Total Knee Replacement
Total knee replacement is a surgical procedure in which damaged parts of the knee joint are replaced with artificial parts. The procedure is performed by separating the muscles and ligaments around the knee to expose the knee capsule(the tough,gristlelike tissue surrounding the knee joint).The capsule is opened exposing the inside of the joint.The ends of the thighbone (femur) and the shinbone(tibia) are removed and often the underside of the kneecap(patella) is removed. The artificial parts are cemented into place . Your new knee will consist of a metal shell on the end of the femur, a metal and plastic trough on the tibia, and if needed a plastic button in the kneecap. Total knee replacements are usually performed on people suffering from arthiritis and are above 50 years of age. However even younger people may undergo the surgery if their disability warrants it.
The circumstances vary somewhat, but generally you would be considered for a total knee replacement if.
· You have daily pain.
· Your pain is severe enough to restrict not only work and recreation but also the ordinary activities of daily living.
· You have significant stiffness of your knee.
· You have significant instability (constant giving way) of your knee.
· You have significant deformity (knock-knees or bowlegs).
An artificial knee is functionally as good as the natural knee. The operation will provide pain relief for at least 20 to 25 years. If replacement provides you with pain relief and if you do not have other health problems, you should be able to carry out normal activities of daily living. The artificial knee may at best allow you return to active lifestyle and some recreational sports like golf,swimming etc. Activities that overload the artificial knee must be avoided. About 90 percent of patients with stiff knees before surgery will have better range of motion after a total knee replacement.
Total knee replacement is a major operation. About one patient in a hundred develops one or more complications requiring you to stay in the hospital longer.
The most common complications are not directly related to knees and usually do not effect the results of the operation. These complications include urinary tract infections, blood clot in a leg, or blood clot in lung.
Complications affecting the knee are less common but do rarely occur.
Some causes of knee pain are:
· Loosening of the prosthesis.
· Infection in the knee.
A few complications such as infections,loosening of prosthesis and stiffness may require reoperations. Infected artificial knees sometimes have to be reoperated. This is usually done as a two stage procedure with the first stage involving removal of the infected implant and a thorough cleaning.The surgeon then inserts an antibiotic loaded cement spacer which is retained for a period of 6-8 weeks.After control of the infection a new implant is inserted.The results of this surgery are very gratifying and successful.
About 85 to 90 percent of total knee replacements are successful for up to 20 to 25 years. The major long term problem is loosening. This occurs because either the cement crumbles (as old mortar in a brick building) or the bone melts away (resorbs) from the cement. The 20 year survival of these implants is about 94%,and the 25 year survival almost 84%.
Loosening is in part related to your weight and activity. For this reason we advise that after total knee replacement one should try and keep one’s weight under control. A loose painful artificial knee is usually replaced. The results of the second operation are almost as good as the first. Preparing for total knee replacement begins several days ahead of the actual surgery date. Sometime this can be done in your local community hospital. Maintaining good physical health before your operations is important. Activities which will increase upper body strength will improve your ability to use a walker or crutches after the operations.
A blood transfusion is often necessary after knee surgery. You may wish to donate several pints of blood prior to your surgery. Then you are required to do a transfusion so that you may be able to receive your own blood. This is called autologous blood donations. The first donation is must be within 45 day of the surgery and the last. no less then seven day before your surgery. When donating blood. You must be healthy, without a cold, flu or infections, as you could get this same illness when your blood is transfused at the time of surgery. Eat a nourishing meal two hours prior to donations, and avoid strenuous exercise for twelve hours following the procedure.
The blood donor center will check the blood count before drawing additional units. A prescription for iron will be given. Iron may be constipating for some people, so sometime a stool softener is prescribed. Stool softeners can also be purchased over the counter.
The physician may order blood test and urinalysis before surgery to make sure that a urinary tract infection is not present. Urinary tract infections are common, especially in older women, and often go undetected. Teeth need to be in good condition. An infectious tooth or gum may also be a possible source of infection for the new knee. The orthopaedic surgeon may ask you to see a medical doctor, especially if medical problems have been present in the past.
When making preparations for surgery, you should begin thinking about the recovery period following surgery. A patient with a new total knee replacement will need help at home for the first few weeks. Assistance with dressing, getting meals, etc. may be necessary. Most often discharge from the hospital is anticipated in about one week. Your energy levels will not have returned to normal. If assistance from someone at home is not possible it may be necessary to think about making arrangements to stay a few weeks in an extended care facility. We would be glad to offer you any assistance in terms of local accomodation after your discharge from the hospital.
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