The replacement of natural joints with artificial ones is a constantly improving form of treatment for severe arthritis (primarily osteoarthritis and rheumatoid arthritis). No longer does severe damage to joints mean lifelong pain, dependence on crutches, or confinement to a wheelchair. Over the past three decades, reconstructive surgery has restored mobility and relieved pain for thousands who suffer from degenerative conditions. In the United States alone, more than 200,000 total joint replacements are performed each year by orthopedists.
How Is It Done?
A total joint replacement is a surgical procedure. The patient is given an anesthetic, and the surgeon replaces the damaged parts of the joint with artificial materials. For example, in the knee joint the damaged ends of the bones that meet at the knee are replaced, along with the underside of the kneecap. In the hip joint, the damaged ball is replaced by a metal ball with a stem that fits down into the femur. A new, plastic socket is implanted into the pelvis to replace the old damaged socket. Total joint replacement can be performed on other joints as well, including the ankle, shoulder, hip, fingers, and elbow. Most often, hips and knees are the joints needing replacement.
The materials used in a total joint replacement are designed to enable the joint to move in the same way as the normal joint. The artificial components are generally composed of a metal piece that fits closely into a matching sturdy plastic element. The metals are varied and include stainless steel, or alloys of cobalt, chrome, and titanium. The plastic material is a polyethylene that is extremely durable and wear-resistant. Also, a bone cement is often used to anchor the bone to the new, artificial component. ‘Cementless’ joint replacements have also been developed. In these replacements, the prosthesis and the bone are made to fit together directly.
The recovery period following surgery will vary depending on the patient and on the joint that has been replaced. In general, the orthopedist will encourage the patient to use the joint shortly after the operation. In the case of a total hip or knee replacement, the patient will be standing and beginning to walk within several days. A physical therapist will instruct the patient in the use of crutches or cane. If the shoulder, elbow, or wrist joint has been replaced, use of the new joint can begin very soon after surgery. The patient will learn to do appropriate exercises to move and strengthen the joint.
Risks and Complications
There are risks with any surgical procedure. The person considering total joint replacement should tell the orthopedic surgeon about any additional medical conditions that might complicate the surgery. The patient’s regular physician should be told of the proposed surgery. Before the operation, the patient should discuss with the anesthesiologist the anesthesia type and possible risks involved.
The much-feared but uncommon complication of total joint replacement is infection. Less than 1% of all total hip replacements can be expected to become infected. Infection may occur just in the area of the wound or deep around the prosthesis. It may occur during the hospital stay or after the patient goes home. It may even occur years after the operation. Infections in the wound area are generally treated with antibiotics. Deep infections may require further surgery and removal of the prosthesis.
Spread of infection from another part of the body to a joint replacement has been known to occur. To prevent such infection, persons with total joint replacements generally are given antibiotics before dental cleaning and more extensive dental procedures, as well as before other types of surgery. If an infection occurs, it must be treated with antibiotics.
Other complications that are directly related to the implanted prosthesis can be grouped into several categories:
Loosening: Loosening of the prosthesis is the most common mechanical problem occurring after total joint replacement. Loosening causes pain, and if loosening is significant a second total joint replacement may need to be performed. New methods of fixing the prosthesis to bone may minimize or eliminate this problem.
Dislocation: This complication sometimes occurs after total hip replacement, generally right after the operation. In most cases, the orthopedic surgeon can relocate the dislocated hip manually. Rarely is another operation necessary. A brace may be worn for a period of time after dislocation occurs.
Wear: Although some wear can be measured in artificial joints, it occurs slowly. Wear may contribute to looseness, but it is rarely necessary to do corrective surgery because of wear alone.
Breakage: Breakage of an implanted joint is rare. A second operation is necessary if this occurs.
Impaired Nerve Function: Nerves in the vicinity of the total joint replacement are damaged during the operation. This generally occurs when the orthopedic surgeon must correct considerable joint deformity in order to implant the prosthesis. With time, these nerves usually begin to function normally again.
The main benefit to the patient after total joint replacement is pain relief, which often is quite dramatic. Although there may be some soreness in the replaced joint after surgery, this will eventually disappear and muscle strength will return with exercise.
Motion of the joint will generally improve. The extent of improvement will depend on how stiff the joint was before the operation. An extremely stiff joint will continue to be stiff for some time after total joint replacement.
Most older persons can expect their total joint replacement to last a lifetime. It will give years of pain-free living that would not have been possible otherwise. Some younger persons with a total joint replacement who are quite active may have to have a second total joint replacement. Materials and surgical techniques are improving rapidly, however, because of the efforts of orthopedists working with engineers and other scientists.
In the management of arthritis, health professionals must consider the whole person. They must treat not only the pain and stiffness in patients’ joints, but the anxieties in their minds, taking fully into account patients’ personalities, backgrounds, and personal problems. No factor is more important in the treatment and rehabilitation of the arthritis patient than maintenance of psychological balance under the stressful conditions imposed by the disease. Complex emotional and vocational problems resulting from chronic disability often require the attention of psychologists, social workers, and vocational specialists. In the overall management of arthritis, these specialists must work in close cooperation with each other and with the doctors, therapists, relatives of the patient and others involved, if best results are to be achieved.
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