Total Knee Replacement
About the Procedure
Total knee replacement surgery involves removing the surface of the knee joint and replacing it with metal and plastic surfaces. This is most commonly performed for arthritis of the knee in which the smooth surface cartilage has worn away and bone is rubbing against bone, causing significant pain and deformity.
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.
When is total knee replacement considered?
Knee replacement works best in patients who have severe arthritis throughout the entire knee. This is most commonly seen in older patients, but can occur in younger patients after infection, or significant injury.
The circumstances vary somewhat, but generally, you will be considered for a total knee replacement if:
- You have daily pain.
- Your pain is severe enough to restrict work, recreation, and the ordinary activities of daily living.
- You have significant stiffness in your knee.
- You have significant instability (constant giving way) of your knee.
- You have significant deformity (knock-knees or bowlegs).
- You have failed to respond to other forms of treatment, including activity modification, anti-inflammatory medications, and cortisone injections into the knee.
What can I expect from an artificial knee?
An artificial knee is not a normal knee, nor is it as good as a normal knee. However, the operation will provide pain relief for at least ten years and may allow you to return to active sports or heavy labor under your physician's instructions.
If you don't have other health problems, you should be able to carry out many normal activities of daily living. About 90 percent of patients with stiff knees before surgery will have better motion after a total knee replacement. However, activities that overload the artificial knee must be avoided.
What are the risks of total knee replacement?
Total knee replacement is a major operation. Complications usually result in a longer hospital stay.
The most common complications are not directly related to the knee and usually do not affect the result of the operations. These complications include:
- Urinary tract infection
- Blood clots in a leg
- Blood clots in a lung
Complications affecting the knee are less common, but in these cases, the operation may not be as successful. These complications include:
- Some knee pain
- Loosening of the prosthesis
- Infection in the knee
A few complications such as infection, loosening of prosthesis, and stiffness may require re-operation and you would be able to walk with the aid of a cane or crutches, and a shoe lift.
Can I have both knees operated on at the same time?
The surgeons at MHP are highly trained in knee replacement surgery and can replace both knees at the same time, if the degree of arthritis in both is severe. This obviously involves a slower period of recovery, but most patients who undergo bilateral replacements are glad that they did this, following recovery.
How long will I be in the hospital after surgery?
The hospital stay usually ranges from three to four days. Patients who live with a person who can assist them are usually able to go home without much problem. Patients who live alone need to find another person to stay with them after they return home to assist with everyday activities.
How long wll I be on crutches or use a walker?
Most patients use crutches or a walker for about four to six weeks or until instructed otherwise by their physician.
What activities can I do following knee replacement?
It takes about three months for the knee to recover to a point where you are back to full activity. Obviously, some patients recover faster and others slower, depending upon age, health status, personal motivation, and response to rehabilitation.
The purpose of knee replacement surgery is to relieve pain, allowing you to return to a high level of function. This means that most activities are okay once you have completely healed. However, most surgeons recommend that you avoid "impact" type of activities, such as running, aerobics, cutting or pivoting sports, or other activities that place a high degree of stress on the knee. Walking, bicycling, cross-country skiing, and bowling are often approved.
How successful is total knee replacement surgery?
Results are generally very good; most people are relieved of nearly all of their knee pain and the replaced joint will usually last ten years, depending on patient use and activity levels. This may vary from person to person.
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.
Loosening is in part related to your weight and activity. A loose, painful artificial knee can usually, but not always, be replaced. The results of a second operation are not as good as the first, and the risks of complication are higher.