Definition
Knee joint replacement is a surgical procedure that is undertaken to replace a painful, damaged or diseased knee joint with a prosthetic or artificial joint. The artificial joint can be made of plastic and/ or metal. Pain can significantly be reduced with this surgery and also considerably restore joint function.
Indications
In most cases, doctors recommend knee joint replacement surgery for patients of osteoarthritis. It is a degenerative, joint disease which affects mostly middle-aged and older adults. In Osteoarthritis breakdown of joint cartilage and adjacent bone takes place.
Few other forms of arthritis also lead to degeneration of the knee joint such as rheumatoid arthritis and arthritis that result from a knee injury.
Conditions such as fractures, torn cartilage, and/or torn ligaments in addition could also, over the years, lead to irreversible damage to the knee joint. Knee joint replacement may be required for some tumors involving the knee.
The procedure
Usually this surgery is performed under general anesthesia. It can also be carried under spinal or epidural anesthesia. Under the influence of general anesthesia the patient is asleep and therefore is not conscious of the pain. Whereas under the influence of the epidural, the site becomes numb before the surgery can be performed.
The surgical procedure is done by an orthopedic surgeon. A surgical cut or an incision or is made over the affected knee. After the damaged cartilage and bone of the knee is removed, the surgeon will place the prosthetic knee in its place. The tibia or the shin bone and femur or the thigh bone are trimmed to fit the prosthesis.
There are 2 types of knee prosthesis which are widely used in replacement surgeries. The first type is cemented prosthesis and the second type is un-cemented prosthesis. Often, surgeons might choose to use a combination of the two to replace a knee joint with. Surgical cement or epoxy is used to attach a cemented prosthesis to the bone. An un-cemented prosthesis attaches the bone with a fine mesh of holes on the surface, so that the bone grows into the mesh and attaches naturally to the prosthesis.
However, there are even more options now available to the surgeons. Newer surfaces are used to make prosthetic knees. These include ceramic on ceramic, metal on metal, or ceramic on plastic for the prosthetic joint.
Pre and Post Care
Before the surgery your complete medical history will be required. Additionally, the physician might perform a complete physical examination, including x-rays, to ensure the patient is in good health before scheduling the surgery. In addition, a meeting with a physical therapist may also be scheduled to discuss rehabilitation after the surgery.
The average surgery duration is about two hours. After the surgery, a large dressing is placed on the knee area. During the surgery, a small tube is placed at the incision site to help drain out excess fluids from the joint area. An IV is placed to provide fluids to the patient until he/she is able to drink. Special stockings might be placed on the legs to reduce the risk of developing blood clots after leg surgery. The doctor would prescribe pain medicines to keep the patient comfortable and if required, antibiotics to prevent infection.
Even while in the hospital, the patient is encouraged to start moving and walking as early as the first day after surgery. Physical therapy would be continued at home. Some patients might be required to use crutches or a walker for a few weeks or even months after surgery. The patient would be advised to undertake only low impact activities, such as swimming and golf, and avoid high impact activities such as aerobics or cycling.
The stitches or staples on the knee would be removed after the incision heals, which could be a few weeks.
Precautions
People having a prosthetic knee joint need to protect against infection. It is advisable that they carry a medical identification card specifying the prosthetic implant at all times. In addition, they must inform their regular health care provider about the prosthetic knee implant.
Further, it is recommended that they take antibiotics before undergoing any dental work or invasive procedure, in order to avoid infections and complications.
Risks
There are a few post operative risks associated with the procedure. These include:
Formation of the blood clots in the legs due to lack of movement. This is also called as deep vein thrombosis or DVT. It could further cause related complications in case the clot travels to other part of the body.
Loosening or displacement of the artificial joint is another possible risk faced by those who have undergone a knee replacement surgery. It is therefore recommended that they should avoid high impact activities and go in for forms of low impact exercises to strengthen the weak joint.
Certain infections which might be serious enough to require removal of the joint can set in.
Hospital Stay
3-5 days, with the actual surgical procedure taking on an average 2 hours.
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