weeks after surgery. The main goal of rehab is to allow you to move your shoulder as far as possible so it's easier for you to do daily activities, such as dressing, cooking, and driving. Most people eventually regain about two-thirds of normal shoulder motion after surgery. However, other factors that affect how much movement you get after surgery are how much movement you had before surgery and whether the soft tissues around your shoulder were also damaged. It is very important that you take part in physical therapy both while you are in the hospital and after you are released from the hospital to get the most benefit from your surgery.
Most people go home 1 to 3 days after surgery. Some people who need more extensive rehab or those who don't have someone who can help at home go to a specialized rehab center for more treatment.
Once you go home, monitor the surgery site and your general health. If you notice any redness or drainage from the wound, notify your surgeon. You may also be advised to take your temperature twice each day, and to let your surgeon know if you have a fever over 100.5 °F(38.1 °C).
You will have an exercise program to follow when you go home, even if you are still having physical therapy. You should use the pulley to move your arm 4 to 5 times each day. If you notice any soreness, try a cold pack on your shoulder and perhaps decrease your activity a bit, but don't stop completely. Sticking to your exercise program will help speed your recovery.
Rehabilitation generally continues after you leave the hospital until you are able to function more independently and you have recovered as much strength, endurance, and mobility in your shoulder as you can. Total rehabilitation after surgery will take several months.
An example of a typical rehabilitation schedule is:
Living with a Shoulder Replacement
Your health professional may want to see you periodically for several months or more to monitor your shoulder replacement. Gradually, you will return to many of your pre-surgery activities.
Stay active to help maintain strength, flexibility, and endurance. Your activities might include light yard work, walking, swimming (once your wound is completely healed and your health professional has approved), dancing, and golf. Your doctor may recommend that you avoid heavy lifting and repetitive activities.
Most people have much less pain after shoulder replacement surgery and are able to do many of their daily activities more easily.
The younger you are when you have the surgery, and the more stress you put on the joint, the more likely it is that you will eventually need a second surgery to replace the first artificial joint. Over time, the components wear down or may loosen and need to be replaced.
Your artificial joint should last longer if you do not do hard physical work or play sports that stress the joint. If you are older than 60 when you have joint replacement surgery, the artificial joint will probably last the rest of your life.